scholarly journals Efficiency of using peroxide-carbonate compounds in reagent complexes for leaching gold hard to recover from placer

2022 ◽  
Vol 962 (1) ◽  
pp. 012058
Author(s):  
A G Sekisov ◽  
T G Konareva ◽  
A Yu Lavrov ◽  
V Yu Burov ◽  
E S Emirziadi
Keyword(s):  
Experimental Studies ◽  
Sodium Cyanide ◽  
Gold Extraction ◽  
Gold Leaching ◽  
Initial Concentration ◽  
Metastable Compounds ◽  
Cyanide Solutions ◽  
Different Order

Abstract The article deals with the data of theoretical and experimental studies of the processes of activation gold leaching using reactive peroxide carbonate compounds, obtained by electrophotochemical treatment of solutions of initial reagents of the corresponding composition, in the composition of reagent complexes. The obtained results of the experiments on the interaction of various carbonate and peroxide-carbonate compounds with sodium cyanide in the process of mixing activated and non-activated solutions with aqueous cyanide solutions in different order definitely prove that supramolecular percarbonate-cyanide compounds are being formed in them. It has been established that these activated solutions, prepared on the basis of the initial hydrocarbonate ones, contain metastable compounds that provide a higher rate of gold extraction from crude minerals than standard aqueous cyanic solutions of the same initial concentration.

scholarly journals ADSORPTION OF PHOSPHATE IONS ON RED SLUDGE

2017 ◽  
Vol 60 (8) ◽  
pp. 80
Author(s):  
Svetlana M. Kramer ◽  
Mariya V. Terekhova ◽  
Inna V. Artamonova
Keyword(s):  
Hydrochloric Acid ◽  
Experimental Studies ◽  
Aluminum Production ◽  
Quantitative Composition ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Phosphate Ions ◽  
Frumkin’S Isotherm ◽  
Ph Range ◽  
Red Sludge

In work the possibility of red sludge (waste of aluminum production by Bayer's method) to adsorb phosphate ions from water solutions at various concentration of ions and in the pH range from 3 to 10 is studied. Relevance of use of red sludge for receiving on its basis of sorbents is reasoned. For identification of the studied object the qualitative and quantitative composition of red sludge was established by the method of the X-ray phase analysis. The technique of red slage activation by hydrochloric acid, and also an adsorption technique of phosphate ions on the red sludge surface is described. Experimental studies of adsorption of phosphate ions on the surface of the red slage activated by hydrochloric acid depending on рН and concentration of initial solution were conducted. The dependence of adsorption phosphate ions on the red slage activated by НСl on рН and on the initial concentration of phosphate ions in solution is presented. These dependences of a relative fraction of distribution of various ions of phosphoric acid on рН are given in work. The form of ion phosphate having the greatest adsorptive activity on the red slage activated by hydrochloric acid in experimental conditions is revealed. Experimental data on dependence of adsorption of phosphate ions on their initial concentration in solution are described by Frumkin's isotherm. The constant of the adsorptive balance, limit adsorption, the parameter of intermolecular interaction of the adsorbed particles are calculated. Optimum conditions for adsorption of phosphate ions on red slage are established.Forcitation:Kramer S.M., Terekhova M.V., Artamonova I.V. Adsorption of phosphate ions on red sludge. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 80-83.

scholarly journals Experimental studies on reactive distillation of propionic acid using n-butanol as entrained

2018 ◽  
Vol 7 (3.29) ◽  
pp. 46
Author(s):  
Raju. Kalakuntala ◽  
R Navya ◽  
T Sisira ◽  
V V. Basava Rao ◽  
Srinath. Surnani
Keyword(s):  
Propionic Acid ◽  
Chemical Engineering ◽  
Reactive Distillation ◽  
Experimental Studies ◽  
Raw Material ◽  
Esterification Reaction ◽  
Distillation Process ◽  
Batch Distillation ◽  
Initial Concentration ◽  
Weight Percentage

