CN102367578B - Combined method for electrolyzing and recovering lead - Google Patents
Combined method for electrolyzing and recovering lead Download PDFInfo
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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
The invention belongs to by electrolytic process and reclaim plumbous technical field.The present invention relates to a kind ofly from refuse battery lead plaster, by electrolytic process, reclaim plumbous method, described method is carried out pre-treatment with separated by the plumbous simple substance in refuse battery lead plaster with the compound containing different valence state lead, and according to plumbous different valence state, adopts different electrolysis processs to carry out co-electrolysis to realize the recovery of high pure metal lead subsequently.
Background technology
The regeneration of resource and recycle are the keys of human social, are also the important channels of reducing environmental pollution.Lead-acid cell, as the store battery of a kind of low price, technology maturation and stable performance, since special invention, has been obtained at aspects such as power truck, automobile and accumulation power supplies widely and has used by French Pulan from 1859.Although lead-acid cell is faced with the competition of lithium ion battery and nickel metal hydride battery in recent years, there is 160 years historical lead-acid celies and still occupied the more than 55% market volume in the whole world, and its output value along with the vigorous and lead-acid cell of automobile demand self improvement and grow steadily.According to statistics, 86% (8,100,000 tons) of the annual lead bullion output in the whole world are used in the manufacturing processed of lead-acid cell.The stable development of lead-acid cell has caused the in short supply of global lead resource, and the high efficiente callback that how to realize discarded lead-acid cell is the Basic Ways that realizes lead resource recycling and reduce lead-acid cell environmental pollution.
Lead acid cell is to consist of plumbous negative pole and plumbic oxide positive pole.In discharge process, there is redox reaction in the lead of negative pole and anodal plumbic oxide, change lead sulfate under sulfuric acid exists.Positive and negative electrode inside also remains unreacted lead and plumbic oxide simultaneously.In discarded lead-acid cell, because anode plate grid is for a long time in the charging state of oxidation, make the lead of electrode pad be oxidized to plumbic oxide and lead sulfate, lose the supporting role to lead plaster simultaneously, cause anodal softening and make battery failure.Therefore,, in the lead-acid cell of scrapping, not only exist and derive from Pb, the PbSO in lead plaster
4, PbO and PbO
2, also have the lead compound producing from the metallic lead corrosion on grid and lug.The composition that these are complicated, has aggravated the difficulty of plumbous removal process.
Since nearly half a century, people mainly adopt pyrometallurgical smelting to reclaim the lead in lead-acid cell.Due at high temperature easily volatilization or oxidation of lead, therefore in pyrometallurgical smelting process, easily produce a large amount of leaded dust, sulfurous gas and lead containing sludge, this has not only reduced plumbous organic efficiency, and causes serious secondary lead to pollute to environment.Through people, update, the most successful pyrometallurgical smelting technology can realize 90% lead recovery at present.However, the drawback that hydrometallurgy can avoid pyrometallurgical smelting to bring to a great extent, this causes the interest of Many researchers.
How to adopt a kind of secondary lead method of effective clean and effective the compound in lead plaster is effectively reduced and obtain the difficult point that pure metallic lead becomes secondary lead technique.Lead compound in waste lead acid battery forms complicated, and the composition between each battery is not identical with ratio yet.In order to simplify secondary lead technique, the patent of the plumbous aspect of the wet reclamation of current report is carried out the processing of preoxidation reduction reaction to lead plaster conventionally in advance, so that the various lead-containing compounds unifications in waste lead acid battery are converted into PbSO
4; Carry out subsequently desulphurization reaction and obtain PbCO
3or PbO; And then recycling fluorine boron (silicon) acid or tartaric acid solution dissolve and obtain solubility lead salt; And final electrolysis solubility lead salt reduces and obtains lead.
Aspect solubility lead salt, wherein representational secondary lead technique is the electrolysis process of acid fluorine boron (silicon) acid solution.Owing to often occurring excessive plumbic oxide in discarded lead-acid cell, investigator has invented respectively and adopt to have added lead powder, sulfurous gas, iron powder, ferrous ion, and even hydrogen peroxide reduces excessive plumbic oxide in lead plaster and obtains the method for lead sulfate in sulfuric acid medium.The object of this preoxidation reduction conversion process is to make lead and plumbic oxide in material all be converted into fully PbSO
4.Subsequently, investigators adopt respectively sodium hydroxide, sodium carbonate, volatile salt or ammoniacal liquor to obtain Pb (OH) as there is desulphurization reaction between alkaline sweetening agent and lead sulfate
2, PbO or PbCO
3.These compounds can be dissolved in HBF
4or H
2siF
6in obtain the sour mixing solutions of fluorine boron (silicon) lead plumbate-fluorine boron (silicon).This mixing solutions of electrolysis can obtain galvanic deposit lead at negative electrode, anode obtains oxygen, the a small amount of plumbic oxide of while by-product, specifically can be with reference to USBM technique (the Journal of Metals of report in 1985,1985,37 (2): 79-83), the US Patent No. .Patent 4769116[P of Italian Engitec company] and the Italian Ginatta US.Patent 4451340[P of house journal].
Although the advantage of this this class technique is directly to obtain electrolytic lead, this class technique is from itself existing serious shortcoming seriously to restrict the industrial applications of these techniques, described shortcoming comprise substantially following some:
1, preoxidation reduction reaction process is consuming time longer, consumes a large amount of Pb, Fe and SO simultaneously
2in reductive agent and sulfuric acid, not only increased the cost of this step, and increased the processing cost of follow-up alkaline desulfurization;
2, power consumption is relatively high, and the electrolyzer of electrolytic process is pressed as 2.7-3.2V, and the energy consumption of lead per ton is generally about 700-950KWh;
3, in preoxidation reduction process and electrolysis waste solution, remain the lead ion of higher concentration, this not only has larger corrodibility to equipment, and larger to the murder by poisoning of environment;
4, anode is followed and is separated out a large amount of plumbic oxide by products in electrolytic process, has reduced plumbous organic efficiency, and it is very large to cause secondary reduction to process load.
For above shortcoming, some researchs adopt Seignette salts or citric acid to come electrolysis process that plumbous compound is dissolved in complexing to overcome the shortcoming of fluoroboric acid.For example, " Chen Weiping, a kind of new technology [J] of hydrometallurgic recovery waste lead accumulator filler. Hunan University's journal, 1996,23 (6): 111-116 ".But equally also there is the problems such as the higher and a large amount of plumbic oxide of anode by-product of the energy consumption of electrolytic process in this technique.
