Low-temperature method for desiliconization of polymetallic slags by ammonium bifluoride solution

Throughout the period of operation of non-ferrous metal deposits, a significant amount of waste has been accumulated. The accumulated waste contains valuable metals in concentrations that allow considering them as valuable raw materials. However, it is worth noticing the presence of problems that previously did not allow for more complete extraction of the target components. Such problems include the presence of significant amounts of silicon dioxide in the form of a silicate matrix, the removal of which will allow the extraction of valuable components with the elimination of industrial waste areas. The paper considers a method for removing silicon from the polymetallic slags. According to the results of the work, it was found that silicon passes into solution in the form of ammonium hexafluorosilicate. Iron, aluminum, and a number of other components react with ammonium hydrofluoride, but do not leach into the solution due to their low solubility in the resulting system. After removing silicon, the solid residue was subjected to pyrohydrolysis to obtain a product that can be subjected to magnetic separation to obtain a magnetic iron concentrate and a non-ferrous metal concentrate. The formed concentrate can later be used to extract zinc, lead, silver, etc. The productive solution was directed to the deposition of silicon with the subsequent production of silicon dioxide. The resulting solution can be directed to evaporation in order to regenerate and reuse ammonium hydrodifluoride.