The Research On Removing Ca Deepness From Copper Sulfate

Copper sulfate is an important basic industrial material.With the raw materialdifferent,the preparation methods of copper sulfate are not the same,and there are manyfactors influencing product quality,but controling the impurity content of lixiviant isone of the key issues.Because the preparation of cupper sulfate use industrial wastescontaining copper in the more enterprises,so the composition of copper leachingsolution is complex and solution requires high purification process,which causes thedifficulty at further purification of calcium and may affect on the purity and grain sizeof product.In this paper, the calciferous copper sulfate feed liquid as the researchobject,it has been conducted an experimental study on the possibility of removing thecalcium deeply by extraction technology and proposed a method of calcium removalbased on changing the copper ion valence state and developed a comparativelyeconomic and feasible process of producing the high grade copper sulfate.In this study,through extraction processes of the different degree,the effects ofdifferent P204concentration、phase ratios、the extracting time and pH on extractingcalcium were investigated.Adopting the method of change the copper ion do deeplydecalcified,and different valences of copper ions was studied on the modified effect ofremoving Ca²⁺in the copper sulfate solution.The effecting factors such as time、temperate、consumption of NaCl and NaOH、pH、addition amount of CuCl seed crystaland ratio of liquid to solid etc has been studied on effect of CuCl precipitation andtransformation rate、Cu₂O leaching rate and Ca²⁺removal.The research result that: 1.Extraction conditions:C（P204）=1.2mol/L、O/A=6：1，3min、PH=2.0,the calciumion concentration can be reduced from1.0g/L to0.2g/L and the copper extraction ratewas3%in single stage extraction; Under the same conditions, the concentration of Ca²⁺was reduced from0.7g/L to0.01g/L in the Level3cross-flow extraction, but thecopper extraction rate reached17%; With the same conditions, the copper extractionrate8%, the concentration of calcium was0.1g/L; C（P204）=1.4mol/L、O/A=8:1,through the four-stage countercurrent extraction, the concentration of calcium ion islower than0.06g/L in raffinate at the third grade, and the copper extraction rate is20%.It’s difficult to achieve the cost-effective depth of calcium removed by changingextraction process.2.The precipitation of CuCl was prepared at such conditions that the reactiontemperature is80℃,40min, PH=1.5～2.0, SO₂as reducing agent, NaCl as precipitantand the content of Ca is less than0.04%, precipitation rate96%, and Ca²⁺separationwas achieved; CuCl was more than99%transformed to Cu₂O at the conditions that100℃，NaOH10%，ratio of liquid to solid5:1,2h, controlled by the chemical reactionsteps; The Cu₂O Leaching rate was96%by Sulfuric acid leaching process at theconditions that90℃, ratio of liquid to solid8:1,1h, controlled the diffusion stepsoutside, activation energy4.11kJ/mol; By cooling crystallization, Cu₂O stripping liquidproduced high purity CuSO₄·5H₂O. The depth removal of Ca`was achieved bychanging copper ion valence, CuCl, Cu₂O, CuSO₄and other kinds of products can beproduced.