Cobalt Ore

Cobalt ores are often found in association with copper(II) sulfide. Cobalt is a silver-gray metal and is used mainly for alloying with iron. Alnico steel, an alloy of iron, nickel, cobalt, and aluminum, is used to make permanent magnets such as those in loudspeakers. Cobalt steels are hard enough to be used as surgical steels, drill bits, and lathe tools. The color of cobalt glass is due to a blue pigment that forms when cobalt(II) oxide is heated with silica and alumina. 

Flotation of Oxide Copper and Copper Cobalt Ores... 

In recent years, a new class of collectors, consisting of xanthated fatty acids (TY collector), and monoester-modified xanthate (PM230) have found industrial applications with improved metallurgical results. From plant practice, treating oxide copper and copper cobalt ores, two basic flotation methods are practiced (a) sulphidization flotation method, and (b) anionic flotation method. 

This method is the most commonly used in beneficiation if oxide copper-bearing ore. The reagent schemes used to treat oxide copper ores, mixed copper sulphide oxide ores and oxide copper cobalt ores varies from one ore type to the next, mainly by type of collector and sulphidizer used. 

The choice of reagent scheme depends largely on the type of natural ore to be treated. The three main groups of reagents used in beneficiation of oxide copper and copper cobalt ores include (a) sulphidizers, (b) collectors and (c) modifiers and depressants. 

Most operating plants that treat oxide copper and copper-cobalt ores are found in Central Africa and Southern Africa regions. A few operations exist in Chile, Brazil and Peru, where they treat mixed oxide sulphide ores or oxide copper gold ore. 

Bulatovic, S., Bigg, A.C.T., and Yen, T., Laboratory Development Testwork on Kolwezi and Komoto Oxide and Mixed Copper Cobalt Ores, Report of Investigation No. 3, 1979. 

Cobalt is also found in seawater, meteorites, and other ores such as linnaeite, chloanthite, and smaltite, and traces are found mixed with the ores of silver, copper, nickel, zinc, and manganese. Cobalt ores are found in Canada and parts of Africa, but most of the cobalt used in the United States is recovered as a by-product of the mining, smelting, and refining of the ores of iron, nickel, lead, copper, and zinc. 

In 1736 the brothers Henric and Olof Kalmeter discovered at Los, Farila parish, Halsingland, a cobalt ore which they at first exported in tiris form. In 1744, however, a smalt works employing skilled workers from Germany was built flrere (39). 

Although no one had ever succeeded in extracting copper from Kupfernickel, J. H. Linck (or Link) stated in 1726 that, since it gives green solutions when dissolved in nitric acid, it must be a cobalt ore... 

He stated that the alloy was suitable for ornamental articles which would not come into contact with acid or salt and that if the copper, nickel, and cobalt ores from Riddarhytta, Hakansboda, Tunaberg, etc. 

Space will not be devoted here to emphasis of the vast technological importance of iron and the steels nor to the discussion of ferrous metallurgy. However, typical processes for obtaining cobalt and nickel from natural sources are outlined in Table 24-1. The process for cobalt is somewhat oversimplified, for cobalt ores often contain, in addition to iron and arsenic, nickel, silver, or copper, which must also be removed. Note that nickel is conveniently purified by conversion to its volatile carbonyl, Ni(CO)4, unstable at high temperatures Mond process). 

Preparation of Cobalt.—The metallurgy of cobalt is complicated by the fact that cobalt ores invariably contain a certain amount of nickel. Since these two metals closely resemble one another in their chemical properties it will be evident that their complete separation on a commercial scale is a matter of considerable difficulty. It is not usually required, however. The details of the actual methods employed in the commercial production of cobalt are kept fairly secret, more particularly as regards the initial stages of the preparation of the crude oxide. We shall, therefore, content ourselves by giving in outline accounts of a few different methods that may be employed. It is convenient to discuss the subject in three sections, namely ... 

I. Preparation of cobalt oxide from cobalt ores. 

It is doubtful if these methods have ever been employed for manufacturing purposes. European arsenical cobalt ores have been worked for cobalt oxide by a process similar to that described later (see p. 86) for working up arsenical nickel ores. Moreover, a certain amount of cobalt oxide is also derived from the arsenical nickel ores, since these usually contain appreciable quantities of cobalt. 

Uses.—Cobalt has not hitherto been utilised to any important extent in the industries, but Canada is making systematic efforts to develop its utility in view of the fact that rich stores of cobalt ores are found in that country. A few years ago practically the only use for cobalt was the production of the blue colour in the glass ana ceramic industries, and for the production of a blue paint. For these industries an annual production of 300 or 400 tons of cobalt sufficed.2... 

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