ABSTRACTThe selective chlorination of cyanidation tailing (CT) for the extraction of gold and silver has been investigated. The reaction operated at different conditions and their effect on the extraction of Au and Ag was studied. The mineral samples were characterized by fire assay, X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electronic microscopy (SEM).
Miller's Gold Chlorination process was introduced by F.B. Miller. The refining process employs chlorine gas, which passed into molten gold covered with a layer of borax and silica, and reacts with most of metals present in the molten charge. Platinum group metals do not react. Basically, gold is slightly attacked in the first moments and all the chlorides formed rise to the surface and are ...
Gold Extraction and ... chlorination, biooxidation etc are available to treat these ores to expose the gold particles before cyanidation. Thioura leaching was developed as a potential substitute to cyanide leaching due to its lower toxicity and greater rate of gold and silver dissolution. Other
The rate of dissolution of gold by chlorine is much faster than that by cyanide (Filmer et al., 1984). Also, due to presence of chloride ions, there is no passivation of gold surfaces during chlorination. The major disadvantage of the chlorine–chloride system is the high reactivity of chlorine in reaction with sulfide and gangue carbonate ...
However, its use in mining has become the focus of intense attack by various groups throughout the world; as a consequence, a renewed effort has been launched to find suitable alternative lixiviants to recover gold. Chlorination was the most popular process to extract gold, before it was rendered obsolete with the advent
The selective chlorination of cyanidation tailing for the extraction of gold and silver investigated. The reaction operated at different conditions and studied their effect on the extraction of Au ...
Gold extraction refers to the processes required to extract gold from its ores.This may require a combination of comminution, mineral processing, hydrometallurgical, and pyrometallurgical processes to be performed on the ore.. Gold mining from alluvium ores was once achieved by techniques associated with placer mining such as simple gold panning and sluicing, resulting in direct recovery of ...
The solution, he continued, is the greenest solvent next to water, so eliminates the vast number of environmental concerns that come with long standing methods of gold extraction. In this ...
gold ores, and the use of the chlorination process after the 1870s to improve the extraction rate of the gold from the ore. The validity of the comment by Jan Todd on the lack of knowledge in Australia about chemical extraction processes and chlorination will be assessed as part of this discussion. Calcination
Technical Note Gold extraction by chlorination using a pyrometallurgical process M.W. Ojedaa,*, E. Perinob, M. del C. Ruiza a Instituto de Investigaciones en Tecnología Química (INTEQUI), Universidad Nacional de San Luis-CONICET, C.C. 290, 5700 San Luis, Argentina bÁrea de Química Analítica, Universidad Nacional de San Luis, San Luis, Argentina ...
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
Sep 30, 2018· In this work, a chlorination roasting method for the extraction of precious metals (gold and silver) from the cyanide tailings (CT) was investigated. The decomposition mechanism of the CaCl 2 used as chloride agent was presented during the chlorination roasting. The Au and Ag recovery as high as 91.6% and 54.7% under the optimum experiment ...
The feasibility to recover the gold present in alluvial material, by means of a chlorination process, using chlorine as a reactive agent, has been studied.
The Newbery–Vautin chlorination process is a process to extract gold from its ore using chlorination developed by James Cosmo Newbery and Claude Vautin.. Background. The process of extracting gold from ores by absorption of the precious metal in chlorine gas, from which it is reduced to a metallic state, is not a very new discovery.
Chlorination processes for gold extraction have continued to be both studied and applied commercially in the intervening years (Putnam, 1944, Muir et al., 1982) and are applied in commercial application in many modern precious metals refineries (Crundwell et al., 2011). 1.2. Chemistry
The direct chlorination of a pure gold was also studied up to a temperature of 1223 K. These experiments demonstrated that the precious metal is not attacked at that temperature, in agreement with the literature, which indicates that the reaction of direct chlorination of gold is produced at high temperatures (Panias and Neou-Syngouna, 1990).
May 14, 2013· Gold, precious forever but especially lately, is a tricky metal. Bound up in consumer electronics, jewelry and the ores that it comes from, gold is difficult to extract.
Feb 05, 2013· The earlier practical applications of chlorine to gold extraction were known as Mears' and Plattner's processes, and consisted in placing the material to be operated on in vats with water, and introducing chlorine gas at the bottom, the mixture being allowed to stand for a number of hours, the minimum about twelve, the maximum forty-eight.
Gold recovery yield (ratio between Au onto GAC and Au in the roasted material) is about 97%: this means that the gold extracted by chlorination is completely adsorbed onto GAC (the difference between extraction and global recovery yield is probably due to operating errors).
Chloride–hypochlorite oxidation and leaching of refractory sulfide gold concentrate 63 Fig. 1. The Pourbaix diagram of Fe–S at [Fe] –= 10 4 M, [S] = 10– M and 25 C (the chlorine species regions are also marked) (Marsden and House, 2005) Fig. 2.
Bromine acts more energetically than chlorine, and has also been employed in the extraction. The recovery of the gold is effected similarly, and the bromine is then liberated by the action of chlorine, but it is impossible to prevent loss of bromine. Cyanide-process The extraction of gold by the cyanide-method is of great technical importance.
Experience has shown how difficult it is to obtain information regarding laboratory tests in connection with the chlorination-process for the extraction of gold from its ores, and I therefore present the following method, somewhat in detail, for the benefit of those who may desire to pursue research work in this field.. The ore chosen was a partly-decomposed porphyry, extremely siliceous and ...
The history of the chlorination process is interesting, and not commonly known, so that a brief account of it will not be out of place. Dr. Percy—rightly called the father of English Metallurgy —in 1848 read a paper on the value of chlorine as a means of extracting gold .
technologies for high temperature chlorination, gold extraction, tantalum extraction and titanium extraction: Spouse(s) Lillian D. Dunn, married 1944-1992 (her death) Wendell Earl Dunn Jr. (August 30, 1922 – December 24, 2007) was an American chemical engineer, metallurgist, and inventor.