Gallium: Cominco has been at the interface between the semiconductor materials and the components industries since the commercialization of the transistor in the early fifties. Based on our commitment to R&D, we have become the largest merchant supplier of several specialty semiconductor substrates including LEC-grown semi-insulating gallium arsenide wafers on this continent. The following remarks are … Read more

The first known attempts to apply a REM roll separator to a heavy mineral sands application were made in South Africa and Western Australia in 1985. At that time, an ilmenite beneficiation process, which was normally achieved with cross-belt separators, was tested with a full-size machine. The performance was not good because only a single … Read more

Figure 1 presents a simplified process flow diagram of the Dense Sludge process. The most significant change between Dense Sludge technology and conventional metals treatment is the method by which the alkali source is added. In conventional treatment systems, the alkali is added directly into the influent to achieve a desired pH setpoint. Generally, that … Read more

What are the benefits of having an OSA on-stream analyser? The assays are utilized for control in many ways, starting from individual control loops to overall optimization in the flotation circuits. Reagent dosages in the cleaner flotation stages are controlled by feedback from concentrate quality. For instance, the depressant in the zinc cleaner circuit is … Read more

Marked ball wear testing described in a 1948 paper by Norman is an invaluable test method to measure relative and/or absolute wear rates of balls under identical mill operating conditions. Preparation of balls at Armco consists of drilling a 6.4 mm diameter hole in each ball with an electrical discharge machine (EDM), cleaning, weighing, placing … Read more

Flameless AAS provides a means to increase flame AAS sensitivity, by up to 200 times. Interferences from aqueous leachates and digestates are so great, however, that flameless AAS has found application mainly after organic extraction. Thereby, the analytical sensitivity is increased far beyond that of the SX/flame- AAS methods. Interferences Interferences from other elements have … Read more

One of the minor but occasionally troublesome problems in the Creede plant is related to the clayey nature of some of the ore from the mine. At times the thickener underflow is so clayey that it forms a rope which can almost be carried around without a bucket. As described in the previous report: ” … Read more

Part of Zinc Hydrometallurgy and Zinc Solvent Extraction includes the zinc and iron sulphate solution from the hot acid leach will typically contain 80-100 g/l Zn, 20-30 g/l Fe, mostly in the ferric state, and 40-60 g/l free sulphuric acid. The sulphuric acid concentrations will depend upon the leaching techniques used, and the composition of … Read more

Alunite has been described both by the chemical formula [KAl3(SO4)2(OH)6] and by the chemical formula [K2SO4·Al2(SO4)3·2Al2O3·6H2O]. The latter gives an erroneous impression that water is structurally associated with the mineral. The former representation is therefore, to be preferred. It is more in conformity with the crystal structure of alunite. The structure of alunite is similar … Read more