Lead wastes processing

FIELD: metallurgy.

SUBSTANCE: method of lead extraction from lead wastes containing one or more of Pb, PbO, PbO2 and PbSO4 includes treatment with aqueous solution of citric acid with production of lead citrate. Then lead citrate is extracted from the aqeuous solution, and the extracted lead citrate is converted into Pb and/or PbO. The method for processing of lead accumulator batteries, containing or more of Pb, PbO, PbO2 and PbSO4 includes mixing of a paste of lead plates of accumulator batteries with the aqueous solution of citric acid for production of lead citrate. Then lead citrate is extracted from the aqueous solution, and lead citrate is converted into lead and/or lead oxide. Further Pb and/or PbO are included into a plate of an accumulator battery.

EFFECT: simplified process and its improved cost-effectiveness.

17 cl, 7 dwg, 8 tbl, 1 ex

 

The technical FIELD

In the present invention, a method for selection of lead from lead-containing wastes. In particular, the present invention relates to a method of extraction of lead from waste batteries and for the final product obtained by this method.

The LEVEL of TECHNOLOGY

More than 50% of the world production of lead is produced by processing of lead waste. It is believed that processing is subjected to approximately 90% of lead in lead-acid batteries. Recycling of lead batteries includes processing lead paste contained in batteries, with the aim of separating lead from the other components of the battery. This process may include both mechanical methods of separation, and chemical methods such as hydrometallurgical process, electrolysis and smelting (pyrometallurgical process).

Most frequently used approach in which a paste of the battery loaded in the traditional blast furnace smelting and decompose at elevated temperatures with the release of metallic lead. Pasta battery contains a large amount of sulfur in the form of PbSO4. For the decomposition of this compound requires relatively high temperatures, typically 1100°C and above. Pyrometallurgical processing PbSO4/sub> hampered by the need to introduce additional process steps to prevent emissions of SO2into the environment. As a result of high-temperature processes formed a huge amount of harmful fumes containing lead dust and slag. Control harmful emissions from roads and often requires expensive specialized equipment. Processing these malicious products is often laborious and time consuming.

Hydrometallurgical methods are used to bind sulphur, which is contained in the paste rechargeable battery in the form of soluble sulfates, which can be separated from the insoluble products of lead, obtained at the stage of processing. However, the selected lead products often retain a significant amount of sulfur in the form of PbSO4. When placing this product in the melting furnace is a need for additional stages to maintain emissions of SO2at acceptable levels.

Getting lead by electrolysis also has its disadvantages because it requires a complex chemical reagents for transfer of lead in solution in a format suitable for processing in the electrochemical cell. These cells require a large amount of energy.

In the patent US 4,118,219 described method of recycling lead-kislotno the x rechargeable battery packs. This method includes a step of transformation of Pb and PbO in PbSO4using sulfuric acid. In the pasta battery PbO2restore either by calcination or by using a reducing agent such as hydrogen peroxide, followed by treatment with sulfuric acid to obtain PbSO4. PbSO4remove the pasta from the battery, by using a highly concentrated aqueous ammonia leach solution of ammonium sulfate. The aqueous solution is filtered off from undissolved impurities and then dissolved lead is transferred to the carbonate of lead, which is separated from the undissolved impurities and unreacted Pb and PbO. The lead carbonate is transferred to PbO or Pb in the kiln for firing.

In the patent US 4,269,810 described by way of desulfatation lead-kislotnyi paste rechargeable batteries by adding aqueous solutions of processing reagents, such as Na2CO3or NaOH, to the crushed components of the battery. During this process, PbSO4reacts with the specified reagent with the formation of metal sulfate such as sodium sulfate, soluble in aqueous solution, and the precipitated lead compounds, for example, PbCO3and Pb(OH)2. Precipitated lead compounds extracted along with solid oxides PbO and PbO2using traditional methods divided the I, such as sedimentation or centrifugation.

The authors of the present invention it is obvious that the modern methods of disposal of lead from waste batteries require a number of stages to obtain the lead, suitable for industrial production, for example for use in the manufacture of batteries.

The product obtained most of the known processing methods lead contains lead in the form of a number of different forms. The exact composition of the product is difficult to control and predict, with this composition may depend on the composition of the used lead-containing wastes. Thus, further processing to obtain a product suitable for industrial use.

Need a simple and harmless way of recycling lead from the paste of the battery. This method should also be cost-effective and to comply with the legislation on the protection of the environment. It is also necessary to exclude the transportation of lead waste batteries to specialized sites for processing and to provide such a method which could be applied on the spot. The absence of transport costs will contribute to the sustainable development of such processing methods.

The INVENTION

The authors of the present invention was developed about the same a method of processing lead waste.

Accordingly, the present invention is primarily a method for processing of lead from lead waste.

In the first aspect of the present invention, a method for processing of lead from lead waste, comprising the following stages:

a) treatment of lead wastes aqueous solution of citric acid to produce lead citrate;

b) isolation of citrate of lead from aqueous solution; and

C) convert the selected lead citrate in Pb and/or PbO.

In a preferred embodiment of the invention lead waste is a lead paste rechargeable batteries. Most preferably, the waste contains lead PbSO4, PbO2, PbO and Pb.

In a preferred embodiment of the invention the pH value of an aqueous solution of citric acid is in the range from 1.4 to 6.

Optionally, an aqueous citric acid solution additionally contains one or more components selected from the group comprising metal citrate, and hydrogen peroxide.

In one embodiment of the invention an aqueous solution of citric acid contains hydrogen peroxide, and the desired molar ratio of PbO to hydrogen peroxide is from 1:0.1 to 1:4. Optional, the molar ratio of PbO to citric acid is in the range from 1:1 to 1:7.