In order to reduce, adopt necessary preoxidation reduction conversion process in solubility lead salt electrolysis process, and overcome the problems such as anode plumbic oxide by product that dissoluble lead ion produces at anode discharge, investigator has invented directly the lead plaster of lead-acid cell has been coated in to the wet processing that carries out catholyte reduction on pole plate simultaneously.For example, the German Patent of 1985 (DE3402338A) and English Patent (GB 1368423 and GB1428957) have in succession been reported lead plaster have been fixed on a metallic cathode, then in dilution heat of sulfuric acid, carried out the method that electrolytic reduction obtains lead powder and sulfuric acid.Chinese patent ZL200710157084.X subsequently (a kind of method of electrolytic reduction regenerating waste lead acid accumulator containing lead plaster slob mid lead resource) and Chinese patent ZL2008101114308.3 (acid wet method electrolysis reclaims the method for waste lead acid battery accumulator cell lead) further improve reduction rate and the reduction efficiency of lead sulfate by the combined action of semicontinuous electrolysis or dual power supply and activator, realized the direct-reduction of lead-acid cell lead plaster and reclaimed the sulfuric acid up to 30% electrolytic process by-product.
The advantage of this acid Solid phase electrolysis method is to obtain lead powder and sulfuric acid by Direct Electrolysis, but it carries out its electrolytic process and need to, up to single groove electrolysis voltage of 2.9-3.1V, make the electrolysis energy consumption that causes lead per ton of electrolytic process up to more than 920KWh/t (Pb) in acidic solution.The powdered metallic lead of high-ratio surface is also the Another reason that affects its application in the oxidational losses of fusion process in addition.
The high power consumption bringing due to high theoretical electrolysis voltage in order to reduce acid Solid phase electrolysis, some investigators have invented and lead plaster have been carried out to the plumbous technology of wet reclamation that direct solid phase reduction obtains lead powder in alkaline process medium.Representational technique for example Chinese patent CN88103531 and and pertinent literature " new technology of Solid phase electrolysis method-a kind of secondary lead [J]. nonferrous metal and utilization, 2005, (12): 16-17 " report secondary lead technique.After the further improved patent of scientific research person also comprise: 2002 report Chinese patent CN02132647.9 and the Chinese invention patent (ZL200910024467.9) of Lei Li rising sun seminar of Southeast China University.Above-mentioned this characteristic feature of an invention be the positive and negative pole lead paste that first battery crushing obtained directly and water grind, make it to become the sticking paste of tool, then be coated in again on wire netting or metal frame electrode and make negative electrode, then adopting stainless steel electrode is anode, and adopting sodium hydroxide solution is that electrolytic solution carries out constant-current electrolysis.Some patent has reported that the variation of employing constant pressure type Faradaic current carrys out the terminal of auxiliary judgment electrolysis.Alkalescence Solid phase electrolysis method has reduced the voltage of electrolytic process to a great extent, thereby has saved to a certain extent electrolysis energy consumption.
In recent years some patents have been improved some shortcomings that early stage alkalescence is coated with cream on this basis.For example proposed to adopt the rectangular frame with grid structure as negative electrode, thereby improved the cream amount that is coated with, and adopted the mode of constant-potential electrolysis and the variation of constant-potential electrolysis process electric current to control the terminal of electrolysis.The advantage of the method be in large increase single operation carry plumbous amount, thereby reduced to a certain extent hand labor, its shortcoming is the lead plaster complicated component of each batch of material, thereby the impedance between each batch of negative electrode differs greatly, cause in actual electrolytic process curent change remarkable, the 15-35% that is difficult to drop to according to the Faradaic current with a certain particular batch peak point current judges electrolysis terminal, thereby often has a large amount of lead compounds that thoroughly do not reduce in actual product.In addition because constant-potential electrolysis has the advantages that Faradaic current floats and changes according to activity substance content and pole plate impedance, cause electrolysis actual current in mid-term very large, make a big chunk voltage loss in the internal resistance of polarization of electrode and solution, this makes the method actual power consumption very uneconomical, conventionally also up to 547-880 degree electricity.
That during nearest distinctive work also comprises, mentions passes through the separated positive/negative plate of mechanical means, then in electrolytic solution, carries out the method that electrolysis obtains plumbous and lead dioxide powder.Because the just as easy as rolling off a log expansion of lead-acid cell is softening, thereby the method is to the sorting of the softening positive plate that expands particularly difficulty.Due to lead and the lead dioxide powder of this explained hereafter equivalent, cause the organic efficiency of actual metal lead to only have 50%.
Contriver finds in analyzing lead plaster composition, and the lead sulfate the lead plaster obtaining from waste lead acid battery only accounts for the 35-45% of lead plaster gross weight conventionally, and lead powder and plumbic oxide are respectively 15-25% and 30-40%.The content of plumbous oxide is less.In existing electrolytic process, investigator, for the facility of electrolysis, carries out preoxidation reduction reaction by lead and plumbic oxide in sulfuric acid, makes Pb and PbO wherein
2and H
2sO
4reaction generates PbSO
4.Often due to PbO
2content higher than the content of Pb, people also usually additionally add a certain amount of reductive agent (as Fe, SO
2and Pb) make PbO wherein
2be reduced to PbSO
4, this process not only needs to consume a large amount of reductive agents and sulfuric acid, and corresponding device resource, increases a large amount of extra NaOH also to follow-up sweetening process simultaneously and consumes the PbSO that this part newly increases
4.Add existing electrolysis solubility lead salt and prepare the power consumption up to 600-1000 KWh/ton in secondary lead process, the level far above existing pyrogenic process plumbous 550 degree per ton, causes industrial prospect remote.
In alkaline Solid phase electrolysis process, although although alkaline electrolyte can reduce the energy consumption of electrolytic process to a certain extent, but in fact due to the restriction of existing processing condition, fail the different compounds in lead plaster to carry out selectively electrolysis, but adopt the electrolysis mode of single high cathodic polarization, the actual groove of electrolytic process is pressed also up to 1.9-2.6V, the energy consumption of secondary lead per ton is also up to 550-880 degree electricity, add the discontinuous mechanized operation of alkaline solid phase painting cream method, the difficulty that has caused actual industrialization to produce.
In sum, still mainly there is following shortcoming in existing plumbous recovery technology:
1, in the pre-treatment step reclaiming at lead, often need to consume a large amount of reductive agents and need a large amount of alkaline matters to carry out desulfurization to the sulfocompound in lead, this has greatly increased process costs; With
2, plumbous removal process still needs to consume a large amount of electric energy.
Summary of the invention
An object of the present invention is to provide a kind of method that lead that can significantly reduce reductive agent, alkaline matter and power consumption reclaims, described method is carried out selectivity pre-separation by plumbous simple substance in scrap lead with containing the compound of different valence state lead, and according to plumbous different valence state, adopts different electrolysis processs to carry out co-electrolysis to realize the recovery of high pure metal lead subsequently.
According to an aspect of the present invention, the invention provides a kind of from lead plaster the method for electrolytic recovery lead, comprise: (1) with deionized water wash and carry out solid-liquid separation, obtains the mixture and the dilution heat of sulfuric acid that contain lead sulfate, lead and plumbic oxide by described lead plaster; (2) described solution reacted and carries out solid-liquid separation for the second time with excessive NaOH solution, obtaining containing Na
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide, and contain Pb and PbO
2solid mixture; By the described Na that contains
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide at ion-exchange membrane electrolyzer, comprise constant-current electrolysis stage and constant-potential electrolysis stage electrolysis stage by stage to reclaim pure lead; (4) mixture of described lead and plumbic oxide is adopted constant-current electrolysis the combination plating formula galvanic deposit refining process that two stage voltage are controlled reclaim pure lead.
