Study On Removal And Reuse Of Chromium Recycling Solution

Ion exchange method, which has been successfully applied to chromium-containing wastewater recycling, is currently one of the most effective methods to control pollution and recover precious metals. In order to maximize the benefits of Chromium recycling, there are two main problems we need to solve:Firstly, the sodium ion concentration is high in the chromium recovery solution, and part of sodium ions will be necessary to remove; Secondly, to determine how much sodium ion concentration can affect the quality of decorative chromium plating. According to the actual production and research status at home and abroad, cation resins are used to remove sodium ions, the process of sodium removal are studied, and the sodium ion concentration gradient of chromium bath tank experiments are conducted. Conclusions are as follows:Part1:Conditions of sodium removal process(1)Selection of the resin. Using nine kinds of cationic resin do static experiments under the same conditions screening out two kind of sodium removal resins:D and G.(2)Regeneration Conditions. Based on the static experiments of cationic resin, resin D’s regeneration process conditions are obtained. When the concentration of sulfuric acid is10%, regeneration9h,3:1as the regeneration of volume ratio between10%sulfuric acid and resin, more than98%of resin regeneration degree can be reached.(3)Dynamic test. With the method of downstream feed-countercurrent regeneration, rinse water consumption for three times the size of resin, the optimum feed flow for Q=12ml/min.Part2:Influence of sodium ion concentration on the plating quality(1)Removal of impurities in sodium removal solution. This experiment adopts the way of evaporation concentration recycle sodium-free liquid recycle to the plating tank, remove the impurities, showed that chromium recovery liquid sodium off after the return to the plating tank is completely feasible.(2)Effect of sodium ions on the plating quality. The high concentration of sodium ions not only causes the loose chromium layer, poor corrosion resistance, but also leads to adverse reactions in the low zone, impede the precipitation of chromium, and seriously affect the appearance and quality of the product. Experimental results show that when the concentration of sodium ion in decorative chromium plating tank is not higher than5.8g/L, the bath electroplating performance can meet the requirements of electroplating produce.