In a preferred embodiment, Rea is Itachi of the invention the temperature of the aqueous solution of citric acid support in the interval from 0 to 45°C.

In a preferred embodiment of the invention, the ratio of solid and liquid phases in an aqueous solution of lead waste must be in the range from 1:1 to 1:50.

In a preferred embodiment of the invention selected lead citrate transferred to Pb and/or PbO by annealing. Most preferably, the temperature of calcination was in the range of from 250 to 1100°C. Further, in the preferred embodiment of the invention the oxygen partial pressure during annealing is from 0.01 to 5 ATM.

The second aspect of the present invention is a method of recycling of lead batteries, comprising the following stages:

a) obtaining a lead paste of lead batteries;

b) processing said lead paste of lead batteries with an aqueous solution of citric acid to produce lead citrate;

c) isolation of citrate of lead from aqueous solution;

d) transforming the selected lead citrate in Pb and/or PbO; and

e) the inclusion of Pb and/or PbO in the plate of the rechargeable battery.

In a preferred embodiment of the invention related to the second aspect of the invention, the lead citrate allocate together with PbSO4as one component. Further, it is desirable to precipitate Pb and/or PbO contained PbSO4.

In the following aspect n the present invention proposed a rechargeable battery, containing plates obtained from recycled lead waste by any of the methods described above in the present invention.

In another aspect of the present invention proposed a calcination product containing Pb, PbO and PbSO4for use in the manufacture of plates for storage batteries.

BRIEF DESCRIPTION of DRAWINGS

Detailed description of the invention are presented with reference to figures, in which:

Figure 1. X-ray spectra of different structures lead citrate ([3Pb·2(C6H5O7)]·3H2O), (a) is derived from the data presented in Kourgiantakis et al. Inorganica Chimica Acta, 2000, 297, 134; (b) selected from PbO; (C) selected from PbO2; and (d) of the PbSO4.

Figure 2. Obtained using scanning electron microscope (SEM) image monohydrate citrate lead (Pb(C6H6O7)·H2O), synthesized from (a) PbO (×4000 magnification); (b) PbO2(×4300 increase); and [3Pb·2(C6H5O7)]·3H2O, synthesized from (s) PbSO4(× 4500 increase).

Figure 3. Obtained using a transmissive electron microscope (TEM) image of the compounds Pb(C6H6O7)·H2O, synthesized from PbO.

Figure 4. The DSC curve for compound Pb(C6H6O7)·H2O obtained from PbO.

Figure 5. The DSC curve for compound [3Pb·2(C 6H5O7)]·3H2O obtained from PbSO4.

6. The mass loss as a function of temperature of annealing, the firing of lead citrate, obtained from pure PbO (triangles), PbO2(circle) and PbSO4(diamonds).

7. The x-ray spectrum of the products of calcination of lead citrate at different temperatures (Pb - triangles; PbO - circle).

DETAILED description of the INVENTION

Used herein, the term "lead" refers to elemental lead or a compound containing one or more atoms of lead. In this application with reference to elemental lead use the symbol Pb. Similarly, when referring to a specific compound containing lead, represent the formula, as, for example, PbO and PbO3for monoxide and lead dioxide, respectively. For convenience, the term "citrate lead" mean Pb(C6H6O7) and its hydrates, and other stoichiometric compounds, for example 3Pb·2(C6H5O7), and their hydrates. In some aspects of the invention, the term "citrate lead" refers to Pb(C6H6O7) and its hydrate, and the reaction product PbSO4with a water solution of citric acid and sodium citrate. In other aspects of the invention, the term "citrate lead" refers to Pb(C6H6O7) and its hydrates.

Waste lead depict ablaut a waste, lead gained during the industrial process, where the lead is a by-product or waste derived from waste products containing lead. Most of the waste of lead are a paste of spent batteries. Waste lead is also available from the cable jacket, lead sheets used in the construction industry, paints, material used in nuclear repositories, and electroceramic based on PbO.

Waste lead mostly include material containing one or more substances such as Pb (lead), PbO (lead monoxide), PbO2(lead dioxide) and PbSO4(lead sulfate). Waste lead may contain other substances, depending on the source of waste. In the lead waste can be included minor amounts of alloys of metals such as Sa and Sb.

Lead in the paste lead-rechargeable batteries (also known as active battery weight) is usually in the form of PbSO4, PbO2, PbO and Pb. Lead wastes of dry lead batteries contain these components in the range of 55-65 wt.%, 15-40 wt.%, 5-25 wt.% and 1-5 wt.% respectively. Other components of the battery pastes contain, but are not limited to, black coal, plastics, fibers and sulfacetamide connection. The battery is ornago paste may contain sulfuric acid. The exact composition of the battery paste will depend on the specific composition of the rechargeable battery, and the method of producing a battery paste. How the selection paste from rechargeable batteries are well known to specialists in the field of technology related to battery recycling. An example of such a method is described in US 4,118,219.

In accordance with the method proposed in the present invention, waste lead-treated with an aqueous solution of citric acid. Citric acid is a relatively cheap, readily available organic acid. Citric acid is widely used in the food industry and is produced from biological raw materials in the amount of 1.5 million tons per year worldwide. It is available on an industrial scale in the form of monohydrate citric acid. Aqueous solutions of citric acid made in accordance with standard techniques. In some alternative aspects of the present invention instead of citric acid or together with it can be used other organic acids. Preferred carboxylic acids are acetic and oxalic acid. In alternative aspects of this invention, the citric acid solution is a solution of organic acid, lead salt, citric acid corresponds to a lead salt of an organic acid.

predpochtitelno aqueous solution of citric acid is saturated, with a concentration of not more than 2.5 mol/l, 2 mol/l and 1.5 mol/l is Preferable that the concentration of citric acid in aqueous solution was not less than 1 mol/l, 0.5 mol/l or 0.1 mol/L. the Most preferred concentration of the aqueous solution of citric acid is 1.2 mol/L.

