The Origin of Aluminum Flocs in Polluted Streams_science

高三英语材料科学单选题60题1.Metal is a common material in engineering. Which of the following is not a metal?A.ironB.aluminumC.glassD.copper答案：C。

本题考查材料科学中金属的概念。

铁（iron）、铝（aluminum）和铜（（copper）都是常见的金属。

而玻璃（（glass）是一种非金属材料，主要由硅酸盐等组成。

2.Which material is often used for insulation?A.steelB.plasticC.goldD.silver答案：B。

在材料科学中，塑料（（plastic）常被用作绝缘材料。

钢（steel）、金（（gold）和银（（silver）都是导电性能较好的金属材料，不适合用于绝缘。

3.In the field of materials science, which one is a composite material?A.woodB.paperC.concreteD.water答案：C。

混凝土（（concrete）是一种复合材料，由水泥、骨料和水等组成。

木头（（wood）是天然材料。

纸（（paper）主要由纤维素等组成，不是复合材料。

水（water）是一种化合物，不是复合材料。

4.Which material is known for its high hardness?A.rubberB.leatherC.diamondD.cloth答案：C。

在材料科学中，钻石（（diamond）以其高硬度而闻名。

橡胶（rubber）、皮革（leather）和布（cloth）的硬度都较低。

5.Which of the following materials is ductile?A.brickB.glassC.copperD.stone答案：C。

在材料科学中，铜（（copper）是一种具有延展性（（ductile）的金属材料。

小学上册英语第二单元暑期作业英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.I eat _____ (breakfast) in the morning.2.The _____ (小象) plays in the water.3. A ______ is a large body of ice that moves slowly.4.What is the capital city of Cuba?A. HavanaB. SantiagoC. CamagüeyD. Holguín5.The _______ (小百灵鸟) sings sweetly at sunset.6.I saw a raccoon in the _________. (垃圾桶)7.What do you call a popular social gathering?A. PartyB. MeetingC. ConferenceD. EventA8.The Earth's crust is rich in various ______ materials.9.She is ___ her dress. (choosing)10.How many months are in a year?A. 10B. 11C. 12D. 13C11.The __________ (历史的教训) is invaluable.12.The owl uses its ______ (耳朵) to locate prey.13.What is the name of the famous ancient city in Peru?A. Machu PicchuB. TikalC. Chichen ItzaD. PetraA14.The first female Nobel Prize winner was ________ (居里夫人).15.We are going to the ________ today.16.What is the fastest land animal?A. HorseB. CheetahC. LionD. DogB17.The first person to propose the heliocentric theory was ______ (哥白尼).18.What do you call a story that teaches a lesson?A. FableB. NovelC. PoemD. BiographyA Fable19.The garden is ______ with colorful flowers. (filled)20.We see _____ (birds) in the sky.21.We have a ______ (愉快的) time during family outings.22.The owl is wise and can turn its _________ (头) 180 degrees.23.The __________ (历史的影响) can be seen in modern society.24.What do we call the force that pulls objects toward the Earth?A. MagnetismB. GravityC. FrictionD. PressureB25.The _____ (马) runs swiftly.26.What do you call a person who studies human cultures?A. AnthropologistB. SociologistC. ArcheologistD. All of the aboveD27.The _____ (摩天轮) is exciting.28.What do we call a group of fish swimming together?A. SchoolB. FlockC. PodD. Gaggle29.Which animal says "meow"?A. DogB. CatC. CowD. SheepB30.The capital city of Finland is _____.31.Which animal is known for its trunk?A. LionB. ElephantC. DogD. CatB32.My grandma is a great __________ (故事讲述者).33. A chemical reaction that occurs between metals and acids is called a ______ reaction.34.I like to go ________ (驶船) on weekends.35. A _______ can help to demonstrate the behavior of waves.36.The city of Yaren is the capital of _______.37.What do you call a person who repairs cars?A. MechanicB. ElectricianC. PlumberD. PainterA38.The chemical symbol for osmium is ______.39.The first woman to pilot a commercial jet was _______. (阿梅莉亚·埃尔哈特)40.What is the capital of China?A. ShanghaiB. BeijingC. GuangzhouD. Shenzhen41.What do you call a person who travels in space?A. AstronautB. PilotC. ScientistD. ExplorerA42.ts can ______ (在干旱条件下繁荣). Some pla43.We will visit the ________ this weekend.44.What do you call a large animal that lives in the ocean and has tusks?A. SealB. WalrusC. DolphinD. WhaleB45.We are learning about _______ (动物) in school.46.What do we call the study of ecosystems and their interactions?A. EcologyB. BiologyC. ZoologyD. Botany47.I love to _______ (参加) art classes.48.Snakes are _______ creatures.49.My cousin is very good at ____ (math).50.I can make music with my ________ (玩具类型).51.The __________ (历史的连接) unites us.52.The antelope runs very ________________ (快).53.Every year, we celebrate my birthday with a big ________ (聚会) and lots of cake.54.Planting _____ (药用植物) can provide natural remedies.55.The chemical formula for lead nitrate is _______.56.What do we call a person who studies the history of art?A. Art HistorianB. CriticC. CuratorD. ArtistA57.The _____ (树木砍伐) poses a threat to habitats.58.I enjoy going to the ______ (博物馆) to see exhibits and artifacts.59.Planting flowers can enhance ______ (社区) beauty.60.The ____ has a shiny shell and is often found in gardens.61. A ____(community garden) fosters local cooperation.62.She is learning to ________ the guitar.63. A catalyst is a substance that speeds up a ______.64.I enjoy making ________ (美食) for my family.65.In a chemical reaction, the rate can be influenced by factors such as concentration, temperature, and _____.66.What is the main ingredient in lemonade?A. OrangeB. LemonC. LimeD. GrapefruitB67. A ______ (自然保护) effort can restore habitats.68.The _____ (grapefruit) tree has fragrant flowers.69.I enjoy ______ (playing) video games.70.The ____ is a friendly animal that loves to be petted.71.What is the name of the place where you can see wild animals?A. ZooB. FarmC. AquariumD. CircusA72.The chemical formula for potassium nitrate is _____.73.What is the name of the famous ancient ruins in Mexico?A. TeotihuacanB. Machu PicchuC. Angkor WatD. PetraA74.What do we call a piece of land surrounded by water on all sides?A. PeninsulaB. IslandC. CoastD. BayB Island75.What do you call a plant that grows in the desert?A. CactusB. FernC. MossD. FlowerA76.What do we call the protective covering of the human body?A. SkinB. HairC. BonesD. Muscles77. A __________ is a type of chemical bond formed through electrostatic attraction.78.What is the opposite of kind?A. MeanB. NiceC. GentleD. CaringA79.My sister is very _____ (聪明).80.The __________ (历史的文化背景) enrich understanding.81.What is the name of the famous bear in the Hundred Acre Wood?A. PaddingtonB. Winnie-the-PoohC. Yogi BearD. BalooB82.The stars twinkle _______ (在夜空中).83. A _____ is a region characterized by specific weather patterns.84.The __________ (历史的永恒) resonates with humanity.85.collaborative initiative) addresses shared concerns. The ____86.The water is ___ (hot).87.Which of these is not a vegetable?A. CarrotB. PotatoC. AppleD. TomatoC88.public awareness campaign) educates about critical issues. The ____89.The _______ (Constitutional Convention) took place in 1787 to draft the US Constitution.90.The country of Spain is famous for its ________ (西班牙以其________而闻名).91. A crab can be found in both salt and ________________ (淡水).92.The manatee is a gentle _______ (巨兽).93.The capital of Saint Vincent is __________.94. A windmill converts wind energy into ______.95.What do we call a person who studies the effects of population growth?A. DemographerB. SociologistC. AnthropologistD. EconomistA96.The first successful test of a nuclear bomb occurred in ________ (1945).97.What do we use to measure temperature?A. RulerB. ThermometerC. ScaleD. StopwatchB98.What is the opposite of "hot"?A. ColdB. WarmC. BoilingD. SpicyA99. A ______ (猫) can jump very high.100.When it’s very hot, I like to eat ______ (冰淇淋).。

