Development of Technology of Utilization of Products of Ferritization Processing of Galvanic Waste in the Composition of Alkaline Cements

Abstract

A study of the products of ferritization processing of galvanic waste: sludge and spent process solutions is carried out. As a result of experiments on dynamic leaching of heavy metal ions, the immobilization properties of the sludge, obtained at different process parameters of ferritization are determined. It is shown that the level of immobilization of heavy metals in ferrite sludge after leaching is 99.96 wt % and in the sludge of traditional wastewater neutralization <97.83 wt %. The studies determine the possibility of reliable utilization of ferritized galvanic waste – introduction into the charge to produce alkaline cements. It is found that the main crystalline phases in the structure of alkaline cements with ferrite sludge are calcite, quartz and heavy metal ferrites. In addition, jelly-like formations are found, which are further capable of crystallization. Such formations reliably bind heavy metals in the chemical structure of cement. It is found that when using up to 10 wt % of ferrite sludge in the total weight of cement, the compressive strength of artificial stone reaches 40 MPa, which meets the requirements of the current standard. The chemical stability of the alkali cement matrix using ferrite sludge is confirmed by the study of leaching of heavy metals for one day in neutral, alkaline and acidic media. It is shown that the degree of immobilization of heavy metal ions in cement with a ferrite sludge content of 30 wt % is >99.98 %. In addition, the concentrations of heavy metal ions during leaching meet the national and international standards for their MPC in drinking water and soil. This approach will allow solving the problem of utilization of hazardous galvanic waste and production of general construction materials.