Waste lead can be treated with an aqueous solution of citric acid by mixing them. Stirring of the mixture can be carried out by mixing setup, controlled by a magnetic stirrer or with a mechanical stirrer with paddle. On a broader scale, this mixture can be placed in a container equipped with a stirring mechanism. Other methods of mixing will be obvious to a person skilled in this technical field.

Waste lead-containing Pb and/or PbO, treated with an aqueous solution of citric acid to obtain a citrate Pb from Pb and/or PbO.

In some preferred embodiments of the present invention, the waste of lead treated with an aqueous citric acid solution, optionally containing citrate metal, to obtain lead citrate from PbSO4. It is preferable to use the alkali metal citrate, namely sodium citrate. Sodium citrate is widely used in the food industry to regulate pH, as a preservative and for Ulu is deprivation taste of food. Sodium citrate is available on an industrial scale in the form of dihydrate (Na3(C6H5O7)·2H2O). Aqueous solutions of citric acid, optionally containing a metal citrates, constructed in accordance with standard technology.

Treatment of waste lead-free aqueous citric acid solution, optionally containing sodium citrate, leads to the formation of sodium sulfate as a by-product. The sodium sulfate can be distinguished from the treated solution either before or after removal of lead citrate. The sodium sulfate is widely used in industry, for example in the production of detergents, and, if necessary, isolated from the treated solution of the sodium sulfate can be put into production after appropriate treatment. The use of by-products of the present process is advantageous because it reduces the overall cost of production of lead.

Citrate lead can be obtained from the PbO2using only an aqueous solution of citric acid in accordance with the method described in Ferracin et al., Hydrometallurgy 2002, 65, 137. However, the reaction rate increases significantly when added to an aqueous solution of hydrogen peroxide.

In some preferred embodiments of the present invention, the waste of lead treated with an aqueous citric acid solution, additional is but containing hydrogen peroxide, to obtain citrate lead from PbO2. Aqueous solutions of citric acid, optionally containing hydrogen peroxide, are produced in accordance with standard technology. As an alternative way of PbO2restore using known reducing agents. For this you can use metal hydrides or hydrogen. The recovery phase may be carried out before processing wastes specified water solution.

Additional reagents described in the preferred embodiments of the invention may be added to an aqueous solution of citric acid to the waste treatment lead to or during processing.

First, the waste of lead can be treated with an aqueous solution of citric acid to obtain a citrate Pb from Pb and/or PbO, and then an additional reagent, such as hydrogen peroxide or sodium citrate may be added to the solution to obtain the citrate of lead from other sources of lead, such as PbO2or PbSO4. Sequential processing of waste lead in this way allows you to optimize the conditions at each stage of processing for a particular reaction, thereby providing a high output on lead citrate and, therefore, a high rate of recycling of lead.

In an aqueous solution of citric acid may be added one or more additional the additional components. To modify the properties of the solution treatment can be added to the solvent. Added component may contribute to the dissolution of materials from waste lead or contribute to the dissolution of the reaction products of an aqueous solution of citric acid with the waste of lead. The solution can be added alcohol, preferably alkilany alcohol. The most preferred options are ethyl or methyl alcohols. In addition, the added component may contribute to the deposition of certain substances from the specified solution for processing. As specified additional components, you can use a metal hydroxide, preferably an alkali metal hydroxide, preferably potassium hydroxide or sodium hydroxide.

As an additional component, you can use acids, for example inorganic or organic acid. It is preferable that this was acetic, hydrochloric or nitric acid. Strong acids increase the solubility of the formed lead citrate in aqueous solution. Another advantage of using an inorganic acid, such as HCl, is that the reaction admixture or alloyed elements are dissolved in aqueous solution and, thus, are removed from the contaminated lead citrate. Less reactive p is mesnie elements, such as Sb, Cu, Bi and As, can also be selected by the reaction of their soluble chlorides with lead powder with the aim of deposition and excretion of these metals for further use.

As an additional component can be used inhibitor, such as a neutralizing substance, such as a base, or a saturated salt solution, such as sea water. The inhibitor reduces the activity of an aqueous solution of citric acid or reduces the activity of an additional reagent, or other component in the citric acid solution.

Additional components may be added before, during or after processing of waste lead.

Waste lead after treatment with an aqueous solution of citric acid can be again separated from the other components of rechargeable batteries that are intended for further processing or proper disposal. Recycled lead waste can be recovered using the methods of the present invention for the most complete selection of lead. First, the waste of lead can be treated with an aqueous solution of citric acid, and then separated from the solution. Dedicated pasta can then be processed with an aqueous solution of citric acid or treated with a solution containing an additional reagent, as described above. Step-by-step holding% the SAR processing allows each stage under optimum conditions for a more complete selection of citrate of lead from a source of waste lead.

The pH value of an aqueous solution of citric acid shall be not less than 1.4, 2 or 3. Preferably, the pH of an aqueous solution of citric acid did not exceed a value of 6 or 5. There can be any combination of upper and lower bounds of the intervals of pH. The optimum value of pH can be set by the concentration of citric acid in solution. Additionally, in an aqueous solution of citric acid can be added to any other acid to achieve a suitable pH. Aqueous citric acid solution may be a buffer solution. The amount of lead obtained in the form of citrate lead them lead waste, increases with the preferred pH values.

