PHYSICAL AND CHEMICAL PROCESSES OCCURRING IN THE GRANULATED PHOSPHORUS SLAG DUMPS

Abstract

One of the most dangerous man-made mineral formations located in the territory of Kazakhstan is disposal areas for granulated phosphorus slag, since its shells contain initially the dangerous gases such as PH3, H2S, HF, etc. Permanent sources of such gases are also Ca3P2 (intrinsically poisonous gas), CaS and CaF2. In the structures of phosphorous ash disposal areas, the chemical and physical-chemical processes contain initially gases, which may be in different modifications. For example: • Phosphene (PH3) in the form: PH3→P2O5→HPO3→H3PO4; • Hydrogen sulfide (H2S): H2S→H2SO3→ H2SO4; • Hydrogen fluoride and silicon tetrafluoride: HF→SiF4→H2SiF6→H2SiO3; • Carbon oxide (СО): СО→СО2→СОСl2. Such chemical processes intensify greatly the anthropogenic effect of phosphorous ash disposal areas on the environment – biogeocoenosis. In addition to the processes related to gas components, in the phosphorous ash disposal areas, the hydration processes occur as a result of interaction of slag with water. Thereat, sub-microcrystalline CSH(I) and calcium are generated. Depth of slag hydration reaches 1…3 μm. Such processes form a thin layer on the surface of slag particles resulting in linking of separate grains into a whole. Therefore, the surface of phosphorous ash disposal areas has the certain strength with cracks, through which water, air, snow, etc. are penetrating into the disposal area. It is evident that granulated phosphorus slag in the form of disposal areas has very adverse impact on the biogeocoenosis, causing the pressing need for their disposal; moreover, such slags are valuable raw material for the construction industry and agriculture only after their decontamination from dangerous gases. Keywords. Granular phosphorus slag, dumps, hazardous gases, chemical reactions.