首页
登录
职称英语
Eight percent of the Earth’s crust is aluminum, and there are hundreds of alu
Eight percent of the Earth’s crust is aluminum, and there are hundreds of alu
游客
2023-12-18
33
管理
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. [br] 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://tihaiku.com/zcyy/3284289.html
相关试题推荐
[originaltext]Nearly75percentofU.S.doctorsbelievemiraclescanoccur,
[originaltext]Likehundredsbeforethem,ateamof10Americansarrivedatt
[originaltext]Likehundredsbeforethem,ateamof10Americansarrivedatt
[originaltext]Likehundredsbeforethem,ateamof10Americansarrivedatt
[originaltext]Likehundredsbeforethem,ateamof10Americansarrivedatt
Whilethepercentageofurbanresidentsishigherinrelativelydevelopedcou
Forhundredsofyears,farmershaveselectedandbredplantsandanimalstof
Forhundredsofyears,farmershaveselectedandbredplantsandanimalstof
Forhundredsofyears,farmershaveselectedandbredplantsandanimalstof
Sixty-eightpercentofAmerica’swealthisgeneratedbymanufacturing.Ifthe
随机试题
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeve
Inasurprisinginteractionatsea,hugewhalesharksfollowfishingnetsne
This______bowlwasboughtfromChinaataratherhighprice,butitseemednoon
Fewpracticesareaswidespreadamonghumanculturesastheceremonialwed
[originaltext]Nowinitssixteenthyear,thisyear’sWomen’sClubtenkilom
[originaltext]W:Haveyoufinishedthatpaintingforthenewstudentcenter?M:
对个人新发放的小额担保贷款的最高额度为10万元。()
下面是某求助者的EPQ测验结果如下。 该求助者的量表得分,说明他()。
复杂分解爆炸类可爆物的危险性较简单分解爆炸物稍低,其爆炸时伴有燃烧现象,燃烧所需
女性,28岁,发热半个月,弛张热型,伴关节痛、恶寒。体检:皮肤瘀点、Osier结
最新回复
(
0
)