A method for comprehensive recovery of multiple valuable metals from electroplating sludge

Abstract

The invention discloses a method for comprehensively recycling multiple valuable metals from electroplating sludge. According to an existing adopted chemical method for treating electroplating sludge, the treating cost stays at a high level, and moreover a large amount of industrial wastewater needing to be subjected to secondary treating is produced. According to the adopted technical scheme, the method for comprehensively recycling the multiple valuable metals from the electroplating sludge comprises the processes of oxidation slurrying, P204 saponification leaching, nickel anode electrolyte complete back extraction, iron back extraction and hydrochloric acid regeneration, copper extraction electrodeposition, chromium deposition, P204 nickel saponification, P204 zinc extraction electrodeposition, nickel electrodeposition, calcium-nickel separation, magnesium-calcium separation and industrial circulating water treating. The problem that a large amount of water of the electroplating sludge enters a system in the process that the valuable metals are recycled from the electroplating sludge through the chemical method is solved, the valuable metals in the electroplating sludge enter organic phases through saponification leaching, and the self-carried water of the electroplating sludge is blocked outside the system.

Description

technical field [0001] The invention relates to the field of nonferrous metal hydrometallurgy, in particular to a method for comprehensively recovering various valuable metals such as nickel, copper, zinc, iron, chromium, magnesium, calcium, and the like from electroplating sludge by utilizing the characteristics of metal ions and extractants themselves. Background technique [0002] According to the different conditions of electroplating wastewater treatment, electroplating sludge is mainly divided into chromium sludge and non-chromium sludge. The former contains hydroxides of iron, zinc, nickel, copper and other metals in addition to chromium, while the latter It does not contain chromium, and its main components are hydroxides of metals such as iron, zinc, nickel, and copper. However, in fact, most of the wastewater from electroplating small enterprises is composed of chromium-based sludge and non-chromium-based sludge after treatment. Composed of mixed sludge, the curren...

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Problems solved by technology

[0007] The current chemical methods used to treat electroplating sludge fail to effectively solve the problem of water expansion brought into the system by the electroplating sludge itself. During the treatment process, the volume of the system is unbalanced, and a large amount of alkali is used to precipitate excess heavy metals. solution, not only the high cost of treatment, but also the formation of a large amount of industrial wastewater that requires secondary treatment

[0008] The current chemical method used to treat electroplating sludge uses sodium alkali as an organic saponification agent in the process of solvent extraction, and a large amount of sodium ions will enter the solution system, which is an enrichment process in the solution system. It will make the solution more and more viscous, affect the fluidity, and then affect the entire production process, especially the solvent extraction process

[0009] The current chemical methods used to treat electroplating sludge all use neutralization precipitation method, goethite method and yellow sodium (potassium, ammonium) ferrosite method to remove impurities such as iron and aluminum. During the process of removing these impurities, they will form Iron slag, causing secondary pollution

[0010] The current chemical method used to treat electroplating sludge, because the neutralizer, precipitant, saponification agent, etc. used in the system are all sodium alkali or ammonia alkali, resulting in a large amount of sodium ions or ammonia ions in the solution, if not used It is difficult to recycle industrial wastewater by evaporation and crystallization; however, the energy consumption of industrial wastewater treatment by evaporation and crystallization is very high

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