Method for recovering lead from lead paste of waste lead-acid battery

Abstract

The invention relates to a method for recovering lead from lead plaster of waste lead-acid battery, belonging to the recovery treatment technology of the waste lead-acid battery. The method comprises the following steps: carrying out crushing, sorting and rinsing on the waste lead-acid battery by using a special crusher, respectively and independently recovering and utilizing lead or lead alloy grid plate and organic matters, mixing electrolyte, washing liquor and lead paste, placing the mixture into muffle furnace for roasting; carrying out chloridizing leaching on the roasted sand in leachate consisting of sodium chloride, calcium chloride and hydrochloric acid; after chloridizing leaching, carrying out press-filtering, carrying out concentrated treatment on the filter residue, carrying out sharp quenching on the filter liquor to room temperature and standing; after the precipitation is finished, carrying out filtration, returning chloridizing leaching to the filtrate, and obtaining filter residue which is the final product, namely lead chloride. The method is characterized by simple and easy technique, more common and cheaper materials used and equipment, cycle use for chloridizing leaching solution and having no pollution.

Description

technical field [0001] The invention belongs to the recovery and treatment technology of waste lead-acid batteries, in particular to a method for recovering lead in lead paste. Background technique [0002] The scrapped lead-acid batteries are generally collected and processed in a centralized manner. The whole waste lead-acid battery is usually composed of the following four parts: 11%-30% of waste electrolyte, 24%-30% of lead or lead alloy grid, 30%-40% of lead paste, and 22%-30% of organic matter. Among them, the grid is mainly composed of lead and alloys, which can be recycled independently; organic matter such as polypropylene plastic can be recycled as a by-product; lead paste is mainly a slurry-like substance formed after the active material on the plate is charged and discharged: PbSO 4 (about 50%), PbO 2 (about 28%), PbO (about 9%), Pb (about 4%), etc., and may also contain a small amount of Sb (about 0.5%). Since lead paste contains a large amount of sulfate and...

AI Technical Summary

Problems solved by technology

The wet process can be roughly divided into the following types: one is lead paste conversion-leaching-electrolysis method, through desulfurization conversion, lead sulfate and lead oxide are dissolved in acid (or alkali) solution to make lead salt electrolyte, after Generate lead powder after electrolytic deposition, (U.S. Patent US4107007, US4597841 and Chinese patent CN1038505A), but lead paste pretreatment trouble, side reaction is many, energy consumption is big, electrolysis time is long and production cost is high; The 2nd, lead paste direct electrolysis method, Also known as the solid-phase electrolytic reduction method (Chinese published patents 02132647.9, 20071066005.4 and German patent DE3402338A), but due to the limitation of the solubility of lead sulfate in dilute sulfuric acid, the current density is small, the tank pressure is high, and the energy consumption is large, which also limits the industry. Popularization and application; the third is the direct leaching of lead paste-electrolysis method, the lead paste is leached by hot HCl-NaCl solution to generate soluble PbCl 2 solution, after purification, lead is electrolytically deposited, but PbCl 2 It is only dissolved in hot HCl-NaCl solution, and it is easy to precipitate due to temperature drop. At the same time, because it must be in an acidic environment, the electrolysis efficiency is low, and there is a problem of large energy consumption for electrolytic deposition of lead; the fourth is to use chemical methods to dispose of waste lead The material is transformed into some industrial products of lead, such as red lead powder, yellow lead powder, tribasic lead sulfate, etc. , high production costs and impure products

The pyro-wet method combined recovery, represented by Hubei Jinyang Metallurgical Co., Ltd., after desulfurization and conversion, is smelted with oxygen-enriched combustion in a closed rotary short kiln, which also has the disadvantages of the pyro-hydro recovery method