Used Lead Acid Battery / Used Lead Acid Battery Plant

Used batteries pose a threat to our environment and should be managed properly for disposal. Hazardous material makes up most of the ingredients of this product that can leach out into our waterways, contaminating our future resources. Some local agencies currently have imposed regulations to manage this material properly for Used Lead Acid Battery Recycling.

Waste batteries may be considered hazardous waste because of their corrosivity, reactivity, or toxicity. According to battery-producing industry sources, nickel cadmium batteries typically exhibit hazardous waste characteristics, whereas low mercury alkaline and carbon-zinc batteries do not. Alkaline batteries with higher concentrations of mercury and larger mercury batteries would be likely to test as hazardous, and some lithium batteries might be considered reactive. Lead acid batteries are considered corrosive, as well as toxic. (Gel cell batteries, are a subset of Lead acid batteries, and should be treated the same.) Button batteries may or may not test as hazardous, depending on their type and size.

Lead acid batteries are made up of plates, Lead, and Lead oxide with a 35% sulfuric acid and 65% water electrolyte solution. Lead acid batteries represent almost 60% of all batteries sold worldwide. They are used for starting, lighting, and ignition (SLI) service on automobiles and trucks, as well as providing power for automobiles, forklifts, submarines, and almost all other motive vehicles. Lead acid batteries are noted for their ability to withstand varied forms of maltreatment, and are often used as back-up power sources should the primary battery or electrical power fail. Lead acid batteries use a simple set of reactions to provide energy. All styles of these batteries use the same active materials. The positive electrode is Lead dioxide (PbO2), which is converted to Lead sulfate (PbSO4), while the negative electrode is a spongy metallic Lead (Pb), which is also converted to Lead sulfate (PbSO4). The electrolyte is a dilute mixture of sulfuric acid that provides the sulfate ion for the discharge reactions. There are three common types of Lead acid batteries: flooded (or wet), absorbed glass mat (AGM), and gel cell.

Flooded (or wet) Lead acid batteries are those where the electrodes / plates are immersed in electrolyte. Since gases created during charging are vented to the atmosphere, distilled water must be added occasionally to bring the electrolyte back to its required level. The most familiar example of a flooded Lead acid cell is the 12V automobile battery.

Absorbed glass mat (AGM) batteries are a type of sealed Lead acid or valve-regulated Lead acid (VRLA) battery where the electrolyte is immobilized. A highly porous and absorbent micro fiber glass mat, which is partially filled with electrolyte of the desired specific gravity, is used as the separator.

Gel cell batteries are a type of sealed Lead acid or valve-regulated Lead-acid (VRLA) battery. In gel cell Lead acid batteries, fumed silica is added to the electrolyte, causing it to harden into a gel. On subsequent charges some water is lost, drying the gel until a network of cracks and fissures develops between the positive and negative electrodes providing a path for the oxygen recombination.

Some varieties of Lead acid batteries are rechargeable. Newer varieties of Lead acid batteries have been designed that are completely sealed, allowing for cleaner energy sources and a lowered environmental affect when recycled.

Battery Recycling

Batteries contain a range of metals which can be reused as a secondary raw material. There are well-established methods for the recycling of most batteries containing Lead, nickel-cadmium, nickel hydride and mercury. For some, such as newer nickel-hydride and lithium systems, recycling is still in the early stages.

There are a number of different recycling processes for batteries, which are aimed at recovering a variety of materials:

• Lead can be recovered by either separating the different materials that make up the battery (Lead, plastics, acid, etc.) prior to metallurgical processing. Alternatively, batteries can be processed as a whole through heat treatment in a particular type of furnace with metals being recovered at the end of his process.
• NiCd batteries can be reprocessed through a similar thermal technique, which recovers cadmium and iron-nickel for steel production.
• Batteries containing mercury are most commonly processed using a vacuum-thermal treatment, in which the mercury vaporises. It condenses and eventually solidifies when temperatures are reduced and can then be reintroduced into the material cycle.
• NiMH batteries are reprocessed by mechanically separating the individual materials (plastic, hydrogen and nickel) within a vacuum chamber to prevent the escape of hydrogen. The output of this process is a product with high nickel content which can be used in the manufacture of stainless steel.
• Li-Ion batteries are currently reprocessed through pyrolysis (heat treatment) with the primary recovery the metal content.
• Zinc-carbon/air and alkaline-manganese batteries can be reprocessed using a number of different methods, which include smelting and other thermal-metallurgical processes to recover the metal content (particularly zinc).