Indium recovery

Guerreiro, R., Meregalli, L., and Zhang, X. 1988. Indium recovery from sulphuric solutions by supported hquid membranes. Hydrometallurgy 20 109-120. 

Figure 10-Schematic Flow Diagram for Indium Recovery...

The abundance of indium in the earth s cmst is probably about 0.1 ppm, similat to that of silver. It is found in trace amounts in many minerals, particulady in the sulfide ores of zinc and to a lesser extent in association with sulfides of copper, tin, and lead. Indium follows zinc through flotation concentration, and commercial recovery of the metal is achieved by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting and associated lead (qv) and copper (qv) smelting (see Metallurgy, EXTRACTIVE Zinc and zinc alloys). 

Figure 11 Proposed reaction schemes for the recovery of indium (a) and mercury (b) from waste materials using HN(SPPh2)2-I2 as oxidising reagent56,57...

In the commercial flow sheets, these elements are left in the aqueous raffinate after platinum and palladium extraction. Indium can be extracted in the -l-IV oxidation state by amines (see Fig. 11.11), or TBP (see Figs. 11.10 and 11.12). However, although the separation from rhodium is easy, the recovery of iridium may not be quantitative because of the presence of nonextractable iridium halocomplexes in the feed solution. Dhara [37] has proposed coextraction of iridium, platinum, and palladium by a tertiary amine and the selective recovery of the iridium by reduction to Ir(III). Iridium can also be separated from rhodium by substituted amides [S(Ir/ Rh) 5 X 10 ). 

This presentation is an updated review of the economic geology at Mount Pleasant based upon our recent exploration results. There has been a resurgence of interest in these deposit types with the recent recovery of W, Mo, and Sn metal prices. Economic interest in the Mount Pleasant deposits has been heightened due to its hosting of metals that are increasingly important in high technology applications and medicine, such as indium and bismuth. 

Indium may be recovered from zinc ores by several patented processes. Usually it is recovered from residues obtained from zinc extraction. The residues, slags, fume, or dusts from zinc smelting or lead-zinc smelting are treated with a mineral acid. Other steps involved in recovery often vary, but mostly use solvent extraction and precipitation steps. In some processes, treatment with caustic soda yields indium hydroxide. The hydroxide is calcined to obtain oxide, which then is reduced with hydrogen at elevated temperatures to obtain the metal. Distillation or electrolysis are the final steps to... 

Table III is a compilation of the parameters in a typical Cd-109 production run. A sealed stainless steel tube containing 105.8 g of indium was positioned in the proton beam for 56 days. Since the beam was not on continuously for this 56-day period, the integrated exposure of the target was not available. A total of 1553 mCi of Cd-109 was produced with 1427 mCi recovered giving a 92% recovery. The only other radioisotope found was 117 mCi of Cd-115m which cannot be separated.

Indium occurs in very. small amounts in z.ine blende, tungsten, tin and iron ores of certain localities. The recovery or indium from zinc Due dust (sometimes. I part per thousand) is effected by treating with a slight deficiency of HCI and allowing to stand The residue is subjected to a series of treatments until finally pure indium sulfttlc is obtained, a solution of which when electrolyzed yields compact indium metal. A thin surface layer of indium is used on some bearings. 

Carboxylic acids represent a group of readily available and relatively inexpensive extractants. They have found rather limited application in commercial processes, however, probably on account of their generally low selectivity and poor pH functionality. Nevertheless, they have been used for the separation of copper from nickel,the removal of iron from the rare-earth metals, separations among yttrium and the rare earths, 9 he recovery of indium and galliiun, the removal of... 

Fig. 6. LEI signal recovery curves for indium in potassium, sodium, and lithium sample matrices...

The common sources of indium are the minerals dark sphalerite, christophite, and marmatite. Indium is also found in small amounts in manganese, tungsten, zinc, and tin ores. Rarely found as a free element, indium is commonly associated with gallium in tin and zinc ores. The main commercial source for indium is from zinc smelter flue dusts (Smith etal. 1977). Enrichment of indium from zinc residues is performed by acid leaching followed by chemical separation processes. Aqueous electrolysis of indium salts yields a final metal of 99.9% purity. Canada has the greatest resources of indium with approximately 27% of the world s reserves (based on estimated indium content of zinc reserves) and the United States has about 12% of the world reserves (Brown 2000). In recent years, there have been major improvements in the recovery, refining and recycling of... 

At the Harima Works, about 80% of the cadmium present in the raw material is recovered. In fact, about 75% of the cadmium present in the raw material is evaporated during the sintering process and is collected in the sinter dust. The sinter dust is treated with highly acidic process water to extract the cadmium for subsequent recovery in a distillation column. In addition, thallium and indium are extracted and separated fiom the cadmium prior to... 

Apart from lead, blast furnace dusts are often enriched in cadmium, zinc and indium, and can be a source for recovery. Again separation before recycle may be necessary to provide an outlet and prevent the development of heavy circulating loads. 

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