Much research is going on, regarding extraction of metals/precious metals from electronic waste using biochemical methods such as chemical and biological leaching followed by solvent extraction or cementation or adsorption. But in a real life scenario, is it really a viable process, considering the cost of purchase and transport, dismantling/crushing the waste, cost of chemicals, vessels etc. and the amount of heavy or precious metal recovered, cost of purification etc. at the end of process.
there is no single answer. it depends on place, time, nature of metal extraction and many more factors. thanks
Dear Kruti,
You are saying right,In real life the e waste treatment or recovery process are very costly, is it really a viable process, considering the cost of purchase and transport, dismantling/crushing the waste, cost of chemicals, vessels etc.The demand of electrical and electronic equipment has increased dramatically with the advancement in technology. Drastic innovations on the electrical and electronic technologies further shortened the life, and thus enhanced the generation of waste from electrical and electronic equipment or electronic waste (e-waste). The global production of e-waste/WEEE is increasing rapidly and is expected to accelerate in the near future. Currently, 20 to 25 million tons per year of e-waste are being generated globally with major share of Europe, USA and Australasia. However, China, Eastern Europe and Latin America are expected to become significant e-waste producers in the next decade. In Europe, it is expected that the production of e-waste will increase by 45% between 1995 and 2020. Therefore, a three pillars strategy of waste prevention, recycling and reuse has been suggested to minimize the environmental impact and promote the efficient utilization of wasted resources .
E-waste is classified as hazardous material therefore should be managed properly. However, the presence of precious metals (PMs) in e-waste such as gold (Au), silver (Ag), platinum (Pt), Gallium (Ga), palladium (Pd), tantalum (Ta), tellurium (Te), germanium (Ge) and selenium (Se) makes it attractive for recycling,metal extraction processes from e-waste, particularly the existing industrial practices and routes, will be reviewed. Industrially, different metallurgical routes are used to extract valuable metals from e-waste. Both pyrometallurgical and hydrometallurgical processes are commonly employed to recover PMs. These routes will be described and their advantages and disadvantages will be outlined. In the final part of this paper, insights into e-waste recycling in the Australian context will be presented. The challenges and barriers associated with recovery of the PMs will be highlighted.
Regards,
Prem Baboo
You can find organisms able ot absorb however it is imposible to separate them
It is extremely dependent to the type of waste, economic factors and location of plant. For instance, in countries with high costs of energy, the leaching and bioleaching methods can be a good alternative for pyrometallurgical methods. In some countries the environmental laws are very rigid. Again biohydrometallurgical methods can be used. In addition, for wastes with high volume and low metals concentration it would be better to use the hydrometallurgical methods because these methods are more economic and save energy.
In fact it is extremely dependent to the type of waste, extracting the elements from e-waste mining operations can release toxic chemicals into the environment, and the leaching ponds needed to extract rare earth elements can themselves “leach” into ground water. An increased need for these materials is therefore accompanied by increased environmental risks. E-waste contains precious metals including gold, silver, copper, platinum, and palladium, but it also contains valuable bulky materials such as iron and aluminium, along with plastics that can be recycled. Furthermore, e-waste is a very rich source from which valuable metals may be recovered. However, some of the disadvantages of precious metal e-waste include toxic metals such as mercury, lead, cadmium, and polybrominated flame retardants.Copper is among the most valuable metals for most scrappers. Pound for pound, it is worth more than most other common metals and is the king of non-ferrous metals. Not all copper products are worth the same, though, and the price of copper can change dramatically over time compared to other metals. In fact, they often contain valuable materials like plastic and precious metals including gold, silver, platinum, nickel, zinc, aluminium and copper. These materials can easily be recovered and recycled into something new, which prevents electronics being made from new or 'virgin' materials.