Reactive distillation is a cost effective chemical engineering process intensification method which involves the reaction and separation simultaneously in a single unit. In the present work the system selected was Propionic acid and n-butanol which undergoes esterification reaction to form butyl propionate. Propionic acid is an important raw material from a biodegradable polymer. The experiments were done in both conventional batch distillation and reactive distillation. In conventional batch distillation no catalyst were used were as in reactive distillation amberlite catalyst used with various weight percentage. several experiments performed by varying the initial concentration(i.e. 0.1,0.2,0.4,0.6,0.8,0.99) of Propionic acid, mole ratios of Propionic acid & n-butanol(that is 1:1 ,1:1.5 ,1:2 And amberlite catalyst weight percent (i.e. 1,2 and 3).the conventional batch distillation and reactive distillation were compared. it is found that maximum conversion obtained in conventional distillation process is 81% and in reactive distillation is 95.1% at the optimum conditions are at initial concentration 0.6 ,mole ratio 1:2 And amberlite catalyst weight percentage 3 .And the recovery of water is more in reactive distillation as compared with the conventional batch distillation .So reactive distillation process is better than conventional distillation.  

Biooxidation of a Refractory Gold Ore: Implications of Whole-Ore Heap Biooxidation

2017 ◽  
Vol 262 ◽  
pp. 65-69 ◽  
Author(s):  
Bo Wei Chen ◽  
Jian Zhi Sun ◽  
He Shang ◽  
Biao Wu ◽  
Jian Kang Wen
Keyword(s):  
Pulp Density ◽  
Tianshan Mountain ◽  
Gold Mine ◽  
Gold Extraction ◽  
Gold Leaching ◽  
Gold Ore ◽  
Refractory Gold ◽  
Gold Reserve ◽  
Initial Ph ◽  
South Tianshan

The Sawayardun Gold Mine, the first Muruntau type gold mine in China, was located in the south Tianshan Mountain, Xinjiang Province. The gold reserve was 127 t with an average gold grade of 2.36 g/t. Due to the high content of arsenic and antimony, the traditional flotation-roasting-cyanidation process was not suitable. The direct cyanidation gold extraction for the raw ore was 44.70 %. Thus, biooxidation experiments in shaker flasks were conducted for this ore. The optimum conditions were obtained as inoculation volume 10 %, initial pH 1.7, pulp density 15 %, temperature 33 °C, leaching time 10 days, with the arsenic oxidation rate of 75.12 %. Then the biooxidation residues were test for gold leaching using NaCN, green gold leaching agent and thiourea. After 24 h leaching rate at pulp density of 33%, gold leaching agent dosage of 2 kg/t ore, the gold extraction for NaCN, green gold leaching agent and thiourea were 91.50 %, 86.23 % and 91.09 %, respectively. The high gold extraction showed a bright future for the whole-ore heap biooxidation of this refractory gold ore.

scholarly journals Analysis of the current state of technologies in the field of recycling technogenic gold-containing raw materials

2021 ◽  
Vol 25 (1) ◽  
pp. 97-107
Author(s):  
A. О. Vasilkova ◽  
N. V. Vasilkov ◽  
О. D. Khmelnitskaya ◽  
G. I. Voyloshnikov
Keyword(s):  
Noble Metals ◽  
Raw Materials ◽  
Cost Effective ◽  
Sodium Cyanide ◽  
Future Research ◽  
Gold Extraction ◽  
Current State ◽  
Mill Tailings ◽  
Cyanide Consumption ◽  
Technogenic Raw Materials

 In this article, we review existing approaches to recycling technogenic raw materials (ore dumps, metallurgical production slag, mill tailings of ore-dressing plants, etc.), containing non-ferrous and noble metals, which are accumulated in almost non-ferrous metallurgy industries. An analysis of existing technologies for processing technogenic raw materials (pyrite cinders and flotation tailings of concentration plants), which include enrichment, pyro- and hydrometallurgical and combined ways of extracting valuable components, was conducted on the basis of a review of published sources. It was shown that enrichment (screening, desliming in a hydrocyclone, enrichment using a concentration table, magneticliquid separation, flotation), pyrometallurgical and combined ways for extracting noble metals from this type of raw materials are unprofitable. The most satisfactory results were obtained using hydrometallurgical methods to extract valuable components from technogenic raw materials. Various solvents, such as sodium cyanide, thiocarbamide, sodium thiosulphate and sodium sulphite were tested as leaching agents. Cyanation proved to be the most effective way to extract noble metals from technogenic raw materials; however, this process is characterised by a high consumption of sodium cyanide. Therefore, it is of importance to discover an approach to extracting valuable components from such problematic products in order to make their processing more cost-effective by reducing cyanide consumption while maintaining gold extraction. According to the obtained results, gold-containing raw materials are promising in terms of extraction of nonferrous and noble metals using hydrometallurgical technologies. Future research should identify rational methods for processing technogenic gold-containing raw materials in order to make the technology more profitable for extracting valuable components. 

