Indium production

The world s supply of indium comes as a by-product of zinc and lead refining and is produced in China (110 tonnes per year), Japan (70 tonnes), Canada (50 tonnes), Belgium (40 tonnes) France (10 tonnes), and Germany (10 tonnes), with smaller production in a few other countries. The total refined indium production is around 340 tonnes per year, most of which goes into indium tin oxide (70%) and indium semiconductors (15%) with a few other uses, such as low melting alloys in fire-sprinkler systems in... 

The PV technologies that currently demonstrate the potential to meet the cost and performance projections of this study are thin film CdTe and CIS PV, which raises questions regarding the resource availability of tellurium and indium to meet the required scale of PV production. The tellurium and indium production estimates of Zweibel1,24 indicate that the tellurium and indium resource bases are likely sufficient to support the manufacture of 50 GWp/year of CdTe and CIS PV. This conclusion is highly sensitive to assumptions about layer thickness and the availability and price of tellurium and indium. It needs to be emphasized that the tellurium and indium re source production projections are based on soft resource data analysis and substantial variation in assumed layer thicknesses and module efficiencies. An important devel... 

An economic evaluation of expanding secondaiy metal production facilities to support the timely growth in tellurium and indium production. This should also include further assessments of the economically recoverable tellurium and indium resource bases. 

Figure 7-30. Indium production by direct decomposition of its oxide (In203) in atmospheric-pressure thermal plasma. Composition of products (1) Iu203 (condensed phase) (2) In20 (3)02 (4)0 (5) In.

Table III - Typical Analysis of the Final Indium Product...

Figure 5 - Refined Indium Production PROCESS DESCRIPTION...

Indium is mainly won from residues during the metallurgical treatment of indium-rich zinc and lead ores. The residues are dissolved in acid and indium chloride precipitates at the inlet of chlorine gas. The indium chloride is purified from tin, copper and lead using liquid-liquid extraction. A concentrated indium solution is obtained, from which indium is precipitated on zinc sheets. The spongy metal is scraped off, fused and cast into bars. For normal use, purification by electrolysis is satisfactory. For semiconductor purposes, repeated electrolysis and zone melting create an extreme purity. In 2001 the refined indium production was about 300 tonnes. 

The conventional electrochemical reduction of carbon dioxide tends to give formic acid as the major product, which can be obtained with a 90% current efficiency using, for example, indium, tin, or mercury cathodes. Being able to convert CO2 initially to formates or formaldehyde is in itself significant. In our direct oxidation liquid feed fuel cell, varied oxygenates such as formaldehyde, formic acid and methyl formate, dimethoxymethane, trimethoxymethane, trioxane, and dimethyl carbonate are all useful fuels. At the same time, they can also be readily reduced further to methyl alcohol by varied chemical or enzymatic processes. 

Production. Indium is recovered from fumes, dusts, slags, residues, and alloys from zinc or lead—zinc smelting. The source material itself, a reduction bullion, flue dust, or electrolytic slime intermediate, is leached with sulfuric or hydrochloric acid, the solutions are concentrated, if necessary, and cmde indium is recovered as 99+% metal. This impure indium is then refined to 99.99%, 99.999%, 99.9999%, or higher grades by a variety of classical chemical and electrochemical processes. 

Economic Aspects. Production of indium has been reported from Belgium, Canada, China, France, Germany, Italy, Japan, the Netherlands, Pern, the United Kingdom, and the United States, as well as countries in the CIS (the former Soviet Union) (5). 

Indium prices vary by purity level according to the number of mines. For 99.97 or 99.99% pure indium Meta/Bu//etm magazine s free-market prices ranged from 160 to 190/kg in 1993. Prices have trended downward since 1988. This, coupled with the fact that consumption increased during this period, is evidence that supply is ahead of demand. The most notable production increases have occurred at Indium Corp. of America, Nippon Mining Co. Ltd., Cominco Ltd., and Metaleurop S.A. The largest increase was made by Indium Corp. A 30-t increase was announced in 1988 in 1993 Indium Corp. announced plans to increase production by another 30 t to be phased in with demand, bringing the company s actual and planned increases to 60 metric tons over the 1988 level. 