The temperature of the aqueous solution of citric acid can be controlled during processing. Preferably the temperature of the solution is maintained not lower than 0°C, 10°C or 15°C. it is Also desirable that the solution temperature did not rise above 25°C, 35°C or 45°C. be any combination of upper and lower boundary temperatures. As was established by the authors, the amount of lead obtained in the form of citrate of lead from lead waste, increases at the preferred temperatures.

Treatment of lead wastes aqueous solution of citric acid can be set in such a way as to affect the output lead citrate. Preferably, the time of reaction the AI should not be less than 1 minute, 5 or 10 minutes. It is also desirable that the response time does not exceed 90, 60, or 20 minutes. Any combination is possible intervals of time. As was established by the authors, the output lead citrate increases as the preferred time of reaction. The reaction can be stopped by removing the processed lead waste from the aqueous solution or by adding the inhibitor in the reaction mixture.

The ratio of the solid and liquid phases (the ratio of the mass of the original waste lead to the mass of water in the solution for processing), the concentration of citric acid, the concentration of possible additional reagents, the ratio of citric acid/lead and the ratio of citric acid/possible additional reagents are chosen so that to increase the output lead citrate.

As was established by the authors, the amount of bound lead in the solution remaining after removal of lead citrate, can be minimized, and consequently, to maximize the output of lead in the form of citrate in certain respects, the solid and liquid phases. The ratio of the solid and liquid phases should be 1:x, where x refers to the liquid phase and does not exceed 50, 25 or 10. Preferably, the value of x was at least 1 or 2. Any combination is possible the largest and smallest values in the specified interval.

The reaction of transformation of PbO2in lead citrate can proceed with the Maxi is real output under certain relations reagents. Preferably the molar ratio of PbO2the citrate of an alkali metal, preferably sodium citrate, should be 1:x, where x belongs to the alkali metal citrate. It is better that the value of x was at least 1, 2 or 3 and not more than 5, 6 or 7. The optimal value of x equals 4. There can be any combination of upper and lower bounds of the intervals of these relations.

The molar ratio of PbO2to H2O2can be represented in the form 1:y, where x corresponds to the H2O2. The value should not be less than 0.1, 0.5, or 1 and not more than 3 or 4. The most preferred value of y is 2. There can be any combination of upper and lower bounds of the intervals of these relations.

The authors showed that it is possible to choose conditions for the processing of lead, the corresponding optimal output lead citrate containing PbSO4.

The number of PbSO4in lead citrate can be controlled by selecting certain conditions of handling waste lead. The amount of citrate of metal used in the solution for processing, chosen so as to minimize or, on the contrary, most fully to carry out the reaction of transformation of PbSO4in lead citrate. Other reaction conditions can be varied to change the number of PbSO4in the final product of lead citrate. A qualified specialist in this field, those who IKI should be obvious, the choice of conditions largely depends on the type of lead waste. Unlimited subject to change: reaction temperature, reaction time, concentration of reagents, the ratio of the reactants and the ratio of liquid and solid phase.

Citrate lead is poorly soluble in aqueous solution of citric acid. When the processing of waste lead is completed, an aqueous solution containing citrate lead can be separated from the remaining undissolved lead waste. The separation can be performed by decanting the solution, filtration or centrifugation. Citrate of lead can then be obtained from the solution of the following methods.

Citrate of lead can be separated from solution by precipitation. The beginning of the deposition may contribute to the change in the solution temperature, the variation of the concentrations of the components of the solution or the introduction of the seed. In addition or as an alternative for beginning and continuing the deposition process in the solution can be introduced incremental components. In a preferred embodiment of the invention in a solution containing citrate lead, add acetic acid to start and develop deposition. Such techniques are well known to experts in the art, however, can be used and other methods of deposition, known to specialists.

Osujdenni the citrate of lead can be separated from the remaining solution by filtration, decanting or centrifugation. The separated solution can again be treated to maximize the release of citrate of lead from solution. Usually the citrate of lead is deposited in the form of the monohydrate of lead citrate.

As another possible method of deposition of lead citrate from a solution obtained after processing of lead waste and separate it along with other undissolved components. Then lead citrate can again be dissolved and separated from the lead impurities, and then precipitate and isolate, as described above.

The resulting lead citrate may be refined in subsequent stages. Citrate lead can be recrystallized. Other methods for removal of lead citrate will be obvious to experts in the given field of technology.

Preferably the obtained lead citrate is clean enough. The content of citrate of lead by weight shall be not less than 80%, 90%, 95% or 99%.

The resulting citrate lead turn in Pb and/or PbO, which can be used in the production of lead batteries.

Citrate lead can be turned into a Pb and/or PbO by annealing. To obtain Pb and/or PbO you can also use electrolysis. The method of obtaining citrate lead by electrolysis of an aqueous solution is not efficient enough due to the low solubility of the lead compounds. DL is increasing the citrate solubility of lead in the electrolysis process can be used for more solvents.

The calcination of lead citrate is particularly advantageous, because the citrate acts as a fuel in the firing process, which increases the temperature of annealing. This allows to reduce the required amount of energy supplied in the kiln, and hence to reduce the economic costs at the stage of annealing. This process is called "smokorowski synthesis". As sources of thermal energy contained in the citrate are biological sources, the process is carried out with a balance of zero carbon emissions. As can be seen from Figure 5, when the calcination of lead citrate allocated significant amounts of thermal energy.

