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2016720ensp ensp30000 kg of gold in 1990 Thiobacillus ferrooxidans was used to recover gold from a complex ore under laboratory conditions9 The ore contained 82 Fe 078 Cu 088 As and 35 g Auton with pyrite hematite arsenopyrite and chalcopyrite as the mai n metalbearing minerals Initial gold recovery by
Recovery of gold from refractory ores requires a pretreatment to liberate the gold particles from the host mineral in particular in the case of stibnite sb 2 s 3 the antimony sb forms stable compounds with sodium cyanide nacn during the cyanidation process as a consequence cyanide consumption increasespretreatment is usually an
With the high recovery rate strong ore adaptability pretreatment screening the coarse granular materials the dissolution rate of gold increases linearly to the maximum with the cyanide concentration then increases slowly when the cyanide concentration reaches 015 the dissolution rate of gold has nothing to do with the cyanide
2020618ensp enspoxidation pretreatment process reactors are typically maintained at 12 to 2ph through the use of lime addition if the ph drops below this range then bacterial growth slows at elevated ph the oxidation reaction is less effective thus gold recovery is reduced the pulp is typically 20 solids the combination of low ph and
Gold vat leaching process is currently widely used in smallscale gold mines because of a series of advantages including high recovery rate strong adaptability to ore low cost and simple process the basic principle is first to leach the gold from the ore with cyanide solution containing oxygen and then to extract the gold from the leaching solution with zinc powder or zinc wire
Man has held a fascination with recovering and acquiring gold almost since the beginning of time this paper will attempt to put the multitude of recovery processes into a current day perspective
Therefore to extract gold more easily the sulfide lattice must be oxidized and decomposed pretreatment of refractory gold ores via methods such as roasting chemical oxidation pressure oxidation ultrafine grinding and biological oxidation can be used to expose the encapsulated gold and cause an increase in the gold recovery rate 11 15
Cyanide leaching has been applied to separate gold from ore for over 120 years gold ores can be classified as free milling complex or refractory based on gold recovery achievable by direct cyanidation 1 high gold recoveries from freemilling gold can easily be obtained by conventional cyanide leaching 2 refractory gold ores have the low gold extractions by the cyanidation and are
20151028ensp enspthese costs are incremental increases associated with the biooxidation pretreatment of the refractory ore do not include neutralization and they assume that the treatment section is associated with an operating facility mining milling flotation cyanide leaching gold recovery tailings disposal
201683ensp ensp22 c as solution temperature increases the gold dissolution rate dso increases within limit fig 4 shows the effect of temperature on gold extraction from the gold precipitate dissolved in a solution containing 05 naoc15 hc1 and 1 gl nacl 82 of the gold was extracted in one hour at 27 c 92 at 43 c and 97 at 55 c further
Gold recoveries of 10 and 80 are achieved at 12 and 167 lbton hypochlorite consumption respectively increasing hypochlorite concentration increases the rate of extraction fora given hypochlorite consumption gold extraction increased with decreasing ore bed height
The ratio of the gold contained in the supernatant liquid and the gold originally contained in the ore preferably determined by fire assay is termed the leach ratio of the ore the leach ratio is a rough but reliable measure of the percentage gold recovery that can be expected to be obtained from gold ores via standard cyanide leach operations
2019913ensp enspincreased demand for gold leads to the search for more gold resources most of the gold 23 is obtained from the processing of nonrefractory gold ores generally gold ore is treated by cyanidation and then gold is recovered by zinc powder cementation activated carbon adsorption or ion exchange resin adsorption etc however with the development and utilization of goldrich ore
2006213ensp ensptable1 chemical composition of ore au gt as s c gold concentrate rich gold ore gold ore 3882 3665 528 307 1555 319 142 167 the experiment and conditions of cyanidingleaching is as followed the ore pretreated together with water are put into the airfilled cyanidingleaching reactor the ph value of the
At the same time the gold locked within hematite is effectively released so the leaching rate of gold cyanide increases about 10 than that in actual factory production the results have an actual significance in guiding industrial production
