Study On Desulfurization Of Arsenic Residue By Phosphorus Slag Base Low Temperature Ceramic Cementitious Material

At present, many areas of China are suffering from arsenic contaminations and there is a spreading trend of this phenomenon. Arsenic contamination seriously endangers humans’lives; what’s more, the frequent occurrences of arsenic contaminations generate serious adverse impacts on the community. For example, the Arsenic waste residues generated in the metallurgical industry contain high levels of arsenic, Pb, Zn, Cu, Sn, Cd, Cr, Hg and other heavy metals. Long-term stockpiling not only occupies the land, but also pollutes the soil and water, and thus endangers human’s health. Therefore, effective governances for arsenic-containing wastes have great significance on ecological environment and the sustainable development of metallurgical industry.In this paper, the arsenic residue desulfurization generated from tin smelting process of Yunnan Tin Group was employed as the research object, according to the physical and chemical properties of arsenic residue desulfurization, leaching toxic experiments were used to study the influence factors of arsenic leaching. Based on the cementing material principles, phosphorus slag, fly ash calcium, activation tailings were used as raw materials, proper activators were employed to explore stabilization/solidification process of arsenic residue desulfurization, which provide the basis for the safe disposal of waste containing arsenic. The result shows as follow:(1) According to the leaching toxic experiments, pH, calcium ions, Fe3+ions and silicate make great different on arsenic leaching, while carbonates, sulfates have no significant effect on the concentration of arsenic leaching; Calcium ions, silicate, alkaline environments can inhibit the arsenic leaching, while acidic environments and the presence of Fe3+ions can increase the concentration arsenic leaching.(2) In this thesis, the cementitious material composition systems were determined by the active material content single factor experiments. Based on the impact of the content of each component on the solidified performance during cementitious materials and economic cost, the best ratio of phosphorous slag-based cementitious material system is:phosphorous slag:silicate:mineral activator:high calcium ash: activated tailings=0.65:0.12:0.1:0.05:0.08.(3) The main process parameters which effect solidified performance were investigated and the optimum conditions are:aggregate contents are20%, solidified products are protected under atmospheric pressure steam and chemical admixtures are4.5%sodium silicate. Under this condition, the arsenic residue desulfurization reached a maximum at45%.(4) XRD, SEM and other analytical methods were employed to analysis arsenic residue desulfurization and solidified products. Cementitious materials hydrations react with active ingredient calcium sulfate in arsenic residue desulfurization to generate hydration aluminum silicate, calcium silicate mineral crystal and a lot of amorphous materials. The Arsenic residue desulfurization particle surfaces are rough, uneven and with obvious defects. While solidified products are dense under the wrapping, filling and cementation of hydration products.(5) Based the35,000t/a phosphorus slag-based cementitious material producing projects and45,000t/a arsenic residue desulfurization processing as a standard, the equipment, raw materials and cost during production process were balanced analyzed. The results show that arsenic residue desulfurization solidified by phosphorous slag-based chemically bonded ceramics technology have a significant benefit on society, economy and environment, and have broad application prospects.