Spiral classifier transformation
Classification is the process of preparing an important mineral processing, grading and results of operations, will directly affect the index concentrator subsequent jobs. Grading equipment beneficiation process used for many reasons, spiral classifier is one of them. Compact spiral classifier, easy to use, with the mill closed composition gravity, is still widely used in selected plants. But the spiral classifier large area, low-grade efficiency, but also limits its application. In recent years, some grinding and classification operations, there have been replaced with cyclone spiral classifier and mill closed trend. Therefore, how to improve the efficiency of spiral classifier, to play its inherent advantages to become an important research topic.
Spiral Classifier experts conducted a systematic analysis of the theoretical foundation, established under the settlement conditions of turbulence and interference spiral classifier unsteady flow fractionation kinetic differential equations. According to the characteristics of the traditional spiral classifier, the improved methods and measures, design and manufacture of a semi-industrial type 300mm × 4300mm spiral classifier. The improved spiral classifier, the basic principle has not changed, just the way of discharge and stirring traditional way spiral classifier were adjusted to shorten the path of movement of qualified mineral particles in a hierarchical machine, a qualified fine grade timely discharge transversely through the overflow hole and overflow control running rough. By increasing the spiral mixing blade in the staging area, reducing fine grit in the folder to avoid pulp reflux, reduce anti-mineral enriched, so as to improve the spiral Classifier efficiency.
Experts around the spiral classifier improvements carried out experimental system parameters, including the concentration of the test ore, grading machine slope test, the position of the test to the mining flow test, the weir height and overflow hole. Experimental data show that the first improvements, spiral classifier transfer efficiency is only 30% -50%, after improvement, spiral classifier transfer efficiency of 50% -70%. Comparison, the improved spiral classifier, its classification efficiency than before improved by an average of 10-17 percent, a testament to our research work to achieve the desired purpose.
Learn more about: http://www.mineralclassifying.com/
2015年11月5日星期四
How is Cyanide used in mining?
There are two types of cyanide-leaching processes used by the modern mining industry. Vatleaching, where extracted ore is combined with cyanide in vats, and heap-leaching (described below).
Cyanide-leaching allows mining companies to reopen and expand mines containing what were previously unprofitable mineral reserves. The heap-leaching process, more commonly used than vat-leaching, involves - · digging enormous pits, so large they could swallow cities, and piling the extracted ore into heaps that would cover many football fields several hundred feet high; · spraying a cyanide solution over the heaps so that the cyanide trickles down through the ore, bonding with microscopic flecks of gold or silver, whereupon a heap pad (a rubber blanket) underlying the heap channels the solution into a holding pond; and · stripping the solution of the precious minerals, recovering the used cyanide, then respraying the cyanide solution over the heap. In the extraction of copper, nickel, cobalt and molybdenum, cyanide is used during the milling and concentration processes.
Learn more about: http://www.goldcyanide.com
Cyanide-leaching allows mining companies to reopen and expand mines containing what were previously unprofitable mineral reserves. The heap-leaching process, more commonly used than vat-leaching, involves - · digging enormous pits, so large they could swallow cities, and piling the extracted ore into heaps that would cover many football fields several hundred feet high; · spraying a cyanide solution over the heaps so that the cyanide trickles down through the ore, bonding with microscopic flecks of gold or silver, whereupon a heap pad (a rubber blanket) underlying the heap channels the solution into a holding pond; and · stripping the solution of the precious minerals, recovering the used cyanide, then respraying the cyanide solution over the heap. In the extraction of copper, nickel, cobalt and molybdenum, cyanide is used during the milling and concentration processes.
Learn more about: http://www.goldcyanide.com
Gold cyanide in mining
Gold cyanide in mining
Cyanide is a naturally occurring chemical that is found in low concentrations throughout nature including in fruits, nuts, plants, and insects. It has been used by the mining industry to separate gold and silver particles from ore for over 120 years. With proper management, cyanide can be used safely and without harming the environment despite its toxicity.
Background information on cyanide
Cyanide is the general term for chemicals which contain a cyano group (triple-bonded carbon and nitrogen with the chemical formula CN) that occur naturally or are human-made in various forms. Low concentrations of cyanide are present in the everyday environment including as a stabilizer in table salt, in over 1000 plants including cassava and bamboo shoots, and in the pits of stone fruits like plums and apricots. [1, 2] In fact, the greatest source of cyanide exposure for people and free-ranging animals comes from eating food plants and crops that contain cyanide. [3]
Cyanide is also a useful industrial chemical; over one million tonnes of it are used annually in electroplating, metal processing, the production of organic chemicals and plastics, and in photographic applications. [2] The mining industry has used cyanide to process ore for more than 120 years, and uses less than 20% of the global production of industrial cyanide. [2, 4]
Role of cyanide in ore processing
Cyanide, in the form of a very dilute sodium cyanide solution, is used to dissolve and separate gold from ore. [3] The process used to extract gold using cyanide was developed in Scotland in 1887, and was first used in large scale commercial mining by the New Zealand Crown Mines Company at Karangahake in 1889. [3, 4] Cyanide leaching is considered to be a much safer alternative to extraction with liquid mercury, which was previously the main method of removing gold from ore. [5] Cyanide leaching has been the dominant gold extraction technology since the 1970s, although small-scale and artisanal miners continue to use mercury in some areas of the world. [3] In Canada, more than 90% of mined gold is extracted from ore using cyanide. [3]
The concentration of cyanide used in this process is normally in the range of 0.01% and 0.05% sodium cyanide (100 to 500 parts per million). [2] As part of their best practices, mines use as little cyanide as possible for environmental, safety, and economic reasons. [2] Cyanide leaching is usually done along with a physical process like milling, crushing, or gravity separation. The pH of the resulting slurry is raised by adding lime or another alkali to ensure that cyanide ions do not change into toxic cyanide gas (HCN). [6] The gold is then further concentrated and reduced, before being smelted into gold bullion. Click here to see a demonstration of the gold excavation and refinement process.
