gold extraction equipment with cyanide

still using cyanide to extract gold? you are out! | cnfree

still using cyanide to extract gold? you are out! | cnfree

According to the China Golden Yearbook 2014 released by the China Gold Association in September 2014 (hereinafter referred to as the yearbook), Chinas proven resource reserves have grown for ten consecutive years in 2013, and the identified resource reserves are 8974.74 tons, ranking second in the world. The output of gold has increased for 14 consecutive years, ranking first in the world for 7 consecutive years. In 2013, the output exceeded 400 tons, reaching 428.16 tons-including 350.84 tons of mineral Gold included-which made China the only country in the world that have a production exceeding 400 tons in 2013, with a proportion of 15.9% in the worlds total output. In China, there exists more small and less large gold mines. Small-scale gold mines account for 88%, medium gold mines 9.82%, while large gold mines only 2.18%. According to data disclosed by the listed gold mining companies in industry association, more than 1 million tons of various gold extraction reagents were consumed per year on gold mine reagent companies comprehensive analysis, with the output value of about 15-30 billion RMB. At present, most cyanidation gold extraction plants use cyanide as gold extraction reagent. As is well known, cyanide is a kind of highly toxic hazardous chemical, so any mis-operation in transportation, storage, use and other links will cause the events of serious environmental pollution, malignant poisoning, etc. Therefore, many countries and regions have legislated against or restricted the use of sodium cyanide to extract gold and strictly implemented relevant environmental protection regulations. Numerous environmental agencies, government agencies at all levels, gold mining companies and people around the mines are trying to find an environmental gold extraction product that can replace cyanide in gold production. Yantai YANTAI ITAO MINERAL PROCESSING REAGENTS CO., LTD., based on theory of gold and silver refining and market demand of gold ore, finally launched a new environmental gold extraction reagent-CNFREE eco-friendly gold leaching reagent after hundreds of tests. At present, this reagent has been widely used in various gold ore processing plants, and results show that its final effect is significantly higher than that of gold extraction with cyanide. Besides, the reagent is a common chemical product, while cyanide is a highly toxic product. The fundamental reason why CNFREE eco-friendly gold leaching reagent can rapidly replace sodium cyanide and occupy the market share of gold reagent is that it has an absolute advantage over sodium cyanide in environmental protection, safety, investment cost and use. 1. Good for Environmental Treatment As an innovative product that replaces highly toxic sodium cyanide, CNFREE eco-friendly gold leaching reagent can eliminate the environmental pollution and harm of cyanide, benefiting the country, the people and even the mankind. 2. Good for the Safe Production and Management Cost Reduction of Mining Enterprises Due to the strict approval and supervision procedures for the purchase, transportation, storage, custody and use of sodium cyanide, the management cost of the enterprise is increased; while CNFREE eco-friendly gold leaching reagent is environmentally low-toxic, which can be managed and used as common chemical products. 3. Easy to Operate and Promote CNFREE eco-friendly gold leaching reagent can replace sodium cyanide without changing the original equipment and process in the actual production of gold mine, thus make it convenient to popularize. The segment industry of eco-friendly gold extraction reagent is a blue ocean market with a broad development space. With the increasing market demand of eco-friendly gold extraction reagent, as well as the great support of states policies and funds to small and medium-sized enterprises in science and technology, the company is faced with great development opportunities. In the future, Yantai YANTAI ITAO MINERAL PROCESSING REAGENTS CO., LTD. will be determined to become the worlds leading eco-friendly gold extraction reagent enterprise.

According to the China Golden Yearbook 2014 released by the China Gold Association in September 2014 (hereinafter referred to as the yearbook), Chinas proven resource reserves have grown for ten consecutive years in 2013, and the identified resource reserves are 8974.74 tons, ranking second in the world. The output of gold has increased for 14 consecutive years, ranking first in the world for 7 consecutive years. In 2013, the output exceeded 400 tons, reaching 428.16 tons-including 350.84 tons of mineral Gold included-which made China the only country in the world that have a production exceeding 400 tons in 2013, with a proportion of 15.9% in the worlds total output. In China, there exists more small and less large gold mines.

Small-scale gold mines account for 88%, medium gold mines 9.82%, while large gold mines only 2.18%. According to data disclosed by the listed gold mining companies in industry association, more than 1 million tons of various gold extraction reagents were consumed per year on gold mine reagent companies comprehensive analysis, with the output value of about 15-30 billion RMB.

At present, most cyanidation gold extraction plants use cyanide as gold extraction reagent. As is well known, cyanide is a kind of highly toxic hazardous chemical, so any mis-operation in transportation, storage, use and other links will cause the events of serious environmental pollution, malignant poisoning, etc. Therefore, many countries and regions have legislated against or restricted the use of sodium cyanide to extract gold and strictly implemented relevant environmental protection regulations. Numerous environmental agencies, government agencies at all levels, gold mining companies and people around the mines are trying to find an environmental gold extraction product that can replace cyanide in gold production. Yantai YANTAI ITAO MINERAL PROCESSING REAGENTS CO., LTD., based on theory of gold and silver refining and market demand of gold ore, finally launched a new environmental gold extraction reagent-CNFREE eco-friendly gold leaching reagent after hundreds of tests. At present, this reagent has been widely used in various gold ore processing plants, and results show that its final effect is significantly higher than that of gold extraction with cyanide. Besides, the reagent is a common chemical product, while cyanide is a highly toxic product.

