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This section describes the following leaching processes: AL, HPAL, DNi, NPAL, the Caron process (carbonic acid leaching), phosphoric acid leaching, and …
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The process involved the leaching of anode slime in sulfuric acid medium. At room temperature, sulfuric acid leaching without any additive resulted in poor recoveries of metals other than copper. With the addition of MnO2 to the leaching system at room temperature, an increase in the recovery values of copper, selenium, and tellurium was …
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The most viable alternative to aqua regia, however, is the use of chlorine gas in combination with hydrochloric acid. In this process, chlorine gas is bubbled through a vigorously agitated suspension of atomized gold powder and hydrochloric acid. Gold dissolution occurs by the following reaction: (34.15) 2 Au + 2 HCl + 3 Cl 2 → 2 HAuCl 4
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Leaching, often gold, is the process of extracting a soluble constituent from a solid by means of a solvent. In extractive metallurgy, of gold, it is the process of dissolving a certain mineral (or minerals) from an ore or a concentrate, or dissolving certain constituents from materials such as a calcines, mattes, scrap alloys, anodic slimes, ...
Studies by Kim et al. (2016) assessed the recovery process of lanthanum and cerium utilizing hydrochloric, sulfuric, and nitric acid. Their leaching tests revealed that the best agent for REEs is hydrochloric acid at ambient temperature and pressure, as recovery rates of 92 and 94% were registered . Shen, Y., Jiang, Y., and Qiu, X. (2017 ...
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The development of a hydrometallurgical hydrochloric acid based leaching process for the treatment of nickeliferous laterites of various types is described. ... of hydrochloric acid by pyrohydrolysis with by-product recovery of magnesia some of which might be used for acidity control in the process. Attempts to leach successive batches …
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Highlights Leaching temperature, leaching duration, sulfuric acid to ore weight ratio and particle size of the limonitic nickel laterite ore were studied. Optimum parameters determined as 255 o C, 0.30 sulfuric acid to ore weight ratio, a particle size of −850μ, 1 h of leaching duration with 30% w/w. 87.3% of Ni and 88.8% of Co in …
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Hydrochloric acid leaching has been widely used in the recovery process of vanadium due to its efficient selectivity. It was necessary to further separate vanadium from hydrochloric acid leaching solution. Four extractants of P204, P507, Cyanex272, and N1923 were compared for extraction of vanadium from a simulated hydrochloric …
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The development of a hydrometallurgical hydrochloric acid-based leaching process for the treatment of nickeliferous laterites of various types is described. A key step is the separation and ...
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Leaching at atmospheric pressure requires more sulfuric acid consumption compared to high-pressure sulfuric acid leaching. AL [13, 28] is an economical method because of its temperature characteristics and open vessel requirement, which avoids expensive autoclaves.At low temperatures, though, this avoids the need for autoclaves …
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Lower CAPEX b, d, e, g, h Higher acid consumption (to obtain acceptable nickel recoveries) c, e, f, h Residue more voluminous (from tank leaching) b, h More magnesium in the waste liquor compared to limonite HPAL c, d, e, h May consume more limestone c, h No significant improvement in OPEX (depending upon how second generation HPAL plants ...
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95% copper from the leach liquor [12]. Another leaching process used a spent acid etching solution with the assistance of ultrasound at 300 W and further adjustment of pH by lime to 2.5, obtaining a high Cu leaching efficiency of 93.76% and a noticeably low Fe extraction of 2.07% [9]. Sulfuric leaching
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The sulfation-roasting-leaching process has the potential to change this scenario once it can be applied to all kinds of nickel laterite ores and does not consume much acid, as in the atmospheric ...
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Recovery of rare earth elements (REEs) from tailings is the solution to the waste of valuable resource and hazard of tailing dam. In order to lower the cost and increase the rate of REEs recovery, we investigated leaching kinetics and dissolution mechanisms of REE slag in hydrochloric acid (HCl) solution, and present a method for …
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The AMAX Acid Leach Process for oxide nickel ores generates leach liquors that can vary considerably in their nickel, cobalt, iron, aluminum, manganese, and magnesium concentrations.