Cyanide toxicity and management
Cyanide is toxic in large doses and is strictly regulated in most jurisdictions worldwide to protect people, animals, and the aquatic environment. Cyanide prevents the body from taking up oxygen, resulting in suffocation, which may be fatal to humans and animals without prompt first aid treatment. [7] However, people and animals can rapidly detoxify non-lethal amounts of cyanide without negative effects, and repeated small doses can be tolerated by many species. [3] Some long-term health effects have been observed in people who have a diet high in cyanide-containing plants such as cassava, and include goiter and depressed thyroid function. [8]
In fact, "[d]espite its high human toxicity, there have been no documented accidental human deaths due to cyanide poisoning in the Australian and North American mining industries over the past 100 years which indicates that the hazard of cyanide to humans has been controlled by minimizing the risk of its handling and of industrial exposure."[6, p.4] Even in areas where cyanide is used extensively by artisanal miners with limited waste containment and safety practices, "human fatalities are relatively minimal particularly when compared with mercury or other hazards" [9, pp.109-110].
In high concentrations, cyanide is toxic to aquatic life, especially fish which are one thousand times more sensitive to cyanide than humans. [10] Because the greatest environmental threat from cyanide to aquatic life is from intentional or unintentional discharges into surface waters, water monitoring and water management on mine sites is very important. [11] Regulations frequently limit the amount of cyanide which may be discharged into the environment, and there are a number of water treatment technologies available to remove cyanide from mine water. [2]
Birds and other wildlife are also potentially at risk from cyanide poisoning if they are using tailings ponds for drinking or swimming. [12] In order to prevent wildlife fatalities, cyanide levels in tailings ponds can be reduced to safe levels by minimizing the amount of cyanide used, removing cyanide in waste streams and recycling it, and by using chemical or biological reactions to convert the cyanide into less toxic chemicals. [13] A standard of 50 mg/L weak acid dissociable (WAD) cyanide is widely accepted to be a safe level for water accessible to wildlife, and has essentially eliminated the number of migratory bird deaths from this cause. [6, 11] Only a few hundred birds are killed by cyanide each year. [11] Deterrents like fencing, polyethylene balls, and netting are also used to keep birds out of water bodies on mine sites. [3]
Cyanides do not cause cancer, and do not build up or "biomagnify" in the food chain. [12] They do not persist in the environment, and are quickly broken down into less toxic chemicals by sunlight and air. [2]
Accidental Spills
Where cyanide has been accidentally released into surface waters, it has been investigated and changes have been made in the industry to prevent such releases happening again. One such change is the adoption of the International Cyanide Management Code. This code was developed following several cyanide spills, in particular the Baia Mare spill in Romania in 2000. In the Baia Mare case, a dam failure that spilled cyanide into nearby waters resulted in widespread contamination, fish deaths, and economic harm–but no human deaths.
In such spills, the cyanide is rapidly destroyed through natural processes, such as evaporation, and the effects on aquatic life–while significant–are not long-term. [3] In the Baia Mare spill, the cyanide concentration decreased rapidly with increasing distance from the spill. After the contaminated water had passed, aquatic micro-organisms and plankton recovered within a few days. [10]
In Japan, an earthquake in 1980 resulted in a large amount of cyanide entering a stream from a gold mine. While the spill killed all life in the stream, cyanide was detectable for only three days after the spill; within 1 month flora began to regrow on above-water stones, and within 6-7 months the populations of fish, algae, and invertebrates had recovered. [3, p.29] Cyanide was also not detectable in water and sediments in Yellowknife Bay in the Northwest Territories from 1974 to 1976, despite a continuous input of cyanide-containing effluents from a gold mining operation (a practice that would not be permitted today). [3]
Legal framework for mines using cyanide
Many jurisdictions, including Canada and Australia, recommend that mines that use cyanide do so in a manner consistent with the International Cyanide Management Code, which involves minimizing the amount of cyanide used; designing measures to protect surface and groundwater; designing and operating systems that reduce cyanide levels in effluent; and preventing spills.
