Recoverable metals we can find inside electronics


The metals contained in PC's commonly include aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, gallium, gold, iron, lead, manganese, mercury, palladium, platinum, selenium, silver, and zinc. Eight of these metals (shown in bolded type) are listed as hazardous by the Resource Conservation and Recovery Act (RCRA), one of the Federal laws that control the disposition of waste in the United States. This law prohibits companies from incinerating some types of electronic scrap or disposing of it into municipal landfills.

Historically, recovering precious metals from electronic scrap has been one of the greatest economic incentives for the electronics recycling industry. However, in an effort to cut costs, manufacturers have gradually reduced the precious metal content in electronic products, and this trend is likely to continue (Porter, 1998). Information on the specific amounts of individual precious metals (gold, silver, and the platinum group metals) recovered is unavailable, but as much as one-third of the precious metals recovered from scrap may be gold (Sean Magaan, Noranda, Inc., Micro Metallics Corp., oral commun., 1999). The value of the 1 t of precious metals recovered from electronic scrap in the United States in 1998 (table 1) probably exceeded $3.6 million. This value was obtained by assuming that the precious metals recovered consisted of 60% silver and 40% gold, palladium, and platinum. The average price used to calculate the value was $5.10 per troy ounce of silver and an average of $300 per troy ounce of gold, palladium, and platinum. Several U.S. companies reported producing more than 1,500 troy ounces per year of precious metals from electronic scrap (Dawn Amore, National Recycling Coalition, oral commun., 1999).

Circuit boards and batteriescontain most of the heavy metals, and circuit boards contain the highestprecious metal values. One metric ton of circuit boards can contain between 80 and 1,500 g of gold and between 160 and 210 kg of copper (Veldhuizen and Sippel, 1994). This is 40 to 800 times the concentration of gold contained in gold ore mined in the United States and 30 to 40 times the concentration of copper contained in copper ore mined in the United States. Gold in an obsolete computer has little or no value. Like ore, it must be collected, concentrated, and refined in order to acquire a high value. The United States and foreign mineral processing companies use electronic scrap from computer circuit boards for two reasons:

(1)          it has a high precious metal content and
(2)          it contains much lower levels of deleterious elements common to ores, such as arsenic, mercury, and, especially, sulfur.

These elements can contribute potentially harmful atmospheric emissions (Rob Bouma, Noranda, Inc., oral commun., 2000) and could result in additional costs for recovery and disposal. Military electronic scrap, mostly computer circuit boards, received from the former Soviet Union (Nadeau, 1999) are especially sought for recycling because of their comparatively high precious metal content. The scrap can contain 10 times the amount of precious metals than mined ores and significantly higher amounts of precious metals as electronic components produced elsewhere.

In the mid-1980's, one of the world's largest mining companies, Noranda, Inc. (Noranda) of Canada, investigated ways to make their smelters more profitable. Feasibility studies and testing determined that "mining" computer and other electronic scrap would bring a welcome supplement of copper and precious metals to their smelters. Noranda' s findings indicated that the concentration of some metals in average computer and other electronic scrap may be more than twice that found in ores.

So in 1984, Noranda began processing small amounts of scrap (Reid, 1999) and, by 1999, was the largest electronics recycling plant in North America, receiving more than 50,000 t/yr of electronic scrap from 300 to 400 suppliers in 18 countries (Nadeau, 1999; Reid, 1999). Recyclable materials are considered to be an important feed for Noranda' s smelters, as essential as ore concentrates are to the operation' s profitability Rob Bouma, Noranda, Inc., written and oral commun., 1999). In order to treat electronic scrap more efficiently, a subsidiary of Noranda in California entered into an agreement with the Hewlett-Packard Company. Hewlett-Packard provides approximately 1,400 t of obsolete PC’s and other computer-related electronic scrap to Noranda for recycling on a monthly basis (Reid, 1999). After the computers are dismantled and the components are separated and tested, the useable components are sold, and the shredded metals are separated to be sold as scrap or transported to Noranda’s smelters in Canada. Hewlett-Packard pays Noranda for this service and, in return, is assured that components with toxic materials are treated legally, thus avoiding potential liability (Reid, 1999). Hewlett-Packard reuses or recycles nearly 1,600 t or 99 percent by weight of materials received from its customers and company operations.
Major electronic companies also recycle. IBM operates ten materials recovery plants around the world. In 1997, these operations processed more than 62,000 t of manufacturing scrap equipment, obsolete IBM machines, and customer-returned equipment. More than 90 percent was recycled and less than 5 percent was sent to landfills (Amore, 1999).
Gold recycling

Introduction of computer recycling for Gold


Obsolete computers contain significant amounts of recoverable materials including metals from wires and circuit boards, glass from monitors, and plastics from casings (fig. 1). For example, 1 metric ton (t) of electronic scrap from personal computers (PC’s) contains more gold than that recovered from 17 t of gold ore. In 1998, the amount of gold recovered from electronic scrap in the United States was equivalent to that recovered from more than 2 million metric tons (Mt) of gold ore and waste.

