Nickel refining

Nickel [7440-02-0] Ni, recognized as an element as early as 1754 (1), was not isolated until 1820 (2). It was mined from arsenic sulfide mineral deposits (3) and first used in an alloy called German Silver (4). Soon after, nickel was used as an anode in solutions of nickel sulfate [7786-81 A] NiSO, and nickel chloride [7718-54-9] NiCl, to electroplate jewelry. Nickel carbonyl [13463-39-3] Ni(C02)4, was discovered in 1890 (see Carbonyls). This material, distilled as a hquid, decomposes into carbon monoxide and pure nickel powder, a method used in nickel refining (5) (see Nickel and nickel alloys). 

Estimated 1994 worldwide usage of nickel compounds exclusive of use in nickel refining is shown in Table 3. Nickel compound prices are also given. 

The approximate worldwide aimual usage of nickel chemicals at 10 t, other than for steel and nickel refining, in 1994 was, for plating salts, 12—15 catalysts, 10—12 specialty ceramics, 3—4 specialty chemicals, 2—3 and other specialties, 1—2. 

Ammonium sulfate is also recovered as a by-product in large amounts during the coking of coal, nickel refining, and organic monomer synthesis, particularly during production of caprolactam (qv). About four metric tons of ammonium sulfate are produced per ton of caprolactam which is an intermediate in the production of nylon. 

Naphthylamine Nickel refining Bladder — carcinoma Respiratory tract — carcinoma... 

Colorless to yellow liquid with a musty or sooty odor. Intermediate in nickel refining. Used to produce high-purity nickel powder and to coat metals with nickel. 

To protect humans and other mammals, proposed air-quality criteria range from 0.01 to less than 1.0 mg/m3 for metallic nickel and slightly soluble nickel compounds, 0.015-0.5 mg/m3 for water soluble nickel compounds, and 0.005 to 0.7 mg/m3 for nickel carbonyl (Table 6.10). Inhalation of nickel subsulfide concentrations (0.11 to 1.8 mg Ni/m3) near the current threshold limit value of 1 mg Ni/m3 can produce detrimental changes in the respiratory tract of rats after only a few days of exposure (Benson et al. 1995). Additional animal studies are recommended to identify minimally effective inhalation exposure levels for the various nickel compounds (USPHS 1993). Continued monitoring of nickel refining, nickel-cadmium battery manufacture, and nickel powder metallurgy installations is recommended because ambient air levels of bioavailable nickel at these... 

Toxicology. Metallic nickel and certain nickel compounds cause sensitization dermatitis. Nickel refining has been associated with an increased risk of nasal and lung cancer. 

The Nickel Producers Environmental Research Association (NiPERA) is sponsoring research on the application of inductively coupled plasma-mass spectroscopy (ICP-MS) to isotopic analysis of nickel in biological samples, on the development of sampling instrumentation for assessing workers exposure to nickel in the nickel industry, and on methods for utilizing newly developed analytical methods, such as laser beam ionization mass spectrometry, for the identification and speciation of nickel compounds in powders and dusts with particular reference to nickel refining. 

As mentioned earlier, nickel carbonyl is a volatile intermediate in the Mond process for nickel refining. This compound also is used for vapor plating of nickel in the semiconductor industry, and as a catalyst in the chemical and petrochemical industries. The toxicity of the compound has been known for many years Exposure of laboratory animals to the compound has induced a number of ocular anomalies, including aiioplidialiiiiaandinicrophtlialmia, and has been shown to be a carcinogenic for rats. 

Table 1 gives data on the current world production of cobalt. In 2002, approximately 50% of cobalt produced worldwide was a by-product of nickel refining, while some 18% was obtained from refining secondary products and scrap metal. Newfound ore deposits in Australia and Africa are expected to add significantly to world production, with six new refining operations having been commissioned in these areas between 1999 and 2001. As can be seen in Table 2, the major use of cobalt is as a component of superalloys, which are designed for use at elevated temperatures. 

Impure nickel, refined by smelting sulfide ores in a blast... 

Use Organic synthesis (methanol, ethylene, isocyanates, aldehydes, acrylates, phosgene), fuels (gaseous), metallurgy (special steels, reducing oxides, nickel refining), zinc white pigments. 

Metals having a zero oxidation state can still be complexed by a similarly soft bonding ligand such as carbon monoxide. Nickel carbonyl, Ni(CO)4, is a gas used in the nickel refining industry in order to volatilize and purify nickel from its ores. It is interesting to note that... 

Colourless liquid with high vapour pressure at room temperature. Exposure can occur during electroplating and nickel refining. Vapour is insoluble in water and penetrates deep into the lung, causing pulmonary oedema and cancer. 

A variant of this process was developed in Australia by AUSMELT in 1998 their process used a closed induction furnace but with an air feed to bum the cadmium in the furnace and recover it in the form of cadmium oxide. The process produced nickel matte which had to be sent to the nickel refiners and highly contaminated cadmium oxides that had to be sent to the producers of primary cadmium. This required a higher investment than closed furnaces and the products extracted were somewhat less effectively recyeled than the nickel-iron and cadmium metal residues. 

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