In Canada, cyanide is considered to be a hazardous substance, and provincial and federal legislation requires it to be transported, handled, and disposed of by fully trained personnel in certified storage containers. [12] Its disposal and discharge into the environment at mine sites is regulated provincially through the use of permits and licences. [12] In addition, the cyanide concentration of effluent leaving a metal mining operation must be below the maximum allowable concentration of 1.0 mg/L prescribed by the Metal Mining Effluent Regulations under the federal Fisheries Act. Cyanide in effluent is measured through water sampling and in 2010 metal mines achieved 100% compliance for cyanide. [14]
Alternative technologies to cyanide
Although cyanide can be safely used, the mining industry continues to research alternatives to cyanide and improve the techniques for managing the cyanide it does use. In some cases it may be possible to concentrate gold using gravity separation. However, this is not economical or feasible when the other ore components are of similar density or when the concentration of gold is low. [6]
Alternative extraction chemicals have also been studied, but they can be equally or more damaging to the environment than cyanide [6, 11]. Risk-based assessment by the US Environmental Protection Agency and Purdue University concluded that a cyanide-lime system was the safest chemical extraction method for recovering gold taking into account risk to the environment and workers [11].
Mining industry innovations have also included new cyanide-destruction technologies and management strategies to reduce cyanide concentrations, toxicity, and potential impacts. [2
Cyanide is a naturally occurring chemical that is found in low concentrations throughout nature including in fruits, nuts, plants, and insects. It has been used by the mining industry to separate gold and silver particles from ore for over 120 years. With proper management, cyanide can be used safely and without harming the environment despite its toxicity.
Background information on cyanide
Cyanide is the general term for chemicals which contain a cyano group (triple-bonded carbon and nitrogen with the chemical formula CN) that occur naturally or are human-made in various forms. Low concentrations of cyanide are present in the everyday environment including as a stabilizer in table salt, in over 1000 plants including cassava and bamboo shoots, and in the pits of stone fruits like plums and apricots. [1, 2] In fact, the greatest source of cyanide exposure for people and free-ranging animals comes from eating food plants and crops that contain cyanide. [3]
Cyanide is also a useful industrial chemical; over one million tonnes of it are used annually in electroplating, metal processing, the production of organic chemicals and plastics, and in photographic applications. [2] The mining industry has used cyanide to process ore for more than 120 years, and uses less than 20% of the global production of industrial cyanide. [2, 4]
Role of cyanide in ore processing
Cyanide, in the form of a very dilute sodium cyanide solution, is used to dissolve and separate gold from ore. [3] The process used to extract gold using cyanide was developed in Scotland in 1887, and was first used in large scale commercial mining by the New Zealand Crown Mines Company at Karangahake in 1889. [3, 4] Cyanide leaching is considered to be a much safer alternative to extraction with liquid mercury, which was previously the main method of removing gold from ore. [5] Cyanide leaching has been the dominant gold extraction technology since the 1970s, although small-scale and artisanal miners continue to use mercury in some areas of the world. [3] In Canada, more than 90% of mined gold is extracted from ore using cyanide. [3]
The concentration of cyanide used in this process is normally in the range of 0.01% and 0.05% sodium cyanide (100 to 500 parts per million). [2] As part of their best practices, mines use as little cyanide as possible for environmental, safety, and economic reasons. [2] Cyanide leaching is usually done along with a physical process like milling, crushing, or gravity separation. The pH of the resulting slurry is raised by adding lime or another alkali to ensure that cyanide ions do not change into toxic cyanide gas (HCN). [6] The gold is then further concentrated and reduced, before being smelted into gold bullion. Click here to see a demonstration of the gold excavation and refinement process.
Cyanide toxicity and management
Cyanide is toxic in large doses and is strictly regulated in most jurisdictions worldwide to protect people, animals, and the aquatic environment. Cyanide prevents the body from taking up oxygen, resulting in suffocation, which may be fatal to humans and animals without prompt first aid treatment. [7] However, people and animals can rapidly detoxify non-lethal amounts of cyanide without negative effects, and repeated small doses can be tolerated by many species. [3] Some long-term health effects have been observed in people who have a diet high in cyanide-containing plants such as cassava, and include goiter and depressed thyroid function. [8]
In fact, "[d]espite its high human toxicity, there have been no documented accidental human deaths due to cyanide poisoning in the Australian and North American mining industries over the past 100 years which indicates that the hazard of cyanide to humans has been controlled by minimizing the risk of its handling and of industrial exposure."[6, p.4] Even in areas where cyanide is used extensively by artisanal miners with limited waste containment and safety practices, "human fatalities are relatively minimal particularly when compared with mercury or other hazards" [9, pp.109-110].