Uses. Indium s first commercial use was in the production of dental alloys (see Dental MATERIALS), but its first significant use was in the production of bearings for heavy-duty and high speed service (see Bearing materials). The advent of jet engines has reduced this use, but indium is still used in high performance engines. 

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. 

Semiconductors. Phosphine is commonly used in the electronics industry as an -type dopant for siUcon semiconductors (6), and to a lesser extent for the preparation of gaUium—indium—phosphide devices (7). For these end uses, high purity, electronic-grade phosphine is required normally >99.999% pure. The main impurities that occur in phosphine manufactured by the acid process are nitrogen [7727-37-9] hydrogen [1333-74-0] arsine [7784-42-17, carbon dioxide [124-38-9], oxygen [7782-44-7], methane [74-82-8], carbon monoxide [630-08-0], and water [7732-42-1]. Phosphine is purified by distillation under pressure to reduce the level of these compounds to <1 ppm by volume. The final product is sold as CYPURE (Cytec Canada Inc.) phosphine. 

At the start of the nineteenth century, platinum was refined in a scientific manner by William Hyde WoUaston, resulting in the successful production of malleable platinum on a commercial scale. During the course of the analytical work, WoUaston discovered paUadium, rhodium, indium, and osmium. Ruthenium was not discovered until 1844, when work was conducted on the composition of platinum ores from the Ural Mountains. 

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

Zirconium oxide is used in the production of ceramic colors or stains for ceramic tile and sanitary wares. Zirconia and siHca are fired together to form zircon in the presence of small amounts of other elements which are trapped in the zircon lattice to form colors such as tin—vanadium yellow, praseodymium—zircon yellow [68187-15-5] vanadium—zircon blue [12067-91 -3] iron—zircon pink [68412-79-3] indium—vanadium orange (105—108). 

Indium is now commercially recovered from the flue dusts emitted during the roasting of Zn/Pb sulfide ores and can also be recovered during the roasting of Fe and Cu sulfide ores. Before 1925 only 1 g of the element was available in the world but production now exceeds 80 000 000 g... 

In a separate report, preparation of the lithium enolate of 31 in the presence of indium trichloride and benzaldehyde provided a 77% yield of 32 with complete trans selectivity however, sequential addition of indium trichloride and benzaldehyde provided Barbier-type products. Organotin enolates have also been used in a Darzens-type... 

Soldered joints present their own characteristic corrosion problems usually in the form of dissimilar metal attack often aided by inadequate flux removal after soldering. Such joints have always been a source of concern to the electrical industry. Lead-containing solders must be used with caution for some types of electrical connection since PbfOHjj.PbCOj may be found as a corrosion product and can interrupt current flow. Indium has been found to be a useful addition to Sn-Pb solders to improve their corrosion resistanceHowever, in view of the toxicity of lead and its alloys, the use of lead solders, particularly in contact with potable waters and foodstuff s, is likely to decline. 

The Al-Zn-Sn alloys require careful heat treatment in their production. Inevitably this leads to more expense and inconvenience. The advent of the alloys containing mercury or indium rendered these alloys very much less attractive. Presently Al-Zn-Hg alloys are under some pressure because... 

Numerous proprietary electrolytes have been developed for the production of harder and brighter deposits. These include acid, neutral and alkaline solutions and cyanide-free formulations and the coatings produced may be essentially pure, where maximum electrical conductivity is required, or alloyed with various amounts of other precious or base metals, e.g. silver, copper, nickel, cobalt, indium, to develop special physical characteristics. 

These mesylates, in turn, can be converted to enantioenriched allenyltin, zinc, and indium reagents which add to aldehydes with excellent diastereo-and enantioselectivity to afford either syn- or anti-homopropargylic alcohols or allenylcarbinols (eq 2, 3, and 4).3 4 Adducts of this type serve as useful intermediates for the synthesis of polyketide and hydrofuran natural products.5... 

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