Sandioss, an alternative reactive to NaCN for the Au leaching process by agitation for an oxide type mineral

2018 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Manlio Heras Romero ◽  
Nilton Quispe Ciudad ◽  
Juan Vega Gonzales
Keyword(s):  
Atomic Absorption ◽  
Sodium Cyanide ◽  
Variance Analysis ◽  
Gold Content ◽  
Leaching Tests ◽  
Gold Extraction ◽  
Fire Assay ◽  
Leaching Process ◽  
Mineral Type

The influence of the Sandioss reagent was studied as an alternative for the gold’s leaching by agitation of a mineral-type oxide. The evaluated variables were: the hydrogen potential (pH) with levels 7, 9 and 11, the concentration of Sandioss leach at 250 ppm, 500 ppm and 750 ppm, and the leaching time at 12, 24 and 48 hours. For each concentration of the leaching agent, a test was conducted in parallel with sodium cyanide at a pH = 11 to prevent the volatilization of cyanide. The solutions taken were analyzed by atomic absorption to determine the gold content in solution and tails were analyzed by fire assay. From the result of the leaching tests it can be concluded that for a better gold extraction with the Sandioss leaching, it is obtained at a concentration of 750 ppm of Sandioss, pH of 11 and time of 48 hours, obtained 79.15% extraction. Finally, the variance analysis at a level of 95% confidence shows that the variables studied significantly influence the extraction of gold and is presented as an alternative to the use of NaCN.

scholarly journals The Adsorption Efficiency of Chemically Prepared Activated Carbon from Cola Nut Shells by on Methylene Blue

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Julius Ndi Nsami ◽  
Joseph Ketcha Mbadcam
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Experimental Studies ◽  
Isotherm Models ◽  
Solution Ph ◽  
Batch Mode ◽  
Initial Concentration ◽  
Adsorption Isotherm Models ◽  
Pseudo Second Order ◽  
Blue Solution

The adsorption of methylene blue from aqueous solution onto activated carbon prepared from cola nut shell has been investigated under batch mode. The influence of major parameters governing the efficiency of the process such as, solution pH, sorbent dose, initial concentration, and contact time on the removal process was investigated. The time-dependent experimental studies showed that the adsorption quantity of methylene blue increases with initial concentration and decreasing adsorbent dosage. The equilibrium time of 180 min was observed and maximum adsorption was favoured at pH 3.5. The dye removal using 0.1 g of adsorbent was more than 90%. This dosage (0.1 g) was considered as the optimum dosage to remove methylene blue from aqueous solutions. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir adsorption isotherm models. The kinetics of methylene blue solution was discussed by pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption process follows the Elovich rate kinetic model, having a correlation coefficient in the range between 0.9811 and 1.

scholarly journals Experimental study on thiosulfate leaching of gold from a high copper gold concentrate

2021 ◽  
Vol 271 ◽  
pp. 04001
Author(s):  
Chen Yanbo ◽  
Qin Guanglin ◽  
Li Guangsheng ◽  
Zhu Xingfu ◽  
Yu Congquan ◽  
...  
Keyword(s):  
Environmental Problems ◽  
Sodium Cyanide ◽  
Cyanide Leaching ◽  
Gold Leaching ◽  
Leaching Process ◽  
High Copper ◽  
Copper Gold ◽  
Cyanide Consumption ◽  
The Cost ◽  
Thiosulfate Leaching