Preferably the temperature of ignition is not less than 250°C, 350°C or 450°C and should not exceed 1100°C, 800°C or 650°C. be any combination of upper and lower bounds of temperature.

Obtained by calcination of Pb and/or PbO must be clean. The content of Pb and/or PbO by weight should be at least 80%, 90%, 95% or 99%.

The ratio of Pb to PbO in the product of annealing depends on the temperature of annealing. At high temperatures the dominant product is Pb, and at lower temperatures is dominated by the PbO. The calcination of lead citrate in air at atmospheric pressure provides a sufficiently pure product Pb at selected temperatures. Preferably the temperature is round of ignition is not less than 800, 900 or 1000°C.

The calcination of lead citrate in air at atmospheric pressure provides a sufficiently pure product PbO at selected temperatures. The temperature of calcination should not exceed 500°C. or 400°C.

The partial pressure of oxygen during combustion in the combustion chamber influences the composition of the combustion product. At low partial pressure of oxygen is the dominant product is Pb, and at high partial pressure of oxygen is dominated by the PbO.

At low partial pressure of oxygen getting Pb, practically free from PbO. This method eliminates pyrolysis method described previously for the production of Pb from lead citrate (see US 3,297,590). As described in that document and get vysokopetrovsky product due to the presence of very small particles of carbon powder obtained lead. The present invention eliminates the danger when working with pyrophoric Pb.

Preferably the combustion chamber is oxygen. While it is preferable that the partial pressure of oxygen during combustion in the combustion chamber was not less than 0.01 ATM, 0.05 ATM or 0.1 MPa and not greater than 0.5 ATM, 1 ATM and 5 ATM. The optimal value of partial pressure of oxygen is 0.21 ATM (atmospheric pressure). It is most preferable to carry out the calcination in air at standard pressure.

May is oboe combination of upper and lower bounds of partial pressures.

The product of the calcination can be controlled by selecting suitable reaction conditions. Therefore, you may receive a product that meets the requirements of a particular production, in which it will be used. Thus, the ratio Pb/PbO in the resulting product does not depend on the number of Pb, PbO, PbO2and PbSO4in the waste batteries.

Changing the flow rate of oxygen and the presence of impurities in the obtained lead citrate affect the final composition and chemical structure of the product of the calcination. In preferred embodiments of the flow rate is controlled. In some cases, lead citrate enter the additives before or during calcination.

Handling of waste lead can be chosen in such a way as to ensure the output lead citrate content PbSO4. Citrate lead may contain at least 0.1 wt.%, 0.5 wt.% or 1 wt.% PbSO4. This lead citrate contains not more than 3 wt.%, 5 wt.% or 10 wt.% PbSO4. There can be any combination of upper and lower limits weight percent impurities.

Preferably the calcination of lead citrate under such conditions, to PbSO4was not contaminated. Therefore, citrate lead not heated above the temperature of 1100°C, above which decomposition begins PbSO4.

At elevated temperatures bSO 4decomposes with evolution of SO2emissions which require environmental control over the environment. Processing of SO2for this reason it is technically expensive process. As was established by the authors, citrate lead can be turned into a Pb and/or PbO at the selected annealing temperatures without decomposition PbSO4and allocation of SO2.

Derived from citrate Pb and PbO can be used in industry. Pb and PbO are typically used in the production of lead batteries. As a rule, positively and negatively charged plates of lead acid batteries are made of lead-containing granules PbO. The product of the considered process of annealing can serve as a source of such lead-containing granules PbO. In addition, the conditions of preparation of Pb and/or PbO from lead citrate according to the method proposed in the present invention, allow to obtain a granular product suitable for direct use in the production of plates of lead acid batteries. The advantage of this method is that the product obtained after calcination and containing Pb and/or PbO with a small admixture of PbSO4described in this application can also be used in the manufacture of battery plates.

According to the usual procedure manufactured by Garrett, Borg is of plate electrodes, lead pellets PbO is mixed with dilute acid, as a rule, dilute sulfuric acid, and the resulting paste (active mass) is applied on lead net structure, which is then subjected to processing. During the process formed a small number of PbSO4that perform a very important function of linking granules, ensuring the mechanical strength of the plates of the batteries. The present invention presents a method of obtaining lead calcination product containing Pb and/or PbO with a small admixture of PbSO4. PbSO4mainly used as a binder in the manufacture of battery plates.

After the battery is assembled, PbO turns into a PbO2on the positively charged plate and Pb on the negatively charged plate. The transformation occurs in the electrolytic environment on the basis of an aqueous solution of sulphuric acid in the process of electrochemical oxidation and reduction with the use of electric current necessary force. PbSO4not exposed to the electrochemical process and continues to perform the role of a binder material in the plates of the battery. In modern methods of manufacture of accumulators metallic lead is used as the source material for the floor of the treatment PbO. Proposed in the present invention has the significant advantage as it allows to directly obtain the raw materials for the production of battery plates.

Preferred and/or distinctive features from one part of the description of the present invention may be used in any other part or Subpart of the description, unless otherwise expressly agreed.

Various other aspects and implementations of the present invention will be obvious to a person skilled in the art given the description above. All documents mentioned in the description, fully incorporated into the present description by reference.

Some aspects and preferred implementations of the invention are illustrated below using specific examples with links to graphic materials.

EXAMPLES

Synthesis of lead citrate

Were investigated reaction conditions for the synthesis and processing of lead citrate. Preliminary experiments were conducted using lead compounds that are commercially available, as models of waste paste rechargeable batteries.