In high concentrations, cyanide is toxic to aquatic life, especially fish which are one thousand times more sensitive to cyanide than humans. [10] Because the greatest environmental threat from cyanide to aquatic life is from intentional or unintentional discharges into surface waters, water monitoring and water management on mine sites is very important. [11] Regulations frequently limit the amount of cyanide which may be discharged into the environment, and there are a number of water treatment technologies available to remove cyanide from mine water. [2]
Birds and other wildlife are also potentially at risk from cyanide poisoning if they are using tailings ponds for drinking or swimming. [12] In order to prevent wildlife fatalities, cyanide levels in tailings ponds can be reduced to safe levels by minimizing the amount of cyanide used, removing cyanide in waste streams and recycling it, and by using chemical or biological reactions to convert the cyanide into less toxic chemicals. [13] A standard of 50 mg/L weak acid dissociable (WAD) cyanide is widely accepted to be a safe level for water accessible to wildlife, and has essentially eliminated the number of migratory bird deaths from this cause. [6, 11] Only a few hundred birds are killed by cyanide each year. [11] Deterrents like fencing, polyethylene balls, and netting are also used to keep birds out of water bodies on mine sites. [3]
Cyanides do not cause cancer, and do not build up or "biomagnify" in the food chain. [12] They do not persist in the environment, and are quickly broken down into less toxic chemicals by sunlight and air. [2]
Accidental Spills
Where cyanide has been accidentally released into surface waters, it has been investigated and changes have been made in the industry to prevent such releases happening again. One such change is the adoption of the International Cyanide Management Code. This code was developed following several cyanide spills, in particular the Baia Mare spill in Romania in 2000. In the Baia Mare case, a dam failure that spilled cyanide into nearby waters resulted in widespread contamination, fish deaths, and economic harm–but no human deaths.
In such spills, the cyanide is rapidly destroyed through natural processes, such as evaporation, and the effects on aquatic life–while significant–are not long-term. [3] In the Baia Mare spill, the cyanide concentration decreased rapidly with increasing distance from the spill. After the contaminated water had passed, aquatic micro-organisms and plankton recovered within a few days. [10]
In Japan, an earthquake in 1980 resulted in a large amount of cyanide entering a stream from a gold mine. While the spill killed all life in the stream, cyanide was detectable for only three days after the spill; within 1 month flora began to regrow on above-water stones, and within 6-7 months the populations of fish, algae, and invertebrates had recovered. [3, p.29] Cyanide was also not detectable in water and sediments in Yellowknife Bay in the Northwest Territories from 1974 to 1976, despite a continuous input of cyanide-containing effluents from a gold mining operation (a practice that would not be permitted today). [3]
Legal framework for mines using cyanide
Many jurisdictions, including Canada and Australia, recommend that mines that use cyanide do so in a manner consistent with the International Cyanide Management Code, which involves minimizing the amount of cyanide used; designing measures to protect surface and groundwater; designing and operating systems that reduce cyanide levels in effluent; and preventing spills.
In Canada, cyanide is considered to be a hazardous substance, and provincial and federal legislation requires it to be transported, handled, and disposed of by fully trained personnel in certified storage containers. [12] Its disposal and discharge into the environment at mine sites is regulated provincially through the use of permits and licences. [12] In addition, the cyanide concentration of effluent leaving a metal mining operation must be below the maximum allowable concentration of 1.0 mg/L prescribed by the Metal Mining Effluent Regulations under the federal Fisheries Act. Cyanide in effluent is measured through water sampling and in 2010 metal mines achieved 100% compliance for cyanide. [14]
Alternative technologies to cyanide
Although cyanide can be safely used, the mining industry continues to research alternatives to cyanide and improve the techniques for managing the cyanide it does use. In some cases it may be possible to concentrate gold using gravity separation. However, this is not economical or feasible when the other ore components are of similar density or when the concentration of gold is low. [6]
Alternative extraction chemicals have also been studied, but they can be equally or more damaging to the environment than cyanide [6, 11]. Risk-based assessment by the US Environmental Protection Agency and Purdue University concluded that a cyanide-lime system was the safest chemical extraction method for recovering gold taking into account risk to the environment and workers [11].
Mining industry innovations have also included new cyanide-destruction technologies and management strategies to reduce cyanide concentrations, toxicity, and potential impacts. [2
2015年11月3日星期二
Vibrating Screen installation
Vibrating Screen installation
1, the Vibrating Screen before installation, first read the instructions in the installation rules, in accordance with the requirements of the specification are complete inspection unit and damage, in the case of the power to ensure that parts intact small test re-boot properly.
2, follow the installation drawings for equipment adjustment, wherein the support base chassis must be mounted horizontally on a flat surface, based on the foundation should have sufficient rigidity and strength.
3, Vibrating Screen bottom support Brace corners must have lifting hole, according to plans require lifting, not directly linked to lifting the entire machine in the shaker.
4, to ensure that a minimum of 50mm gap between the screen box and hopper, chute and other similar non-moving parts.
5, the shock absorber spring press height matching, respectively the front or rear end of the left and right sides of the spring height equal as possible, the error does not exceed 5mm.