Due to Na
2[Pb (OH)
4] and PbO between be the molar relationship of 1: 1, therefore for convenience of description, this patent is narrated below part and is directly adopted PbO concentration to carry out the PbO concentration of dissolving in equivalently represented solution.
In one embodiment, the concentration of described excessive sodium hydrate solution is 2 to 15mol/L, preferred 3-9mol/L, and described reaction is at 20 to 120 ℃, preferably at the temperature of 45 to 105 ℃, carries out.
In one embodiment, the condition of described constant-current electrolysis is: 60 to 120 ℃ of electrolyte temperatures; Cathode current density 50 is to 3500A/m
2; Anodic current density 400 is to 5000A/m
2; Ionic membrane apparent current density 100 is to 4500A/m
2; And
The condition of described constant-potential electrolysis is: electrolyte temperature is 40 to 115 ℃, and the plumbous oxide concentration in electrolytic solution is greater than 5g/L; In this electrolyzer, the plumbous oxide concentration of electrolytic solution is reduced to 5g/L when following, adopt constant voltage voltage to proceed electrolysis, it is 1.0 to 2.0V that the groove of controlling constant-potential electrolysis is pressed, and the constant-potential electrolysis time is 100 to 1200min, the concentration 0.2g/L of plumbous oxide or when following in solution, stops electrolysis.
In one embodiment, the condition of described constant-current electrolysis is: 65 to 105 ℃ of electrolyte temperatures; Cathode current density 300 is to 1000A/m
2; Anodic current density 500 is to 4000A/m
2; Ionic membrane apparent current density 300 is to 4500A/m
2; And
The condition of described constant-potential electrolysis is: electrolyte temperature is 65 to 105 ℃, and the voltage of constant-potential electrolysis is between 1.35 to 1.95V.
In one embodiment, described electrolysis stage by stage is sequentially carried out in constant current mode cationic membrane electrolyzer and constant pressure type cationic membrane electrolyzer, or sequentially carries out in same cationic membrane electrolyzer.
In one embodiment, the constant-current electrolysis that described two stage voltage are controlled also comprises in conjunction with galvanic deposit refining process: (1) adopts constant-current electrolysis pattern, under 0.3 to 1.2V voltage, in 0.5 to 8.5M sodium hydroxide solution, make the plumbic oxide in described mixture be reduced to plumbous oxide; (2) voltage is adjusted into 1.2 to 1.9V, continues electrolysis so that described plumbous oxide is reduced to lead; (3) lead reduction being obtained is electroplated formula galvanic deposit refining process with together with lead in described mixture, and the current density of controlling galvanic deposit refining process is 50 to 3500A/m
2, preferably current density is 100 to 1200A/m
2, corresponding electrolysis voltage is between 0.02 to 0.09V, at negative electrode, obtains pure lead.
Lead recovery method of the present invention can significantly reduce reductive agent, alkaline matter and power consumption, and the lead reclaiming has more than 98% purity.In addition, lead recovery method technique of the present invention is carried out continuously and cyclically, can meet industrialized requirement.
Accompanying drawing explanation
Fig. 1 is the schema of an embodiment of the inventive method; And
Fig. 2 is the schematic diagram of the inventive method ion-exchange membrane electrolyzer used.
Embodiment
Hereinafter carry out with reference to the accompanying drawings to describe in more detail illustrative embodiments.Described accompanying drawing is used for illustrating the present invention, but not is limited.
The inventor finds, owing to containing PbSO in lead plaster
4, PbO
2plumbous with PbO and simple substance.Because simple substance lead does not need to participate in electrochemical reaction, therefore in actual process, only consider the plumbous reduction of its excess-three kind different valence state.Every kind of material all has own specific reduction potential, for example, and PbSO
4, PbO
2be respectively with the reduction potential of these three kinds of compounds of PbO:
PbSO
4+2e＝Pb+SO
4 2- E
0＝-0.355V
PbO+2e+H
2O＝Pb+2OH
- E
0＝-0.578V
PbO
2+2e+H
2O＝PbO+2OH
- E
0＝0.248V
Known according to electropotential data, above-mentioned three kinds of compounds are in identical electrolysis pendular ring border, and the most easily that reduction is PbO
2, and the PbO of difficult reduction.That is to say, for the PbO in component
2, can adopt lower electrolysis voltage to carry out, for the PbO in forming, should adopt higher electrolysis voltage to guarantee carrying out smoothly of electrolysis.Yet existing electrolytic recovery splicer's skill was not considered the difference of current potential between different valence state lead, but all adopt the mode of high cathodic polarization reduction to carry out electrolysis, cause actual electrolysis energy consumption higher.
The inventor further finds, for example, same, adopts under the condition that oxygen is oxygen evolution reaction, and the equilibrium potential of oxygen under alkaline condition is E
0=0.401V, so the PbO of 1mol and PbO
2adopt the present invention to be progressively reduced to stage by stage plumbous current potential and electric energy respectively following (wherein the electric weight of 1mol electronics calculates by 26.8Ah):
(1)PbO：
Theoretical electrolysis voltage: 0.401-(0.578)=0.898V
Theoretical electrolysis electric energy: 2*26.8Ah*0.898V=48.13Wh
(2)PbO
2(PbO
2-PbO-Pb)：
First part: PbO
2be reduced to PbO
Theoretical electrolysis voltage: 0.401-0.248=0.133V
Theoretical electrolysis electric energy: 2*26.8Ah*0.133V=7.13Wh
Second section: the PbO that reduction generates is further reduced to Pb
Theoretical electrolysis voltage: 0.401-(0.578)=0.898V
Theoretical electrolysis electric energy: 2*26.8Ah*0.898V=48.13Wh
Total energy consumption is: 7.13+48.13=55.26Wh
If according to solubility lead salt electrolysis mode, actual is by the PbO of the Pb of 1mol and 1mol
2first be converted into 2mol+compound of divalent lead.Wherein the electrolysis situation of acidic conditions and alkaline condition is as follows respectively:
(1) acidic conditions (2mol Pb
2+)
Now the acid deposition potential of oxygen is E
0=1.229V, Pb
2+being reduced to Pb is E
0=-0.126V.
Theoretical electrolysis voltage: 1.229-(0.126)=1.355V
Theoretical electrolysis electric energy: 4*26.8Ah*1.355V=145.26Wh
(2) alkaline condition (2mol PbO)
Theoretical electrolysis voltage: 0.401-(0.578)=0.898V
Theoretical electrolysis electric energy: 4*26.8Ah*0.898V=96.27Wh
Solid phase electrolysis is also the PbO being equivalent to the Pb of 1mol and 1mol
2the PbO that regards 2mol as adopts same electrolysis voltage to carry out electrolytic reaction.
By above-mentioned detailed calculating, contriver finds, the present invention is obtained single electrolysis object and is adopted optionally electrolysis mode by simple and effective ground solid-liquid separation pattern, can obtain in theory the electrolysis energy consumption of minimum 55.26Wh, much smaller than the level of existing acid pattern 145.26Wh and Alkaline Mode 96.27Wh.