Being sold chemically pure lead oxide (PbO, Acros Organics), lead dioxide (PbO2, Fisher Scientific), lead sulfate (PbSO4, Fisher Scientific), citric acid monohydrate (C6H8O7/sub> ·H2O, Acros Organics), and, if necessary, 27.5% solution of hydrogen peroxide (H2O2) in water (Aldrich) and sodium citrate (Na3C6H5O7·2H2O, Fisher Scientific) were used as starting materials.

Reactions were carried out in a beaker with magnetic stirrer with heating. In all experiments, the total volume of an aqueous solution of citric acid was 30 ml. of the Reaction mixture was stirred at a constant speed of 250 rpm, except in special cases. The reaction temperature was set and controlled by means of a contact thermometer. Completeness of the reaction was assessed by the change in color of the reaction mixture, and by selection and analysis of samples during the reaction.

At the end of the reaction the solution was filtered, and the solid phase was collected and analyzed. The filtered solutions were analyzed for residues of lead using atomic emission spectrophotometer with an induction-coupled plasma (ICP-AES) (Varian Liberty AX Sequentional ICP-AES).

Each experiment was performed at least three times.

In the following experiments the ratio of the liquid and solid phases was determined as the ratio of the mass of starting materials containing lead to the mass of water in the reaction mixture.

Under the lead content in the solution is meant the amount of lead in the form of ions, the remaining dissolved in the reaction mixture. The lead obtained from the solution contains precipitated lead citrate, and nerastvorim and unreacted starting material containing lead. The lead content in the solution is expressed in mass units, and the percent by weight of water. Thus, 0.5% of lead in 30 ml of solution equivalent to 0.15 g of lead.

A high percentage of lead means that the output lead from the reaction mixture is low. Accordingly, the low percentage of lead means that the level of recycling of lead is high.

It should be borne in mind that a high percentage of lead in the solution may indicate a high rate of conversion of starting materials of lead in lead citrate. A high percentage of lead means that under these conditions, the reaction of receipt of citrate of lead from solution has a low output.

Low interest lead concentration in the solution may indicate high yield lead-free processing in the form of nerastvorimogo and unreacted starting material. However, in practice, in the presence of a sufficient amount of the reagent was found that most of the raw materials reacted. In many reactions of the starting materials were completely consumed.

Getting citrate lead from PbO

Processing PbO aqueous solution of citric key is lots was carried out at different temperatures, the ratios of the reagents, the relationship of the liquid and solid phases under a variety of reaction time, as shown below in Tables 1 and 2. Upon completion of the reaction, the obtained precipitate was allowed to settle for 15 minutes and then was filtered. The collected solids were washed with distilled water, filtered and left to dry over night at 80°C to obtain Pb(C6H6O7)·H2O.

Getting citrate Pb from Pb

As was established by the authors, the behavior of Pb similar to PbO. Therefore, reaction conditions and the results described above for the PbO, in General, applicable to Pb.

Getting citrate lead from PbO2

Processing PbO2aqueous solution of citric acid and 27% solution of hydrogen peroxide was carried out at different temperatures, ratios of reactants, the relationship of the liquid and solid phases under a variety of reaction time, as shown below in Tables 3, 4 and 5. Upon completion of the reaction, the obtained precipitate was allowed to settle for 15 minutes and then was filtered. The collected solids were washed with distilled water, filtered and dried at 80°C to obtain Pb(C6H6O7)·H2O.

Sample Pb(C6H6O7)·H2O was obtained by the method described in Ferracin et al. Hydrometallurgy, 2002, 65,137. In accordance with this method PbO2treated aqueous solution is imoney acid for 24 hours to obtain lead citrate. Adding hydrogen peroxide to the original citric acid solution was allowed to carry out processing within 1 hour.

In further studies it was shown that the reaction of 1 mol of PbO2with 2 mol H2About2and 4 mol C6H8O7.H2O at 20°C for 60 minutes gives reproducible high yield of lead citrate.

Although PbO2not restored in the presence of one hydrogen peroxide under mild conditions, in the presence of citrate Pb4+quickly restored to Pb2+. It is believed that in the process of dissolution complex mechanism of hydrogen peroxide plays a role of reducing agent together with citric acid in solution.

Getting citrate lead from PbSO4

Processing PbSO4aqueous solution of citric acid and sodium citrate were carried out at different temperatures, ratios of reactants, the relationship of the liquid and solid phases under a variety of reaction time, as shown in Tables 6, 7 and below. Upon completion of the reaction, the obtained precipitate was allowed to settle for 15 minutes and then was filtered. The collected solids were washed with distilled water, filtered and dried at room temperature to obtain [3Pb·2(C6H5About7)]·3H2O.

Analytical study

Raw materials and final products on ayvali using infrared spectroscopy with Fourier transform (FT-IR; Tensor 27, Bruker Optics). The asymmetric stretching vibrations at 1599 cm-1and 1662 cm-1as well as symmetric stretching vibrations at 1520 cm-1and 1327 cm-1indicates the presence of carboxyl groups in the analyzed compounds and the strong absorption of the carboxyl group in this area. The spectral data are consistent with previously described in the literature (Kourgiantakis et al. Inorganica Chimica Acta, 2000, 297, 134; Bellamy, Tables of characteristic infrared group frequencies, infrared spectra of complex compounds, Chapman and Hall, 1980; Lin-Vien et al. The reference characteristic IR and Raman frequencies of organic compounds, Academic Press, London, 1991).

X-ray spectra (PCA) of the dried reaction products were removed on the x-ray diffractometer Philips (Cu α, 40 kV, 25 mA, calibrated using a Si standard). Radiographs compounds Pb(C6H6O7)·H2O allocated from the PbO and PbO2it was impossible to decrypt by using existing x-ray database (International crystallographic database).

