Combined method for electrolyzing and recovering lead

Abstract

The invention provides a method for electrolyzing and recovering lead from lead plaster, which comprises the following steps: 1) washing the lead plaster by deionized water and performing solid-liquid separation to obtain a mixture of lead sulphate, lead and lead dioxide as well as a dilute sulphuric acid solution; 2) reacting the solution and excessive NaOH solution, and performing a second solid-liquid separation to obtain a mixed solution containing Na2[Pb(OH)4] and sodium hydroxide, and a solid mixture containing Pb and PbO2; 3) performing phase-divided electrolysis containing a constant current electrolytic phase and a constant voltage electrolytic phase to the mixed solution composed of Na2[Pb(OH)4] and sodium hydroxide in an ion-exchange membrane electrolyzer for recovering pure lead; and 4) electrolyzing a mixture of lead and lead dioxide by constant current controlled by using two-phase voltage, and combining electrolytic deposition to recover pure lead. The combined method for electrolyzing and recovering lead is capable of substantially minimizing the recovery of reducing agent, alkaline matter and lead consumed by electric energy, and raising purity of the recovered lead.

Description

technical field [0001] The invention belongs to the technical field of lead recovery by electrolysis. The invention relates to a method for recovering lead from waste battery lead paste by electrolysis. The method pretreats and separates the lead substance in the waste battery lead paste and the compounds containing lead in different valence states, and then according to the lead Different valence states adopt different electrolysis methods for joint electrolysis to realize the recovery of high-purity metallic lead. Background technique [0002] The regeneration and recycling of resources is the key to the sustainable development of human society and an important way to reduce environmental pollution. Lead-acid battery, as a battery with cheap price, mature technology and stable performance, has been widely used in electric vehicles, automobiles and energy storage power sources since it was invented by Plante in France in 1859. Although lead-acid batteries are facing compe...

AI Technical Summary

Problems solved by technology

[0007] Although the advantage of this type of process is that it can directly obtain electrolytic lead, the serious shortcomings of this type of process itself have seriously restricted the industrial application of these processes, and the described shortcomings generally include the following points:

[0008] 1. The pre-redox reaction process takes a long time and consumes a lot of Pb, Fe and SO 2 Such reducing agents and sulfuric acid not only increase the cost of this step, but also increase the processing cost of subsequent alkaline desulfurization;

[0009] 2. The power consumption is relatively high. The voltage of the electrolyzer in the electrolysis process is 2.7-3.2V, and the energy consumption per ton of lead is generally about 700-950KWh;

[0010] 3. There is a relatively high concentration of lead ions remaining in the pre-oxidation reduction process and electrolytic waste liquid, which is not only highly corrosive to equipment, but also highly toxic to the environment;

[0011] 4. A large amount of lead dioxide by-products are precipitated during the electrolysis process of the anode, which reduces the recovery efficiency of lead and leads to a large load of secondary reduction treatment

[0021] 1. In the pretreatment step of lead recovery, it is often necessary to consume a large amount of reducing agent and a large amount of alkaline substances to desulfurize the sulfur-containing compounds in lead, which greatly increases the process cost; and

[0022] 2. The lead recovery process still consumes a lot of electricity

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