Cadmium consumption

Cadmium consumption in 2001 was about 16000 tonne (according to the World Bureau of Metal Statistics), 17% less than the previous year. Japan used the metal mainly for NiCd batteries and was the largest consumer country. Belgium and the... 

The International Cadmium Association (ICdA) in Brussels, Belgium, made an estimate of cadmium consumption for different end uses in 2001. Batteries account for 75%, pigments 12%, coatings and plating 8%, and stabihzers for plastics and similar purposes 4%. The remaining small amount of cadmium, 1%, is used in some very special applications such as nonferrous alloys and as cadmium telluride (CdTe) for electronic compounds. 

The Model 412 PWR uses several control mechanisms. The first is the control cluster, consisting of a set of 25 hafnium metal rods coimected by a spider and inserted in the vacant spaces of 53 of the fuel assembhes (see Fig. 6). The clusters can be moved up and down, or released to shut down the reactor quickly. The rods are also used to (/) provide positive reactivity for the startup of the reactor from cold conditions, (2) make adjustments in power that fit the load demand on the system, (J) help shape the core power distribution to assure favorable fuel consumption and avoid hot spots on fuel cladding, and (4) compensate for the production and consumption of the strongly neutron-absorbing fission product xenon-135. Other PWRs use an alloy of cadmium, indium, and silver, all strong neutron absorbers, as control material. 

Cadmium-based pigments have been hit particularly hard by environmental regulations. As the result, consumption in 1993 was estimated to be between 1.5—5 thousand metric tons. The future of this pigment category is particularly questionable in North America. 

The apparent United States consumption of cadmium in 1988 was estimated to be 3620 t. Of the 2482 t imported, over 85% came from Canada, Mexico, Germany, and AustraUa. The principal domestic producers and suppHers of cadmium metal are ASARCO, Inc. Big River Zinc Corp. Jersey Miniure Zinc Co. and Zinc Corp. of America. 

In 1988 the estimated apparent consumption pattern for cadmium was batteries (qv), 32% coating and plating, 29% pigments (qv), 15% plastics and synthetic products, 15% and alloys and other uses, 9% (16). 

These batteries account for - 50% of 1990 U.S. annual consumption of cadmium and are used ia heavy-duty, long-life appHcations such as rechargeable tools, apphances, iastmments, and electronics (36). 

Cadmium. In 1989, U.S. consumption of cadmium for coatings was 1474 t (7), compared to 1552 t in 1970, 2089 t in 1979, and 1230 t in 1985. Cadmium plating amounts to about 15% of total cadmium production (see Cadmiumand cadmium alloys). Of the cadmium being plated in 1989, 30% was for automotive parts, over 22% for electronics, and 18% for industrial fasteners. Because of cadmium s high and weU-pubHcized toxicity and very tight waste restrictions, there are considerable efforts to develop alternative materials, and the quantities of cadmium used in electroplating ate expected to decrease. The price of cadmium anodes in early 1993 was about l/kg. 

Dry cells (batteries) and fuel cells are the main chemical electricity sources. Diy cells consist of two electrodes, made of different metals, placed into a solid electrolyte. The latter facilitates an oxidation process and a flow of electrons between electrodes, directly converting chemical energy into electricity. Various metal combinations in electrodes determine different characteristics of the dry cells. For example, nickel-cadmium cells have low output but can work for several years. On the other hand, silver-zinc cells are more powerful but with a much shorter life span. Therefore, the use of a particular type of dry cell is determined by the spacecraft mission profile. Usually these are the short missions with low electricity consumption. Diy cells are simple and reliable, since they lack moving parts. Their major drawbacks are... 

The excellent resistance of zinc to corrosion under natural conditions is largely responsible for the many and varied applications of the metal. In fact nearly half the world consumption of zinc is in the form of coatings for the prevention of corrosion of steel fabrications exposed to the atmosphere and to water. For its varied applications zinc is obtainable in a number of grades. Ordinary commercial (G.O.B.) zinc contains up to about I -5% total of lead, cadmium and iron. Electrolytic zinc has a minimum zinc content of 99-95% and contains small amounts of the same impurities. Special high-purity zinc has a minimum of 99-99% zinc. Even purer zincs are commercially available. 

Into a conical flask, pipette a 50.0 or 100.0 mL aliquot of the solution and adjust the pH to 1-2 with aqueous ammonia solution (use pH test-paper). Add five drops of xylenol orange indicator and titrate with additional 0.05 M EDTA until the colour changes sharply from red to yellow. This gives the bismuth content. Record the total (combined) volume of EDTA solution used. Now add small amounts of hexamine (ca 5g) until an intense red-violet coloration persists, and titrate with the standard EDTA to a yellow end point the further consumption of EDTA corresponds to the lead-plus-cadmium content. 

To determine the cadmium content, add 20-25 mL of the 1,10-phenanthroline solution and titrate the liberated EDTA with the 0.05M lead nitrate solution until the colour change from yellow to red-violet occurs — a little practice is required to discern the end point precisely. Introduce further 2-5 mL portions of the 1,10-phenanthroline solution and note whether the indicator colour changes if so, continue the titration with the lead nitrate solution. The consumption of lead nitrate solution corresponds to the cadmium content. 

The determination of lead in blood is the most widespread clinical use of ASV The technique is attractive because it is rapid, simple and reproducible A recent advance is to couple ASV to flow injection analysis in order to automate the process so that smaller samples and shorter analysis time can be achieved Lead is also routinely determined in bonemeal meant for human consumption by ASV Both lead and cadmium are determined in agricultural crops by ASV... 

Accumulation of cadmium in agricultural soils leads to increased cadmium uptake by crops and vegetables, grown for human consumption.17... 

There are two main uses for cadmium in batteries (particularly Ni-Cd batteries), which account for almost three quarters of the consumption, and in pigments and plastics stabilizers. 

In adults, a study of 75 autopsies of persons who had resided in a soft-water, leached soil region of North Carolina found a positive correlation between lead level in the aorta and death from heart-related disease (Voors et al. 1982). The association persisted after adjustment for the effect of age. A similar correlation was found between cadmium levels in the liver and death from heart-related disease. (Aortic lead and liver cadmium levels were considered to be suitable indices of exposure.) The effects of the two metals appeared to be additive. Potential confounding variables other than age were not included in the analysis. The investigators stated that fatty liver (indicative of alcohol consumption) and cigarette smoking did not account for the correlations between lead, cadmium and heart-disease death. 

Many cases of foodborne cadmium poisonings were reported in 1940s in England, France, New Zealand, the U.S., the U.S.S.R., and other countries. They were caused by consumption of lemonade, coffee, wine, and other products that had been prepared or stored in cadmium-coated containers, or in refrigerators with cadmium-coated freezers. 

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