AMMONIA TECHNOLOGY FOR PROCESSING SULFATE-CONTAINING SOLUTION OBTAINED DURING SULFATION OF KAOLIN CLAYS

This article discusses the technology of ammonia treatment of a sulfate-containing solution obtained as a result of the sulfation of kaolin clays from the Chashma-Sang deposit located in the Republic of Tajikistan. The main objective of the study is to obtain a mixture of aluminum and iron hydroxides, as well as to extract ammonium sulfate as a by-product. The research was conducted in laboratory conditions, where the influence of temperature and duration of the ammonia treatment process on the efficiency of precipitation of the target products was studied in detail. The experiments showed that at a temperature of 85 °C and a process duration of 30 minutes, the degree of precipitation of the mixture of aluminum and iron hydroxides, as well as the yield of ammonium sulfate in the solution, exceeded 98%. Analysis of the precipitate revealed that the proportion of aluminum hydroxide (Al(OH)3) is over 86%, and iron hydroxide is about 13.2%. According to X-ray phase analysis, the obtained mixture of hydroxides is not characterized by clearly defined diffraction peaks, which indicates its amorphous structure. At the same time, the synthesized ammonium sulfate corresponds to the reflexes of the mineral masagnite ((NH4)2SO4), which indicates a high degree of purity of the product obtained. The results of physical and chemical studies have established that the obtained ammonium sulfate complies with the requirements of GOST 9097-82 for technical ammonium sulfate. The technical and economic analysis confirmed the high efficiency and economic feasibility of the proposed processing technology, especially considering that each ton of precipitated aluminum and iron hydroxide mixture yields more than 2.4 tons of ammonium sulfate as a by-product. The results obtained confirm the feasibility of introducing this technology into industrial practice, which allows for the efficient use of local resources and minimization of production waste.