That is to say, to the Pb in solid mixture and PbO
2, PbO only
2in+need to obtain electron reduction be Pb to 4 valency lead.Consider PbO
2there is higher oxidisability, by PbO
2the reducing process that carries out two continuous separate stages is saved the power consumption of electrolytic process.Adopt subsequently and electroplate deposition process again, by the lead powder of powdery at anode dissolution, then negative electrode again galvanic deposit to obtain fine and close galvanic deposit plumbous.
It should be noted that, the plumbous oxide content in scrap lead cream is very low, can think that it reacts generation lead sulfate with Waste Sulfuric Acid in the washing stage, or as separated the entering of solid, contain Pb and PbO when solid-liquid separation
2solid mixture in.Because plumbous oxide content is very low, unless there is specified otherwise, generally can ignore.
Therefore, the present invention is a kind of method that lead that can significantly reduce reductive agent, alkaline matter and power consumption reclaims.Fig. 1 is the schema of an embodiment of the inventive method.With reference to Fig. 1, waste lead acid battery obtains plastic waste, grid and lead plaster through broken and screening.Plastic waste and grid are carried out to routine recovery.The composition of lead plaster mainly comprises lead, lead sulfate, plumbic oxide, plumbous oxide and Waste Sulfuric Acid.The lead plaster obtaining from waste lead acid battery is washed and solid-liquid separation with deionized water, obtain the mixture and the dilution heat of sulfuric acid that contain lead sulfate, lead and plumbic oxide.Mixture after above-mentioned washing is reacted with excessive NaOH solution and solid-liquid separation for the second time, make PbSO wherein
4react to generate with NaOH and contain Na
2[Pb (OH)
4], Na
2sO
4with the mixing solutions of NaOH with contain Pb and PbO
2solid mixture.According to the redox potential of different valence state lead, respectively at the Na containing+divalent lead
2[Pb (OH)
4] mixing solutions, and described in the contain+plumbic oxide of 4 valency lead and plumbous solid mixture carry out respectively independently electrolysis mode and reclaim respectively lead.
Therefore, the invention provides a kind of from lead plaster the method for electrolytic recovery lead, comprising: (1) with deionized water wash and carry out solid-liquid separation, obtains the mixture and the dilution heat of sulfuric acid that contain lead sulfate, lead and plumbic oxide by described lead plaster; (2) described solution reacted and carries out solid-liquid separation for the second time with excessive NaOH solution, obtaining containing Na
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide, and contain Pb and PbO
2solid mixture; (3) by the described Na that contains
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide in ion-exchange membrane electrolyzer, carry out constant current and the electrolysis in two stages of constant voltage to obtain pure lead; (4) mixture of described lead and plumbic oxide adopted to the constant-current electrolysis of two stage voltage controls and reclaim pure lead in conjunction with galvanic deposit.
In one embodiment, the concentration of described excessive sodium hydrate solution is 2 to 15mol/L, and preferably 3 to 9mol/L, and described reaction is at 20 to 120 ℃, preferably at the temperature of 45 to 105 ℃, carries out.
Particularly, the constant-current electrolysis pattern that the mixture of described lead and plumbic oxide is first adopted in rare NaOH two stage voltage control is progressively reduced to plumbous oxide and lead by the plumbic oxide in mixture at negative electrode, then lead powder reduction being obtained is transferred in another electrolyzer and the metallic lead in lead powder is transferred in electrolytic solution with constant-current electrolysis refining pattern as new anode, and galvanic deposit forms fine and close metallic lead to metallic cathode.
In one embodiment, electrolysis to the mixture of described lead and plumbic oxide comprises: (1) adopts constant-current electrolysis pattern, under 0.3 to 1.2V voltage, in 0.5 to 8.5M sodium hydroxide solution, make the plumbic oxide in described mixture be reduced to plumbous oxide; (2) voltage is adjusted into 1.2 to 1.9V, continues electrolysis so that described plumbous oxide is reduced to lead; (3) lead reduction being obtained carries out galvanic deposit with together with lead in described mixture, to obtain pure lead.
Than the mixture of plumbous and plumbic oxide is carried out to conventional electrolysis, two stage voltage of the present invention are controlled formula constant-current electrolysis pattern can further reduce power consumption in conjunction with galvanic deposit, and can obtain the fine and close metallic lead that industrial value is higher.
Will be containing Na
2[Pb (OH)
4], NaOH and Na
2sO
4mixing solutions in ion-exchange membrane electrolyzer, carry out, and sequentially comprise constant-current electrolysis and pulse electrolysis.Can first in an ion-exchange membrane electrolyzer, carry out constant-current electrolysis, be transferred to subsequently in another electrolyzer and carry out pulse electrolysis again, the difference of described two ion-exchange membrane electrolyzers is that power supply is different.By changing power supply, also can in same electrolyzer, sequentially carry out constant-current electrolysis and pulse electrolysis.Electrolysis result is to obtain lead at negative electrode, at anode, obtains oxygen.
In one embodiment, take that to use respectively constant current mode cationic membrane electrolyzer and pulsed cationic membrane electrolyzer be example, electrolytic process comprises the following steps stage by stage:
(1) will be containing Na
2[Pb (OH)
4], NaOH and Na
2sO
4electrolytic solution inject constant current mode cationic membrane electrolyzer and carry out constant-current electrolysis, wherein the condition of constant-current electrolysis is: electrolyte temperature is 60 to 120 ℃, preferably 65 to 105 ℃, more preferably 75 to 100 ℃; Cathode current density is 150 to 3500A/m
2, preferably 300 to 1000A/m
2, more preferably 400A/m
2; Anodic current density is 400 to 5000A/m
2, preferably 500 to 4000A/m
2; Ionic membrane apparent current density is 300 to 4500A/m
2;
(2) as Pb (OH)
4 2-when concentration is reduced to 5g/L (in plumbous oxide), will be containing Na
2[Pb (OH)
4], NaOH and Na
2sO
4electrolytic solution be injected in constant pressure type electrolyzer and carry out constant-potential electrolysis, until Pb (OH)
4 2-concentration is less than 0.2g/L (in plumbous oxide), and wherein the condition of constant-potential electrolysis is: electrolyte temperature is 40 to 115 ℃, and preferably 65 to 105 ℃, more preferably 85 to 100 ℃; It is 1.0 to 2.0V that the groove of constant-potential electrolysis is pressed, and preferably 1.35 to 1.95V, and the constant-potential electrolysis time is 100 to 1200min, just to the concentration 0.2g/L of plumbous oxide in solution or when following, stops electrolysis.
In one embodiment, in one embodiment, to the described Na that contains
2[Pb (OH)
4] and the electrolysis of the mixing solutions of NaOH comprise constant-current electrolysis and constant-potential electrolysis subsequently, wherein,
The condition of described constant-current electrolysis is: 60 to 120 ℃ of electrolyte temperatures; Cathode current density 150 is to 3500A/m
2; Anodic current density 400 is to 5000A/m
2; Ionic membrane apparent current density 300 is to 4500A/m
2; And
The condition of described constant-potential electrolysis is: electrolyte temperature is 40 to 115 ℃; Cathode current density is 60 to 2000A/m
2; It is 1.0 to 2.0V that the groove of constant-potential electrolysis is pressed, and preferably 1.35 to 1.95V, and the constant-potential electrolysis time is 100 to 1200min, just to the concentration 0.2g/L of plumbous oxide in solution or when following, stops electrolysis.
