Cadmium battery recycling

Nickel-cadmium batteries are rechargeable because the nickel and cadmium hydroxides products adhere tightly to the electrodes. More than 1.5 billion Ni-Cd batteries are produced every year. These batteries are not without drawbacks, however. Cadmium is a toxic heavy metal that adds weight to the battery. Moreover, even rechargeable batteries degrade eventually and must be recycled or disposed of in a benign way. 

Shredded circuit boards. Circuit boards are metal boards that hold computer chips, thermostats, batteries, and other electronic components. Circuit boards can be found in computers, televisions, radios, and other electronic equipment. When this equipment is thrown away, these boards can be removed and recycled. Whole circuit boards meet the definition of scrap metal, and are therefore exempt from hazardous waste regulation when recycled. On the other hand, some recycling processes involve shredding the board. Such shredded boards do not meet the exclusion for recycled scrap metal. In order to facilitate the recycling of such materials, U.S. EPA excluded recycled shredded circuit boards from the definition of solid waste, provided that they are stored in containers sufficient to prevent release to the environment, and are free of potentially dangerous components, such as mercury switches, mercury relays, nickel-cadmium batteries, and lithium batteries. 

Nickel-cadmium rechargeable batteries are being researched. Alternatives such as cadmium-free nickel and nickel hydride systems are also being researched, but nickel-cadmium batteries are unlikely to be totally replaced. Nickel-cadmium batteries can be reprocessed to reclaim the nickel. However, currently, approximately 80% of all nickel-cadmium batteries are permanently sealed in appliances. Changing regulations may result in easier access to these nickel-cadmium batteries for recycling. 

To reduce the amount of waste, start with pollution prevention. Starting with pollution prevention leads to less or no leftover waste that could potentially become hazardous wastes. The use of rechargeable batteries results in a longer life span and use fewer batteries. However, rechargeable batteries still do contain heavy metals such as nickel-cadmium. When disposing of rechargeable batteries, recycle them if possible. 

Like many technological innovations, nickel-cadmium batteries carry risks as well as benefits. After being discharged repeatedly, they eventually wear out. In theory, worn-out nicad batteries should be recycled. In practice, however, many end up in garbage dumps. Over time, discarded nicad batteries release toxic cadmium. The toxicity of this substance makes it hazardous to the environment, as cadmium can enter the food chain. Long-term exposure to low levels of cadmium can have serious medical effects on humans, such as high blood pressure and heart disease. 

In 1990, 10,600 tons of soil contaminated with cadmium and lead from a former battery recycling facility in Savannah, Illinois, were treated with the STC Remediation, Inc., reagents. The vendor states that the reagents, on-site technical support personnel, and the on-site quality assurance personnel cost 51.00 per ton of soil treated (D113382, p. 13). 

Despite the fact that cadmium is very toxic and that the number of batteries based on this metal (i.e. nickel-cadmium cells) is very significant, there are very few recycling plants in operation. One very effective recycling process has been designed and developed by SAFT NIFE AB in Sweden to treat both industrial and consumer nickel-cadmium batteries. The flow... 

Morrow 1998, The Importance of Recycling and Performance to Life Cycle Analyses of Nickel Cadmium Batteries, S International Nickel-Cadmium Battery Conference, Prague, Czech Republic, September 20-21,1998. 

Spent Portable Nickel-Cadmium Batteries Quantities processed for recycling in 2000... 

Figure 2. Nickel-Cadmium Batteries Collected for Recycling in North America...

In the Cadmium Recovery Facility, fNMETCO reclaims cadmium from spent NiCd batteries and produces a high purity cadmium shot known as Cadmet A or Cadmet B. The majority of recycled cadmium is returned to the battery industry for the production of new nickel-cadmium batteries. fNMETCO s Cadmium Recovery Facility began operations in 1995, and since that time, fNMETCO has been the only true recycler of NiCd batteries in North America. 

ENVIRONMENTALLY SOUND RECYCLING OF NICKEL CADMIUM BATTERIES... 

There are only a handful of appropriate facilities in the world for reclaiming nickel cadmium batteries, and all are subject to scrutiny and permitting by their national governments. Therefore, identification of an appropriate recycling destination is simple and, so long as collected materials are routed to one of these facilities, the transboundary shipping requirements that make up the OECD amber scheme are unnecessaiy. 

Well-established Ni-Cd battery recycling plants are operational in France, Germany and Sweden. These plants, one of which has been in operation since 1977, recover the cadmium, nickel and iron from batteries collected throughout Europe and elsewhere across the world. 

Ever since the nickel-cadmium battery came into existence, experts have been studying ways to recycle it. The first really widely-used batteries were of the open type. Their recovery at the end of their life was due to the ease with which they could be opened and the positive electrodes isolated so as to re-use the nickel. 

In Japan, NIPPON RECYCLE CENTER developed its process in the 70 s, although its dedicated plant specifically designed to treat nickel-cadmium batteries only came into operation in Korea in 1984. 

NIFE, one of the two largest manufacturers of industrial nickel-cadmium batteries in the world, began recycling cadmium by treating its own waste before treating its customers spent batteries. 

The situation of the nickel-cadmium battery manufacturers is different they are rarely involved in the treatment of the waste they produce or of their customers spent batteries, except for NIFE in Sweden and ENERGIZER in Florida, USA (which has a small unit basically designed to treat manufacturing dust and sludge from the wastewater treatment system). However, they provided the economic means for both the start-up and the growth of the main recycling companies currently in operation. 

Moreover, the cost of treating nickel-cadmium batteries is quite clear - the supplier contributes to the cost, i.e. that part of the cost not covered by recycling the nickel and the cadmium - and significantly below the cost for saline and alkaline batteries. 

No plant recycling nickel-cadmium batteries currently uses this type of process, not just because of the risks of explosion, but also because of the difficulty of capturing the particles. The standards in respect of the cadmium content of the air in treatment plants reach exposure limit values that it is very hard to comply with. 

The SAFT AB recycling plant at Oskarshamn/Sweden is fully integrated in the manufacturing plant for industrial nickel-cadmium batteries. It demonstrates the commitment of the major european NiCd battery producer to control the life-cycle of the products introduced on the market. Process development started in 1978 and the operation reached industrial scale in 1986 (Figure 6). 

INMETCO is capable of handling both portable and industrial NiCd batteries, and is permitted to recycle up to 10,000 tons of NiCd batteries per year. Since INMETCO is primarly a stainless steel recycler, the economics of their NiCd battery recycling process is not as dependent on current cadmium prices as are those of recyclers who are dedicated to NiCd battery recycling alone. 

There is nothing new about recycling batteries and waste products from nickel-cadmium batteries but several developments have occurred in the last twenty years. 

Historically lead-acid, silver oxide and industrial nickel cadmium batteries were collected by entrepreneurs and recycled at the end of their lives due to the economic value in the materials they contained. 

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