Study On The Treatment Of Arsenic-alkali Residue By Water Leaching-catalytic Air Oxidation Technology

Arsenic-alkali residue is a typical solid waste produced by antimony smelting system.In addition to arsenic,it also contains a large number of antimony and alkali,which has high economic value.However,due to the similar properties of arsenic and antimony,and the high disposal cost,it is difficult to comprehensively utilize arsenic-alkali residue.As a result,arsenic-alkali residue is still mainly disposed in the form of storage,which not only causes a lot of waste of resources,but also brings heavy environmental risks to enterprises.Therefore,the research on comprehensive utilization of arsenic-alkali residue has important practical significance for the sustainable development of antimony industry in China.Based on the material characteristics of arsenic-alkali residue,this paper proposes the use of water leaching-catalytic air oxidation technology to treat arsenic-alkali residue.By means of the systematic characterization of solution composition and residue,the leaching law of arsenic-alkali residue in aqueous solution was found out,and the optimal conditions for the preliminary separation of arsenic and antimony are obtained.On this basis,carry out the selection and preparation of catalysts that have a catalytic effect on As(?)and Sb(?)in the air oxidation leaching solution,explore the reaction law of catalyzing air oxidation and separation of arsenic and antimony,and obtain the best reaction conditions to achieve arsenic The deep separation of antimony lays the foundation for the subsequent recovery of arsenic and alkali.Through systematic experimental research,the following conclusions are obtained :The results of water leaching test showed that temperature and time had significant effects on the leaching and separation of arsenic and antimony.The optimal leaching conditions obtained in the experiment were as follows : leaching temperature was 90 ?,leaching time was 5 h,leaching liquid-solid ratio was 3:1,and stirring speed was 300 rpm.Under the optimal experimental conditions,the leaching rate of arsenic in arsenic-alkali residue can reach 97.96 %,while the leaching rate of antimony is less than 0.7 %.The arsenic content in leaching residue is only 0.09 %,while the antimony content is 59.70 %,which is higher than that in arsenic-alkali residue.It is further confirmed that the initial separation of arsenic and antimony can be achieved by water leaching.The results of catalytic air oxidation test showed that the introduction of manganese salt into the reaction system could effectively accelerate the oxidation of As(?)by air,and this catalytic effect was derived from the new ecological manganese dioxide.Further experimental studies showed that the amount of catalyst and the initial pH of solution had significant effects on As(?)in the leaching solution by air oxidation.The optimal catalytic oxidation conditions were as follows : the molar ratio of As/Mn was 12.74:1,the initial pH of the solution was 13.40,the stirring speed was 300 rpm,and the air flow rate was 1.0 L / min.Under these conditions,the As(?)in the leaching solution could be completely oxidized after 2 h of reaction;the antimony precipitation rate can reach 80%,and the deep separation of arsenic and antimony have been realized.In addition,the oxidation rate of As(?)can be further accelerated by changing the oxidant from air to pure oxygen,and the time required for complete oxidation is reduced from 2 h to 1.25 h.