NEW METHODS IN LEAD RECYCLING OF WASTE BATTERIES

 

 

 

There are many ways to convert battery lead to raw lead. These methods can be divided into two groups of regenerative and electrolysis. In electrolysis, using electricity and electrodes in an electrolyte containing lead will lead to recovery. This method has fundamental flaws, and is only used in specific manufacturing lead foil. The disadvantages of this method include :

  1. The high initial cost of investment for the construction of reservoirs and electrodes.
  2. Using the electrodes over time.
  3. The low yield but high purity.
  4. Due to the high amount of power consumption, the overall production cost will be dear.

The oldest method is to use concentrates of lead sulfate and to recycle lead directly by fossil fuels or natural gas which is difficult. In this method a large proportion of the carbon needed to recycle lead is provided by the plastic battery cases. The recycling reaction is based on carbon dioxide and carbon which is easy and very efficient, but it is undesirable from an environmental standpoint. The disadvantages of this method are as follows:

  1. The emission of polluting gases such as carbon dioxide and sulfate gas play an important role in the air pollution and changes in ecosystem of the region.
  2. The probability of acid rainfalls resulting from SOx gases in the region.
  3. The undesirable odor in the environment and the possibility of leakage of lead-smeared wastewater.
  4. The evaporation of some percent of lead compounds having adverse environmental and humane impacts so that lead factories in residential environments are always considered a risk.
  5. Creating large amounts of wastewater for which completely separate units are needed to be built.
  6. The use of high-temperature furnace in approximately 1000 . These furnaces only operate using fossil fuels or electricity that are either pollutants or are costly.
  7. There is no possibility of the complete separation of metal components in this method.

The following figure shows the overall process in this method.

figure 1

New methods that are being conducted are mostly on the basis of the detachment of battery parts and recycling of waste batteries separately, based on which the battery cases are sent to polyethylene recycling factories and battery acid after recycling will be used to make new batteries. Lead compounds contain at least 50% of lead sulfate. The recycling and fusion process of these compounds is carried out in furnaces and in the presence of Coke as a recycling agent to gain pure lead. Lead compounds involve the emissions of Sox gases and cause irreparable damage to the environment. 1-4 reactions are reactions that are carried out at this stage to reduce the emission of such gases as less as possible.

Regarding all these operations, this method has the following disadvantages:

  1. The slow production process.
  2. The emissions of sulfur and carbon dioxide (in comparison to other methods, its emission is less).
  3. It is extremely costly for initial production and filter.
  4. The need for the fusion furnace for the extraction and ingot casting.

The following figure shows the process of recycling in this method.

figure  2

In the new methods of removing sulfur and lead, sulfate with sodium carbonate is used. The final product is used as pulp for recycling lead in the furnaces. This leads to a sharp reduction of SOx emissions.

New methods of extracting lead from old batteries:

In the previous method, using a desulfurized solution results in the production of lead compounds, whereas these compounds, even though scarce, still carry the risk of environmental pollution. The new methods, attempts have been made to reduce extraction temperature. In addition to it, the use of new materials has significantly reduced the pollution. For example, in one method, the use of a strong acid produces soluble compounds of lead at various concentrations. Therefore, the lead production in this sample at 350 ℃ and by adding Nano-catalysts for sequestration will be possible while reducing the environmental risks and having higher economic efficiency as well. The product obtained from this process can all be recycled and sold. This complex has succeeded in the introduction of a new method based on the Basel standards through the use of new ways and its reliance on technical knowledge of its staff. In addition, the conducted experiments show that this method can result in the production of highly purified lead. The advantages of this method can be mentioned as following :

  •  
  • Timing of lead extraction process.
  • The initial and reaction temperature has been low and less energy is required for the process.
  • Reduction of time and temperature extraction process prevents the oxidation and overshooting of lead as slags.
  • The low operating temperature (60 ° C maximum) and a minimum amount of sulfur gas emission.
  • Low initial production costs so that only a tank with heating and stirring capability is needed.
  • Receiving the Basel standards in the nonproduction of toxic waste.
  • The side products capable of industrial sales.
  • The possibility of reuse of the solution
  • The selective liquidation of lead compounds.
  • No need for ingot casting.
  • Ability to produce various types of lead salts  such as lead Citrate, lead Nitrate and Oxides.

It should be noted that this method, besides being environment-friendly, requires low initial investment and therefore is quite comparable to the old methods.

Lead X-Ray diffraction analysis

Name and formula
Reference code: 00-003-1153
PDF index name: Lead
Empirical formula: Pb
Chemical formula: Pb
Status, subfiles and quality
Status: Marked as deleted by ICDD
Subfiles: Inorganic
Quality: Blank (B)
Comments
Deleted by: Deleted by NBS card.
Sample source: Specimen from Langban, Sweden.
References
Primary reference: Harcourt., Am. Mineral., 27, 89, (1942)
Peak list
No. h k l d [A] 2Theta[deg] I [%]
1 2.84000 31.475 90.0
2 2.45000 36.650 70.0
3 1.74000 52.553 80.0
4 1.49000 62.260 100.0
5                     1.42000    65.703      40.0
  6                     1.23000    77.549      10.0
  7                     1.13000    85.950      70.0
  8                     1.11000    87.889      70.0
  9                     1.01000    99.401      70.
Stick Pattern

New methods of extracting lead from old batteries:

  •  
  • Timing of lead extraction process is so fast.
  • The initial and reaction temperature has been low and less energy is required for the process.
  • Reduction of time and temperature extraction process prevents the oxidation and overshooting of lead as slags.
  • The selective liquidation of lead compounds.
  • The side products capable of industrial sales.
  • Ability to produce various types of lead salts such as lead Citrate, lead Nitrate and Oxides.
  • No need for ingot casting.
  • The low operating temperature (60 °C maximum) and a minimum amount of sulfur gas emission.
  • The possibility of reuse of the solution
  • Low initial production costs so that only a tank with heating and stirring capability is needed.
  • Receiving the Basel standards in the nonproduction of toxic waste.
JPatent
  •  
  •  
  •  
  •  
  •