Great care should therefore be employed when removing acid by draining thecasing. Once it is collected, it is important that the acid be neutralised toincrease the pH (and hence reduce its corrosiveness) but also to remove thelead dissolved in the acid.

The acid should be diluted with an excess of water to give a 5 to 10-folddilution. The liquid should then be neutralized by mixing with an equal volumeof agricultural lime, or other alkaline material containing calcium carbonate, orsodium hydroxide. Use ofhydrated lime has the advantage of lower cost per unit of neutralizing capacitywhen compared to sodium hydroxide.

Coral rock may be an alternative in many PICs, although use of calciumcarbonate or sodium hydroxide is preferred. The coral rock to be used shouldbe dead coral, preferably washed ashore which can be crushed finely andadded to the liquid requiring neutralization. If the ro ck is to be used, it shouldbe crushed into very small particles to increase the surface area so that the neutralization reaction can proceed as fast as possible. If large particles areadded to the acid it may take a lot longer for the same neutralization level tobe reached.

After the additive has been mixed with the acid, universal paper is to be usedto test the resulting pH of the liquid. (Universal paper can be purchasedcheaply from chemical companies, again contact details are included later).Once the liquid has reached a pH of 7.5 it has been neutralised and is safe todischarge to the environment. It is important to ensure that the pH is withinthe range of pH 7-8, as outside of this range there will be levels of lead stilldissolved into solution.

To remove the lead precipitates after neutralization, the solution must then befiltered. Soil can be used as an appropriate filter medium. A column of soilcontained in a metal container ie. 44 gallon metal drum with each endremoved, may be suitable for this purpose. The liquid once drained throughthis filter is ready for release to the environment.

The soil should be regularly replaced if large quantities of battery acid is beingfiltered. It is crucial that the soil must be encapsulated by mixing with wetconcrete and can then be disposed to landfill as general waste. If the soil isnot mixed with concrete, the lead will leach through the soil and becomemobile in landfill leachate in high concentrations.

Another way to treat acid is to process it by reacting it with sodium hydroxideto convert it to sodium sulfate, an odorless white powder used in laundrydetergent, glass and textile manufacturing. This process takes a material thatwould be discarded and turns it into a useful product.

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.

Classification:
Generally there are two types of Lead-acid storage batteries, based on their method of construction Flooded or Sealed. Flooded (or wet) Lead acid batteries are those where the electrodes / plates are immersed in electrolyte. Sealed Lead acid or valve-regulated Lead acid (VRLA) battery where the electrolyte is immobilized. All Lead-acid batteries produce hydrogen and oxygen gas (gassing) at the electrodes during charging through a process called electrolysis. These gases are allowed to escape a flooded cell, however the sealed cell is constructed so that the gases are contained and recombined.

Lead Acid Battery waste Recycling
The grid structure in both batteries is made from a Lead alloy. A pure Lead grid structure is not strong enough & therefore other metals like antimony, calcium, tin, and selenium in small quantities are alloyed for added strength and improved electrical properties.
The electrolyte in a Lead-acid battery is a dilute solution of sulfuric acid (H2SO4). The negative electrode of a fully charged battery is composed of sponge Lead (Pb) and the positive electrode is composed of Lead dioxide (PbO). The separator is used to electrically isolate the positive and negative electrodes.

Waste Batteries:
The typical Lead-acid battery comprises of: metal grids, electrode paste, Sulphuric acid, connectors and poles of Lead alloy, and grid separators made up of PVC. The battery components are contained in corrosion and heat-resistant housing usually composed of plastic (polycarbonate, polypropylene, or polystyrene).

The composition of waste batteries include:Lead: 25-30%(alloy, components, (grids, poles))Electrode paste (fine particles of lead oxide and lead sulphate): 35-45%Sulphuric Acid 10% to 15%Polypropylene: 5-8%Other plastic (PVC, other plastic): 1-3%Other materials 0-5%
In the past, grids were mainly made from antimony Lead alloys, but new trends show an increase in the usage of calcium Lead alloys. The electrode paste of used batteries is a mixture of Lead sulphate and Lead oxide. The composition of typical battery scrap material is given in Table.

Drained Lead Acid Battery Scrap
Drained Lead Acid Battery Scrap shall consist of whole drained lead/acid batteries. May contain plastic or rubber cases, but may not contain wooden, metal or glass cases. Similar to ISRI code RAINS.
This is the most preferred type of raw material for Lead recyclers/smelters or recycling/smelting Industries. We provide Rotary based Smelting plants for processing such raw material with equipments & machines for handling & separation of Lead.

Lead additions improve the appearance and cutting properties of crystal glass. Small additions are also made to optical and electrical glass. The major application of leaded glass is in television screens and computer monitors to protect viewers from the harmful X-rays generated by these appliances. Lead-containing glazes are used for some pottery, tiles and tableware.

Lead compounds were universally added to petrol to improve its efficiency at low cost. This has been the major source of lead emissions to the environment. It is now being phased out almost universally because of concerns about health impacts.