小学下册英语第4单元测验试卷英语试题一、综合题(本题有50小题，每小题1分，共100分.每小题不选、错误，均不给分)1 Plastic is a type of _____.2 A solvent can be a liquid, solid, or _____.3 Which day comes after Friday?A. ThursdayB. SaturdayC. SundayD. Monday答案: B4 The freezing point of water is ______ degrees Celsius.5 The _______ of an object can be tested using a balance scale.6 What is the name of the process that causes rocks to break down?A. ErosionB. WeatheringC. SedimentationD. Compaction答案:B7 The __________ (历史的精神) lives on in our traditions.8 My dad is a __________ (修车工).9 What do we call a natural satellite of the Earth?A. StarB. MoonC. PlanetD. Comet10 What is 100 50?A. 40B. 50C. 60D. 70答案:B11 A molecule is formed when two or more atoms bond ______.12 I need to _____ (finish/start) my homework.13 What time is it when the big hand is on 12 and the small hand is on 3?A. 12:00B. 3:00C. 6:00D. 9:0014 The ________ was a period of great artistic achievement in Italy.15 She has a _______ who is very tall.16 The _____ (植物体验设计) can foster creativity and learning.17 The __________ (植物的习性) is fascinating to study.18 An electric circuit needs a ______ to flow.19 The frog's skin is ______ (湿润) and smooth.20 The ________ (历史文化) shapes our identity.21 The capital of Uzbekistan is __________.22 What color do you get when you mix red and white?A. PinkB. PurpleC. BrownD. Orange答案:A23 He is an expert in _____ (数学).24 What do we call a young female kangaroo?A. JoeyB. CalfC. KitD. Lamb答案：A25 What is the capital of Canada?A. OttawaB. TorontoC. VancouverD. Montreal26 A _____ (植物活动) can promote environmental awareness.27 My favorite ___ (小动物) is the rabbit.28 The _______ (狗) wagged its tail.29 My grandmother makes _______ (美味的食物).30 What do you call a person who travels in space?A. AstronautC. ScientistD. Engineer答案: A31 We will _______ (have) a picnic today.32 The puppy is _____ in the yard. (playing)33 Napoleon Bonaparte was a leader from ________.34 What do bees make?A. MilkB. HoneyC. SugarD. Jam答案：B35 Which animal can fly?A. DogB. CatC. BirdD. Fish答案: C36 The chemical formula for sodium thiosulfate is __________.37 What do we call a scientist who studies rocks?A. BiologistB. GeologistC. ChemistD. Physicist38 What do you use to draw?A. PencilB. ForkC. SpoonD. Plate39 My _____ (玩具枪) is for playtime.40 A black hole is a place in space where ______ cannot escape.41 The park is very ________.42 ower brought the first Pilgrims to ________ (美洲). The Medi43 The puppy is very ________.44 The Great Wall stretches over ________ kilometers.45 What do you call a group of stars?A. GalaxyB. UniverseC. ClusterD. Constellation答案:D46 What do we call a baby dog?A. KittenB. PuppyC. CubD. Calf答案:B. Puppy47 The _______ of light can be reflected off surfaces.48 The ______ lives in colonies.49 The Renaissance was a period of great _______ and art.50 The rabbit has long _______ (耳朵) to hear well.51 The baby is crying ___. (loudly)52 She has a beautiful ________.53 The _______ (鲸鱼) is often seen surfacing for air.54 I like to climb the ______.55 I like to ________ in the summer.56 The crow is known for its ______ (智慧).57 What is the primary reason for seasons on Earth?A. Earth's distance from the SunB. The tilt of Earth's axisC. The phase of the MoonD. Solar flares58 The capital of Vanuatu is ________ (瓦努阿图的首都是________).59 What is the term for a word that sounds the same but has a different meaning?A. AntonymB. SynonymC. HomonymD. Adjective答案:C60 The stars are ___ (twinkling) in the sky.61 What do we call the act of finding something out?A. DiscoveryB. ExplorationC. InvestigationD. Research答案: A62 The girl has a kind ________.63 What color do you get when you mix blue and yellow?A. GreenB. PurpleC. OrangeD. Brown答案: A64 The _____ (garden) is full of colorful flowers.65 The unit of measurement for mass is called a ______.66 The __________ is a famous archaeological site in Greece. (雅典)67 What is the main purpose of a book?A. To cookB. To readC. To writeD. To draw68 What do you call the time when flowers bloom?A. WinterB. SpringC. SummerD. Fall答案: B69 What is the capital of Colombia?B. MedellínC. CaliD. Cartagena答案:A70 The __________ (社区建设) fosters connection.71 The boy has a cool ________.72 A saturated solution does not change when more solute is ______.73 What is the freezing point of water?A. 0 degreesB. 32 degreesC. 100 degreesD. 212 degrees答案: A74 They are _____ (playing) outside.75 The _____ is the second planet from the sun.76 What do you call a group of players on a sports team?A. SquadB. CrowdC. AudienceD. Team77 What is the fourth planet from the sun?A. EarthB. MarsC. Jupiter78 I love to read about ________.79 My sister plays ________ (排球).80 A ____ is a gentle giant that enjoys eating plants.81 I enjoy going to the ______ (博物馆) with my family. We learn about history and see ______ (古老的东西).82 What is the name of the first man on the moon?A. Yuri GagarinB. Neil ArmstrongC. Buzz AldrinD. John Glenn83 My friend is a _____ (摄影师) who takes amazing pictures.84 What is the name of the famous scientist known for his work on vaccination?A. Edward JennerB. Louis PasteurC. Jonas SalkD. Albert Sabin答案: A85 The sea horse is a unique _______ (生物).86 The __________ tells us it will be sunny next week. (天气预报)87 What is the fastest land animal?A. CheetahB. LionC. HorseD. Gazelle88 The ancient Mayans are known for their ________ calendar.89 The main component of lipids is ______.90 What do we call a large body of water surrounded by land?A. OceanB. LakeC. RiverD. Stream答案:B91 What do we call the act of creating something new?A. InventionB. InnovationC. CreationD. All of the above答案: D92 The chemical symbol for aluminum is ______.93 I have a _____ (跳绳) that I use to exercise. 我有一根用来锻炼的跳绳。