About maintaining the level of the screen surface after installation, otherwise between the spring seat and support the pad thin iron sheet
Learn more about: http://www.mineralscreen.com
1, the Vibrating Screen before installation, first read the instructions in the installation rules, in accordance with the requirements of the specification are complete inspection unit and damage, in the case of the power to ensure that parts intact small test re-boot properly.
2, follow the installation drawings for equipment adjustment, wherein the support base chassis must be mounted horizontally on a flat surface, based on the foundation should have sufficient rigidity and strength.
3, Vibrating Screen bottom support Brace corners must have lifting hole, according to plans require lifting, not directly linked to lifting the entire machine in the shaker.
4, to ensure that a minimum of 50mm gap between the screen box and hopper, chute and other similar non-moving parts.
5, the shock absorber spring press height matching, respectively the front or rear end of the left and right sides of the spring height equal as possible, the error does not exceed 5mm.
About maintaining the level of the screen surface after installation, otherwise between the spring seat and support the pad thin iron sheet
Learn more about: http://www.mineralscreen.com
2015年10月8日星期四
Gold cyanide extraction process improvement
As with cyanide leaching solution to extract gold cyanide is called gold extraction process, it is the main method of modern extracted from ore or concentrate in gold.
Basic steps of:
Cyanidation gold extraction process include: cyanide leaching, leaching pulp washing filter, pulp cyanide solution or cyanide gold extraction and smelting finished a few basic steps.
Process Improvement
1, used oxidant (oxygen or oxide) and extending oxygenase CIL process in the leaching process , such as epoxy resin extraction and the like. The benefits of using secondary oxidant: First, improve gold, silver leaching rate; second is to accelerate the leaching rate, shorten the leaching time; third is to reduce cyanide consumption, reduce the amount of lead nitrate. Our Longtoushan Gold leaching using help make the leaching rate increased by 4.31%. Secondary oxidant as the best technology to optimize applications have cyanide process, widely promoted around the world.
2, the use of ammonia - cyanide leaching of copper and gold ore system of gold and copper ore, copper concentrate containing cyanide leaching, the technology will show the strong vitality.
3, Edging leaching process can strengthen the leaching effect. Such as the recent Shanxi Bureau of Geology and Geological Team 216 TW-type tower mill using dip machine combined arsenic refractory gold concentrate is edging leaching, processing capacity of 30 tons / day, in the grinding fineness of 95% to 98% - Under conditions of 400 mesh, the gold leaching rate increased by 8%. If you use dip machine mill tower implement new technology edging dipped in gold mines can promote the use of cyanide gold extraction process would be a major innovation.
Basic steps of:
Cyanidation gold extraction process include: cyanide leaching, leaching pulp washing filter, pulp cyanide solution or cyanide gold extraction and smelting finished a few basic steps.
Process Improvement
1, used oxidant (oxygen or oxide) and extending oxygenase CIL process in the leaching process , such as epoxy resin extraction and the like. The benefits of using secondary oxidant: First, improve gold, silver leaching rate; second is to accelerate the leaching rate, shorten the leaching time; third is to reduce cyanide consumption, reduce the amount of lead nitrate. Our Longtoushan Gold leaching using help make the leaching rate increased by 4.31%. Secondary oxidant as the best technology to optimize applications have cyanide process, widely promoted around the world.
2, the use of ammonia - cyanide leaching of copper and gold ore system of gold and copper ore, copper concentrate containing cyanide leaching, the technology will show the strong vitality.
3, Edging leaching process can strengthen the leaching effect. Such as the recent Shanxi Bureau of Geology and Geological Team 216 TW-type tower mill using dip machine combined arsenic refractory gold concentrate is edging leaching, processing capacity of 30 tons / day, in the grinding fineness of 95% to 98% - Under conditions of 400 mesh, the gold leaching rate increased by 8%. If you use dip machine mill tower implement new technology edging dipped in gold mines can promote the use of cyanide gold extraction process would be a major innovation.
2015年9月18日星期五
The main method of gold cyanidation gold processing of non-mention
Gold cyanide extraction method is the most common and most stable method of gold and silver ore and materials, but there are also leaching time (leaching cycle) long (one week to one year heap leaching, agitation leaching of 24 to 72 hours), organic carbon, antimony, arsenic, copper, zinc and other harmful elements very sensitive, causing a significant reduction of gold, silver leaching rate, the disadvantage substantial increase in production costs, in particular the Act cyanide is highly toxic, damage to the environment is considerable. Therefore, how to improve gold, silver leaching rate, reduce costs, find an alternative non-toxic or highly toxic cyanide toxicity smaller new technology and new technology is an important research topic.
Non-cyanidation leaching agents include thiourea, oxygen, bromine, iodine, ammonia, thiocyanate, calcium polysulfide and the like.
(1) of the Act thiourea under acidic conditions gold dissolution speed, non-toxic, selective than cyanide, is not sensitive to the base metal impurities, in dealing with some gold-bearing materials, such as anode slime, gold uranium acid and sulfuric acid leaching slag and so have some advantages, but high drug consumption, leaching equipment perishable, the lack of effective method for recovering gold from thiourea solution.