In one embodiment, described electrolysis stage by stage is sequentially carried out in constant current mode cationic membrane electrolyzer and constant pressure type cationic membrane electrolyzer, or sequentially carries out in same cationic membrane electrolyzer.
Fig. 2 is the schematic diagram of ion-exchange membrane electrolyzer used in an embodiment of sublevel segmentation electrolysis.With reference to Fig. 2, ion-exchange membrane electrolyzer comprises direct current (or constant voltage) power supply 1; Containing Na
2[Pb (OH)
4], NaOH and Na
2sO
4electrolyte entrance 2; Lead electrode sheet 3; Galvanic deposit lead 4; Lead concentration sensor 5; Containing NaOH and Na
2sO
4electrolyte outlet 6; Cationic membrane 7 (as Nafion cationic membrane); Nickel plating anode 8; NaOH storage tank 9; Crystallization NaOH storage tank 10.
Under electric field action, Pb (OH)
4 2-formation of deposits galvanic deposit lead 4 on lead electrode sheet 3, OH
-the (not shown) that produces oxygen at nickel plating anode 8 places, Na
+by selectivity cationic membrane from anode to movable cathode.In electrolytic process, at positive terminal, adding NaOH stage by stage.When the NaOH in NaOH storage tank too much consumes, in NaOH storage tank, add crystallization NaOH.In the electrolytic solution of electrolysis after completing, comprise NaOH and sodium sulfate stage by stage.
Concrete reaction is as follows:
Negative electrode: [Pb (OH)
4]
2-+ 2e=Pb+4OH
-(III)
Ionic membrane: 2Na
+ (anode)→ 2Na
+ (negative electrode)(IV)
Anode: 2OH
--2e=1/2O
2+ H
2o (V)
Total reaction: Na
2[Pb (OH)
4]=Pb+1/2O
2+ 2NaOH (VI)
The present invention utilizes the selectivity of cationic membrane to see through principle, and cationic membrane allows Na
+from anode to cathodic migration, thereby improve the NaOH concentration at negative electrode place, and stop [Pb (OH)
4]
2-from the migration of negative electrode anode, thereby prevent that electrolytic process Anodic place from generating by product plumbic oxide, and anode place can generate industrial useful by product oxygen.
The electrolysis stage by stage that the present invention adopts can improve electrolytic efficiency and reduce power consumption.During constant-current electrolysis, electrolytic deposition is most of plumbous rapidly.During constant-potential electrolysis, adopt constant voltage mode to carry out follow-up electrolysis, realizing realization in the lead ion solution of lower concentration is energy-conservation and electrolysis thoroughly.Because pulse electrolysis is non-lasting large-current electric solution, it is automatically to reduce its corresponding response current according to the reduction of the ionic concn in solution, and this has guaranteed the efficiency of electrolysis on the one hand, has guaranteed on the other hand the electrolysis degree of depth.If continue large electric current constant-current electrolysis, certainly will in electrolytic process, be reduced and a large amount of by-product hydrogen by the water of negative electrode, cause reducing current efficiency.
The present invention adds NaOH at positive terminal can make holding anode end Na
+concentration, and then keep carrying out continuously of electrolytic reaction, and the raw material that the NaOH adding can directly circulate as the next one comes complexing PbO to use.
The present invention during electrolysis stage by stage to add in NaOH storage tank crystallization NaOH not only can improve NaOH storage tank in the concentration of NaOH, and can prevent that direct NaOH solid from adding heat release and the boiling phenomenon causing.Crystallization NaOH (NaOH2H
2o) for example with frozen water, processing NaOH solid obtains.
By adding NaOH2H in the electrolytic solution that comprises NaOH and sodium sulfate after completing to segmentation electrolytic process
2o further separates out the sodium sulfate in electrolytic solution, and the sodium sulfate of separating out is filtered.Residue NaOH solution is returned to above-mentioned alkali leaching purification Cheng Jinhang to be recycled.Working cycle comprises the following steps:
(1) in the electrolytic solution containing NaOH and sodium sulfate after electrolysis, add crystallization NaOH, progressively separate out Na
2sO
410H
2o crystal;
(2) electrolytic solution is after filtration after this sodium sulfate crystal, electrolytic solution (being mainly NaOH) returned to above-mentioned alkali leaching and purify Cheng Jinhang and recycle.
The present invention during working cycle to adding crystallization NaOH to make: (1), under common-ion effcet, impels the sodium sulfate in electrolytic solution to separate out, and reaches the object of the direct reclaim(ed) sulfuric acid sodium of non-evaporation; (2) NaOH adding directly comes complexing PbO to use as the raw material of next one circulation; (3) add crystallization NaOH to produce hardly heat release and boiling phenomenon, than noncrystalline NaOH, be more conducive to sodium sulfate and separate out.The sodium sulfate producing and oxygen are as by-product recovery.
As can be seen here, in the present invention selective electrolysis and the electrolysis of sublevel segmentation are combined with, can further reduce power consumption, and whole technique can be carried out continuously and cyclically.In addition also can produce as Na,
2sO
410H
2the valuable by products such as O crystal.
In sum, method of the present invention has following features:
(1) in implementation process of the present invention, the present invention passes through the mode of pre-wash for the first time, removed sulfuric acid and other soluble impurity of in former lead plaster, being mingled with, thereby be that follow-up sulfur removal technology reduces the consumption of NaOH and the purity of raising secondary lead is offered help;
(2) in solid-liquid separation process for the second time, the present invention utilize alkaline NaOH in the lead plaster after cleaning+compound of divalent lead carry out separated timely and effectively, thereby obtained the Na of only contain+divalent lead ion
2[Pb (OH)
4] basic solution and the mixture of the separated lead powder obtaining and lead dioxide powder; With
(3) lead compound of different valence state is carried out to electrolysis independently:
A, adopt the compound of come in thorough electrolytic solution+divalent lead of ion-exchange membrane electrolysis stage by stage;
B, employing two one-step electrolysis modes are progressively reduced and are processed Pb and PbO
2in PbO
2, it is progressively transformed to PbO and Pb, the lead powder finally by plating formula galvanic deposit refining mode, above-mentioned reduction being obtained again galvanic deposit becomes fine and close electrolytic lead.
Method of the present invention can greatly be saved the consumption of acid, reductive agent and alkaline matter and electric energy, makes whole method be applicable to industrial applications.
Embodiment
embodiment 1
By 12V, the 10AH waste lead acid battery sold on the market carry out fragmentation, separation obtains 2.6kg lead plaster.Get 200 grams of lead plasters wherein first and 150ml deionized water wash and filter, obtain containing 2% (wt.) dilute sulphuric acid and 196 grams of lead plasters.The NaOH of this lead plaster and 1 liter of 10M carries out alkaline desulphurization reaction at 95 ℃ subsequently, after keeping the reaction times to be 1.5h, carries out immediately heat filtering and obtains 1 liter of NaOH solution that contains 70g/LPbO and 95 grams and contain Pb and PbO
2solid mixture.
