Method for removing and recovering heavy metal in sludge through electrolytic method

Abstract

The invention discloses a method for removing and recovering heavy metal in sludge through an electrolytic method. The method includes the steps that the water content of the sludge is adjusted to 90%, then the sludge is stirred; a chemical agent is selectively added, stirred and pretreated; an electrolyzer is assembled and stirs the sludge for electrolysis; the heavy metal is recovered finally. The sludge is directly put in an anode region, the sludge is directly acidized with H+ generated through water electrolysis through an anode, acid does not need to be added additionally, secondary pollution is reduced, and the removal rate of the heavy metal is increased. In addition, the sludge is directly put in the anode region, an electrode can make full contact with the sludge, the current efficiency is fully used, and the electrolysis efficiency is high. The action of electrochemical reaction of a cathode and anode is used well, the membrane exchange area between the sludge and electrolyte is increased, the ionic migration distance is reduced, the heavy metal removal rate is high, the electric energy use ratio is large, the problem of heavy metal recovery is improved, the dual purposes of reducing pollution and recovering resources can be achieved, and environment value and economic benefits are achieved.

Description

technical field [0001] The invention belongs to the field of resource utilization of solid waste, and in particular relates to a method for removing and recovering heavy metals in sludge by electrolysis. Background technique [0002] The data show that the Zn content in the sludge produced by my country's urban sewage treatment plants can reach 783.4-3096.3mg / kg (dry weight), Cu can reach 131.2-394.5mg / kg (dry weight), in addition, it also contains some other heavy metals, such as Cd, Cr, Hg, Ni, Pb, etc. The existence of these heavy metals not only seriously affects the subsequent safe disposal of sludge, but also causes a great waste of metal resources. Taking Zn as an example, according to the 2010 urban sludge output of 30 million tons (80% water content), the Zn content is calculated as 1500mg / kg (dry weight), and the Zn content in it reaches 9000 tons. According to the Shanghai Futures Exchange Zn The recent quotation is 15,000 yuan / ton, and the economic value is 135 m...

AI Technical Summary

Problems solved by technology

Due to the advantages of simple operation, stable operation, and not easy to cause secondary pollution, the electrochemical method has attracted much attention. However, traditional electrochemical treatment devices either place the waste between the cathode and anode stages, and add Electrolyte, the current efficiency cannot be fully utilized; or the waste is placed on the anode, but the contact between the electrode and the sludge is not sufficient, resulting in low electrolysis efficiency