Uncovering the Origin of MetallurgyMetallurgy is the science and technology of extracting metals from their ores, refining them, and preparing them for use. It is a crucial aspect of human civilization and has played a significant role in shaping our world. The origin of metallurgy is a topic of great interest to historians, archaeologists, and scientists alike. In this essay, we will explore the different perspectives on the origin of metallurgy and try to uncover the truth behind this fascinating subject. One perspective on the origin of metallurgy is that it emerged independently in different parts of the world. This theory suggests that humans discovered the properties of metals through trial and error and developed the necessarytechniques to extract and refine them. This is supported by the fact that early metallurgy was found in several regions, including the Middle East, Asia, andSouth America. For example, the ancient Egyptians were known to have used copper and gold for decorative purposes, while the people of the Andes used copper to create intricate jewelry and ornaments. Another perspective on the origin of metallurgy is that it was developed through cultural diffusion. This theory suggests that metallurgy was first developed in one region and then spread toother parts of the world through trade and migration. For example, some historians believe that metallurgy was first developed in the Middle East and then spread to Europe and Asia. This is supported by the fact that the earliest known metal objects were found in the Middle East, such as the copper beads from the 6th millennium BCE found in the area now known as Iraq. A third perspective on the origin of metallurgy is that it was developed as a result of environmental factors. This theory suggests that the availability of certain metals in a particularregion led to the development of metallurgy in that area. For example, the abundance of copper in the Middle East and the Andes may have led to the development of early metallurgy in those regions. Similarly, the availability of iron in certain parts of Africa may have led to the development of ironworking in those areas. Regardless of the origin of metallurgy, it is clear that it played a crucial role in the development of human civilization. The ability to extract and refine metals allowed humans to create tools and weapons that were stronger and more durable than those made from stone or wood. This, in turn, led to thedevelopment of agriculture, trade, and the rise of civilizations. In conclusion, the origin of metallurgy is a fascinating subject that has captured the attention of historians, archaeologists, and scientists for centuries. While there are different perspectives on how metallurgy first emerged, it is clear that it played a crucial role in shaping our world. The ability to extract and refine metals allowed humans to create tools and weapons that were stronger and more durable, leading to the development of agriculture, trade, and the rise of civilizations. As we continue to uncover new evidence about the origin of metallurgy, we will gain a deeper understanding of our shared history and the remarkable achievements of our ancestors.。

小学下册英语第6单元综合卷(含答案)考试时间：100分钟（总分:100）B卷一、综合题(共计100题共100分)1. 填空题：The lion is known as the king of the _______ (动物园).2. 选择题：What do we call a typical breakfast food?A. CerealB. SandwichC. SaladD. Soup3. 听力题：A chemical equation represents a chemical ______.4. 听力题：A ______ is a representation of scientific relationships.5. 填空题：We visit our __________ during holidays. (家人)6. 填空题：A ____(natural resource management) aims for responsible use.7. 填空题：The ________ was a major turning point in World War I.8. 听力题：Some _______ grow in water, like lilies.9. 听力题：A sound that is high-pitched has a high ______ (frequency).10. 填空题：A tortoise can live for many ________________ (年).11. 听力题：The __________ point is the temperature at which a solid becomes a liquid.12. 选择题：What is the tallest mountain in the world?A. K2B. EverestC. KilimanjaroD. Denali答案: B13. 填空题：The _______ (Nazi regime) was responsible for the Holocaust during World War II.14. 填空题：I want to _______ (学习) piano.15. 听力题：The capital of Tuvalu is _______.16. 选择题：What is the capital of Japan?A. SeoulB. BeijingC. TokyoD. Bangkok答案:C17. 选择题：What do you call the study of ancient civilizations?A. AnthropologyB. ArchaeologyC. HistoryD. Sociology18. 填空题：My favorite thing to do at the beach is ______.19. 听力题：The pH scale measures how __________ or basic a solution is.20. 选择题：What do we call the area of land that is lower than the surrounding area?A. HillB. ValleyC. MountainD. Plateau21. 听力题：The chemical symbol for cerium is ______.22. 填空题：__________ (基因工程) involves chemical reactions to modify DNA.23. 听力题：The __________ is a region known for its educational institutions.24. 选择题：What is the capital of Cuba?A. HavanaB. SantiagoC. CamagüeyD. Holguín答案: A25. 填空题：In _____ (埃及), you can find many pyramids.26. 听力题：The puppy likes to play with a ______ (ball).27. 听力题：I like to eat ___ (vegetables).28. 填空题：The first Olympic champion was _______. (科罗比乌斯)29. 填空题：The river is ________ (清澈).30. 选择题：What do we call the part of the plant that grows underground?A. LeafB. StemC. RootD. Flower答案: C31. 填空题：My mother is a _____ (护士) providing care with compassion.The first recorded Olympic Games were held in _______.33. 听力题：The chemical symbol for hafnium is ______.34. 听力题：The weather is _____ outside today. (nice)35. 填空题：My cousin is very __________ (勤奋的) and studies hard.36. 选择题：What is the name of the famous ancient city in Italy?A. PompeiiB. RomeC. FlorenceD. Venice答案: A37. 选择题：What do you call a large, round cheese?A. CheddarB. GoudaC. BrieD. Wheel答案：D38. 选择题：What is the process of water turning into vapor called?A. CondensationB. EvaporationC. PrecipitationD. Sublimation答案: B39. 选择题：What is the name of the famous detective created by Arthur Conan Doyle?A. Hercule PoirotB. Sherlock HolmesC. Miss MarpleD. Sam Spade40. 填空题：My grandmother makes the best __________. (饼干)The fish swims in the __________.42. 听力题：The chemical formula for selenium dioxide is _____.43. 填空题：Roots anchor the plant in the __________ (土壤).44. 填空题：I love my teddy bear because it is ________ (可爱的) and soft. I hug it every night beforeI ________ (睡觉).45. 选择题：What do we call the process of planting seeds?A. SowingB. HarvestingC. GrowingD. Cultivating答案：A46. 选择题：What is the capital of France?A. BerlinB. MadridC. ParisD. Rome47. 听力题：Dark matter makes up a large part of the universe but cannot be ______ directly.48. 选择题：What do you call the sound a sheep makes?A. GrowlB. BleatC. RoarD. Quack答案: B49. 听力填空题：I think that every person has the potential to be __________.50. 听力题：The chemical formula for aluminum oxide is ______.I like _____ (to run/to walk).52. 听力题：The process of changing from liquid to gas is called ______.53. 选择题：What do you call a story that is written in the form of letters?A. DiaryB. EpistolaryC. AutobiographyD. Memoir答案: B54. 听力题：The _____ (temperature/humidity) is hot today.55. 填空题：I can build a house with my ________ (玩具名称).56. 听力题：A ______ has a pouch for carrying its baby.57. 选择题：What is the coldest season of the year?A. SpringB. SummerC. FallD. Winter答案:D. Winter58. 听力题：The ____ swims in rivers and loves to catch fish.59. 听力题：A meteor is a small piece of rock that burns up in the ______.60. 填空题：I love to _______ (参加) art classes.61. 听力题：My grandma enjoys baking ____ (cakes) for birthdays.62. 选择题：What do we call the study of living things?a. Zoologyb. Botanyc. Ecologyd. Biology答案:d63. 填空题：My sister enjoys __________ (参加) dance classes.64. 填空题：My _______ (狗) barks at everyone who passes by.65. 选择题：What do you call the middle of the Earth?A. CrustB. MantleC. CoreD. Shell答案: C66. 选择题：What animal is known as man's best friend?A. CatB. DogC. RabbitD. Hamster答案:B67. 听力题：Bees help in ______ by pollinating flowers.68. 听力题：A __________ is formed through the accumulation of marine sediments.69. 选择题：What do we call the main character in a story?A. ProtagonistB. AntagonistC. NarratorD. Author答案: A70. 听力题：A mixture is made of two or more ______ substances.71. 填空题：My hamster loves to hide in its ______ (洞).72. 听力题：The ____ is a colorful fish that can swim in aquariums.73. 听力题：Metals are usually ______ conductors of electricity.74. 听力题：The stars are ___ (twinkling/shining) in the night.75. 填空题：The _____ (果实) of a pumpkin is very large.76. 填空题：My mom is a __________ (艺术教育者).77. 选择题：What is 16 4?a. 10b. 11c. 12d. 13答案:c78. 填空题：I see a big _______ in the park (我在公园看到一只大_______).79. 填空题：I like to showcase my ________ (玩具).80. 选择题：What is the capital city of Japan?A. BeijingB. SeoulC. TokyoD. Bangkok答案:C81. carbon capture technology) helps reduce emissions. 填空题：The ____82. 填空题：My dad is my strong _______ who always helps me when I need it.83. 选择题：What is the main language spoken in the UK?A. SpanishB. FrenchC. EnglishD. German84. 听力题：An ion is an atom that has gained or lost one or more ________.85. 小羊) jumps and plays in the meadow. 填空题：The ___86. 填空题：The first successful test of a nuclear bomb occurred in ________ (1945).87. 选择题：What do we call a person who studies the effects of human activities on the environment?A. Environmental ScientistB. EcologistC. BiologistD. Chemist答案: A88. 听力题：The ______ teaches us about nature.89. 填空题：The tortoise has a hard _________. (壳)90. 选择题：What is 7 x 3?A. 18B. 20C. 21D. 2491. 听力题：Baking soda is used as a ______ agent.92. 选择题：What is the capital of Japan?A. KyotoB. TokyoC. OsakaD. Hiroshima93. 填空题：My collection of ________ (玩具名) keeps growing! One day, I hope to have a ________ (形容词) display for them.94. 填空题：The __________ (历史的情感表达) enhance connections.95. 填空题：I love to watch _____ (蝴蝶) flutter around the flowers.96. 填空题：The _____ (生态修复) helps restore damaged ecosystems.97. 选择题：What do you use to see far away?A. BinocularsB. Magnifying glassC. MicroscopeD. Telescope答案：D98. 听力题：The chemical formula for aluminum chloride is _______.99. 选择题：What do we call the largest land animal?A. GiraffeB. ElephantC. HippoD. Rhino答案:B100. 听力题：__________ are formed when two or more elements are chemically bonded.。