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In a leaching solution containing 1 g/L NaCl, 1 % HCl and 2 % NaOCl, nearly 90 % of the gold was extracted in only 30 minutes. Additions of hydrochloric acid will reduce the sodium hypochlorite requirement A leach solution containing 1 g/L NaCl, 5 % HCl and 1 % NaOCl achieved nearly the same per cent gold extraction under the same …
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In this paper the results of aluminum leaching from calcined coal waste are reported. Techniques including XRD, SEM, and FTIR were used to characterize the coal waste before and after calcination. Three additives were evaluated during the calcination process to improve the extraction of Al 2 O 3 by hydrochloric acid dissolution. The …
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Hydrochloric acid is another media used in magnesium extraction tests, as in the case of Özdemir et al. (2009) who leached previously dried magnesite tailings with hydrochloric acid, with particle sizes ranging from 750 down to 37.5 μm, an acid concentration between 0.1 and 2 M, a reaction temperature of 10 to 40 °C, a solid-liquid …
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During the leaching process, toxic NO x gases are released. The NO x emissions depend on the acid concentrations, temperature and air flow rates of the …
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The kinetic analysis of kaolinite dissolution in hydrochloric acid was performed with the aid of homogeneous and heterogeneous reaction models shown in Table 2 as previously reported in the literature [1, 3, 13].The experimental result was applied to the models shown in Table 2 to obtain the kinetic model that best describes …
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The most viable alternative to aqua regia, however, is the use of chlorine gas in combination with hydrochloric acid. In this process, chlorine gas is bubbled through …
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Iron control in the atmospheric acid leaching (AL) of nickel laterite was evaluated in this study. The aim was to decrease acid consumption and iron dissolution by iron precipitation during nickel …
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Coal Fly Ash (CFA) is a hazardous waste from coal-fired power plants, but has increasingly become a popular supplementary cementitious material for cement in the construction industry. As a secondary resource of REE, its main advantage lies in its fine particle size that eliminates the need for costly and energy-intensive comminution. In this …
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A hydrochloric acid hydrometallurgical process was evaluated for Ni and Co extraction from a low-grade saprolitic laterite. The main characteristics of the …
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Hydrochloric acid regeneration has become a vital stage in most chloride process flowsheets. Pyrohydrolysis has been the traditional method of regenerating hydrochloric acid from a variety of chloride solutions, including magnesium, iron and …
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Magnesium is widely used in varieties industrial sector. Dolomite is one source of magnesium besides seawater. The extraction of magnesium from dolomite ores can be done by leaching process.
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ABSTRACT. The kinetics of the leaching of natural magnesite with hydrochloric or nitric acid has been studied. Relatively high values of the apparent activation energy (from 46.5 to 70.0 kJ mol −1), but especially the low values of the apparent reaction order for H + cations, n, have shown that the whole process is …
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To investigate the leaching rules and mechanism of a hard rock uranium ore, this paper conducted conventional leaching experiments based on the chemical composition and mineral occurrence status of the ore. Various factors affecting leaching were explored, and experimental data were fitted using the shrinking-core model. The …
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3.1. Chloride based processes – literature survey. Hubler and Archibald (1938) patented a process for leaching high Mg % ore in cold 4 to 20% HCl continuing leaching to acidity <1% to give selectivity for Ni over Fe. Pawel (1952) employed a similar route using a ceramic-lined reactor with hydroxide precipitation of the metals by MgO …
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Leaching process is commonly used in the extractive metallurgy due to its low-cost implication, eco-friendly procedure, low-energy requirement as well as ability to treat low-grade ores17. The three processes commonly used for extraction of alumina from clays are; (1) the acid leaching with sulfuric acid, hydrochloric acid or nitric
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In the context of the circular economy, there is a need for advanced methods to recover metals from industrial waste, yet classical hydrometallurgical techniques are limited. Here, we review ultrasonic-assisted hydrometallurgical leaching with focus on the use of acids, bases, oxidants, bacteria and electrolysis. Oxidative leaching is done with …
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