Molybdenum Extracting And Acid Recovering From High Acid Solution

Molybdenum is an important strategic metal. The extraction of molybdenum from solution has been extensively investigated, where they are mainly focus on the extraction of molybdenum from the low acid solution or alkaline solution. However, molybdenum obtained from the high acid solution was rarely reported. According to high Mo acid solution, the free acid not only can not be recycled, but consume large mount of alkali to adjust the acidity based on present techniques. Therefore, the present paper reported a new method to directly extract Mo from high acid solution by using extractant HBL101. Where, we focus on the preparation of the acid leaching solution of Ni-Mo ore, the direct extraction of the high acid solution of molybdenum and the recovery of the acid from raffinate. The results can be shown as followings.The leaching rate of Mo and Ni were closed to100%and～90%under the optimum process, respectively. The optimum process could be:8mol/L H+, molar ratio of hydrochloric and sulfuric acid is3:2, NaClO3are0.04times theoretical, liquid-solid ratio4:1, temperature90℃and time2h.Mo can be directly extracted by HBL101from high acid leaching solution (3.96mol/L H+with hydrochloric and sulfuric acid) of Ni-Mo ore. More than97%of molybdenum was extracted in one-stage extraction using an organic system of10%HBL101+5%TBP+75%sulphonated kerosene and a feed containing12.8g/L Mo,3.96mol/L H+with an A/O ratio of1:1.5at30℃for5min. And, it was being well selectivity for Mo with the separation of Mo over Ni, Fe, Ca, Mg, Al, Cu, Zn and P, As. The stripping of Mo was91.89%in single-stage stripping using6mol/L NH3·H2O with an A/O ratio of1:4at30℃for20min after washing with pure water.The saturation capacity of extracting Mo of10%HBL101+5%TBP+75%sulphonated kerosene is12.09g/L. The extraction distribution isotherms of the HBL101was also drawn. After a two-stage countercurrent extraction and three-stage counter current stripping, the extraction rate and stripping rate of Mo were99.8%and99.9%, respectively. The concentration of Mo in stripping solution is33g/L. After2times reflux stripping and4times reflux stripping, the concentration of Mo in stripping solution increases to143.67and227.28g/L, respectively. In the whole process of extraction-reflux stripping, the impurity removal rate of nickel, iron, calcium, magnesium, copper and zinc was100%, while phosphorus, arsenic, and aluminum was above99%, and the impurity of silicon was about50%.In the verification experiment, the results show that, the single-stage extraction of Mo is91.97%, and P and Ca have not been extracted, while the extraction rate of Si was about3.24%with an A/O ratio of1:1.5at25～30℃for5min. Also, HBL101shows a positive effect for the extraction of Mo at high sulfate acid solution and sulfate acid solution.In the saturated capacity method to study the extraction of Mo with HBL101from the acid solution, the mechanism can be shows as:In the diffusion dialysis process, the results show that the migration speed of H+in the A membrane is faster than that of B, the rejection rate of nickel ions in A membrane is higher, and the water permeability is also greater. In the once-pass operation, it shows that the recovery rate of acid was related to the flow, flow ratio and other factors. When the liquid flow rate and water flow ratio were90ml/L and1:1, the recovery rate of the acid reached about53%, the reject rate of copper, iron, magnesium was over92%, the reject rate of nickel was over96%. Meanwhile, H+in the dialysis fluid reached2.15mol/L. It can also be leached for circulation which means that the nickel entering dialysis was not lost absolutely.The direct extraction of Mo with HBL101from the high acid solution takes advantages of short process, high selectivity, and high recovery of Mo. Simultaneously, the process of regulating the acidity can be avoided, the acid in raffinate can be recycled. Thus, the process provides a new way under high acid conditions.