小学上册英语第1单元真题英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The ______ of a plant can tell you a lot about its habitat. (植物的叶型可以告诉你很多关于其栖息地的信息。

)2.What do we use to write on paper?A. BrushB. PencilC. RulerD. Eraser3.________ (植物多样性保护研究) is crucial for health.4.Which part of the plant conducts photosynthesis?A. RootsB. StemC. LeavesD. FlowersC5.The ______ (小鹰) soars high above, scanning the ground for small ______ (动物).6.What is 9 4?A. 3B. 4C. 5D. 6B7.My teacher is a ______. She makes learning fun.8.What do you call the main road in a city?A. AlleyB. StreetC. PathD. Lane9.bay) is a body of water partially surrounded by land. The ____10.The chemical properties of a substance depend on its _____.11.The ancient Romans created a system of _____.12.Which gas do humans breathe in?A. OxygenB. HydrogenC. Carbon DioxideD. NitrogenA13.Ferns are a type of ______ (植物) that do not have flowers.14. A flamingo has long ______ (腿) and stands on one foot.15.The element with atomic number is __________.16.What do you wear on your feet?A. HatB. SocksC. GlovesD. ScarfB17.I enjoy _______ (听音乐)。

小学上册英语第五单元期末试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the name of the famous explorer who discovered America?A. Marco PoloB. Christopher ColumbusC. Ferdinand MagellanD. Vasco da GamaB Christopher Columbus2.We will _______ (一起去) the concert.3.The _____ (蜜蜂) play an important role in pollination.4.How many players are on a basketball team?A. 5B. 6C. 7D. 85.What is the main color of a fire truck?A. YellowB. RedC. BlueD. Green6.What is the color of the sky on a clear day?A. GreenB. BlueC. YellowD. GrayB7.Which animal says "meow"?A. DogB. CatC. CowD. SheepB8.Which is the largest ocean on Earth?A. AtlanticB. IndianC. ArcticD. PacificD9.What is the capital of Canada?A. TorontoB. VancouverC. OttawaD. MontrealC Ottawa10.The capital of Georgia is ________ (格鲁吉亚的首都是________).11. A ______ (植物爱好者) enjoys learning about species.12.What do we call a scientist who studies the earth and its composition?A. BiologistB. GeologistC. ChemistD. PhysicistB13.The chemical formula for aluminum oxide is ______.14.What is the common name for the respiratory organ in humans?A. HeartB. StomachC. LungsD. BrainC15.I like to _______ (run) in the morning.16. A compound that has both acidic and basic properties is called an ______.17.What is the name of the famous mountain range in North America?A. RockiesB. AndesC. HimalayasD. Alps18.What is the color of a healthy leaf?A. BrownB. YellowC. GreenD. RedC19.What do we call the imaginary line that divides the Earth into Northern and Southern Hemispheres?A. EquatorB. Prime MeridianC. Tropic of CancerD. Tropic of CapricornA20.The Andromeda Galaxy is the closest galaxy to the ______.21.What is the main ingredient in sushi?A. RiceB. NoodlesC. BreadD. PotatoesA22.The _______ can be a great topic for science projects.23.The __________ (历史的价值) lies in its lessons for the future.24.We saw a ________ at the aquarium.25.What is the name of the famous ancient city in Iraq?A. BabylonB. UrukC. NinevehD. AssurA Babylon26.What is the term for a baby chicken?A. PuppyB. KittenC. ChickD. Calf27.The car is ___. (fast)28.I enjoy playing ______ (乐器) and practicing music every day.29.Which planet is known for its storm called the Great Red Spot?A. SaturnB. JupiterC. MarsD. NeptuneB30.What do we call a large, heavy animal that can swim?A. DolphinB. WhaleC. HippoD. All of the above31.I love to _____ (visit) botanical gardens.32.________ (生态平衡) depends on plant health.33.The main component of the ozone layer is ______.34.看图选词。