In 1997, it was found that sodium sulfite can inhibit the irreversible decomposition of alkaline thiourea to some extent, promote the dissolution of gold, gold dissolution can select rows from the gold-bearing waste; that the sodium silicate is an alkaline thiourea gold extraction efficiency stabilizer.
(2) a halogen and halide salt used in the Act reagent mainly chlorine, bromine, iodine, chloride, iodide, bromide, etc., e.g., chlorine, hypochlorite, chloride method, K reagent, Geobrom3400 , Bio-D reagents and other oxidants. Chlorine leaching process, both as an oxidizing agent, and as a complexing agent to generate AuCl32-, halogen ions (X-) is Au2 + Au + and strong ligand chloride leaching carbon material suitable for processing gold ore containing arsenic, antimony burn slag, re-election of gold concentrate containing arsenic and pyrite gold ores.
Bromide method is to replace one of the most promising cyanide leach gold extraction process, the advantage of cheap, high leaching, leaching speed, non-toxic, non-corrosive, agents can be recycled, the recovery of gold from the pregnant solution convenient. Many foreign research iodide method using iodine - iodide solution than cyanide leaching method can be obtained with high gold leach rates from iodine - iodide direct electrowinning of gold is also possible.
(3) of the Act nitrile using malononitrile (also known as cyanuric acid nitrile), cyanoacetamide and acetonitrile three kinds of nitrile to extract gold. In dealing with carbonaceous gold ores, nitrile cyanide gold leaching rate is much higher than the law. In dealing with oxidized ores and sulfide ores, its gold leaching with cyanide leaching rate as effective, but its high price.
(4) Method i.e. microorganisms capable of biological agents leach gold, which the cellular components of microbial protein, microbial metabolites of amino acids (glycine, histidine, aspartic acid, etc.). Protein and gold to form a complex with a negatively charged, this complex was purified by amino acid groups of the nitrogen atom, form a stable gold complex.
(5) of the Act coal golden reunion is the use of flotation reagents to improve the hydrophobic characteristics of the gold particle surface by the collision of the mixing process, the hydrophobic gold particles into the Aggregates. Contained gold aggregates through cycles, enrichment and ashing, the resulting ash after baking or other means smelting process to be finished gold.
(6) polysulfide Act and the Act uses lime sulfur and lime sulfur leaching of gold and silver produced by the reaction reagents, chelating polysulfide ions S22-, S32-, S42-, S52-, etc., which gold ions strong complexing ability, in a suitable oxidant (such as potassium permanganate, etc.) with the next, or by means of disproportionation polysulfide ions, can effectively dissolve gold and silver.
(7) Other methods Other methods are humic acid method, FM reducing reagent, thiosulfate method.
Non-cyanidation leaching agents include thiourea, oxygen, bromine, iodine, ammonia, thiocyanate, calcium polysulfide and the like.
(1) of the Act thiourea under acidic conditions gold dissolution speed, non-toxic, selective than cyanide, is not sensitive to the base metal impurities, in dealing with some gold-bearing materials, such as anode slime, gold uranium acid and sulfuric acid leaching slag and so have some advantages, but high drug consumption, leaching equipment perishable, the lack of effective method for recovering gold from thiourea solution.
In 1997, it was found that sodium sulfite can inhibit the irreversible decomposition of alkaline thiourea to some extent, promote the dissolution of gold, gold dissolution can select rows from the gold-bearing waste; that the sodium silicate is an alkaline thiourea gold extraction efficiency stabilizer.
(2) a halogen and halide salt used in the Act reagent mainly chlorine, bromine, iodine, chloride, iodide, bromide, etc., e.g., chlorine, hypochlorite, chloride method, K reagent, Geobrom3400 , Bio-D reagents and other oxidants. Chlorine leaching process, both as an oxidizing agent, and as a complexing agent to generate AuCl32-, halogen ions (X-) is Au2 + Au + and strong ligand chloride leaching carbon material suitable for processing gold ore containing arsenic, antimony burn slag, re-election of gold concentrate containing arsenic and pyrite gold ores.
Bromide method is to replace one of the most promising cyanide leach gold extraction process, the advantage of cheap, high leaching, leaching speed, non-toxic, non-corrosive, agents can be recycled, the recovery of gold from the pregnant solution convenient. Many foreign research iodide method using iodine - iodide solution than cyanide leaching method can be obtained with high gold leach rates from iodine - iodide direct electrowinning of gold is also possible.
(3) of the Act nitrile using malononitrile (also known as cyanuric acid nitrile), cyanoacetamide and acetonitrile three kinds of nitrile to extract gold. In dealing with carbonaceous gold ores, nitrile cyanide gold leaching rate is much higher than the law. In dealing with oxidized ores and sulfide ores, its gold leaching with cyanide leaching rate as effective, but its high price.
