STUDY OF THE PROCESS OF OBTAINING HALF-HYDRATE CALCIUM SULFATE FROM A DISTILLER LIQUID FOR THE PRODUCTION OF SODA ASH

Abstract

Distiller liquid of soda ash production is released in large quantities and is not completely re-processed. It is directed and stored by the waste storage. Complex processing of such waste has not yet been solved, so it is necessary to study and develop effective methods of processing. Thermodynamic interaction of calcium chloride distillation liquid with sodium sulfate and (DG_т⁰) reaction calculated in the temperature range 0-100 °C (273-373К), and has negative values, which indicates the possibility of the reaction of interaction of calcium chloride with the sodium sulfate with the formation of NaCl, CaSO₄·0,5H₂O, CaSO₄·2H₂O, MgSO₄, and NaOH. With increasing temperature the thermodynamic probability образования СаЅО₄.2H₂O is reduced due to the decrease of negative values DG_т⁰. During the study, the main content of the sediment, which consists of CaO and SO₄^2-, was determined. The interaction of calcium chloride with sodium sulfate proceeds at a temperature of 95 °C and the degree of decomposition is 96.4%. The contents in the sediment of CaSO₄.0,5H₂O confirmed by XRD and SEM.