Leaded mother liquor through routine standing and purify after enter and in electrolyzer, carry out electrolysis with ion-exchange film.First in this electrolyzer, carry out constant-current electrolysis, control cathode and anodic current density are 700A/m
2, electrolysis temperature is 90 ℃, electrolysis voltage is 1.44V.When electrolysis time reaches after 100min, when now lead concentration is less than 5g/L after testing, now proceed to the constant-potential electrolysis stage.Now controlling electrolysis temperature is 80 ℃, and the electrolysis voltage of constant voltage is 1.60V.When electrolysis is actual, reach after 600min, in electrolysis mother liquor, the concentration of plumbous oxide is reduced to below 0.2g/L.Electrolysis mother liquor after electrolysis is again brought up to the actual concentrations of NaOH after 10M after supplementing NaOH, and electrolytic solution is cooled to 5 ℃, now in solution, separates out Disodium sulfate decahydrate crystal.This mother liquor is carried out to solid-liquid separation and obtain 10M NaOH solution and sodium sulfate crystal, this leaded NaOH mother liquor returns in desulfurization process and recycles.
Separation obtains 95 grams and contains Pb and PbO
2the NaOH solution of 5 grams of 2M of solid mixture allocate, obtain a kind of brown paste, be then squeezed in 6*8cm
2on strip metal mesh electrode, form the lead compound layer that thickness is about 3mm.Then the electrolyzer that its immersion is contained to alkaline electrolyte carries out cathodic reduction reaction stage by stage.First adopt 20mA/cm
2current density (960mA) carry out slowly electrolysis, until groove presses and to be elevated to 0.99V, thereby the plumbic oxide in mixture is progressively changed into as plumbous oxide in electrolyzer.Then this electrode proceeds to the quick electrolysis stage, adopts 100mA/cm
2(4800mA) carry out the electrolysis of subordinate phase, making plumbous oxide in mixture obtain electronics electrolysis is powdered metallic lead.Now controlling electrolysis temperature is 80 ℃, and electrolysis voltage is 1.32V.When electrolysis voltage is elevated to 1.85V, stop electrolysis and take out lead powder electrode, be moved in another electrolyzer and carried out alkaline electrolysis refining process.Anode using this lead powder as this electrolyzer, pure plumbous thin slice (6*8cm
2) carry out alkaline electrolysis refining for negative electrode.There is anodic oxidation and dissolve in the lead powder on mesh electrode now gradually, obtains electrolytic lead on lead electrode plate simultaneously.This electrolyzer adopts the 9M NaOH electrolytic solution of the PbO that contains 70g/L, and electrolysis temperature is 75 ℃, and current density is 50mA/cm
2, this groove of electroplating formula electrorefining is pressed as 0.083V.
Through Measurement and Computation, negative electrode lead has obtained 152 grams of metallic leads, and its purity is 99.991%, and current efficiency is 98.9%, and the total energy consumption of the Direct Electrolysis process of lead plaster is 332kWh/t (Pb), and plumbous comprehensive recovery is 98.6%.
Getting 1 block specifications is 12V, 45Ah automobile waste lead acid battery, 13.2 kilograms of series of cells gross weights.Adopt conventional mechanical method to refuse battery pulverize with separated after obtain lead plaster, grid, dividing plate and plastics etc.
Get and after the lead plaster powder of 6 kilograms that said process obtains and 5 liters of deionized waters wash, obtain approximately 5.9 kilograms of lead plasters and 5 liters and contain 2% dilute sulphuric acid.
The NaOH of the lead plaster that solid-liquid separation is obtained and 27 liters of 10.5M carries out alkaline desulphurization reaction at 100 ℃, and after keeping the reaction times to be 1.0h, filtered while hot obtains 28 liters of NaOH solution that contain 75g/L PbO and 2.8 kilograms and contains Pb and PbO immediately
2solid mixture.
The cathode compartment that said process is obtained being injected into containing the basic solution of 75g/L plumbous oxide to ionic membrane (Nafion982) electrolyzer, 12M NaOH solution injects in anolyte compartment.This anode electrolytic cell is coated with 2.2mg/cm
2pt
40ru
20c
40the nickel foam of catalyzer is anode, the thin electrode that negative electrode adopts pure lead to make.Regulate power supply output and electrolyte flow rate, make electrolyzer carry out stable electrolytic process, the current density of control cathode and anode is 20mA/cm
2, electrolysis temperature is 85 ℃, the electrolysis voltage of electrolyzer is 1.35V.When the plumbous oxide concentration in electrolytic solution is reduced to 5g/L, stops constant current reaction, and enter constant-potential electrolysis pattern.Now controlling electrolysis temperature is 85 ℃, and the electrolysis voltage of constant voltage is 1.50V.When electrolysis time reaches after 650min, in electrolysis mother liquor, the concentration of plumbous oxide is reduced to below 0.2g/L.Electrolysis mother liquor after electrolysis is again brought up to the actual concentrations of NaOH after 10M after supplementing NaOH, and electrolytic solution is cooled to 5 ℃, now in solution, separates out Disodium sulfate decahydrate crystal.This mother liquor is carried out to solid-liquid separation and obtain 10M NaOH solution and sodium sulfate crystal, this leaded NaOH mother liquor returns in desulfurization process and recycles.
Separation obtains 2.9 kilograms and contains Pb and PbO
2solid mixture add with respect to the NaOH solution of the 2M of its weight 3% and allocate, make it form gradually the brown paste of thickness, be then coated in 20*30cm
2on strip metal mesh electrode, form the lead compound layer that thickness is about 6mm.Then the electrolyzer that its immersion is contained to alkaline electrolyte carries out cathodic reduction reaction stage by stage.First adopt 15mA/cm
2current density (9A) carry out slowly electrolysis, until electrolyzer is pressed, be elevated to 0.9V, this process makes the plumbic oxide in mixture in electrolyzer, obtain electronics progressively to change plumbous oxide into.Then this electrode proceeds to the quick electrolysis stage, adopts 80mA/cm
2(48A) carry out the electrolysis of subordinate phase, make the plumbous oxide in mixture obtain continuing electronics and change powdered metallic lead into.Now controlling electrolysis temperature is 85 ℃, and electrolysis voltage is 1.35V.When electrolysis voltage is elevated to 1.85V, stop electrolysis and take out lead powder electrode, be moved in electrolyzer 2-2 and carried out alkaline electrolysis refining process.Anode using this lead powder as another electrolyzer, two pure plumbous thin slice (20*30cm
2) carry out alkaline electrolysis refining for negative electrode.There is anodic oxidation and dissolve in the lead powder on mesh electrode now gradually, obtains electrolytic lead on lead electrode plate simultaneously.This electrolyzer adopts the 9M NaOH electrolytic solution of the PbO that contains 70g/L, and electrolysis temperature is 80 ℃, and current density is 50mA/cm
2, this is electroplated formula refining cell and presses as 0.089V.
