Showing 01 - 12 of 139 Results

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Thiourea Gold Leaching Metallurgist & Mineral Processing

For the thiourea process to compete industrially with cyanidation, it is essential to develop efficient process(es) to recover the gold from solution. Research on the leaching of gold by thiourea has been reported extensively in the literature, but research on the recovery of gold from leach solutions has not been well documented.

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An innovative thiourea gold leaching process ScienceDirect

When leaching at higher thiourea concentration, namely 100 kg/t, the rate of gold extraction is high: recovery of about 60% Au after 4 h is achieved. When leaching proceeds further the dissolution of gold increases to about 87% Au. Thiourea and sulphuric acid consumption were both 5 g/kg.

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Thiourea H2NCSNH2 PubChem

A leaching agent for gold leaching and silver leaching can be created by selectively oxidizing thiourea, bypassing the steps of cyanide use and smelting. Another common application for use of thiourea is a common sulfur source for making semiconductor cadmium sulfide nanoparticle.

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A REVIEW OF GOLD LEACHING IN ACID THIOUREA SOLUTIONS

Oct 23, 2006· Since the initial report of thiourea as a complexing reagent for gold leaching, considerable research has been directed toward the use of thiourea as an alternative to cyanide for gold extraction from different auriferous mineral resources. At the same time, some fundamental investigations of the system have been reported.

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Thiourea leaching gold and silver from the printed circuit

Highlights Thiourea is a selective and less hazardous agent as an alternative to the conventional and toxic cyanide. The agent was applied to leach gold and silver from PCBs of waste mobile phones. The influence of the particle size, thiourea and Fe 3+ concentrations and temperature was investigated. In the best condition, about 90% of gold and only 50% of silver were leached with a contact

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Thiourea leaching of a copper-gold ore using statistical

Thiourea leaching of gold ores is presented as an alternative to cyanidation. The dissolution of gold in a thiourea solution is an electrochemical process [3]. An acidic medium must be used to ensure the stability of the thiourea and to prevent it from degrading too rapidly. The Au-thiourea complex is formed as follows: + Au + 2SC(NH2)2 ~ Au(SC

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Leaching Gold-Silver Ores With Sodium Cyanide and

LEACHING GOLD-SILVER ORES WITH SODIUM CYANIDE AND THIOUREA UNDER COMPARABLE CONDITIONS By J. A. ~isele,' A. E. ~unt,~ and D. L amps shire^ ABSTRACT There is currently mch interest in how extraction of gold and silver from ores with acidic thiourea solution compares with

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Reaction chemistry of gold leaching in thiourea solution

This study was carried out on a finely disseminated gold-bearing ore from Kaymaz, Turkey. The main objective was to determine the mechanism of reaction between thiourea and Fe 3+ in the thiourea leaching of gold. Thiourea consumption levels were also examined during the leaching operations for different leaching parameters, i.e., molar ratio of ferric sulfate/thiourea, pH, and temperature.

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Pressure Oxidation of a Refractory Sulfide Concentrate and

Table 3 shows the results of the baseline leach tests for the concentrate. These results show that gold extraction with either thiourea or cyanide leaching were similar whereas silver extractions varied. Table 4 gives the thiourea and cyanide leach results for the roasted drill-core concentrate samples.

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process for thiourea and thiosulphate leaching Gold

Nov 09, 2015· Gold Refining Forum. Hobbyists and Professionals Helping One Another. leaching ,i know that it is very dangerous and harmful to envoirnment,so i want to know about other stone which can leach gold and silver also.so i want to know how about thioleaching. process for thiourea and thiosulphate leaching. Post by Barren Realms 007

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An innovative thiourea gold leaching process ScienceDirect

The aim of this experimental work was devoted to the preliminary evaluation of the feasibility of thiourea leaching for the extraction of gold from a domestic gold-bearing ore 4 g/t Au, at laboratory scale. The study has permitted identification of the influence of temperature, leaching agent concentration, pulp density and leaching time on the

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Leaching Pyrite Gold Ore without Cyanide

Thiourea Leaching of Gold. The use of thiourea for gold leaching has been proposed as a process alternative due to the supposed lower toxicity, faster leaching kinetics and the alleged less interference from base metals as compared to cyanide (Sparrow and Woodcock, 1995).

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(PDF) 'In-stope' leaching with thiourea ResearchGate

Since the initial report of thiourea as a complexing reagent for gold leaching, considerable research has been directed toward the use of thiourea as an alternative to cyanide for gold extraction

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Ferric Chloride Thiourea & Brine Leaching to Recover

A second thiourea leach was not effective in recovering silver, as discussed in the thiourea leach section. Additional work should be done to recover the remaining silver, zinc, and other metals. Silver and Gold Recovery from Thiourea. Only minimal effort was expended to recover gold and silver from the thiourea leach solution.

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Dissolution Behavior of Gold in Alkaline Media Using Thiourea

In this work the dissolutive behavior of gold in alkaline medium using thiourea (TU), under different variables, was studied in a theoretical and experimental way, in order to determine the conditions under which it is feasible to dissolve gold in thiourea-alkaline medium. A thermodynamic study was conducted by stone speciation using the method of Ro-jas-Hernández, together with an

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An Overview of the EnviroLeach Gold Recovery Process

An Overview of the EnviroLeach Gold Recovery Process agents have been identified that improve the gold leach kinetics as well as the stability of the gold that has leached into solution. These leach modifying additives are a unique and key component in the effectiveness of this process.

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Gold cyanidation Wikipedia

Gold cyanidation (also known as the cyanide process or the MacArthur-Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. It is the most commonly used leaching process for gold extraction.

