Experimental study on calcium removal from muscovite ore by hydrochloric acid pickling
With the implementation of double carbon policy in China,energy and other high-tech fields have been developed rapidly,the demand for lithium,rubidium and other metals is increasing,muscovite as one of the minerals containing lithium and rubidium has been paid attention to.In this paper,for the problem that the presence of the main impurity calcium will reduce the effective extraction rate when treating muscovite ore by sulfuric acid curing,it is proposed to use hydrochloric acid pickling to pre-calcium removal of muscovite ore.Firstly,the reaction of muscovite and calcite with hydrochloric acid during pickling was analyzed from the thermodynamic point of view.The results show that the muscovite hardly reacts with hydrochloric acid in the range of pickling temperature;when the temperature is higher than 30 ℃,the reaction between calcite and hydrochloric acid can be carried out spontaneously.Secondly,the process parameters such as pickling temperature,hydrochloric acid concentration,pickling time and liquid-solid ratio were investigated,and it has been found that the removal rate of calcium could reach 98.3％,while the loss rate of rubidium and lithium was as low as 2.3％and 3.3％under the conditions of pickling temperature of 70 ℃,hydrochloric acid concentration of 0.5 mol/L,pickling time of 1.5 h,and liquid-solid ratio of 1 mL/g.Therefore,the selective removal of calcium from muscovite ore can be achieved by hydrochloric acid pickling.Characterization of the pickling residue revealed that the calcite phase disappeared from the muscovite ore after pickling,and the ore was mainly composed of muscovite and quartz,while the EDS image showed the disappearance of calcium-enriched areas.Under the same curing and water leaching conditions,comparing the lithium and rubidium leaching rates obtained by two different processes,direct curing and pickling+curing,respectively,it was found that the curing of acid-washed muscovite could increase the lithium and rubidium extraction rate by about 10％to 20％.Finally,it was verified based on the test of calcium removal by acid pickling solution recycling that the acid pickling solution could be recycled three times after acid replenishment(adjusting pH values to 0.3),and the calcium removal rates were all kept above 90％,avoiding a large amount of wastewater generation.
万方数据
维普
