Recovering gold from copper concentrate via the HydroCopper™ process (original) (raw)

Recovering gold from copper concentrate via the HydroCopper™ process

Jom, 2004

HydroCopper™ technology comprises a chloride-leaching method for copper sulfide concentrates and copper production up to semi-products. As compared with the commonly used sulfate solutions, brine solutions offer aggressiveness and stability of the copper(I) ion and, consequently, a lower energy consumption in leaching. Copper(II) ions and oxygen are used as oxidants. Iron reports to the leaching residue as oxide and sulfur as elemental sulfur. Gold is dissolved and recovered in the third stage of the counter-current leaching when the redox potential reaches higher levels.

Hydrometallurgical Recovery of Gold from Mining Wastes

2020

Gold is a highly required material for a wide range of personal and industrial applications. The high demand for gold, together with the shortage of natural resources and high pollution potential of wastes generated during mining and ore processing activities led to search for alternative sources of gold. A possible source is represented by mine wastes resulting from the processing of polymetallic or sulfidic ores. The reprocessing of wastes and old tailings with moderate to low content of gold offers not only a business opportunity, but also enhances the quality of the surrounding environment, changes the land use and offers a wide range of socio-economic benefits. Cyanidation, the most widespread Au leaching option, is progressively abandoned due to the high risk associated with its use and to the low public acceptance. Therefore, alternative methods such as thiocyanate, thiourea, thiosulphate and halide leaching gained more and more interest. This chapter presents the most import...

Copper and cyanide recovery from barren leach solution at the gold processing plant

As easily mined gold deposits are becoming increasingly rare, gold producers are turning to the processing of ores with polymetallic and copper mineralization. These base metals can create metallurgical and waste handling/disposal challenges, which can render the project uneconomic. Base metals such as copper compete for the cyanide reagent used to extract gold, necessitating the need to increase cyanide volumes and consequently, cyanide consumption costs. Copper will also stabilize in tailings water as weak acid dissociable cyanide, a form that is both difficult and costly to destruct. SART (sulphidization‐acidification‐recycling‐thickening) process technology can be applied to remove base metal interferences in gold projects. SART breaks the copper‐cyanide complex and precipitates the copper as a saleable copper sulphide concentrate. With the copper removed, the cyanide can be regenerated as free cyanide for recycle to the gold recovery process. This improves cyanide utilization efficiency and mitigates copper presence in tailings. Additionally, copper recovery generates an incremental revenue source to further improve project economics. Engineering Dobersek GmbH together with BioteQ developed a SART and AVR testing program to recover cyanide and maximize operational efficiencies at a gold processing plant in Kazakhstan with high cyanide consumption in the leach circuit. Results from on‐site testing demonstrated that up to 99.98% of copper can be removed and precipitated as copper sulphide and 60–90% of cyanide can be recovered from the AVR and recycled for leaching, reducing total overall cyanide use. This paper provides an overview of the testing methodology and results together with a discussion on the potential of SART to improve gold production operations to deliver both environmental and economic benefits.

Increased recovery of free fine gold in the leaching process

Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu

The current state of world mineral resources is characterized by a decrease in the quality of minerals. An increase in production and processing volumes is possible only through the development of new deposits and the involvement of off-balance ores, dumps and tailings, slags and other industrial wastes in the integrated mining process. More increasing the need for involving raw materials of complex composition, refractory, low-grade, with small reserves, technogenic mineral waste. It becomes more and more relevant as the discovery and exploitation of new deposits, allowing to increase the gold reserve of the Republic of Kazakhstan. The article presents the results of sorption leaching of ore in order to extract gold associated with sulfides, the processes of opening gold. A representative sample was taken and the phase composition of an additional explored ore body was studied at one of the deposits in Kazakhstan. The ore sample was prepared for research: three-time mixing by the r...

Outotec Copper Chloride Leaching Process for Malanjkhand copper concentrate

Hindustan copper has embarked on an ambitious expansion program to raise the capacity of Malanjkhand copper mines from 2 MTA to 5 MTA. To take advantage of the value addition arising out of conversion of the concentrate to cathode, they have been on the look out for a cost effective technology option for this purpose. It is in this context that Hindustan Copper Limited (HCL) and Outotec have been working to optimise Outotec Copper Chloride Leaching Process for HCL's Malanjkhand sulphide based copper concentrate. HCL's aim is to produce LME grade A copper cathode along with metallic gold and sterling silver, hydrometallurgically from the copper concentrate. Starting from 2013, the process has been tested first with batch tests and later in fully integrated continuous pilot runs with good results. The raw material has been HCL's Malanjkhand copper concentrate containing copper mainly as chalcopyrite with notable silver and gold contents. All testing has been done in Outotec Research Center in Finland. Techno-economical evaluations for the process were done based on the test work and Outotec's internal databases. The Capex (capital expenditure) & Opex (operating expenditure) of Outotec Copper Chloride Leaching Process were found to be very attractive. Initially the concentrate is leached in agitated reactors at atmospheric pressure in copper chloride solution. Copper is subsequently removed from the leachate by solvent extraction and finally recovered in electrowinning. Silver is leached together with copper and it can be recovered from the solution after copper solvent extraction. The copper leaching residue is re-leached in more concentrated chloride media in order to leach gold. Gold is recovered from the solution by activated carbon. The process is flexible with respect to raw materials and is designed to achieve minimal environmental impact and easy scale up.

Valorisation of Mining Waste for Gold Recovery

2018

Purpose: the metals and industrial minerals contained in the tailings produced by mining and quarrying activities, are cause of environmental damage. The objective of this experimental work is the application of innovative technologies for the treatment and exploitation of mining tailings in Romania, in order to recover materials high grade raw to be placed on the market, reducing the volume of the wastes. Further objective, is to optimize some parameters relating to the dissolution of gold and the subsequent recovery from purified solutions, determining beforehand the technical feasibility of the scheme of process developed on a laboratory scale. Methods: the study is focused on hydrometallurgical process for the recovery of gold. The innovative treatment chosen is the thiosulphate process that, compared to conventional cyanide, has several advantages, first of all the most eco-friendly and nontoxic to humans. The conventional process shows operating limits in the case of auriferou...