(4) Method i.e. microorganisms capable of biological agents leach gold, which the cellular components of microbial protein, microbial metabolites of amino acids (glycine, histidine, aspartic acid, etc.). Protein and gold to form a complex with a negatively charged, this complex was purified by amino acid groups of the nitrogen atom, form a stable gold complex.
(5) of the Act coal golden reunion is the use of flotation reagents to improve the hydrophobic characteristics of the gold particle surface by the collision of the mixing process, the hydrophobic gold particles into the Aggregates. Contained gold aggregates through cycles, enrichment and ashing, the resulting ash after baking or other means smelting process to be finished gold.
(6) polysulfide Act and the Act uses lime sulfur and lime sulfur leaching of gold and silver produced by the reaction reagents, chelating polysulfide ions S22-, S32-, S42-, S52-, etc., which gold ions strong complexing ability, in a suitable oxidant (such as potassium permanganate, etc.) with the next, or by means of disproportionation polysulfide ions, can effectively dissolve gold and silver.
(7) Other methods Other methods are humic acid method, FM reducing reagent, thiosulfate method.
Interview with Executive Vice President of the Chilean National Commission Copper Sergio Hernández
How can "1 + 1" generated "> 2" effect? Although it is not the only answer, but the "win-win cooperation, complementarity and development," but would be a best choice. For China and Chile to carry out investment and trade activities in terms of the same.
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How can "1 + 1" generated "> 2" effect? Although it is not the only answer, but the "win-win cooperation, complementarity and development," but would be a best choice. For China and Chile to carry out investment and trade activities in terms of the same.
2015, to coincide with the signing of Sino-Chilean FTA occasion of ten years, according to the agreement, starting from January 1 this year, on the basis of free trade agreements on the trading of all Chile's exports to China are zero tariffs. At this point, you can enjoy tariff-free policy before 1611 kinds of goods increased by the 5725 kinds. Avoidance of double customs restrictions between the two countries, trade regime more flexible, and from more closely. In this way, the state furthest apart on two maps forum is "1 + 1" mutual promotion and action, and constantly create "> 2" effect.
Chile is the world's largest copper producer and exporter of copper, while China is the largest consumer of copper and copper importer. According to statistics, China's annual consumption of copper imports 47 percent of the total amount, which has 40% of imports from Chile. Sergio Hernández, executive vice president at the Chilean National Copper Commission opinion, precisely because of such a close relationship between supply and demand, cooperation between the two countries in the field of investment will be just around the corner copper.
Make good use of "China and Chile Week" platform
By 2015, China and Chile established diplomatic relations 45 anniversary usher. To celebrate this important anniversary, the Government of Chile on August 23 - August 28 held a special "China and Chile Week" in Shanghai and Beijing. During the event, the former President of Chile, the Chilean delegation in the Asia-Pacific region, led by Ambassador Extraordinary and Plenipotentiary of Chile Eduardo Frei (Eduardo FREI) about 150 people participated in the multilateral activities. In this delegation, not only on behalf of the Chilean entrepreneurs more than 10 industries, as well as the person in charge from the mining industry, economy, agriculture, engineering, trade and other key sectors of the Chilean government. As executive vice president of the Chilean National Copper Commission, Sergio Hernández this line for Chilean copper enterprises to establish a cooperative relationship with Chinese enterprises spare no effort to publicize.
'' China and Chile Week 'is a good platform, which allows Chinese entrepreneurs and investors a better understanding of the opportunities and advantages of investment in Chile, so as to promote bilateral cooperation in the copper mining enterprises fields. "Sergio Hernández "As a national public service institution, the Chilean National Copper Commission itself does not engage in any mining investment business, its function is to assist the Chilean copper business with Chinese companies to establish or carry out investment cooperation. The 'China and Chile Week', the Commission will Chilean copper to Chinese investors on investment projects and development plans over the next 10 years in Chile's copper industry. "
Copper focus on two areas of cooperation
According to data provided by the Export Promotion Bureau of Chile, in 2014 and Chile bilateral trade amounted to $ 32.671 billion, accounting for 24 percent of Chile's foreign trade volume. During 2002 to 2014, bilateral trade volume of 24% average annual growth rate, Chile's exports to China increased by an average of 25% annually. From China's perspective, in 2014 Chile is China's 24th largest import target country and No. 33 export countries, import and export respectively, accounted for 1.08 percent and 0.56 percent of China's total foreign trade.
