ResultFerrous sulfate, sodium sulfite, potassium sulfite, sulfur dioxide and hydrogen peroxide, formic acid and formaldehyde: Oliver and Richard, 1974: Adsorption: ... Chloride gold leaching is more difficult to apply than cyanide leaching for two main reasons: (1) special stainless steel and rubber-lined …
اقرأ أكثرResultGo to: Abstract. Thiosulfate leaching combined with ion-exchange resins is an innovative alternative for gold recovery. According to the properties of …
اقرأ أكثرResultMohammed R. Ahmed et al. showed that the presence of sodium sulfite can significantly reduce thiourea decomposition, accelerate the gold …
اقرأ أكثرResultSodium sulfite concentration varied between 0 and 0.2 M and ... An acceptable gold leaching rate of 0.18 to 0.27 μmol·m⁻²·s⁻¹ could be obtained under the conditions of above 0.1 mol/L ...
اقرأ أكثرResultThe thiourea gold leaching cyclic voltammetry curves are shown in Figure 2a,b for sodium sulfite and sodium silicate, respectively. As shown in Figure 2 a, with Na 2 SO 3 as a stabilizer and with positive scanning, the cyclic voltammetry curve of this system had its first oxidation peak at 0.16 V, which matched the …
اقرأ أكثرResultThe anodic current in individual and mixed thiosulfate-sulfite solutions was studied by means of voltammetry on a fresh gold RDE surface. An unexpected result was obtained: a new additional current maximum appears on the anodic voltammogram in mixed solutions; it is not observed in the individual solutions of …
اقرأ أكثرResultY.H. Hu, G.F. Guo, and G.Z. Qiu, Study on mechanism of gold leaching by thiourea in the presence of sodium sulphite, J. Cent. South Univ. Technol., 7(2000), No. 3, p. 113. Article CAS Google Scholar S. Ardiwilaga, Effects of cysteine and oxygen on recovery of cemented gold from leach liquors in a …
اقرأ أكثرResultCyanide-free mild chloride leaching was investigated. •. Gold could be recovered even at <520 mV vs. Ag/AgCl in carbon-in-chloride-leach mode. •. Copper was a stronger oxidant than iron in gold leaching. •. Gold was oxidized by in-situ dissolving impurities. •. Seawater contains enough chlorides to dissolve gold.
اقرأ أكثرResultThe capability of gold leaching using copper–tartrate–thiosulfate solutions is comparable to that of cyanidation, as well as the traditional copper–ammonia–thiosulfate leaching system at elevated temperatures. ... (0.02 mol/L) were used to eliminate the interference of sulfite ions and copper–tartrate …
اقرأ أكثرResultA detailed discussion about the recent advances of the technique in gold recovery from pregnant thiosulfate solutions is then …
اقرأ أكثرResultThen the highly basic anion exchanger is regenerated with a solution of a mixture of sodium and ammonium sulfite and sulfate. After the highly basic anion exchanger regeneration, it is transferred to the process of the thiosulfate-gold complex sorption. ... Gold leaching by polythionates (new non-toxic technology) …
اقرأ أكثرResultBy including sodium sulfite in the gold-thiourea system, it was possible to obtain the Au(I)-TU complex at alkaline pH, with a presence of 95.13%. ... The gold leaching kinetics were monitored by ...
