It is predicted that the annual demand for batteries will exceed US $17 billion by year 2000. The fastest growing market segments are the non-lead acid rechargeable battery type which include NiCd, NiMH and Li-ion chemistries. The question one asks is "Where will the mountains of batteries go when spent?"
The answer is recycling. Most industrialized countries passed laws for proper disposal of spent batteries to protect the environment. Recycling plants have been built that reclaim the battery chemicals, as well as steel, copper and other metals, even plastics.
The battery recycling plants sort the batteries and separate the lead-acid and lithium batteries from the NiCds. The process starts by chopping the battery cells into small pieces which are heated until the metal liquefy. The combustible material is burned off, leaving a black slag on top that is periodically removed with a slag arm. The different alloys settle according to their specific weights and are skimmed off like cream from raw milk.
Cadmium is relatively light and vaporizes easily at high temperatures. What appears like a pan boiling over, the cadmium vapor is blown by a fan into a large tube which is cooled with water mist, causing the vapors to condense. Once solidified, the various material are compressed into bales and sent to another facility where cadmium, zinc, silver, copper and other materials are removed, The cadmium content is about 30 percent.
Unfortunately, the present recycling process takes six to ten times the energy to recycle a battery than it takes to obtain such elements as zinc and manganese by other means. A new process is being explored that will be both energy efficient and cost effective. Operational by the year 2000, the batteries will be dissolved in a reagent solution and the metal components recovered. Spent reagent will be recycled without forming any atmospheric, liquid or solid wastes.
Companies using large quantities of batteries return nearly all for recycling. Homeowners have the lowest return ratios, a habit that is expected to improve once more recycling repositories are available and better environmental awareness is emphasized.
NiMH batteries are newcomers to the field of battery cycling. Presently, no practical methods are available to retrieve the raw materials of the NiMH cells. Eventually, recycling will be available for this chemistry as well. Because of the similarities between NiMH and NiCd, the two battery types are often thrown together when it comes to recycling. In economical terms, the NiCd yields more reusable materials than the NiMH with the same amount of energy invested and pollution generated.
The lead acid is the most recycled battery today. Programs are in place to ensure that spent batteries are returned to the vendor. In the USA, 98% of all lead acid batteries are recycled. (In comparison, 65% of aluminum cans, 59% of newspapers and 37% of glass bottles are recycled.)
Lithium batteries contain non-toxic metals. The concern of disposal lies in the possibility of fire if the metallic lithium is exposed to moisture while the cells are corroding. The Li-ion batteries, on the other hand, do not have metallic lithium and this disposal problem does not exist. Sony and Sumitomo Metal have developed a technology to recycle the cobalt content from the Li-ion batteries. Some lithium systems, however, contain toxic and flammable electrolyte.
A large proportion of all batteries consumed are non-rechargeable (primary). Now that mercury has been removed, primary batteries are considered less damaging to the environment than rechargeable batteries (secondary). However, their disposal remains a problem in light of the fact that primary batteries are discarded after only a one-time use.
Caution: In no instance can a battery be incinerated. Disposing a battery by burning will cause them to explode.
Important: In case of rupture, leaking electrolyte or any other cause of skin or eye exposure to the electrolyte, immediately flush with water. If eye exposure, flush with water for 15 minutes and consult physician.