VOLATILITY OF CHEMICAL ELEMENTS DURING THE DEHYDRATION OF SECONDARY SULFATES

Abstract

The relevance. Air pollution due to the activities of the mining and metallurgical industries is a serious problem for the environment. This study was conducted to determine the possible mechanisms of migration and the sources of elements in the atmosphere above the surface of tailings. The main aim of the research is to show that chemical elements can be trapped by the water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. Object: samples from the surface of the Belovo waste heaps (Belovo zinc processing plant, Belovo, Russia). Methods. Powder X-ray diffractometry (XRD) was used to determine the phase compositions of the crystalline substances, their quantitative phase relationships and transformations. An Agilent 8800 ICP-MS instrument (Tokyo, Japan), equipped with a MicroMist nebulizer, was used to determine the elements in the water samples (pore solution and condensates). Also, we used binocular microscope and physicochemical modeling methods. Results. By analyzing the condensates, it was determined that a wide range of chemical elements can migrate with vapor-gas streams from secondary hydrous sulfates under relatively low-temperature conditions (60 °C). Condensate from the wet sample contains high element concentrations due to the input of elements from the pore solution and hydrous sulfates. Alterations in mineral structure and water release are indicated by losses of sample weight. With dehydration, cations and trace elements can be extracted from the crystal lattice, replaced by protons, and can then enter the vapor-gas phase when the solution evaporates.

Keywords

• secondary sulfates
• pore solution
• condensates
• mine tailings
• volatility of chemical elements