Enhanced hydrochloric acid leaching of nickel

Jackson, E.; Lloyd, K.J

doi:10.1016/s0892-6875(00)00139-4

Cited by 3 publications

(5 citation statements)

References 3 publications

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“…Although chloride-based commercial leaching operations were not common, relative researches have been introduced (Rice and Strong, 1974;Majima and Awakura, 1985;Chen et al, 2000;Amer and Ibrahim 2001;Neudorf and Arroyo, 2002;Wan-rong et al, 2010;Chuanlin Fan et al, 2011). Some leaching processes, using hydrochloric acid enhanced with addition of thiourea, were also investigated and introduced the optimal leaching conditions as well as kinetics data (Jackson and Lloyd, 2000).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical factors affecting leaching of laterite ore in hydrochloric acid

Xiong

Chen

et al. 2012

Hydrometallurgy

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Section: Introductionmentioning

confidence: 99%

Physicochemical factors affecting leaching of laterite ore in hydrochloric acid

Xiong

Chen

et al. 2012

Hydrometallurgy

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“…[3][4][5][6][7][8][9][10] One of the methods commercially applied is the direct pressure leaching using sulphuric acid (Moa Bay method) that is operated at the high temperature of 460-523 K. In the process, the nickel oxide in the laterite is dissolved into the pressurized sulphuric acid together with the iron hydrate.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Nickel from Selectively Reduced Laterite Ore by Sulphuric Acid Leaching.

et al. 2003

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The laterite ore with low nickel content deposits in Indonesia can be expected to be an alternative raw material of iron making due to its high iron content. One of the required processes is the separation of nickel and cobalt from the laterite ore by leaching it with H 2 SO 4 at the atmospheric condition. The sample containing 50.88 % iron, 0.03 % cobalt and 0.30 % nickel was selectively reduced with CO/CO 2 mixed gas to obtain metallic nickel and cobalt, as well as magnetite from hematite. Accordingly, in the leaching process metallic nickel and cobalt will be dissolved by controlling the iron dissolving. The effects of various parameters have been examined. These condition include leaching time, temperature (303-343 K), H 2 SO 4 concentration (0.005-1.0) mol/l, as well as extraction rate of nickel.The result of the analysis indicated that the influence of selective reduction could speed up the nickel extraction and obstructed the iron dissolution. The extraction rate of nickel was very high for small particle and slower for larger size. The optimal condition of the test was obtained at the leaching temperature of 343 K, 0.05 mol/l H 2 SO 4 with a sample lower than 4.0 g/l. In 60 min after the test, about 93 mass% of nickel was extracted from the sample smaller than 44 mm. The nickel extraction would be higher by adding the leaching time. The rate of extraction was chemically controlled and the apparent activation energy was 42.2 kJ/mol. At the end of the leaching process, there was residual solid rich-magnetite and minimal nickel.

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“…It has been observed that, at very low pH values, high-concentration thiourea increases the dissolution rate of iron, or other group VIII metal such as cobalt or nickel. , This acceleration includes both cathodic and anodic processes. At microcathodes, the carbon–sulfur double bond is reduced and hydrogen sulfide is generated: normalH 2 NCSNH 2 + 4 normalH → normalH 2 normalS + normalH 2 NCH 2 NH 2 Thiourea may be further reduced and more hydrogen atoms are consumed: , normalH 2 NCSNH 2 + 6 normalH + 2 normalH + → NH 4 + + normalH 2 normalS + CH 3 NH 3 + normalH 2 NCSNH 2 + 8 normalH + 2 normalH + → 2 NH 4 + + normalH 2 normalS + CH 4 …”

Section: Resultsmentioning

confidence: 99%

“…Since H 2 S is released back into the solution close to the metal surface, it can be readsorbed at the microanodes. Owing to this recycling of hydrogen sulfide, anodic dissolution is significantly accelerated. ,, Through this route, the presence of H 2 S does not change the overall acidity of the system but somewhat maintains the H + level at the metal–solution interface, regulating the pH gradient. Also, ferrous ions are transferred from the substrate surface to the solution and microanodes are depolarized.…”

Section: Resultsmentioning

confidence: 99%

“…It has been observed that, at very low pH values, highconcentration thiourea increases the dissolution rate of iron, 27 or other group VIII metal such as cobalt or nickel. 43,44 This acceleration includes both cathodic and anodic processes. At microcathodes, the carbon−sulfur double bond is reduced and hydrogen sulfide is generated:…”

Section: Surface Morphology and Elemental Analysismentioning

confidence: 99%

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Thiourea-Assisted Phosphate Conversion Coating on Mild Steel and Characterizations by Cathodic Polarization and Linear Polarization

Liu

Wan

et al. 2013

Ind. Eng. Chem. Res.

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Using highly acidic phosphating solutions that dissolve rust, brush-on phosphating for large-scale steel structures can reduce the cost of rust removal, without the need of a post-treatment rinse. In very low pH medium, the presence of thiourea helps the formation of high-quality conversion films. A hydrogen sulfide acceleration mechanism is proposed, based on cathodic polarization data and previous studies. The formed films are amorphous and contain high water content, therefore a rather long post-treatment desiccation period is required and supported by analyzing the linear polarization resistance values in a desiccation model.

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Enhanced hydrochloric acid leaching of nickel

Cited by 3 publications

References 3 publications

Physicochemical factors affecting leaching of laterite ore in hydrochloric acid

Physicochemical factors affecting leaching of laterite ore in hydrochloric acid

Recovery of Nickel from Selectively Reduced Laterite Ore by Sulphuric Acid Leaching.

Thiourea-Assisted Phosphate Conversion Coating on Mild Steel and Characterizations by Cathodic Polarization and Linear Polarization

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