题干

CoCl2•6H2O是一种饲料营养强化剂.一种利用水钴矿(主要成分为Co2O3、Co(OH)3,还含少量Fe2O3、Al2O3、MnO等)制取CoCl2•6H2O的工艺流程如图1:

已知:

①浸出液含有的阳离子主要有H+、CO2+、Fe2+、Mn2+、Al3+等;

②部分阳离子以氢氧化物形式沉淀时溶液的pH见表(金属离子浓度为0.01mol/L):

淀物

Fe(OH)3

Fe(OH)2

Co(OH)2

Al(OH)3

Mn(OH)2

开始沉淀

2.7

7.6

7.6

4.0

7.7

完全沉淀

3.7

9.6

9.2

5.2

9.8

③CoCl2•6H2O熔点为86℃,加热至110~120℃时,失去结晶水生成无水氯化钴.

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