Study On The Treatment And Resource Utilization Of Industrial Wastewater Of Wire Rope

Steel wire rope is larger requirement in civil market at present, whose production is four million tons every year. But the pickling section in the course of production will generate a lot of strong acidic wastewater which contains a large concentration of ferrous chloride. However, heavy metal elements zinc and lead in the form of chloride dissolving in the wastewater can confinement the utilization of ferrous chloride. In this paper, complex extraction and precipitation methods were applied to remove heavy metal elements zinc and lead from wastewater of wire rope industries in order to recover the pure ferrous chloride.The forms of metal ions in the wastewater system were analyzed. According to the calculation results, when the concentration of chloride ions in the wastewater was5-6mol/L, lead, zinc and ferrous iron were in the main forms ofZnCl42-,PbCl42-and FeCl+respectively.Complex extraction method was applied to treat heavy metal elements zinc from aqueous phase. Three complexing agents (P204, YP and YA) were selected to serve as extractants of zinc. Certain factors that affecting the treating efficiency such as diluents, pH, extraction time, extraction temperature, initial concentration of zinc, concentration of complexing agents and oil-water ratio (O/W) were discussed. In addition, pH swing effect was also used to study the back extraction of organic phase loaded zinc. The optimized conditions were obtained when under normal temperature, YP whose best concentration was3.5mol/L and methylbenzene were selected as complexing agent and diluent of zinc respectively, the extraction equilibrium time was10min, O/W was1:1, under these condition, extraction rate of zinc from the wastewater system reached more than99%;0.3mol/L NaOH solution was selected as back extractant to recover zinc loading in extractant, and back extraction rate was more than99%.Precipitation was employed to remove lead from the wire rope industries wastewater. Factors affecting on the remove rate of lead, such as precipitator as well as its concentration, pH and temperature were analyzed. Under normal temperature, when Y2selected as precipitator of lead was0.5mol/L, pH of wastewater system was1.0-1.5, the best conditions were obtained, finally remove rate of lead was more than99.5%.After optimization processes of wastewater, content of zinc and lead were both dropped to 10ppm below in the solution system, and the concentration of FeCl2was more than431g/L which achieved processing requirements of related companies and can be used for the production of the purifying agent. Therefore, treatment and resources of wire rope industries wastewater was greatly realized.