However, talking about the situation of Chinese enterprises copper mine in Chile to carry out the investment, Sergio Hernández but somewhat regret. He gestures said:. "'0' Although China is the largest importer of Chilean copper, but due to various reasons, investment cooperation between the two countries in terms of copper but still failed to achieve 'zero' breakthrough, I think, From another perspective also shows that our cooperation with Chinese enterprises in this area has great potential in the future. Chile and China have much in common, is not limited to China is a big consumer of copper and copper mine in Chile is the largest suppliers of this point, China and Chile have strong complementarity. "
Copper exports has always occupied an important position in the Sino-Chilean bilateral trade, the copy of the data from the Chilean National Copper Commission show that in 2013 China imported $ 15.1 billion worth of copper from Chile, accounting for 79 of the country's total exports to China that year %, which accounted for 37.5% of total exports that year of copper; in 2014, Chile's copper production was 5.78 million tons, with exports hit a 7-year high of 5.66 million tons, China is still a superpower copper imports from Chile total imports of nearly 2.2 million tons, equivalent to 38.9 percent of Chile's total copper exports. "Most of Chile's copper exports to China are the original form of copper ore, and smelting in China." Sergio Hernández said, "China has more advanced smelting technology, we hope that the two companies can field in the deep processing of copper to carry out a series of cooperation. At present, including the Chilean Copper Corporation of Chile, including two large copper enterprise in dialogue with Chinese companies, and we expect them to have great new progress. "
In addition, Sergio Hernández also said that open and Technical College is looking forward to cooperation in the field of copper smelting and Chinese research institutions and enterprises, to enhance Chile's copper smelting capacity by training professionals. It is understood that many universities have teaching strengths of Chile and international prestige. Engineering is a relatively mature discipline in Chile, with over 40 years of experience, professional sound education system also makes it received international recognition. Among the most prominent was undoubtedly the mining project, has a world-class level. Sergio Hernández said: "At present, one of the biggest advantages of Chile in the field of engineering is divided into very detailed, each tiny areas have a high level of professional and related technologies, such as earthquake engineering, environmental engineering, solid pipeline transportation , hydrometallurgy and natural surface and underground mining and mine operations, a lot of new technology has also been applied to the project. However, these are not enough. Chile in copper concentrate production and transport still faces enormous challenges, We therefore hope that the excellent copper-producing countries from the introduction of industrial technology, so as to enhance the country's copper concentrate production capacity. "
Chilean copper investment opportunities and challenges
Last September, Chile's Minister of Mines Aurora participated in the International Conference of mineral resources held in Melbourne had said Chilean Mining 2014 - 2025 the amount of investment will reach $ 105 billion. Among them, the copper industry investment will reach $ 81 billion, other mineral projects in gold, silver and iron ore will get $ 23 billion investment. Chile "strategy" recently also announced that the Minister of Mines of Chile and the Chilean National Commission Aurora Williams Copper announced that 2015 ~ 2024 Chile Copper intends to develop 31 projects and 11 other mining projects, the proposed investment were $ 67.035 billion and $ 10.255 billion. If all the projects implemented, to 2024 Chile's copper output will increase by 33% at present. Data over copper project similar to last year, showing that investment in copper mining investment in Chile still occupy an important position in the field.
It is worth noting that the price of copper continued to decline since last year, than in 2011 decreased approximately by about one-third of the peak, which to some extent affected the enthusiasm of investors. Sergio Hernández believes copper prices affected by many factors, including not only the impact of the global economic downturn, the dollar, crude oil and other commodity prices, etc., as well as from China's economic slowdown, demand for smaller, etc. Interaction factors. He admitted that in the next two and half years, copper prices are likely to continue to maintain at a lower level (which does not include the Chilean copper production decline and other factors). "But, from the procurement perspective, the decline in copper prices may well be a good thing." Sergio Hernández also said.
Nevertheless, Sergio Hernández still on Chilean copper investment confidence. He said that Chile has an open, free and stable mining investment environment and high market transparency. In recent years, many countries have chosen to enter Chile to carry out mining investment. Data show that Chile is acceptable in terms of resources mineral foreign capital directly into the more important countries. In order to improve competitiveness, since 2011 Chile has also implemented a series of plans to promote investment and competitiveness, focusing on solving difficulties foreign companies investing in Chile, including energy costs and bureaucratic barriers. In addition, healthy public finances, a sound legal system, stable policy mechanisms and government support has become an important factor in attracting foreign capital. "Although the 2014 Chile exploration spending fell by 22%, less than the world's exploration spending levels, but Chile still has a good investment environment and potential advantages of geological prospecting." Sergio Hernández represented.
In addition, the Chilean government has also taken a series of mature trade policies, designed to successfully combine the Chilean economy and international markets. Today, the Chilean government has been promoting the development of the export industry and the services sector as an important task, in order to attract international investment. "Chile has a very important platform - the relevant provisions of the free trade agreement on services, it can not only provide convenience for the many service companies in Chile, but also that Chilean companies and more than 60 countries, the company established a business relationship escort Escort. "Sergio Hernández added.
Sergio Hernández said: "Although the Chilean mining industry is facing many challenges, such as water and energy, ecological communities, environmental norms standards, but the Chilean mining industry is trying to build a strong innovation ecosystem, the industry association, suppliers, research closely integrated with the service and the country, through the effective use of renewable resources, to strengthen cooperation with domestic and foreign academic and research institutions, and increase investment in human capital and the development of advanced mining systems, to more effectively address the challenges facing the mining industry in order to attract more investors. Therefore, we are also very welcome and look forward to Chinese enterprises to invest in Chile to carry out mine! "
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