Silica/QuartzMichel DumontThe author is with the Minerals and Metals Sector, Natural Resources Canada.Telephone: 613-995-2917E-mail: mdumont@nrcan.gc.caQ uartz (i.e., SiO2, also referred to as silicon dioxide orsilica) is one of the most common minerals on the face of the earth with numerous uses. It is produced and consumed in most countries. Annual world production of silica is estimated at 120-150 Mt.Quartz is not the only mineral composed of SiO2. There are eight other known structures composed of SiO2. They are polymorphs of silicon dioxide and belong to an informal group called the Quartz Group or Silica Group.S UMMARYIn Canada, silica is recovered in: a) lump form for use as metallurgical fl ux and in the manufacture of silicon and ferrosilicon alloys; b) as sand for glass and glass fi bre manufacture, foundry moulding, silicate chemicals, silicon chips, and optical fi bres; and c) as fi nely ground silica fl our for ceramics, chrysotile cement, and concrete products (Table 4).Although Canada is self-suffi cient for most of its silica requirements, signifi cant tonnages of high-quality sand for glass and foundry applications are imported from the United States, mainly by Ontario. As a result of wide-spread availability and low prices, trade is restricted to con-venient cross-border shipments. However, silica with the desired specifi cations for specifi c applications may be shipped to large, distant markets.Preliminary data reported by users (Table 3) in Canada show that silica use was almost 2.6 Mt in 2005, a decrease of 66 255 t from the previous year. Preliminary data (Table 1) reported by Canadian producers for 2006 indicate production was valued at $64.8 million, a $5.1 million increase from 2005, refl ecting the increase in shipments to 1.9 Mt from 1.8 Mt in 2005. Preliminary imports were val-ued at $105.4 million for 2006, an $8.3 million increase from 2005, with the tonnage for imports increasing to2.1 Mt from 1.7 Mt. Preliminary exports for 2006 were valued at $29.0 million, an increase of $2.4 million com-pared to 2005, even though the quantity decreased to373 669 t from 617 235 t.Preliminary data for 2005 (Table 3)1 show that the nonfer-rous smelting and refi ning industry represents 33.5% of the total use of silica in Canada, a decrease of 3.2% from 2004. The primary glass and glass containers, and glass fi bre wool sectors represented 19.5% of total use, an increase of 1.3% from 2004. Foundries, which represented 8.5% of the total use of silica in Canada, decreased 3.9% compared to 2004. Silica use by the chemicals industry represented 3.0% of the total use of silica in Canada, a 2.9% decrease compared to 2004. The use of silica in the cement industry represented 21.0%, but it also suffered a 2.6% decrease compared to 2004. The “other products” category repre-sented 14.5% of total use, a 4.8% decrease compared to 2004.With respect to the reported quantity of silica used by category (Table 4), sand represents 68.6% (1.8 Mt) of the total, a decrease of 42 863 t from 2004. For lump silica, which represents 28.9% (742 573 t) of the total, a slight decrease of 11 299 t from 2004 was observed. Preliminary data for silica fl our, which represents 2.5% (64 963 t) of the total, indicate a decrease of 12 093 t from 2004.O CCURRENCESilica occurs mainly as the mineral quartz. Quartz occurs in many forms, the common being vein and massive intru-sive bodies, silica sand, sandstone, and quartzite. Quartz also occurs as crystals and as masses or aggregates in igneous rocks such as granites or pegmatites. Amorphous, non-crystalline varieties of quartz are less common and include opal, fl int, chalcedony, tripoli, and diatomaceous earth.Although all occurrences of silica are of interest from a geological point of view, commercial interest and develop-ment are usually restricted to vein or intrusive deposits and to silica sand, sandstone, and quartzite deposits. Vein and intrusive deposits are igneous in origin and vary widely in47.2 CANADIAN MINERALS YEARBOOK, 2006P RODUCTION AND M ARKET C ONSIDERATIONSThe economics of the production and sale of the many types of silica are governed by many factors, but world demand for silica is controlled mostly by the fortunes of the glass and foundry industries. Throughout North America, the silica sand industry is highly competitive and the indus-try is dominated by a few large producers. A silica sand source location close to its users is important due to trans-portation cost considerations and, thus, silica is shipped only to local or regional markets. Bene fi ciation is the key to producing high-quality glass or foundry sand from most deposits.The diverse uses of silica and quartz complicate market demand analysis. In the glass sector, construction and automobile markets drive fl at glass sales, new construction being the basis for fi breglass sales. These markets aredriven by the Gross Domestic Product. Silica sand demand in container glass is in fl uenced by: reductions in the num-ber of consumption points through industry rationalization; decreased production as a result of strong competition from PET bottles (i.e., made of virgin resin of polyethylene terephthalate), aluminum, and paper containers; and increasing and mandated recycling rates in the glass con-tainer industry. Use in foundry applications depends on metal production (depending upon automobile sales, etc.) combined with recycling ef fi ciencies and competitive sands. Hydraulic fracturing sand demand is in fl uenced by the price of oil, regional oil production factors such as fl ow rate and pressure, and changes in drilling technologies.S UPPLYSilica deposits of commercial interest occur in all10 provinces. The important Canadian production sites are discussed below. The provinces of Quebec, Ontario, and Alberta are the main producers of silica, followed bySaskatchewan, British Columbia, and Nova Scotia. Gener-ally, silica is extracted in open pits or by dredging.Newfoundland and LabradorShabogamo Mining and Exploration Co. Ltd. began mining its Roy’s Knob quartzite deposit near Labrador City inOctober 1999. The company’s washing and screening plant is located in Wabush, Labrador. The quartzite product is sent by rail to Sept-Îles, Quebec. Shabogamo supplies quartzite to Silicium de Bécancour Inc. of Quebec, which uses the material to manufacture silicon metal.Prince Edward IslandThere are no silica quarries currently in operation.shape and size. Such deposits are widespread throughout Canada. The quartz usually varies from white to grey and is relatively free of impurities.Silica sand has a high silica content (95% SiO 2 or more). The silica or quartz particles, derived from the mechanical disintegration and chemical decomposition of siliceous rocks, have been selectively sorted and concentrated by the action of wind or water during transport to new locations where they accumulated to form high-grade deposits.Sandstone is a sedimentary rock composed of quartz grains cemented by a bonding mineral. Sandstones, in which the bonding material is clay, calcite or iron oxide, are usually quite friable and easily reduced to grain size. Others may be more fi rmly cemented by a siliceous cement and thus are more dif fi cult to reduce to grain size. Most sandstones are white, grey or brown and usually contain varying amounts of mineral impurities, e.g., feldspar, hornblende, magnetite, pyrite, iron oxide stain, and mica.Quartzite is a hard, compact, metamorphosed sandstone composed of grains of quartz fi rmly bonded with a sili-ceous cement. The original quartz grains, having coalesced with the siliceous cement to form a continuous homogen-eous mass, are not apparent to the naked eye.T RADEImports for 2006 (Table 1) from the United Statesaccounted for 98.1% of all imports (over 2.0 Mt). Imports of silica sands and quartz sands from the United Stateshave increased 21.4% (361 155 t) from 2005. Imports from the United States come from loosely consolidated and easily processed sandstone or lake sand deposits located near the Great Lakes. Major U.S. operations are located in the states of Illinois, Wisconsin, Michigan, and Indiana. Canada is the leading recipient (source: U.S. Geological Survey [USGS]) of U.S. exports (73%).Combined 2006 imports from the foundry and glass indus-try totaled almost 1.3 Mt. The tonnage of imports by the foundry industry increased by 33.4% from 2005 to 2006. Demand for foundry sand is dependent mainly on auto-mobile and light truck production. The tonnage of imports by the glass manufacturing industry increased by 6.9% from 2005 to 2006.Preliminary data for 2006 indicate that Canada’s exports (Table 1) of silica totaled 373 669 t, a decrease of 39.5% from 2005. The value of these exports totaled over$29.0 million, a 9.2% increase compared to the 2005 value of over $26.5 million. Of the total exports from Canada, 368 726 t (94.7%) went to the United States.SILICA/QUARTZ 47.3has the capacity to produce 50 000 t/y of chemical silicon, electronics-grade silicon metal, and specialty ferrosilicon. Although hampered by a furnace problem at its plant and a strike at its rail carrier (CN), it intends to construct a 3600-t/y facility for the production of solar-grade silicon metal. The company also sells silica fume to the construc-tion industry. In addition, it owns a quartzite deposit north of La Malbaie that is being developed by Sitec Inc. Sitec Inc. is a joint venture between Baskatong Quartz Inc. and SOQUEM Inc. Sitec mines and processes high-purity quartz for a range of end uses, including silicon metal and silicon carbide. The company also operates a custom crushing, drying, and screening plant in