首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Eight percent of the Earth’s crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the r
Eight percent of the Earth’s crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the r
admin
2010-06-18
38
问题
Eight percent of the Earth’s crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the rocks that contain them. The best aluminum ore is bauxite, defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides. Bauxite is the richest of all those aluminous rocks that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum. Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum. Most of the many abundant nonbauxite aluminous minerals are silicates, and like all silicate minerals, they are refractory, resistant to analysis, and extremely difficult to process. The aluminum silicates are therefore generally unsuitable alternatives to bauxite because considerably more energy is required to extract alumina from them.
The intermediate product needed for the production of aluminum is______.
选项
A、hydrated oxides
B、bauxite
C、alumina
D、silicates
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/phlO777K
0
专业英语八级
相关试题推荐
A、HighdivorcerateinthecultureandthenewtrendofDINKinthecountry.B、Rapideconomicgrowthinthepastdecadesdespite
Fromitsbirth,threepowerfulimageshavecolouredideasofwhattheUnitedStateswasandwhatitstoodfor.Onewas"acityo
A、Tofundhugeincreasesinhealthandeducationexpenditure.B、Tohindertheeconomicgrowthbytheway.C、Toearnthetrustof
InearlyJune,theOrganizationforEconomicCooperationandDevelopment(OECD)—thecluboftheworld’swealthyandalmostwealt
InearlyJune,theOrganizationforEconomicCooperationandDevelopment(OECD)—thecluboftheworld’swealthyandalmostwealt
Goodmorning.Thediscussiontopicfortoday’sseminaris"HomelessnessinAmerica."IntheUnitedStates,homelessnesshas【C1】
Goodmorning.Thediscussiontopicfortoday’sseminaris"HomelessnessinAmerica."IntheUnitedStates,homelessnesshas【C1】
TheHistoricalBackgroundofSocialPsychology1Whiletherootsofsocialpsychologylieintheintellectualsoilofthew
Doyourememberallthoseyearswhenscientistsarguedthatsmokingwouldkillusbutthedoubtersinsistedthatwedidn’tknow
Doyourememberallthoseyearswhenscientistsarguedthatsmokingwouldkillusbutthedoubtersinsistedthatwedidn’tknow
随机试题
与成年人相比,儿童少年力量运动疲劳与恢复的特点是()。
某省会城市的市政府拟制定限制电动自行车通行的规章。关于此规章的制定,下列说法中正确的有()。
______beforeweleavetomorrow,weshouldinviteallourfriendstoholdapartytowelcomethem.
我国对建设工程监理市场准入采取了()控制。
扩张性财政政策对证券市场的影响有()。
区位通常是指某一事物与其他事物在空间方位和距离上的关系,具体可标示为一定的()。
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性。
求下列积分。设f(x)=∫1xe-y2dy,求∫01x2f(x)dx;
Answerquestions71~80byreferringtothefollowinggames.Note:AnswereachquestionbychoosingA,B,CorD.Somechoices
Inthisgreatglobalclashofinterests,itistimeforbothsidestosoftentheirangerandseeknewwaystogetalongwitheac
最新回复
(
0
)