The amount of computer waste increases annually as electronic systems play an increasingly important role in all aspects of technology, but significant amounts of material used in the devices are not recovered. Because microchip development is so rapid (Hamilton and Takahashi, 1996), users are able, every 18 months, to purchase computers that are twice as powerful at the same price as those currently available (Jung, 1999). This cyclic trend (with its inherent surplus of old computer components) has been sustained for nearly 20 years of recent computer history. To meet consumer demand, the computer and electronics industry has become the largest manufacturing employer in the United States, representing 11 percent of the gross domestic product and growing at an annual rate of 4 percent (Porter, 1998).

The quantities and types of materials used in computer products to meet this demand are great and varied, as is the potential to recover these computers and their materials for reuse, remanufacturing, and recycling. In 1998, nearly 43 million new PC’s and notebook computers were purchased by consumers in the United States; and it is estimated that in the year 2003, nearly 70 million computers will be purchased by consumers in the United States (National Safety Council, 1999).

In 1997, it was estimated that between 1985 and 2005, approximately 325 million PC’s would become obsolete in the United States (Jung, 1999). In a business environment, the useful life of a PC is about 2 years, while in homes PC’s are used from 3 to 5 years (Jung, 1999). Between 14 and 20 million PC’s become obsolete every year in the United States. About 75 percent of these obsolete computers are not discarded because their owners perceive them to be valuable (Goodrich, 1999); a portion of these will not be recycled. For every three computers purchased in the United States, two will be taken out of service, and this ratio is expected to increase to 1:1 by 2005. It is projected that by 2005, a total of 680 million PC’s will have been sold worldwide. Of that total, it is estimated that 150 million computers will be recycled that year and 55 million computers will end up in landfills along with unreclaimed portions of the 150 million recycled computers (Hamilton and Takahashi, 1996).

Recycling Flow




Figure 2 is a generalized materials flow diagram that shows what happens to obsolete PC’s and their components.

This figure includes

• computers that owners retain (but do not use) or donate or dispose of directly or indirectly to municipal waste and hazardous waste landfills (The U.S. Environmental Protection Agency (EPA) categorizes cathode ray tubes (CRT’s) as hazardous waste, although exemptions exist for disposal of equipment generated by households and small business.)

• computers that can be refurbished and sold or donated by companies or organizations

• what happens to computers that can be dismantled and sold for reuse, melted and recycled, incinerated as a fuel for producing energy, and disposed of in landfills.

Computers and otherelectronic devices represent a large resource of potentially recoverablematerial. Table 1 lists selected types and amounts of material reportedly recovered in 1997 and 1998 from computer and other electronic scrap. In 1998, about 2.6 million PC’s and notebook computers were recycled in the United States, and this number is expected to quadruple by 2003 (National Safety Council, 1999). Recyclers received nearly 50 percent of electronic products directly from manufacturers; about 30 percent from large companies that utilize electronics in their business; and the rest from small companies, government offices, and individuals (National Safety Council, 1999).

Some scrap is unwanted because of low precious metal content and the potentially hazardous nature of some of its materials. For example, the presence of lead in some electronic scrap prevents it from being placed in a municipal landfill. Some refiners actually have to charge as much as $1 per pound to process the scrap because of these deleterious materials (Broughton, 1996).

Some scrap was exported to Taiwan for open burning and chemical processing; however, the Taiwanese government had reportedly become increasingly concerned about the environmental damage caused by this practice (Broughton, 1996). Chinese and other Asian consumers pay 15 to 20 cents per pound for electronic scrap on the U.S. West Coast (Goodrich, 1999). Environmental regulations are less strict (or not enforced), and labor costs are much lower in some of these countries.
Gold recycling

Price Of Gold - Demand for Gold


The current price of gold is at an almost unprecedented high. In fact, the average price in 2011 is lower than only the price attained in 1980 in real terms.

Like most commodity prices, gold price experiences significant fluctuations. And as with all traded commodities, the price is determined by supply and demand. Shifts in supply arise mainly from new gold deposits in the various mines across the world. A major and fluctuating factor in demand for gold is the need for safe investment.

This means that the demand for gold tend to increase when the real rate of return on alternative investments falls. This usually occurs in periods when either the yield on benchmark securities (for example, the US treasury bonds or bill) falls significantly or when there are expectations of higher inflation.

For example, the high gold prices of the 1970s and early 1980s coincided with one of the highest global inflation period. During such periods, smaller shares of gold tend to be put to end uses such as jewelry and industry.
Read more about Gold and Gold recycling Gold recycling

Watch this great video of Gold precipitation on YouTube

This great video is showing of how to precipitate gold from Aqua regia. Solution on this video is a chloride, in which we can find Gold.


It is important to wear proper safety equipment when performing these chemical experiments.

Gold recycling