Читать реферат по английскому: "It Technology Essay Research Paper 10 INTRODUCTIONA" Страница 3

(Назад) (Cкачать работу)

tons of IT equipment waste (including PCs monitors, laptops and peripherals) was

disposed, 15,592 tons was recycled, 24,507 tons was sent for reuse and 6,128 was

put into storage. Some pieces of IT equipment which had been stored or reused in

previous years entered the waste stream in 2000. Of the IT waste disposed, PCs and

servers accounted for an estimated 10,833 tons, monitors accounted for an estimated

10,688 tons, peripherals (scanners, printers, etc) accounted for about 11,474 tons and

laptops accounted for about 977 tons. In 2005, the Waste Flow Tools predict that

approximately 67,324 tons of IT equipment waste (including PCs monitors, laptops and

peripherals, but excluding mainframes and other large equipment) will be disposed,

47,791 tons will be reused, 11,948 tons will be stored and 43,428 tons will be recycled.

Of the total IT waste that will be disposed, PCs and servers will account for an estimated

23,349 tons, monitors will account for an estimated 24,472 tons, peripherals (scanners,

printers, etc) will account for about 17,396 tons and laptops will account for about 2,107

tons.

Note:

The quantities disposed, recycled, stored and reused do not add to the amount of

IT equipment that became obsolete in 2000 because a portion of IT equipment from

storage and reuse from earlier years enters the IT equipment waste flow in 2000.

4.0 Materials Contained in IT Equipment

The challenge encountered in diverting computers and peripherals from the

waste stream through recycling and refurbishing activity result from the diversity of

products and variety of materials contained in each product. For example, each hard

drive contains a range of metals and plastics that can be difficult to separate. It is also

difficult to identify the different plastics contained in each piece of equipment by resin

type.

The composition of personal computers and monitors are given in the Table 2 – 7

and the chart below:

? Precious metals include nickel, manganese, cobalt, barium, tin,

silver, antimony, chromium, cadmium, selenium, mercury, gold and

arsenic.

Many of the materials contained in IT equipment can be potentially hazardous if

improperly managed. For example, printed circuit boards contain heavy metals such as

antimony, silver, chromium, zinc, lead, tin and copper and a CRT in a computer monitor

can contain from 0.7 to 2.7 kg of lead depending on the monitor’s size and year of

manufacture 10.

The production of semiconductors, printed circuit boards, disk drives and

monitors use a number of hazardous materials 11. The lead oxide used in the cathode

ray tubes (CRT) of computer monitors is of particular concern and it has been estimated

that computer monitors represent approximately 15% of the lead found in the municipal

waste stream 12.

Hazardous materials found in obsolete computer equipment can be released to

the environment through the following pathways:

- Incineration of computer equipment concentrates heavy metals in ash residue;

- Landfill disposal of computer equipment, and;

- Recycling and recovery of computer equipment waste.

The estimated quantities of materials contained in disposed PC’s and monitors in

Canada in 1999 and in 2005 are shown in table and chart below:

The hazardous materials contained in computer equipment that are of greatest

concern are summarized below.

Lead

Lead is found in the CRT, in the soldering of printed circuit boards and in other

components of IT equipment. Lead represents approximately 6.3%, by weight of an

average PC 13. Based on the total number of obsolete PC’s and monitors in Canada in

2000, this translates to about 1,356 tons of lead disposed in 2000.

Based on the prediction that 47,821 tons of PCs and monitors will be disposed

in 2005 and assuming that the average composition of this equipment will not change

significantly by that year, 3,012 tons of lead will be disposed with this stream in 2005.

A CRT in a computer monitor can contain from 0.7 to 2.7 kg of lead depending on the

monitors size and year of manufacture. This lead is contained in various components of

the CRT, including: 14

? The glass funnel, which is glass that is 22-25% lead (bound into the glass). Lead

is used in the funnel to shield users from radiation produced by the electron gun.

? The faceplate, which contains 2-3% lead bound into the glass.

? The frit (a glass solder that joins the faceplate and funnel components of the

CRT), which contains 15 to 100 grams per CRT.

The lead contained in the frit is of greater concern because it is in a soluble form

(primarily lead oxide) that can leach 15, while the lead contained in the glass funnel and

in the faceplate is in an insoluble form.

Cadmium

Cadmium is present in certain components, including chip resistors, infrared

detectors, semiconductors, older CRTs and is sometimes present in plastics as a

stabilizer. Cadmium represents approximately 0.009% of a PC by weight 16. Based on

the total number of disposed PC’s in Canada in 2000, this translates to 2.0 tons of

cadmium.

Based on the prediction that 47,821 tones of PCs and monitors will be disposed

in 2005 and assuming that the average composition of this equipment will not change

significantly by that year, 4.5 tons of cadmium will be

Похожие работы