Through Measurement and Computation, negative electrode lead has obtained 4.4 kilograms of metallic leads, and its purity is 99.991%, and current efficiency is 98.9%.Outside the self-discharge of deduction electrolyzer 2-1, the clean power consumption of the Direct Electrolysis process of all lead plasters is 325kWh/t (Pb), and plumbous comprehensive recovery is 99.0%.
From producing 12V, what in 14Ah lead-acid cell workshop, obtain being mingled with waste lead acid battery positive plate scraps 13 kilograms of negative plates, and this refuse battery pole plate obtains approximately 10 kilograms of lead powder after pulverizing, and main component is Pb, the PbSO of electrode self
4, PbO and a small amount of PbO
2.
Get and after the lead plaster powder of 10 kilograms that said process obtains and 5 liters of deionized waters wash, obtain approximately 10 kilograms of lead plaster wet-millings and 5 liters and contain 0.2% dilute sulphuric acid.
The NaOH of the lead plaster that solid-liquid separation is obtained and 50 liters of 11M carries out alkaline desulphurization reaction at 100 ℃, and after keeping the reaction times to be 1.0h, filtered while hot obtains approximately 50 liters of NaOH solution that contain 89g/L PbO and 3.7 kilograms and contains Pb and PbO immediately
2solid mixture.
The cathode compartment that said process is obtained being injected into containing the basic solution of 89g/L plumbous oxide to ionic membrane (Nafion2030) electrolyzer, 12M NaOH solution injects in anolyte compartment.This anode electrolytic cell adopts and is coated with 2.5mg/cm
2pt
40c
60the nickel anode of catalyzer, the thin electrode that negative electrode adopts pure lead to make.Regulate electrolysis power and electrolyte flow rate, make electrolyzer carry out stable electrolytic process, the current density of control cathode and anode is 50mA/cm
2, electrolysis temperature is 95 ℃, the operating voltage of electrolyzer is 1.31V.Now at negative electrode, obtaining observing fine and close electrolytic lead generates.When the plumbous oxide concentration in electrolytic solution is reduced to 5g/L, stops constant current reaction, and enter constant-potential electrolysis pattern.Now controlling electrolysis temperature is 95 ℃, and the electrolysis voltage of constant voltage is 1.45V.When electrolysis time reaches after 670min, in electrolysis mother liquor, the concentration of plumbous oxide is reduced to below 0.2g/L.Electrolysis mother liquor after electrolysis is again brought up to the actual concentrations of NaOH after 10M after supplementing NaOH, and electrolytic solution is cooled to 5 ℃, now in solution, separates out the Disodium sulfate decahydrate crystal of minute quantity.This mother liquor is carried out to solid-liquid separation and obtain 10M NaOH solution and sodium sulfate crystal, this leaded NaOH mother liquor returns in desulfurization process and recycles.
Separation obtains 3.7 kilograms and contains Pb and PbO
2solid mixture add with respect to the NaOH solution of the 2M of its weight 3% and allocate, make it form gradually dark thickness paste, be then coated in 30*50cm
2on strip metal mesh electrode, form the lead compound layer that thickness is about 3mm.Then the electrolyzer that its immersion is contained to alkaline electrolyte carries out cathodic reduction reaction stage by stage.First adopt 10mA/cm
2current density (15A) carry out slow electrolysis, until electrolyzer is pressed, be elevated to 1.15V, this process makes the plumbic oxide in mixture in electrolyzer, obtain electronics progressively to change into as plumbous oxide.Then this electrode proceeds to the quick electrolysis stage, adopts 100mA/cm
2(150A) carry out the electrolysis of subordinate phase, make the plumbous oxide in mixture obtain continuing electronics and change powdered metallic lead into.Now controlling electrolysis temperature is 85 ℃, and electrolysis voltage is 1.31V.When electrolysis voltage is elevated to 1.75V, stop electrolysis and take out lead powder electrode, be moved in another electrolyzer and carried out alkaline electrolysis refining process.Anode using this lead powder as this electrolyzer, two pure plumbous thin slice (30*50cm
2) carry out alkaline electrolysis refining for negative electrode.There is anodic oxidation and dissolve in the lead powder on mesh electrode now gradually, obtains electrolytic lead on lead electrode plate simultaneously.This electrolyzer 2-2 adopts the 9M NaOH electrolytic solution of the PbO that contains 75g/L, and electrolysis temperature is 85 ℃, and current density is 50mA/cm
2, this is electroplated formula refining cell and presses as 0.079V.
Through Measurement and Computation, negative electrode lead has obtained 7.7 kilograms of metallic leads, its purity is 99.991%, current efficiency is 99.2%, two portions lead plaster is by self power generation respectively, the clean power consumption of Solid phase electrolysis-alkaline electrolysis refining Direct Electrolysis process is 319kWh/t (Pb) stage by stage, and plumbous comprehensive recovery is 99.1%.
From lead-acid cell producer, obtain because of the softening junked-auto lead-acid cell that returns in advance factory of scrapping of positive plate.This battery obtains containing PbO through Mechanical Crushing, washing
2just very main plumbous mud and more completely negative electrode grid.
Get and after the plumbous mud powder of 10 kilograms that said process obtains and 5 liters of deionized waters wash, obtain approximately 10 kilograms of wet plumbous mud and 5 liters and contain 3% dilute sulphuric acid.
The plumbous mud that solid-liquid separation is obtained and the NaOH of 30 liters of 12M carry out alkaline desulphurization reaction at 100 ℃, and after keeping the reaction times to be 1.5h, filtered while hot obtains approximately 30 liters of NaOH solution that contain 75g/L PbO and 6.8 kilograms and contains Pb and PbO immediately
2solid mixture.
The cathode compartment that said process is obtained being injected into containing the basic solution of 75g/L plumbous oxide to self-power generation type ionic membrane (Nafion2030) electrolyzer, 12M NaOH solution injects in anolyte compartment.This anode electrolytic cell is coated with porous foam nickel anode, the thin electrode that negative electrode adopts pure lead to make.The output rating and the electrolyte flow rate that regulate power supply, make electrolyzer carry out stable electrolytic process, and the current density of control cathode and anode is 30mA/cm
2, electrolysis temperature is 90 ℃, the operating voltage of electrolyzer is 1.342V.At electric tank cathode, can observe the precipitation of electrolytic lead.Along with the reduction of plumbous oxide concentration, the electrolysis voltage of electrolytic process is rising thereupon.
When the plumbous oxide concentration in electrolytic solution is reduced to 5g/L, stops constant current reaction, and enter constant-potential electrolysis pattern.Now controlling electrolysis temperature is 99 ℃, and the electrolysis voltage of constant voltage is 1.43V.When electrolysis time reaches after 630min, in electrolysis mother liquor, the concentration of plumbous oxide is reduced to below 0.2g/L.Electrolysis mother liquor after electrolysis is again brought up to the actual concentrations of NaOH after 10M after supplementing NaOH, and electrolytic solution is cooled to 5 ℃, because lead sulfate content in raw material is low, now in solution, does not almost have Disodium sulfate decahydrate crystal to separate out.This mother liquor is carried out to solid-liquid separation and obtain after 10M NaOH solution and impurity, this leaded NaOH mother liquor returns in desulfurization process and recycles.