The conventional cyanide leaching process is used to extract gold from a high copper gold concentrate. Because the copper associated minerals consume sodium cyanide in large quantities, the cost of the reagents is high and the economic benefit is not ideal. At the same time, a large number of cyanide tail slag are produced, which brings a series of environmental problems. In order to solve the environmental problems caused by excessive sodium cyanide consumption and cyanogen slag, the feasibility of leaching gold by thiosulfate in copper ammonia system was studied. The gold leaching rate of thiosulfate was increased to more than 90% by using the direct thiosulfate leaching process and pretreatment thiosulfate leaching process, which was close to the gold leaching index of sodium cyanide at the production site.

scholarly journals Generation of sodium cyanide by coal gasification for gold recovery factories

2021 ◽  
Vol 25 (4) ◽  
pp. 488-497
Author(s):  
N. V. Vasyunina ◽  
I. V. Dubova ◽  
S. P. Baksheev ◽  
M. R. Kovel ◽  
V. V. Makarova
Keyword(s):  
Coal Gasification ◽  
Sodium Cyanide ◽  
Gold Recovery ◽  
Production Costs ◽  
Hydrocyanic Acid ◽  
Solution Ph ◽  
Laboratory Setup ◽  
Naoh Solution ◽  
Cylindrical Furnace ◽  
Cyanide Solutions

The aim was to assess the technological feasibility of generating sodium cyanide by coal gasification, to study the effects of the process parameters (temperature, experiment duration, coal type) on the concentration of sodium cyanide in the resulting solutions, as well as to identify optimal modes of the process. Experiments were carried out on a laboratory setup consisting of a tubular cylindrical furnace equipped with a working compartment in the form of a corundum tube. Lignite and charcoal, preliminarily crushed to increase the specific surface area, were investigated. A solution of sodium cyanide was produced by sorption of gaseous hydrocyanic acid (a syngas component) with a sodium carbonate solution. A NaOH solution (pH = 10) installed in an ice bath was used in the system of absorbers. The content of sodium cyanide in the solution was determined by the titrimetric method. The HSC Chemistry 5.1 software package was used for thermodynamic calculations. During the gasification of charcoal in the temperature range 600–800oC, sodium cyanide solutions with a concentration of 0.03–0.08 wt% were obtained. An increase in temperature from 600 to 900oC led to a 4-fold decrease in the concentration of sodium cyanide in an alkaline solution, under the same duration of the experiments. A regression equation was derived for the dependence of the NaCN concentration in solution on the temperature of coal gasification and the duration of the process. It was shown that the generation of sodium cyanide by coal gasification under laboratory conditions yields sodium cyanide concentrations in solution comparable to those used for gold cyanidation at gold recovery plants. The installation of sodium cyanide generation lines directly at the production areas of gold recovery plants will reduce the production costs by eliminating expenses for purchasing, transporting and storing reagents.

scholarly journals Recovery of Gold from Ore with Potassium Ferrocyanide Solution under UV Light

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 387
Author(s):  
Ziyuan Liu ◽  
Jue Kou ◽  
Yi Xing ◽  
Chunbao Sun
Keyword(s):  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Light Response ◽  
Extraction Process ◽  
Potassium Ferrocyanide ◽  
Sensor Surface ◽  
Gold Extraction ◽  
Solution Ph ◽  
Gold Leaching ◽  
Two Stages

In this study, potassium ferrocyanide, a nontoxic cyanide precursor in dark and diffuse reflection environment, was applied as reagent for the leaching of gold. The free cyanide ions could gradually release from potassium ferrocyanide solution under the ultraviolet light. Orthogonal leaching experiments were performed in gold ore to analyze the effect of solution pH, potassium ferrocyanide dosage, and temperature in a potassium ferrocyanide solution system under UV light. Response surface methodology (RSM) was applied to explore the role of potassium ferrocyanide in gold leaching; optimized results showed that the gold recovery reached 67.74% in a high-alkaline environment at a 12.6 pH, 3.8 kg/t potassium ferrocyanide dosage, 62 °C, and irradiance of 10 mW·cm−2. The gold leaching kinetics were monitored by quartz crystal microbalance with dissipation (QCM-D) of potassium ferrocyanide solution. The results indicate that the gold extraction process could be divided into two stages: adsorption and leaching, and a rigid adsorption layer formed on the reaction surface. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis of the gold sensor surface after leaching reaction showed that –C≡N appears on the gold sensor surface, and the gold is oxidized to form AuCN complexes.

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