Behaviour of macro- and microelements in the process of isothermal evaporation of the industrial sewages of the Nebit-Dag iodine plant

The physicochemical processes taking place during isothermal evaporation (40 deg C) of industrial sewages of the iodine plant are studied. Found is the sequence of salt precipitation: halite, carnallite and tachhydrite. It is shown that in the process of evaporation boron is accumulated in the solution. With the increase of acidity of the brine (up to pH<=1.6) the loss of iodine, mainly, due to its oxidation by ions of trivalent iron and coprecipitation by the organic part of the brine are observed. The main part of strontium is concentrated in the solution and only the small part of strontium is coprecipitated in the form of SrSO4 at the beginning of salt precipitation and in the form of SrCl2 in the final stage of the process. It is found that in the process of concentration acidity increases up to the definite brine point, and at stage of precipitation of magnesium salts it reduces as a consequence of the decrease of relative components of macro and microcomponents in the brine