Crystallographic data analysis (CIF file) for Pb(C6H6O7)·H2O, in the Cambridge database structures were taken from the server's chemical database (Chemical Database Service), and from these data received x-ray connection. Figure 1 shows compared the e x-ray spectra of citrate Pb(C 6H6O7)·H2O, selected from PbO (b) and PbO2(C)with the spectrum of Pb(C6H6O7)·H2O synthesized according to the method presented in Kourgiantakis ibid associated with the stored crystallographic (CIF) data (a). Also on the figure presents spectrum of the compound [3Pb·2(C6H5O7)]·3H2O obtained from PbSO4(d).

The structure of the material was studied using emission scanning electron microscopy (SEM) (FESEM-JEOL 6340F) and transmission electron microscopy (TEM) (TEM-JEOL 200CX).

Obtained using scanning electron microscope (SEM) image covered with palladium compounds Pb(C6H6O7)·H2O, synthesized from PbO and PbO2presented in figure 2(a) and (b) respectively. Obtained using scanning electron microscope (SEM) image of the compounds [3Pb·2(C6H5O7)]·3H2O covered palladium, synthesized from PbSO4presented in figure 2(C).

Image obtained with a scanning electron microscope (SEM)show the similarity of precipitation, synthesized from PbO and PbO2. SEM-image of sediment Pb(C6H6O7)·H2O, synthesized from PbO2indicates that the particle size is smaller than for sediment derived from the PbO. Not limited to any whether what about theory, consider that the reaction involving PbO is governed by the diffusion rate of the citric acid solution through the layers of Pb(C6H6O7)·H2O, deposited during the reaction. This assumption explains the larger size of the particles of Pb(C6H6O7)·H2O with less reaction time. For comparison, the structure of the Pb particles(C6H6O7)·H2O obtained from PbO2on the contrary , depending on the reaction rate, therefore, formed of particles of smaller size. SEM-image of the sediment [3Pb·2(C6H5O7)]·3H2O, synthesized from PbSO4indicates that formed such as lamellar crystals, but smaller and more broken than the crystals in figure 2(a) and (b).

Samples for transmitting electron microscopy (TEM) were prepared by dispersion of Pb(C6H6O7)·H2O in methanol using an ultrasonic bath and then placed on a porous carbon film, strengthened copper grid. Next, the methanol was allowed to evaporate. During the TEM analysis was unexpectedly discovered melt (deterioration) of the sample. Suggested that the process of decomposition compounds Pb(C6H6O7)·H2O as a result of bombardment by electrons during transmission electron microscopy. Figure 3 presents received by the th transmission electron microscope (TEM) image of the compounds Pb(C 6H6O7)·H2Oh, synthesized from PbO.

The calcination

Thermal characteristics of compounds Pb(C6H6O7)·H2O and [3Pb·2(C6H5O7)]·3H2O analyzed using differential scanning calorimetry (DSC) (Q600, SDT, TA Instruments). Samples placed in an atmosphere of pure nitrogen, was heated at a rate of 20°C/min In figure 4 shows the DSC curve for sample Pb(C6H6O7)·H2O, synthesized from PbO. Figure 5 shows the DSC curve for sample [3Pb·2(C6H5O7)]·3H2O, synthesized from PbSO4.

The influence of the temperature of annealing on weight loss during firing of lead citrate, synthesized from various source materials, is shown in Fig.6. The weight loss increases with the temperature of annealing from 300 to 350°C and then remains virtually unchanged in the temperature range of 350°C-400°C. This indicates that citrate can completely decompose at temperatures over 350°C. the weight Loss at a temperature of >350°C for sludge I and II sediment (synthesized from PbO and PbO2) was 48%, which is much higher than for sediment III (synthesized from PbSO4), amounting to 38%.

X-ray products calcination of the precipitate I presented on Fig.7 (Pb - triangles; PbO - circles). The products of annealing amorphous at 300°C and the transfer is completed in the crystalline oxide phase (orthorhombic lead oxide and metallic lead at 350°C, 400°C and 450°C. This also confirms the possibility of complete decomposition of the citrate at temperatures above 350°C in accordance with the results of thermal experiments on weight loss (as shown in Fig.6). The relative intensity of the peaks corresponding phase metal lead decreases, while the relative intensity of the peak phase of the oxide increases with the temperature of calcination between 350°C to 450°C in the course of annealing I, a similar pattern is observed for precipitation II and III. The relative content of PbO and Pb can be controlled using the temperature and partial pressure of oxygen.

Table 1
ExperimentnPbO/ nC6H8O7·H2OThe pace. (C)Reaction time (min)Content. lead R-re (%)
PbO-40.2520601.238
PbO-30.520600.821
PbO-20.75 20600.645
PbO-1120600.490
PbO-51.2520600.359
PbO-6220600.0455
PbO-72.520600.057
PbO-1220150.143
PbO-11120300.186
PbO-120600.490
PbO-1220150.144
PbO-14 130150.160
PbO-1540150.182

The ratio of the liquid and solid phases in the above experiments was 1:5.

Table 2
ExperimentThe pace. (C)Solid/Liquid phaseContent. lead R-re (%)
PbO-12201:50.144
PbO-18201:40.062
PbO-17201:30.017
PbO-17200.017
PbO-23301:30.067
PbO-2040/td> 0.103
PbO-18200.062
PbO-19301:40.097
PbO-24400.111

The reaction time in the above experiments was 15 minutes, and the ratio was equal to nPbO:nC6H8O7·H21:1.