Shawinigan, Quebec.La Compagnie Bon Sable Ltée mines silica sand at Saint-Joseph-du-Lac and Ormstown. The material is used mainly for sandblasting and as a concrete sand; it is also suitable for the production of fi breglass.Silco Sands Inc. mines and grinds silica at its plant inSainte-Clotilde-de-Châteauguay. The products are sold to a chemical company, a cement plant, and a ferromanganese plant.Temisca Inc., a division of Opta Minerals Inc., mines and processes silica near Saint-Bruno-de-Guigues for the golf course, fi ltration sand, hydraulic fracturing (frac), abra-sives, and construction markets. The processing facility includes a 200 000-t/y hydrosizer, as well as screening, drying, and packaging equipment.Béton provincial ltée operates a silica sandstone quarry in Gaspé’s La Rivière County and Société Minière Gerdin Inc. operates a silica sand quarry on a seasonal basis in Saint-Rémi-d’Amherst.Exploration Québec/Labrador (EQL) Inc. mines its quartz deposit from Lac Daviault, near Fermont. Production is crushed on site, but is processed at the Granirex plant(division of DuPont Canada of Ontario) in Thetford Mines, Quebec, for the manufacturing of decorative and durable engineered stone products used in decorative surface appli-cations. EQL is planning to explore other markets for the quartz, including silicon metal.OntarioUnimin Canada Ltd. is also the largest producer of silica in Ontario with a capacity of about 500 000 t/y. Lump quartz-ite from Badgeley Island (150 000-t/y capacity) in northern Georgian Bay is shipped by boat to Canadian destinations for the manufacture of ferrosilicon. The fi ner material, pro-duced by grinding, is shipped to Unimin’s plant at Midland (400 000-t/y capacity), south of Georgian Bay, where it is further processed to a glass-grade silica sand and to silica fl our for ceramic and other uses.Nova ScotiaShaw Resources Ltd., a member of The Shaw Group Limited, produces a high-purity (98.5-99.5%) silica from sand deposits located at Nine Mile River, Hants County, near Shubenacadie. In addition, fi ne sand from its silica operation is bene fi ciated to fl int glass-grade material. Fine sand products are sold in the Maritimes, Quebec, and northeastern United States for use in sandblasting, fi lter sand, traction sand, cement and concrete manufacturing, refractory and decorative sand, and as a fl ux for base-metal smelters.Black Bull Resources Inc. still has no production or revenue mining at its White Rock quartz project inYarmouth County. The site is located 42 km northwest of the deep port of Shelburne. Reserves of 16.3 Mt of high-quality angular and bright white quartz have been esti-mated. The material would be aimed at fi ve different spe-cialized markets: pool plaster aggregate, engineered stone, exterior insulation and fi nishing systems (EIFS), landscape stone, and golf course sand.New BrunswickShaw Resources’ Chaleur Silica Ltd. – a division of The Shaw Group Limited currently operates the Bass River silica quarry, providing silica as fl ux material to the nearby Belledune lead smelter and for use in cement manufacture. It also manufactures abrasive products using raw material from Nova Scotia, Ontario, and the United States. Since 1986, Atlantic Silica Inc. mines and processes a high-grade (+98%) silica deposit located 22 km southwest of Sussex near Cassidy Lake. The quartz pebbles have been used to produce silicon metal and decorative stone. The quartz sand has been marketed for use in sandblasting, sili-con carbide, nursery grit, cement powder, glass, golf course sand, smelter fl ux sand, and fi ltration sand. Most of it is used in eastern Canada, although some is shipped to the United States.QuebecUnimin Canada Ltd., a subsidiary of Unimin Corp. of the United States, is the largest producer of silica in the pro-vince. Silica is mined from a quartzite deposit at Saint-Donat-de-Montcalm and from a sandstone deposit at Saint-Canut. Silica from Saint-Donat is shipped and re fi ned at the Saint-Canut plant near Montréal. The majority of the silica produced by Unimin originates from Saint-Canut where the ore is ground, screened, and bene fi ciated by magnetic separation. Most of Unimin’s output is used in the production of glass containers, fl at glass, and fi breglass; it is also in the silicon carbide industries.Silicium Bécancour Inc. (now owned by Timminco Ltd. of Toronto) operates the silica plant in Bécancour. Its facility47.4 CANADIAN MINERALS YEARBOOK, 2006AlbertaSil Industrial Minerals Inc. of Edmonton produces silica sand from local sand dunes in the Bruderheim area. It also operates a silica processing facility near Edmonton. The silica is sold mainly for the manufacture of fi breglass and as sandblasting material. Other uses are in foundry, fi ltra-tion, fracturing, and railway traction applications. The company also produces silica fl our by processing the silica sand through a ball mill. The fl our is used in thermal insu-lating cement in the oil and gas industries.Cementec Industries Inc. of Calgary produces, among other unique and proprietary products, silica fl our, silica fume, and sandblasting sand for use in the oil and gas and con-struction industries.Hexion Specialty Chemicals of Columbus, Ohio,announced plans (source: Blendon Information Services) to construct a plant in Alberta to produce resin-coated proppants 2 for use in the oil and gas industry. The 150 million-lb/y plant will be built in Sturgeon County.British ColumbiaHeemskirk Consolidated Ltd. of Australia (who purchased Dynatec Corp.’s western operations) mines a high-purity (99.5%) silica sand for diverse industrial applications (e.g., glass grade, foundry sand, additive in refractory cements and ceramics, and use as a functional fi ller/extender for paints) at the Moberly mine in the Golden area. The friable sandstone is ground, screened, washed, dried, and separ-ated into several sizes at a plant near Golden. These differ-ent sizes are sold mainly as glass sand, but also as sand-blasting sand, foundry sand, fi lter media sand, and golf course bunker sand. In 2006, Heemskirk Canada Ltd., a subsidiary of Heemskirk Consolidated Ltd., expects to ship 80 000 t of silica, mainly to Lavington, B.C.Lafarge Canada Inc. mines silica-alumina material from the Buse Lake deposit as feedstock for its Kamloops cement plant.P RICESPrices for actual transactions vary according to geographic region and will take into account the quantity purchased, application, colour, impurities, exact grade purchased, credit terms, and other parameters. Due to the unavailabi-lity of Canadian prices, the following price examples are provided to facilitate an understanding.According to the U.S. Geological Survey 3 (USGS 2005 Review ), the value of silica increased by about 7% between 2004 and 2005 (average value, free on board [f.o.b.] plant). The average price for sand ranged from US$6.75/t forCrystal Quartz Canada, located near Dryden in western Ontario, is the only lascas-grade silica producer in North America. It supplies lascas quartz to North American cultured quartz producers.Signi fi cant amounts of silica are extracted by others across Ontario for use as fl ux for base-metal ore smelting oper-ations in Timmins and Sudbury, for silicon metal produc-tion, for specialty brick production, and for decorative uses. Other Ontario producers are: Arriscraft International Inc. with its Elgin Quarry in Bastard Township; Rapier Resour-ces Inc. with its Deagle Township Quarry, west of Sudbury; Great White Minerals Ltd. with its Fripp Quarry, near Timmins; Northern Mining and Exploration Inc. with its Shaw Township Quarry, in Timmins; and Roseval Silica with its Penhorwood Township Quarry, also near Timmins.ManitobaThere are no known silica quarries currently in operation in Manitoba. Nevertheless, Gossan Resources Ltd. of Winnipeg has consolidated its land position at its Mani-gotagan silica property (source: Blendon Information Services) by acquiring two adjacent quarry leases. The expanded property now encompasses 274 ha. A composite of 19 samples from the property has been tested and yielded a silica content of 94.2%. Tests have also con-cluded that the silica meets metallurgical requirements and may potentially be used as frac sand in shallow gas wells.SaskatchewanHudbay Minerals Inc. (formerly Hudson Bay Mining and Smelting Co., Limited) produces silica in the Amisk Lake area of northern Saskatchewan and is the largest user of the province’s silica sand at its Flin Flon, Manitoba, smelter. Hudbay uses sand as a fl uxing agent that, in the molten state, reacts with impurities in the copper concentrate to produce a slag. The slag, with some of the impurities, is drawn off, leaving matte, a crude form of metal that requires further processing.Red Deer Silica Inc. produces a small amount of silica, northeast of the village of Hudson Bay, for use in golf course bunkers, stucco sand, and sandblasting sand.In mid-2002, the mineral deposit of the Hanson Lake silica sand project was appropriated by Trican Well Services and Saskatchewan Opportunities Corporation (SOCO). The mineral dispositions have been optioned to Winn Bay Sand Ltd., a company af fi liated with the Ochapwace FirstNation. Lonesome Prairie Sand and Gravel Ltd. is the con-tractor carrying out all quarrying operations. All process-ing takes place on site. The silica sand is used as frac sand, predominantly in the gas fi elds in Saskatchewan. It is transported to Burstall, Saskatchewan, just west of the Great Sand Hills, where it is of fl oaded. Customers pick up their orders from this site.SILICA/QUARTZ 47.5Other Uses : Lump quartz and quartzite are used as liningsin ball