Abstract
The effect of flocculants and surfactants of different nature on the process of purification of the MgSO4 mother liquor from Fe3+, Al3+ and Cr3+ impurities by electroflotation was investigated. The study is aimed at increasing the yield of magnesium sulfate by returning the purified mother liquor to the head of the process at the stage of acid decomposition of serpentinitomagnesite. In the experiments, model solutions with a concentration of MgSO4 – 100 g/l, the content ions of Fe3+ – 50 mg/l, Al3+ – 10 mg/l and Cr3+ – 10 mg/l were used. It was determined that all impurities during pH adjustment turn into slightly soluble compounds at values 6 – 7. For the MgSO4 purification process by electroflotation, the optimal current density was established, which is 0.4 A/l. The duration of the process of purification by electroflotation is 30 min. When studying the effect of surfactants of cationic, anionic, nonionic and amphoteric types on the MgSO4 purification process by electroflotation, it was found that the degree of extraction of Fe3+, Al3+ and Cr3+ impurities does not exceed 10-30%, the exception is the presence of an amphoteric surfactant, in which the degree of extraction of Fe3+ is 77 – 78%. It was found that the greatest efficiency of extraction of Fe3+, Al3+ and Cr3+ impurities from MgSO4 solution is achieved in the presence of anionic flocculant Praestol 2540. The degree of extraction for all components reaches 98-99% already at the tenth minute of the process. Thus, the purification of MgSO4 from Fe3+, Al3+ and Cr3+ impurities by electroflotation in the presence of anionic flocculant Praestol 2540 will allow the purified mother liquor to be returned to the beginning of the process at the stage of sulfuric acid decomposition of serpentinitomagnesite during the production of magnesium sulfate, which will increase the yield of the product.
Publisher
Ivanovo State University of Chemistry and Technology