Study On Pretreatment Process Of Chrome Tanning Wastewater And Utilization Of Chrome Resources In Tannery Area

This paper studies the feasibility of heavy metal Chromium resource industrialization in tannery industry concentration area,The recovery and utilization of Chromium in Chromium tanning wastewater can not only prevent and control the heavy metal Chromium pollution and protect the environment,but also realize the reuse of Chromium resources in tannery industry,and find a way to regenerate the scarce Chromium resources.It can also bring good economic and social benefits to enterprises.This paper focuses on the demand of heavy metal emission reduction in leather industry.Taking chromic tanning waste water and chromium-containing waste from tannery production in the tannery industry concentration area of Chengbei Industrial Park in zhanhua District,Binzhou City,Shandong Province as the research object,the chromic tanning waste liquid produced by tannery enterprises was collected and preprocessed in the factory area and deposited into chromium-rich sludge by alkali.Taking chromium-rich sludge as the treatment object,the chromic tanning agent was prepared by acid hydrolysis and oxidation reaction,combined with vitamin K₃byproducts,and then returned to the tannery production process,so that heavy metal Chromium can be put into a clean and closed cycle in the tannery industry,and the chromium-rich sludge produced by the specialized and large-scale centralized treatment of tannery plants can be realized.Firstly,the treatment technology of Chromium tanning wastewater in tannery was studied.NaOH precipitation technology was used to pretreat Chromium containing wastewater.After optimization and selection,the pretreatment specification of Chromium tanning wastewater in tannery enterprises was formulated.The Pre-disposal technology of Chromium-rich sludge was studied.Cr rich sludge produced by tannery enterprises is different in form and composition.After recycling,it must be treated before it is purified,so that the form and composition of the sludge produced by different enterprises can be as identical as possible after the preliminary treatment.The front process of Chromium-rich sludge includes the design and selection of treatment equipment and treatment process.The Chromium purification technology in Chromium-rich sludge is studied.The organic matter in Chromium-rich sludge should be degraded and oxidized.The acid and oxidizer were selected and the acid hydrolysis and oxidation conditions were studied.The impurity removal rate and Chromium purity were required.The preparation of base Chromium sulfate with vitamin K₃ oxidation was studied.The Chromium in Chromium rich sludge is purified and combined with the by products?oxidized residue?produced by the production of vitamin K₃.Under certain conditions,the necessary compatibility materials and additives are added to make the Chromium in the sludge and the Chromium in the production of vitamin K₃ all produce the base Chromium sulfate by reaction.The preparation technology of self-alkalized Chromium tanning agent of Monochamus chinensis was studied.In this paper,the alkali Chromium sulfate tanning agent prepared from Chrome-rich sludge of tanning leather was studied.The drying base Chromium sulfate was added with necessary compatibility material and additives.The results of this research can find a solution for the large amount of Chrome-rich sludge produced each year,which can make the waste of Chromium-rich sludge become valuable,and also reduce the amount of Chromium used in industry.It has great social and economic benefits and provides a possible way for Chromium recycling in leather industry.