Separation obtains 6.8 kilograms and contains Pb and PbO
2solid mixture add with respect to the NaOH solution of the 3M of its weight 3% and allocate, make it form gradually dark thickness paste, be then coated in 30*50cm
2on strip metal mesh electrode, form the lead compound layer that thickness is about 7mm.Then the electrolyzer that its immersion is contained to alkaline electrolyte carries out cathodic reduction reaction stage by stage.First adopt 10mA/cm
2current density (15A) carry out slow electrolysis, until electrolyzer is pressed, be elevated to 0.95V, this process makes the plumbic oxide in mixture in electrolyzer, obtain electronics progressively to change into as plumbous oxide.Then this electrode proceeds to the quick electrolysis stage, adopts 80mA/cm
2(120A) carry out the electrolysis of subordinate phase, make the plumbous oxide in mixture obtain continuing electronics and change powdered metallic lead into.Now controlling electrolysis temperature is 85 ℃, and electrolysis voltage is 1.41V.When electrolysis voltage is elevated to 1.9V, stop electrolysis and take out lead powder electrode, be moved in another electrolyzer and carried out alkaline electrolysis refining process.Anode using this lead powder as another electrolyzer, two pure plumbous thin slice (30*50cm
2) carry out alkaline electrolysis refining for negative electrode.There is anodic oxidation and dissolve in the lead powder on mesh electrode now gradually, obtains electrolytic lead on lead electrode plate simultaneously.This electrolyzer adopts the 9M NaOH electrolytic solution of the PbO that contains 75g/L, and electrolysis temperature is 80 ℃, and current density is 50mA/cm
2, this is electroplated formula refining cell and presses as 0.090V.
Through Measurement and Computation, negative electrode lead has obtained 8.1 kilograms of metallic leads, its purity is 99.991%, current efficiency is 98.7%, two portions lead plaster is by self power generation respectively, the clean power consumption of Solid phase electrolysis-alkaline electrolysis refining Direct Electrolysis process is 317kWh/t (Pb) stage by stage, and plumbous comprehensive recovery is 99.2%.
By preferred implementation and specific embodiment, describe the present invention in detail above, yet it will be understood by those skilled in the art that scope of the present invention is not limited to this, anyly do not deviate from modification of the present invention or change all within the scope of the invention.
Claims (6)
1. a method for electrolytic recovery lead from lead plaster, is characterized in that adopting association type electrolytic process, comprising:
(1) by described lead plaster with deionized water wash and carry out solid-liquid separation, obtain the mixture and the dilution heat of sulfuric acid that contain lead sulfate, lead and plumbic oxide;
(2) described solution reacted and carries out solid-liquid separation for the second time with excessive sodium hydroxide solution, obtaining containing Na
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide, and the solid mixture that contains plumbous and plumbic oxide;
(3) by the described Na that contains
2[Pb (OH)
4] and the mixing solutions of sodium hydroxide at ion-exchange membrane electrolyzer, comprise constant-current electrolysis stage and constant-potential electrolysis stage electrolysis stage by stage to reclaim pure lead, when wherein the concentration of plumbous oxide is less than 0.2g/L in solution, stop electrolysis; With
(4) mixture of described lead and plumbic oxide adopted to the constant-current electrolysis of two stage voltage controls and reclaim pure lead in conjunction with galvanic deposit,
In (3), the condition of described constant-current electrolysis is: 60 ℃ to 120 ℃ of electrolyte temperatures; Cathode current density 150A/m
2to 3500A/m
2; Anodic current density 400A/m
2to 5000A/m
2; Ionic membrane apparent current density 300A/m
2to 4500A/m
2; And
Described constant-potential electrolysis condition is: 40 ℃ to 115 ℃ of electrolyte temperatures; The groove of constant-potential electrolysis is pressed 1.0V to 2.0V; The constant-potential electrolysis time is 100 minutes to 1200 minutes,
The constant-current electrolysis that described two stage voltage are controlled also comprises in conjunction with galvanic deposit:
(a) adopt constant-current electrolysis pattern, under the voltage of 0.3V to 1.2V, in the sodium hydroxide solution of 0.5M to 8.5M, make the plumbic oxide in described mixture be reduced to plumbous oxide;
(b) voltage is adjusted into 1.2V to 2.0V, continues electrolysis so that described plumbous oxide is reduced to lead; With
(c) lead reduction being obtained is electroplated formula electrodeposition process with together with lead in described mixture, to obtain pure lead.
2. the method for claim 1, is characterized in that, the concentration of described excessive sodium hydrate solution is 2mol/L to 15mol/L, and described reaction is carried out at the temperature of 20 ℃ to 120 ℃.
3. method as claimed in claim 2, is characterized in that, the concentration of described excessive sodium hydrate solution is 3mol/L to 9mol/L, and described reaction is carried out at the temperature of 45 ℃ to 105 ℃.
4. the method for claim 1, is characterized in that,
The condition of described constant-current electrolysis is: 65 ℃ to 105 ℃ of electrolyte temperatures; Cathode current density 300A/m
2to 1000A/m
2; Anodic current density 500A/m
2to 4000A/m
2; Ionic membrane apparent current density 300A/m
2to 4500A/m
2; And
Described constant-potential electrolysis condition is: 65 ℃ to 105 ℃ of electrolyte temperatures; The groove of constant-potential electrolysis is pressed 1.35V to 1.95V; The constant-potential electrolysis time is 100 minutes to 1200 minutes.
5. the method for claim 1, is characterized in that, described electrolysis stage by stage is sequentially carried out in constant current mode cationic membrane electrolyzer and constant pressure type cationic membrane electrolyzer, or sequentially carries out in same cationic membrane electrolyzer.
6. the method for claim 1, is characterized in that, in described plating formula electrodeposition process pattern, the current density of controlling electrodeposition process is 50A/m
2to 3500A/m
2, corresponding electrolysis voltage is 0.02V to 0.09V, at negative electrode, obtains pure lead.
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| CN103014347B (en) * | 2012-12-12 | 2014-12-03 | 北京化工大学 | Method for recycling waste lead-acid cells to directly produce lead oxide |
| CN103146923B (en) * | 2013-03-15 | 2015-02-04 | 北京化工大学 | Method for producing lead oxide by recovering waste lead-acid batteries based on atom economy way |
| CN104141045B (en) | 2014-08-20 | 2017-04-12 | 北京化工大学 | Method for recovering lead oxide from waste lead plaster |
| WO2016130675A1 (en) * | 2015-02-10 | 2016-08-18 | Verdeen Chemicals, Inc. | Electrowinning process to recover high purity lead |
| CN110656352A (en) * | 2019-11-01 | 2020-01-07 | 巨江电源科技有限公司 | Recycling method of solid-phase electrolytic secondary lead of waste lead-acid storage battery |
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