Development of the technological process of processing chromium-containing technogenic materials

Abstract

The article is devoted to the development of the technological process for the processing chromium containing technogenic materials, which includes their roasting in the presence of sodium carbonate and the subsequent leaching of chromium from the sinter with water. Using the method of stochastic determinated design of the experiment, a five-factor mathematical model of extracting chromium into a cake was obtained. It is determined that in order to achieve the minimum recovery of chromium in the cake and, accordingly, the most complete isolation of the given metal into the solution, it is necessary to conduct batch roasting under the following conditions: troast. =960 ºС, τroast.= 3h, N = 60 %, and leaching at τleach. =2h and tleach. = 60 ºС. The chemistry of the passing processes is shown. It is shown the usefulness of the obtained mathematical equation for making predictions that are more accurate when introducing the values of the arguments within the given limits of their variation into the given equation and less accurate at a considerable distance from these limits. Calculation in the indicated calcination conditions shows that the recovery of chromium in the solution increases with increasing firing temperature, time of its maintenance and consumption of Na2CO3.