Gold leaching from ore using iodideiodine mixtures is an alternative to gold cyanidation this study evaluated the ability of iodideoxidising bacteria to solubilise gold from ore that was mainly composed of gold pyrite galena and chalcopyrite eight bacterial strains were successfully isolated from brine
201531ensp enspa gold recovery of 81 was attained with the conditions of the experiment 8 40 gl pretreated with 3 m naoh for 48 h download download fullsize image fig 10 gold extraction from the mineral with and without pretreatment np as calculated from fire assay the pretreatment conditions are shown in the block above each bar and in table 2
The grade and recovery of gold in the flotation concentrates were 4944 gt and 3336 respectively the total recovery of gold was 9094 the gravityflotation combined beneficiation pretreatment process provided a feasible method for the refractory gold ore and ensured the effective recovery of gold
The reported techniques provide a rather high gold recovery in followon adsorption cyanidation but high capital and operating expenditures do not allow their application to process poor ore or
2018928ensp enspin addition temperature demonstrated a significant effect on gold recovery percentage and improved the kinetics of oxidation of gold refractory ore as observed from figure 3d the au recovery increases from 8671 to 9672 by increasing temperature from 25 c to 50 c and then remains unchanged with a further increase
20171221ensp enspthe biooxidation stage improves metal recovery qiu et al 15 developed a cyanidation process with a pretreatment stage for silver and gold recovery from a refractory auag ore the pretreatment used pyrite as a reductant where mno2 was reduced to mn2 where it dissolved into the solution silver and gold were then accessible for cyanidation
201532ensp ensptreatment of copperrich gold ore by cyanide leaching ammonia pretreatment and ammoniacal cyanide leaching a d bas e koc e y yazici h deveci hydrometbamppm group division of mineral amp coal processing department of mining engineering karadeniz technical university trabzon 61080 turkey received 28 march 2014 accepted 1 september 2014
Buffer grinding machine pretreatment before mecury gold recovery 20200131t1801140000
A process for recovering gold from goldbearing ores includes the steps of forming a slurry of ground ore and treating the ore with an oxidizing and complexing agent such as hydrogen sulfide or a sulfide salt a chelating agent so 2 air and an anion exchange resin are added to the slurry to subject the ore to a simultaneous sulfurous acid leaching and anion exchange resin adsorption step
The pyrox pretreatment was found to decompose the sulfide matrix of the ore to a greater extent than a 3 hour pal treatmemt however the pal process produced a slightly better gold recovery of 79 compared to the pyrox recovery of 75 and both of these were greater than the 5560 recoveries achieved with the untreated ore
An evaluation of pretreatments to increase gold recovery jan 01 2000 evaluation of pretreatments to increase gold recovery from refractory ore 3 oxidative pretreatments the pyrolysisroasting pyrox pretreatment was carried out by heating about 5og of 75 umre under nitrogen in a furnace at 700 for a period of 30 minutes followed by heating in air at the same temperature for 3 hours
Show full abstract cyanidation of this concentrate recovers only 9 of the gold a pretreatment with ozone before the cyanidation increases the gold recovery to 23 the rest of the gold is in
Gold ores are considered refractory if gold extractions from a conventional cyanidation process are less than 80 even after fine grinding 1 arsenicbearing refractory gold ore has stones extremely difficult to deal with in the stones gold is locked up in arsenic mineral matrix as the form of microscopic or submicroscopic lattice
201931ensp enspthat gold recovery is difficult by thiosulfate leaching without any pretreatment and the recovery of gold only is 101 after roasting and oxidizing the gold leaching rate increases substantially the leaching rate of gold reaches 712 with the optimal leaching technological parameters li et al
Refractory gold ore89 haque k e used microwave to dispose of arsenical pyrite and gold concentrate with pyrite the gold leaching rate reached 9810 liu quanjun etc made a test for a gold mine in guizhou province the ore without microwave pretreatment could be hardly leached in cyanide on the other hand the cyanide leaching of gold ore
201721ensp ensprefractory gold ore is goldcontaining ore that is resistant to recovery by direct cyanidation and carbon adsorption processes more specifically it is an ore that has a gold recovery rate of less than 80 when direct cyanidation is applied to it dr chris fleming senior metallurgical consultant at sgs minerals says in the past two to