Table 3
ExperimentH2O2(mol)With6H8About7·H2O (mol)The pace. (C)Content. lead R-re (%)
PbO2-83202.599
PbO2-1034202.955
PbO2-116 203.520
PbO2-9320Of 2,623
PbO2-244203.049
PbO2-46203.613
PbO2-123202.664
PbO2-564203.202
PbO2-66203.707
PbO2-83202.599
PbO2-943202.624
PbO2-126202.664
PbO2-103202.955
PbO2-244203.049
PbO2-56203.202
PbO2-113203.520
PbO2-446203.613
PbO2-66203.707
PbO2-2203.049
PbO2-34 4303.861
PbO2-13404.801

The ratio of the liquid and solid phases in the above experiments was 1:50. The experiments were carried out for 15 minutes.

Table 4
ExperimentSolid/Liquid phaseContent. lead R-re (%)
PbO2-21:503.049
PbO2-141:101.749
PbO2-191:51.476

The experiments were carried out for 15 minutes at 20°C in the presence of H2O2(4 mol) and C6H8O7·H2O (4 mol).

Table 5
ExperimentH2About2(mol)With6H8About7·H2O (mo is ü) The pace. (C)Stirring speed (rpm)Time (min)Content. lead R-re (%)
PbO2-20202.809
PbO2-214420250402.943
PbO2-2603.049

The ratio of the liquid and solid phases in the above experiments was 1:50.

Table 6
ExperimentnPbSO4/nNa3C6H5O7·2H2OReaction time (min)Temperature (°C)Content. lead R-re (%)
PbSOsub> 4-1100019.792
PbSO4-20500602022.156
PbSO4-3033328.580
PbSO4-402556.083
PbSO4-22022.156
PbSO4-505603023.954
PbSO4-64033.309
PbSO4-72016.286
PbSO4-905120 3018.246
PbSO4-104021.010
PbSO4-1605152043.619
PbSO4-173033.347
PbSO4-26022.156
PbSO4-712016.286
PbSO4-1530015.200

Table 7
ExperimentThe pace. (°C)Citric acid (mol)Content. lead R-re (%)
PbSO4 -220.17.341
PbSO4-210.255.367
PbSO4-20200.53.647
PbSO4-131.02.277
PbSO4-181.52.220
PbSO4-192.02.204
PbSO4-20203.647
PbSO4-25300.54.150
PbSO4-28404.802

All reactions in Tables 6 and 7 were carried out for 60 minutes, and nPbSO4:nNa3C6H5O7·2H2O was 1:2. The ratio of liquid and TV is rdeu phases was equal to 1:3.

Table 8
ExperimentSolid/Liquid phaseContent. lead R-re (%)
PbSO4-131:202.277
PbSO4-291:101.078
PbSO4-261:51.048

All reactions were carried out for 60 minutes in the presence of citric acid (1 mol), and the ratio nPbSO4:nNa3C6H5O7·2H2O was 1:1.

1. The method of extraction of lead from lead waste containing one or more of Pb, PbO, PbO2and PbSO4that includes the following stages:
a) treatment of lead wastes aqueous solution of citric acid with getting lead citrate,
b) isolation of citrate of lead from aqueous solution, and
c) transforming the selected lead citrate in Pb and/or PbO.

2. The method according to claim 1, characterized in that the lead citrate is a Pb(C6H6O7) and its hydrates, as well as product processing PbSO4aqueous solution of citric acid and sodium citrate.

3. The method according to claim 1 or 2, featuring the the action scene, what a waste of a lead is a lead paste from the battery.

4. The method according to claim 1 or 2, characterized in that the pH of an aqueous solution of citric acid is in the range from 1.4 to 6.0.

5. The method according to claim 4, characterized in that an aqueous solution of citric acid further comprises a metal citrate.

6. The method according to claim 5, characterized in that the metal citrate is a citrate.

7. The method according to claim 1 or 2, characterized in that an aqueous citric acid solution further comprises hydrogen peroxide.

8. The method according to claim 7, characterized in that the waste of lead contain PbO, with the molar ratio of PbO to hydrogen peroxide is in the range from 1:0.1 to 1:4.0 and/or the molar ratio of PbO to citric acid is in the range from 1:1 to 1:7.

9. The method according to claims 1, 2 or 5, characterized in that the temperature of the aqueous solution of citric acid support in the interval from 0 to 45°C.

10. The method according to claims 1, 2 or 8, characterized in that the ratio of liquid and solid phases contained in these wastes lead to the liquid solution is in the range from 1:1 to 1:50.

11. The method according to claim 10, characterized in that the selected lead citrate turn in Pb and/or PbO by calcination.

12. The method according to claim 11, characterized in that the temperature of calcination is in the range from 250 to 1100°C.

13. The method according to claim 9, characterized those who, that the oxygen partial pressure during annealing is in the range from 0.01 to 5 ATM.

14. Method of recycling lead batteries containing one or more of Pb, PbO, PbO2and PbSO4that includes the following stages:
a) obtaining a lead paste from the battery,
b) processing the lead paste from the battery with an aqueous solution of citric acid to produce lead citrate,
c) isolation of citrate of lead from aqueous solution,
d) transforming the selected lead citrate in Pb and/or PbO, and
e) the inclusion of Pb and/or PbO in the plate of the rechargeable battery.

15. The method according to 14, characterized in that the lead citrate is a Pb(C6H6O7) and its hydrates, as well as product processing PbSO4aqueous solution of citric acid and sodium citrate.

16. The method according to 14 or 15, characterized in that the lead citrate allocate together with PbSO4.

17. The method according to item 16, characterized in that the Pb and/or PbO include PbSO4.



 

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2 tbl, 2 ex

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