The Preparation Of Composite Sulfates Using High Concentrations Chloride Wastewater And Its Application In Extraction Of Ion-type Rare Earth

Extraction and separation of rare earth can be seen as a simple consuming acid-base and produce large amounts of salt in the process, also is the main source of rare earth separation of pollutants.Consequently, How to recycle chloride wastewater is the main task of rare earth enterprises emission reduction. Aiming at the high concentration of ammonium(sodium) chloride wastewater comprehensive utilization requirements, To carry out the experimental study and industrial about sulfuric acid and chloride was prepared with hydrochloric acid and sulfate compound, and the composite sulfate on ion adsorption type rare earth leaching properties were evaluated. Specific results are as follows:The process conditions of sulfuric acid together with sodium chloride and ammonium chloride wastewater was prepared with hydrochloric acid and sulfate compound respectively(with acid ratio, temperature, time and pressure) impact on the acid concentration, chloride conversion rate and sulfate composite composition. The results show that: with the addition of acid than n(H+): n(Cl-) increased, the conversion rate of chloride to inprove, and under the condition of adding acid than fixed, along with the increase of the concentration of the chloride salt steamed out of hydrochloric acid concentration increased, but its hydrochloric acid steamed out of moles and adding hydrogen ion ratio of the number of moles basically remain unchanged, and under the condition of reduced pressure, can make hydrochloric acid steamed out rate is about 7% higher than atmospheric pressure; When the concentration of chloride for more than 4 mol/L,steamed out of the concentration of hydrochloric acid are higher than the salt concentration, can be directly used for rare earth extraction separation of acid washing and acid refluxing. Steamed out after hydrochloric acid of compound sulfate is directly related to acid ratios, When adding acid ratio higher than 1.8, the main product for ammonium hydrogen sulfate(sodium); When the acid ratio about 1.6 main product for three ammonium hydrogen sulfate; Adding acid ratio was lower than 1.4, there is not the complete transformation of the chloride. The resulting composite sulfate can be used for the leach of adsorption type rare earth, It can replace the sulfuric acid as deposit recycling use of rare earth ammonium bicarbonate pH regulator and ammonium ion supplement.At the same time, also studied the use of acid ammonium sulfate or aluminum sulfate solution for ion adsorption type rare earth leach, in order to improve refractory rare earth leaching, which can be used for recycling aluminum impurities in leaching and stability in tailings. The method is to dissolve the mine slag pretreatment using composite sulfate, rare earth and most of the aluminum dissolved into solution, with the raffinate after extraction of rare earth returns for second stage leaching of rare earth ion adsorption type, the refractory rare earth and tailings of ammonium into solution further recycling, with lime water retaining tail, make the most of aluminum stored in tailings.