Treatment And Reuse To The Wastewater With Chromium In The Process Of Leather Making

Worldwide water shortages have the sustainable utilization of water resources and water saving, wastewater will use received great attention. In the leather industry, chrome tanned is widely used in leather making industry tanning method--although at present there are many studies of vegetable tanning agent and no chrome tanning, but in the short term, chrome tanning method cannot be replaced. Direct emissions of chrome tanning waste water is serious environment pollution, and caused the chromium waste of resources, so governments and research institutions to spend a lot of energy to look for alternative to chrome tanning agent, but still can not found comparable to those of chrome tanning tanning sex tanning materials. Research on chromium removal of chromium and the recycling use of technology has great environmental and economic significance.This topic research the xanthate ester, dithiocarbamate, both triazine class three kinds of heavy metal ion trapping agent of chrome tanning waste water at the beginning of chromium and chromium retanning fatliquoring wastewater in addition to the ability. After processing the supernatant recycling to the wet blue tanning washing, pickling process; Chromium mud after reprocessing the preparation of a new liquid chrome tanning agent can instead of some industrial chromium powder, recycling to leather retanning process, so as to achieve the chrome tanning waste water recycling use.Three kinds of heavy metal ions to capture agent at the beginning of chrome tanning wastewater treatment of optimum reaction pH value of 8.5,8.0,8.0, respectively.Chrome tanning waste water processing volume of 200 mL of workshop, under the respective optimum pH, three kinds of heavy metal capture agent the best dosing quantity and total chromium removal rate is respectively:xanthic acid esters, optimal dosing quantity V=6 mL, maximum total chromium removal rate by 95.93%.Dithiocarbamate salts, V=7 mL optimal dosing quantity, total chromium removal rate up to 94.82%.All triazine, optimal dosing quantity V=5 mL, total chromium removal rate up to 95.97%.Chrome retanning wastewater treatment, this study to join ZnSO4 and other metal salts in the late response, not only can improve the removal rate of chromium, also help grease in wastewater, dye, protei and so on organic matter removal.Supernatant of neutral salt water reuse research, with the increase of cycling times, after the wastewater treatment of chlorine ion content, sulfuric acid root ion content, CODCr content, SS content gradually increased, the first three parameters after reaching a certain number of times in the cycle of rising amplitude decreases in balance, sometimes even lower, but the content of SS will always increase, so it needs to be addressed in the large-scale engineering application SS to the influence of the circulating water. Chromium mud should be dried before can be dissolved in acid, not only directly with concentrated sulfuric acid to dissolve, need to add water dilute, because need to use free water soluble chromium mud.Dissolve after chrome tanning agent is used in the retanning, back to use on the out layer, pH control in 2.6-2.8, alkalinity is less than 33%. With sulfuric acid soluble chromium mud, comprehensive consider solubility and subsequent processing difficulty of sulfuric acid and water quality than control at 1:4 dilution;The quality of concentrated sulfuric acid and chromium mud than determined to be 22%;Stir and let stand for 120 min;Reaction temperature at 30℃, this will make the chromium mud dissolved the most thorough, tanning of chrome tanning agent was the best effect.