Nickel extraction

It has been mentioned in an earlier chapter that nickel deposits are basically of two types sulfidic and lateritic (oxide). The scenario of nickel extraction from nickel sulfide concentrates and nickeliferrous pyrrho tite (these two are the two products of physical beneficiation of nickel sulfide ores), and from limonitics and gamieritics (these are the common lateritic ores) has been presented in Figure 5.6. It can be seen that nickel is extracted from its various sources by pyro, pyro-hydro and hydroprocessing. The account given here pertains to the latter two processes applied to the various nickel sources. 

Tozawa, K. Recent Trend of Nickel Extractive Metallurgy. Tetsu To Hagane-J. Iron Steel Inst. Jpn. 1993, 79, 1-11. 

Nickel dioxide, 77 107 Nickel double salts, 77 113 Nickel electrodes, 3 430 72 216 Nickel electroplating solutions, 9 818t Nickel extraction, 70 791 Nickel ferrite brown spinel, formula and DCMA number, 7 348t Nickel fibers, 77 108 Nickel fluoride complexes, 77 111 Nickel fluoride tetrahydrate, 77 109-110 Nickel fluoroborate, 77 111 Nickel fluoroborate hexahydrate, 4 157t, 158, 159... 

For simple acidic extractants, such as carboxylic or sulfonic acids, the similarity in formation constants does not produce cobalt-nickel separation factors (Sn° 2) sufficiently large for commercial operation (Fig. 11.4). Data for pH versus extraction for some chelating acid extractants does seem to offer the possibility of separation [e.g., for the hydroxyoxime Acorga P50, the pHso for nickel(II) is 3.5 and for cobalt(II) 5.0]. Normally, this pH difference would be suitable for a separation process, but this particular system has hidden complications. The rate of nickel extraction is very slow compared with cobalt and, in addition, although cobalt is initially extracted... 

The nickel extraction can be performed with DEHPA under defined conditions. As described earlier for zinc, the extraction of nickel is pH dependent. The Z)-value for nickel decreases drastically with decreasing pH below 3.5. The extraction of each nickel ion (Ni ) liberates two hydrogen ions (H ) from the extractant H DEHPA, which means that only a very small amount of nickel can be transferred to the solvent before the extraction stops. However, by adding a neutralization reagent (NaOH) into the... 

Fig. 14.3 Nickel extraction plant with simultaneous neutralization.

R. D. Neuman and S. J. Park. Characterization of association microstructures in hydro-metallurgical nickel extraction by di(2-ethylhexyl) phosphoric-acid. J. Colloid Interface Scl, 152(l) 41-53,1992. 

Nickel Nickel extraction and smelting, Nasal cancer lung... 

The availability of strongly chelating extractant reagents for a number of metals has lead to the development of procedures in which the metal is extracted from minimally treated blood or urine and then quantified by atomic absorption analysis. The metals for which such extractions can be used include cobalt, lead, and thallium extracted into organic solvent as the dithiocarbamate chelate, and nickel extracted into methylisobutyl ketone as a chelate formed with ammonium pyrro-lidinedithiocarbamate. 

Ziegler and coworkers at the Max Planck Institut fiir Kohlenforschung (Coal Research) in what was then Mulheim, West Germany were working to expand the scope and utility of the aufbau reaction. It was during this endeavor in 1953 that they accidentally discovered the "nickel effect." This term stemmed from the observation that nickel in combination with triethylaluminum catalyzes dimerization of ethylene to produce 1-butene. Accounts vary on the source of nickel in the formative experiments. It was ultimately attributed to trace nickel extracted from the surface of the stainless steel reactor in which early reactions were conducted. 

A dithizone/chloroform extraction technique for separating ng/l-levels of nickel (Cd, Cu, Zn) from sea water has been developed. The nickel extraction requires an addition of dimethylglyoxime. The metals are concentrated from 100 ml of sea water into 2.0 ml of dilute nitric acid 80). 

R. A. DeRuiter, "Copper and Nickel Extraction from Ammonincel Solution by L1X64N," M.S. 

Ores tested were predominantly limonitic in character, although some contained in excess of 2% magnesium. Leaching and precipitation reactions took place over an extended period of up to 70 hours from addition of acid. Nickel extractions were in excess of 80%, at acid addition rates of around 500 kg/t. Terminal iron solution concentrations of less than 0.5 g/L were typically achieved. Both sodium and potassium additions were made to promote iron precipitation. The potential for using seawater to slurry the ore was noted. Potassium, in the form of a carbonate was also added on occasion to raise the solution pH to around 1.5 to 2. 

Overall acid addition rates are typically in the range of 700 to 900 kg per tonne of combined limonite plus saprolite, depending on the ratio of saprolite to limonite and the nickel extraction desired. 

This study was carried out on a limonitic laterite from New Caledonia. The main objective was to evaluate the atmospheric leaching of the ore in ammonium sulphate media using ferrous sulphate as reductant. Different parameters were examined, such as total ammonia concentration, temperature and ferrous sulphate concentration. At 80 C, 130 g/1 of total ammonia, 2.73 g FeS04/ g ore and pH 8.2, nickel extraction was 64 % while 20 % of cobalt remained in solution after 8 hours. 

Figure 1 Effect of temperature on nickel extraction and iron behavior in ammonia solutions using ferrous sulphate as reducing agent at 600 RPM during 24 hours.

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