and tube mills, and as lining and packing for acid towers. Naturally occurring fl int pebbles may be used as a grinding medium for nonmetallic ores.Silica Sand 4Glass and Glass Fibre : Naturally occurring quartz sands and sands produced by crushing quartz, quartzite, or sand-stone are used in the manufacture of glass, glass fi bre, and fused silica ware. The silica content should be greater than 99% and the iron oxide content should be uniform and less than 0.025%.Other impurities such as alumina, lime and magnesia should be less than 0.15% each. Chromium, cobalt and titanium are undesirable and should be less than 2 or 3 ppm. Uniformity of grain size is important and sand should generally be between 600 and 100 μm in size with a minimum of coarse and fi ne material.Silicon Carbide : Sand for silicon carbide manufacture should have a silica content of 99% and iron oxide and alumina should each be less than 0.1%; lime, magnesia and phosphorus are particularly objectionable. Although coarse-grained sand is preferred, fi ner sands are used where coarser grades are not available. All sand should be plus 150 μm, with the bulk of the sand being minus 2.0 to plus 0.5 mm in size.Hydraulic Fracturing : Silica sand is used as a “propping agent” in the hydraulic fracturing of oil-bearing formations to improve the recovery of oil. The sand should be clean, dry, and have a high compressive strength. The silica content should be high and carbonates and other acid-consuming minerals should be low. The sand grains should be between 850 and 500 μm in size and well rounded to facilitate placement and provide maximum permeability. Foundry Moulding : Naturally occurring sand and sand produced by the reduction of sandstone to grain size are used extensively in the foundry industry for moulding pur-poses. The purity and size of sand used depend on the type of casting and on the particular foundry practice. Iron and steel foundry sands vary in grain size between 850 and 75 μm in closely sized fractions. American FoundrySociety (AFS) numbers vary between 55 and 65 μm, with the bulk of the sand being preferably on three adjacent sieves; a rounded grain shape is preferred. The silica con-tent should be high (99% SiO 2) with low aluminum, iron, sodium, and potassium oxides.Silicate Chemicals : Sand for the manufacture of sodium silicate and other chemicals should be of high purity. Sodium silicate requires a silica content of 99%, the alu-mina less than 1%, the combined lime and magnesia lessmetallurgical fl ux to US$103.85/t for ground foundry sand. For gravel, prices ranged from US$9.29/t for non-metallurgical fl ux to US$49.79/t for fi ltration. U.S. produ-cer prices reported to the USGS for silica commonly ranged from several dollars per tonne to hundreds of dol-lars per tonne, and occasionally exceeded the US$1000/t level. In the United States, ground sand for foundry mold-ing and core, at US$103.85/t, had the highest value per tonne, followed by silica for swimming pool fi lters, US$81.81/t; ground sand used as fi llers for paint, putty and rubber at US$59.32/t; ground sand for ceramics, US$50.30/t; ground sand for scouring cleansers, US$47.96/t; silica for municipal water fi ltration,US$46.02/t; sand for hydraulic fracturing, US$43.45/t; and ground sand for fi breglass, US$40.81/t.M AJOR U SES AND S PECIFICATIONSSilica in the form of quartz, sand, sandstone, and quartzite is used in many applications. Uses may be subdivided on the basis of particle size requirements, e.g., lump silica, 2 or 3 mm to 15 cm or more in size; silica sand, 2 or 3 mm in size down to 75 μm; and silica fl our, which is essentially minus 75 μm in size. Applications for the silica with gen-eral speci fi cations are discussed under the three general size categories stated (CANMET, Summary Report No. 4: Silica ).Lump Silica 4Flux : Quartz, quartzite, and occasionally sandstone and sand are used as fl uxes in smelting base-metal ores with low silica contents. The silica content of the fl ux should be as high as possible, but a small percentage of impurities such as iron oxide and alumina can be tolerated. Size is generally minus 2.5 to 0.5 cm.Silicon Alloys : Quartz, quartzite, and well-cemented sand-stone are used in the manufacture of silicon, ferrosilicon, and other alloys of silicon. The silica content of ferrosili-con should be 98% and the total iron oxide and alumina less than 1.5%. Lime and magnesia should not exceed 0.20% each; phosphorous and arsenic should also be very low. Silicon metal manufacture requires a high-purity quartz grading 99.5% SiO 2 or better with less than 0.04% iron oxide and alumina. Size speci fi cations vary between 5 and 10 cm.Silica Brick : Quartz and quartzite crushed to 2.5 mm are used in the manufacture of silica brick for high-temperature refractory furnace linings. The silica content should be a minimum of 95%, and iron oxide and alumina should each be less than 0.1%. Other impurities such as lime and mag-nesia should be low.47.6 CANADIAN MINERALS YEARBOOK, 2006require precise sizing and a high-purity product. Thus, fur-ther processing and bene fi ciation are normally required to both size and upgrade the raw silica feed material.Further reduction of the silica to a speci fi c size, e.g., minus 850 μm to plus 150 μm, must be carefully carried out to avoid introducing extraneous impurities such as mill iron and other contaminants, and care must be exercised to avoid over-grinding. Whole unfractured grains are pre-ferred in foundry moulding, and fi nes are detrimental in both foundry and glass sand applications. Over-grinding is more dif fi cult to control when the starting material is quartz or quartzite, which do not possess a well-de fi ned granular structure such as when crushing a more weakly cemented friable sandstone. The choice of grinding unit is also important; for example, impact mills produce more frac-tured grains and fi nes than jaw, cone, or roll crushers.Following reduction to the size required, various bene fi cia-tion steps may be used to remove impurities, typically clay, feldspar, carbonates, and ferromagnesian minerals. Bene-fi ciation can include one or more of the following:Screening to remove the coarse and fine fractions, which • usually contain a significant percentage of the total impurity;Magnetic separation to remove iron-bearing minerals;• Jigging or tabling to remove heavy minerals;• Attrition scrubbing and washing to remove clay and • slimes;Flotation to remove minerals that do not respond to • magnetic or gravity methods, e.g., feldspar and pyrite; and Acid leaching to further reduce iron and carbonate • minerals.H EALTH AND S AFETY C ONCERNSCrystalline silica is silicon dioxide (SiO 2). Most minedminerals contain some SiO 2. “Crystalline” refers to the orientation of SiO 2 molecules in a fi xed pattern. The three most common crystalline forms of silica encountered in industry are quartz, tridymite, and cristobalite.Silicosis is a disabling, non-reversible, and sometimes fatal lung disease caused by overexposure to respirable crystal-line silica. Silicosis can be prevented when crystalline silica is used safely and appropriate precautions are taken. Silicosis is preventable if employers, workers, and health professionals work together to reduce exposures (source: U.S. Department of Labor, Occupational Safety & Health Administration). In the United States, any mineral product with a crystalline silica content of >0.05% (down from thethan 0.5%, and iron oxide less than 0.1%. All sand should be between 840 and 150 μm in size.Other Uses : Coarsely ground, closely sized quartz, quartz-ite, sandstone, and sand are used as abrasive grit forsandblasting purposes and for the manufacture of abrasives papers. Various grades of closely sized, round-grained sand are used in water fi ltration plants as a fi ltering medium. Silica sand is used as an additive in portland cement manufacture when the source cement is low in silica.Silica FlourSilica fl our, formed by grinding quartz, quartzite, sand-stone, and sand to 75 μm and fi ner, is used in the ceramic industry for enamel frits and pottery fl int. It is also used in the manufacture of chrysotile cement and autoclave-cured concrete products, as an inert fi ller/extender mineral in rubber and paints, and as an abrasive ingredient in soaps and scouring powders.M INING, P ROCESSING, AND B ENEFICIATIONMiningCommercial silica is obtained from vein quartz, sand, sand-stone, and quartzite deposits. Mining is usually by open-pit benching using standard quarrying methods. Following primary breakage, the rock is trucked to the mill site for further size reduction, processing, and bene fi ciation.ProcessingSilica may be used in lump form, as sand, as a fi nely ground powder, and as silica fl our. Primary crushing of lump silica is readily accomplished by jaw and cone crush-ers, and secondary crushing is done by hammer or impact-type mills. Further reduction to sand size may be accom-plished by roll crusher or rod mill, and to fl our size or fi ner by ball, vibratory or jet-milling, or by attrition grinding in a “stirred” ball mill using small ceramic pebbles as grinding media.Following primary and secondary crushing, lump quartz, sandstone and quartzite for use as fl ux in the manufacture of silicon and ferrosilicon, etc., must be screened to meet size speci fi cations. Screening may result in minor upgrading through the removal of impure fi nes, but such material is essentially used as quarried with no bene fi cia-tion apart from sizing.Bene fi ciationUses requiring silica in the form of sand or fl our, e.g., glass, silicon carbide, foundry and chrysotile cement, usually。

