Use of Expanded Clay for the Treatment of Acidic Wastewater from Mining Enterprises

The extraction of non-ferrous metals such as copper, zinc, and gold leads to the production of a huge amount of processing waste. The danger to the environment posed by mining and metallurgical enterprises processing copper pyrite ores lies in the pollution of surface water bodies with technogenic acidic wastewater. When purifying acidic wastewater from heavy metals, sorption technologies play a pivotal role and their development requires new types of sorbents. Expanded clay, a lightweight porous material that looks like granules with a burnt brown–red surface and dark pores inside, is chosen for the study. This article discusses the composition of expanded clay and the results of research on its sorption capacity at various temperatures under static conditions. In dynamic mode, data on the effect of filtration speed on cleaning effectiveness are obtained. It has been established that the effectiveness of wastewater treatment when using expanded clay varies from 70 to 90% under static conditions and from 3 to 85% under dynamic conditions, depending on the nature of metal cations in the effluent, sorbate temperature, and filtration rate. A recommendation for the use of expanded clay as part of a composite sorbent is given.