اقرأ أكثرResultAbstract. The ammoniacal thiosulfate leaching process for gold and silver extraction has been reviewed in terms of leaching mechanism, thermodynamics, thiosulfate stability, and gold recovery options. The application to different ore types and process options have also been discussed. The thiosulfate …
اقرأ أكثرResultResults led to the conclusion that the leaching rate of gold with acidic thiourea was diffusion controlled, which was supported by the reaction activation energy of 9.32 kJ mol −1 in the absence of sodium sulfite and 7.62 kJ mol −1 in the presence of sodium sulfite. The efficiency of gold dissolution, which reached …
اقرأ أكثرResultGUDKOV et al [81] suggested that the addition of sodium sulfite could stabilize the leaching solution and accelerate the dissolution of gold and silver. However, sulfite ions will also cause a rapid reduction of copper ions which will …
اقرأ أكثرResultThis process first concentrates telluride-type gold ore, then follows by oxidative roasting, cyanide leaching, polysulfide leaching, sodium sulfite reduction, and other processes to recover tellurium and gold (Zhou and Chen, 2008). This method has a complicated process and high investment cost, and is difficult to …
اقرأ أكثرResultThe gold leaching in oxygenated alkaline thiosulphate media obeys a shrinking core kinetic model with an apparent rate constant of the order 10 −5 ... (Ji et al., 2003) that show the effect of copper(II) sulphate, sodium carbonate and sodium sulphite on gold extraction and thiosulphate degradation in oxygenated non …
اقرأ أكثرResultFig. 2 shows the column elution profile for gold loaded resin at 5 BV h − 1 using 1 M ammonium nitrate in the presence and absence of sulfite. In the absence of sodium sulfite, the elution of gold with 1 M ammonium nitrate is still incomplete after 25 BV.Previous work (O'Malley, 2001) required concentrations of …
اقرأ أكثرResultMost agree that the overall cyanide equation for leaching and cyanidation of gold is as follows: 4 Au + 8 NaCN + O2 + 2 H20 = 4 NaAu (CN)2 + 4 NaOH. Cyanide Leaching Chemistry. In a relatively simple system of this type the gold dissolves readily. The only requirements are that the gold be free and clean, …
اقرأ أكثرResultThe ammoniacal thiosulfate leaching process for gold and silver extraction has been reviewed in terms of leaching mechanism, thermodynamics, thiosulfate stability, and gold recovery options. ... a slurry of sodium sulfite is digested with an excess of sulfur to produce thiosulfate. The sodium sulfite slurry …
اقرأ أكثرResultHighlights. Thiosulfate–nitrite–copper is a promising silver leaching alternative system. Cupric–ammonia complexes are produced in-situ without the addition of ammonia in the system. Antlerite and copper hydroxide are produced on the silver particle. Sulfite decreases the oxidative ability of the system and the …
اقرأ أكثرResultEither SMB or Sodium Sulfite, or even sulfur dioxide gas will work fine for reducing gold in HCl-Cl solutions. When highly concentrated the solution will lean towards deep orange to deep red when highly concentrated. I use dry SMB exclusively now days and never have had to heat the solution to get the gold to …
اقرأ أكثرResultThe gold leaching rate evidently increased with the reagent content and slurry temperature of the pretreatment, reaching a maximum of 86.55% at 60 °C and CaO and Na 2 CO 3 concentrations of 16 and 32 g/L, respectively. ... The effects of sodium sulfide and sodium hydroxide concentration, temperature, leaching …
اقرأ أكثرResultAs shown in Table 4, the concentrations of TU were still > 1 g/L in all the three groups with additional sodium sulfite after gold leaching. Especially in X-3 and W-3, in which the concentrations of the lixiviant even remained at 1.27 ± 0.05 g/L and 1.58 ± 0.07 g/L, which meant that only half of the TU reagent was …
اقرأ أكثرResultRizki et al. reported that although the addition of sodium sulfite to the leaching system did not improve the gold recovery, the remaining thiourea in …
اقرأ أكثرResultThereafter, an attempt was made to improve the efficacy of the leaching by adding sodium sulfite (Na 2 SO 3), which has been shown to improve the leaching efficiency of relatively unstable reagents like thiosulfate and thiourea by mitigating their oxidation as described in the following section (Marsden and …
اقرأ أكثرResultA possible process for the recovery of tellurium from antimony and tellurium materials by alkaline sulfide leaching followed sodium sulfite precipitation was proposed. The tellurium and antimony materials were leached in 100 g/L Na 2 S solution at 80 °C for 60 min with L/S ratio of 10:1, in which 91.24% …
اقرأ أكثرResultMost of the gold in the roasting slag is recovered by thiourea/cyanide leaching process, however, the leaching residues (gold tailings) obtained from thiourea leaching process or the sodium cyanide leaching still contain 9–16 g/t gold, which is difficult to recover and is usually discarded with the leaching …
اقرأ أكثرResultThiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of dissolved gold. In this review, the four solutions to reduce the consumption of thiosulfate, including the control of reaction …
اقرأ أكثرResultThus, investigation of the influence of sulfide on the gold leaching process is important to maximize the utilization of RGOs. In this work, the effects …
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