小学上册英语上册试卷(含答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1. A cat loves to chase _______ and play.2.The period in which an element is found indicates its number of ______.3.What kind of animal is a dolphin?A. FishB. MammalC. ReptileD. Amphibian答案:B4.The chemical formula for magnesium chloride is ______.5.What do you call a large body of freshwater surrounded by land?A. OceanB. SeaC. LakeD. River答案:C6.What is the primary ingredient in guacamole?A. TomatoB. AvocadoC. OnionD. Lime答案:B7.The body of water between Europe and Africa is the __________ Sea.8.The __________ (科学发现) change our understanding.9.The chemical formula for aluminum chloride is _____.10.Which insect is known for making silk?A. FlyB. ButterflyC. SilkwormD. Ant答案:C11.The deer is very ______ (优雅) when it moves.12.My friend, ______ (我的朋友), is a talented artist.13.What is the term for a young horse?A. CalfB. FoalC. KidD. Pup答案:B14. A lion is a majestic _______ that roams its territory with pride.15.The __________ is where fish breathe in water.16.The ancient Romans had a complex system of ________ (法律).17.I see a _______ (hawk) flying above.18.The __________ (历史的舞台) sets the scene.19.My teacher tells us stories about ______ (历史) and important people in the world. It’s fascinating to learn about the past.20.The ____ has a long body and slithers on the ground.21.What do we call the story of a person's life?A. BiographyB. NovelC. FictionD. Poetry22.The soup is very ___ (hot).23.What do we call the study of the Earth's physical features?A. GeographyB. GeologyC. MeteorologyD. Cartography答案:A24.My mom is a __________ (社交工作者).25.What is 12 divided by 4?A. 2B. 3C. 4D. 5答案:B26.My friend is a big __________ of movies. (爱好者)27.My favorite color is _____ (蓝色).28.I wear _____ (耳环) for special occasions.29.听录音，判断下列图片是否与录音一致，一致的打“√”，不一致打“X”。