The effect of halite mineral impurities on the technological parameters of the sodium chloride production process

This paper shows the findings of a detailed investigation of the natural halite from the Bakhyt-Tany deposit. The mineral’s composition is sodium chloride with the addition of calcium sulfate, magnesium salts, and some other matters, including a residue of less than 2% insoluble residue. Elemental assaying indicates the occurrence of elements like Ca, Mg, Al, Si, Fe, and Pb, which points to the occurrence of clay and some sulfate impurities. To understand how impurities are distributed in different sizes, a sample was classified using a sieve with a mesh of 0.2 mm. It was discovered that less than twenty per cent of the salt mass is a fine fraction (d < 0.2 mm), where up to 3.4% of insoluble impurities are found, and in the coarse fraction (d > 0.2 mm), this value is less than 1.8%. A mathematical model developed showed that the fine fraction and the total amount of the residue insoluble are directly related, which supports its use for estimating contamination and evaluating the effectiveness of the processes of desalination. Moreover, the generated 3D model revealed that temperature and humidity, in addition to raising the concentration of insoluble impurities, also increase the concentration of such impurities in the fine fraction even more. The results obtained also support the need for the pre-purification of halite before its use in food and other technological applications, and support the statement of the fractionation and desalination based purification process for halite.