Technologies for Lead Recycling Plants

Lead is a metal widely used in industry and commerce. As a metal, it can be recycled from different sources, the most common source currently being depleted lead batteries.

 

However, the process of collecting, disposing, recycling and refining lead has traditionally been a highly polluting and inefficient process, where it is common to have residual lead or slags of 30%, which are discarded or confined. Because lead is a non-biodegradable material with easy organic adherence, it makes its presence in living beings and ecosystems highly toxic.

 

In the case of used or exhausted batteries, the environmental and health impact is greater. Since in addition to lead and other highly toxic metals such as nickel, cadmium and antimony; the presence of sulfuric acid in batteries makes them major sources of contamination. Being the spill of sulfuric acid into the environment, one of the main pollution problems in this process.

 

Our technological developments for lead recycling and used battery management allow for greater efficiencies and minimal environmental and health impacts than traditional recycling technology.

lead recycling
lead recycling
lead recycling

1. Certified Final Disposition for Used Lead Batteries.

We provide traceability in the disposal of this highly toxic waste. We certify the final disposal of any lead battery in the recycling plant closest to the point of origin. This makes it possible to guarantee compliance with the UN Basel Convention for the Transboundary Management of Hazardous Waste. This agreement indicates that any waste must be treated as close as possible to the point of origin. Thus reducing the risks of contamination by transfer.

 

Through the certified collection and final disposal of used batteries, it is guaranteed that none of its toxic components is discarded before entering the nearest recycling plant. Since it is common for informal collectors to dump sulfuric acid from batteries into the environment before delivering them to the recycling plant.

lead recycling
lead recycling
lead recycling

2. Traditional Lead Refining Process

Traditional Battery Recycling Technology takes the following steps as standard:

 

1. Battery crushing and sulfuric acid drainage:

  • In this initial stage, the drained sulfuric acid is neutralized with some alkalizing agent, usually calcium hydroxide or lime. This is because its cost is less than using sodium hydroxide.

  • The calcium sulfate (gypsum) formed is filtered and pressed, forming gypsum blocks which are later sent to a landfill. The gypsum formed cannot be used in any process, since within it, a high amount of lead sulfate is carried, which causes a fraction of lead to reach the landfill and the environment.

2. The mass of lead and crushed plastic are separated by flotation, where the plastic is recovered to later be recycled in the manufacture of new battery boxes.

3. The wet lead and lead sulfate go to the first smelting step, where the first stage of lead production is produced, or commonly known as furnace lead:

  • The first stage of lead smelting is designed to reduce the different chemical species of lead (lead sulfate, lead oxide, etc.) and extract the lead to bring it to a concentration between 60% to 80%.

  • Reducing agents such as petroleum coke, sodium carbonate and iron are added at this stage.

  • As a result of this stage, what is known as furnace slag, or non-leached lead, is formed. This lead, which is a mixture of lead and impurities, is removed from the process and sent to confinement. The lead slag with traditional technology can be in the order of 30% of the total material melted in the first stage.

  • Another of the great pollutants present in this stage is sulfur. This is because the remaining sulfur that remains from the sulfuric acid passes to the primary furnace. The sulfur and hydrogen sulfide produced in this stage vaporize and are expelled into the environment, causing acidity and a bad odor in the vicinity of the recycling plant. In some processes, sleeve filters or similar are used in the chimneys to trap the non-combusted solids, being not very effective in retaining gases.

  • In addition, in the heating process for the foundry, bunker is used, with the environmental and technological challenges that this fuel poses.

4. The lead recovered from the first smelter goes to a refining stage, where the lead is brought to a purity greater than 99%:

  • The lead is brought to a temperature of 450 ° C where sawdust is added to extract remnants of the first smelting stage.

  • Later, Sodium Nitrate is added to oxidize the Antimony, Arsenic and Tin present in the lead, which are removed by flotation in the molten lead. These metals are removed and taken to confinement.

  • Finally, Sodium Hydroxide and Sulfur are added to remove the remaining iron and copper. Once these contaminants are removed, a purity greater than 99.5% lead is achieved.

 

All this process of traditional technology entails a high consumption of reducing and oxidizing materials. Which produces large amounts of slag and untreatable solid waste. And as these materials are present in the foundry, a significant part of the combustion energy is lost in these impurities.

 

This makes the traditional lead smelting process highly costly and polluting.

lead recycling

3. Our Technology for Lead Battery Recycling

Our technological developments allow the lead recycling industry to access great economic savings, with a focus on efficiency and chemical engineering. In addition, the advances made in lead recycling allow benefits to the environment and health.

 

Here are our technology and process management modules:

a. Sulfuric Acid Reconditioning Technology

The sulfuric acid from the crushing of batteries is recovered and enters our sulfuric acid stabilization and reconditioning plant. Where the impurities are removed and the concentration of sulfuric acid is leveled.

 

The resulting sulfuric acid is a stabilized low metal acid at a 20% concentration. This acid is marketed in different industries, where it is used in processes such as:

 

  • PH control in wastewater treatment plants.

  • PH control in cooling towers.

  • Pickling of metals in foundry plants.

  • Manufacture of raw materials such as copper, iron or aluminum sulfate.

  • Acid leveling in batteries in use.

 

With this, the cost of acid neutralization is avoided, and an added value is given to a residual, making it a highly engineered product.

Acid Before Treatment

20% Reconditioned Acid

Sale for Industrial Processes

b. Technology for Slag Reduction and Minimization of Foundry Additives

Our chemical lead oxidation - reduction technology allows the following benefits to be obtained in primary smelting and refining processes:

 

  • Minimization of sulfur and lead sulfates in the primary smelting furnace feed.

  • Lead slag reduction below 10%.

  • Minimal consumption of coke and iron.

  • Sequential elimination of the use of sodium carbonate as a slag binder.

  • Elimination of the use of sodium nitrate in the refining stage.

  • Energy efficiency in the use of environmentally friendly fuels.

 

With these technologies, the company can significantly reduce its slag production and eliminate the use of expensive chemical additives such as sodium nitrate and sodium carbonate.

lead recycling
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