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Thiourea bioleaching for gold recycling from e-waste

The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a thiourea

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(PDF) An innovative thiourea gold leaching process

The aim of this experimental work was devoted to the preliminary evaluation of the feasibility of thiourea leaching for the extraction of gold from a domestic gold-bearing ore 4 g/t Au, at laboratory scale. The study has permitted identification of

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A Method for Leaching or Dissolving Gold from Ores or

lurgical gold extraction routes utilize a leaching step to produce a gold-bearing solution as an intermediate product while the recycling of secondary gold from electronic and precious metal scrap is based on the selective and fast dissolu-tion of the precious metal. Therefore, A Method for Leaching or Dissolving Gold from Ores or Precious

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US4778519A Recovery of precious metals from a thiourea

A method is provided for recovering gold and silver from precious metal bearing materials including ores, leaching residues, flue dust, electronic scrap, jewelry scrap, etc. In the method, the gold and silver are extracted from the precious metal bearing materials with a thiourea solution to form a thiourea leach, and the thiourea leach is contacted with carbon to adsorb the gold and silver

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Dissolution Behavior of Gold in Alkaline Media Using Thiourea

1. Introduction. The use of thiourea (SC(NH 2) 2) (TU) has been studied extensively, mainly because it is not harmful to the environment, nontoxic to human beings, and the dissolution of gold in thiourea solutions is much faster than in cyanide solutions.The dissolution of gold in thiourea solutions was reported for the first time in 1941, and it was continued in 1960 [1] .

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(PDF) An innovative thiourea gold leaching process

The aim of this experimental work was devoted to the preliminary evaluation of the feasibility of thiourea leaching for the extraction of gold from a domestic gold-bearing ore 4 g/t Au, at laboratory scale. The study has permitted identification of

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(PDF) 'In-stope' leaching with thiourea ResearchGate

In situ leaching tests with thiourea as the lixiviant were carried out in two worked-out stopes at the No. 6 shaft at Rand Leases Gold Mining Company.

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Thiourea–thiocyanate leaching system for gold Request PDF

The leaching of gold in thiourea–thiocyanate solutions has been studied by the rotating-disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric, thiourea

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A review of gold leaching in acid thiourea solutions

Since the initial report of thiourea as a complexing reagent for gold leaching, considerable research has been directed toward the use of thiourea as an alternative to cyanide for gold extraction

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(PDF) Gold leaching by use of an N,N '-disubstituted thiourea

Feb 15, 2007· Gold leaching by use of an N,N '-disubstituted thiourea Article (PDF Available) in Separation Science and Technology 36(14)(14):3239-3251 ·

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Thiourea leaching of a copper-gold ore using statistical

Thiourea leaching of a copper-gold ore using statistical design Thiourea leaching of a copper-gold ore using statistical design Lacoste-Bouchet, Pierre; Deschênes, Guy; Ghali, Edward 1998-01-01 00:00:00 Thiourea was used to leach gold from ore containing 0.4% Cu and 5.6 g/t Au. The parameters studied were acid pretreatment, leaching time, pH, thiourea concentration and the oxidizing agents

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A Method for Leaching or Dissolving Gold from Ores or

lurgical gold extraction routes utilize a leaching step to produce a gold-bearing solution as an intermediate product while the recycling of secondary gold from electronic and precious metal scrap is based on the selective and fast dissolu-tion of the precious metal. Therefore, A Method for Leaching or Dissolving Gold from Ores or Precious

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Aurorra Gold Mining: Non Cyanide Leaching

CLS will leach pieces of gold 40 mesh and smaller within 8 to 12 hours. This is a definite advantage over cyanide which can take up to a week to leach 40 mesh gold. This presents a number of trade-offs between CLS and cyanide. In most cases, the CLS leaching system can

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Recovery of Precious Metals from Discarded Mobile Phones

The objective of this work was to recover gold and silver from the printed circuit board (PCB) of discarded mobile phones by thiourea leaching. Effects of thiourea concentration, leaching temperature, leaching time, and ferric ion (Fe3+) concentration on the recovery of gold and silver were investigated. The PCB was pretreated physically to reduce the thiourea consumption and enhance the

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Reaction chemistry of gold leaching in thiourea solution

Dissolution of gold in thiourea solution was reported firstly in 1941[23] and then the theory and process of gold leaching in thiourea solution have been most widely studied throughout the world

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Gold electrowinning from thiourea solutions, Minerals

Sep 01, 2000· The use of thiourea as an alternative non-polluting reagent for gold leaching is very well known. However, the processes of gold recovering from thiourea solutions have received little attention, particularly the electrowinning process. Gold electrowinning from thiourea solutions was studied by linear sweep voltammetry and chronopotentiometry. For potentials more cathodic than 0 mV vs. SCE

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Use of Thiourea Leaching During Gold-Containing Dump

In Tadzhikistan the volume of gold-containing waste converted to gold is 18 tons. This waste is products of amalgamation and cyaniding processes., and with respect to end component content they may be classified as a very rich type of raw material since they contain 1.7–8.5 g/ton of gold, whereas the average gold content in ores extracted for processing in one of the richest deposits of the

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Reaction chemistry of gold leaching in thiourea solution

Dissolution of gold in thiourea solution was reported firstly in 1941[23] and then the theory and process of gold leaching in thiourea solution have been most widely studied throughout the world

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WO2011154607A1 Method of gold leaching Google Patents

A process for recovering gold from gold-bearing raw material is provided. The method comprises a step of leaching the raw material in leach solution comprising thiosulphate anions and trace amount of