The fundamental reason why CNFREE eco-friendly gold leaching reagent can rapidly replace sodium cyanide and occupy the market share of gold reagent is that it has an absolute advantage over sodium cyanide in environmental protection, safety, investment cost and use.

As an innovative product that replaces highly toxic sodium cyanide, CNFREE eco-friendly gold leaching reagent can eliminate the environmental pollution and harm of cyanide, benefiting the country, the people and even the mankind.

Due to the strict approval and supervision procedures for the purchase, transportation, storage, custody and use of sodium cyanide, the management cost of the enterprise is increased; while CNFREE eco-friendly gold leaching reagent is environmentally low-toxic, which can be managed and used as common chemical products.

The segment industry of eco-friendly gold extraction reagent is a blue ocean market with a broad development space. With the increasing market demand of eco-friendly gold extraction reagent, as well as the great support of states policies and funds to small and medium-sized enterprises in science and technology, the company is faced with great development opportunities. In the future, Yantai YANTAI ITAO MINERAL PROCESSING REAGENTS CO., LTD. will be determined to become the worlds leading eco-friendly gold extraction reagent enterprise.

cornstarch replaces cyanide in clean new gold extraction method

cornstarch replaces cyanide in clean new gold extraction method

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, and most modern processes do it with a highly toxic combination of cyanide salts. The cyanide leaches the gold out, but the cyanide can seep into the ground, causing environmental problems and posing threats to human health.

Researchers at Northwestern University recently stumbled upon a solution that uses cornstarch instead. It involves some complex chemistry, but its cheap, biologically friendly and nasty-ingredient-free.

Led by Sir Fraser Stoddart, a chemistry professor at Northwestern, the team discovered this method by accident when looking for something else. A postdoc named Zhichang Liu was trying to make three-dimensional cubes out of gold and starch, aiming to use them as storage containers for gases and small molecules. But a liquid mixture of dissolved gold-bromide salts and a starch-derived sugar didnt form cubes, it formed needles. This was strange, so the team decided to try to replicate it and tested different forms of sugars.

Alpha-cyclodextrin, a cyclic starch fragment with six glucose molecules, is the best way to isolate gold, they found. Zhichang stumbled on a piece of magic for isolating gold from anything in a green way, Stoddart says in a statement. The spontaneous bundle of needles is made of thousands of nanowires, each 1.3 nanometers in diameter, which contain a charged gold atom inside four bromine atoms.

The interaction between the starch fragment and the gold allows the precious metal to be selectively recovered from other materials, including platinum, palladium and others. The researchers already developed a process to isolate gold from scraps, and they hope this will lead to an environmentally friendly, cheap way to recover gold from anything. The research is published in Nature Communications.

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cnlite eco-friendly gold leaching reagent

cnlite eco-friendly gold leaching reagent

CNLITE eco-friendly gold leaching reagent can 100% take place of sodium cyanide for gold processing and refining, including gold CIP, CIL, heap leaching, pool leaching and other cyanide process. Different with cyanide, it is low-toxicity, environmental-friendly and without changing the original cyanide equipment and process.

1. Eco-Friendly: CNLITE is environmental friendly, which can truly achieve the target of green with no severe accidents. 2. Low-Toxicity: It is low-toxicity, non-oxidant risk, non-combustible, non-explosive, and non-radioactive. 3. High Leaching Rate: It can extract gold effectively and have higher leaching rate than sodium cyanide. 4. Stable Performance: It can reduce the influence of harmful substances such as arsenic and sulfur, and make the gold extraction process stable. 5. Wide Range of Application: It is suitable for large and small scale of gold and silver oxide ore heap leaching, pool leaching, CIP, CIL and other leaching process, especially suitable for large-scale heap leaching. 6. Faster Leaching: When heap leaching, the reaction rate is faster than using sodium cyanide. 7. Lower Cost: Because of its special nature, it can reduce the cost of purchasing, shipping, warehousing, usage and environmentally friendly equipment. 8. Easy to Use: Because it can be completely substituted for sodium cyanide in the cyanidation process, it is convenient to use and can replace at any time. 9. Easy to Transport: Due to its stable nature, it can be transported by rail, sea, road and air. There are no transportation restrictions like sodium cyanide. 10. High-Tech Products: It is a high-tech product that can replace sodium cyanide for gold leaching.

1. Small Packaging: The product is graininess or powdered form and packaged in two layers of plastic bags. The inner layer is translucent plastic bag, and the outer one is printed with words. Samples can be provided to customers for trial use. 2. Large Packaging: The net weight of every bag is 25.00KG 0.20KG. Every 40 bags (the net weight of agent is 1 ton) can be packed into a wooden pallet and wrapped with plastic wrap. And the packaging of the product is easy to load and unload, which facilitates international transportation.

Usage: CNLITE is used in the same way as sodium cyanide in heap leaching, pool leaching and agitation leaching of gold ore. The reagent can be dissolved in solution with gold cyanide extraction. When used, the CNLITE gold leaching agent must be agitated with alkaline water at normal temperature and then dissolved in slurry for gold leaching. Activated carbon is the best material for gold leaching in pregnant solution, both pregnant solution and lean solution can be reused in production. When the solution temperature is higher than 10 C, it has the best gold leaching effect.

Alkalinity Adjustment: Generally, the pH of the slurry is adjusted to 10-12 using alkaline substances such as lime and caustic soda. After the raw ore is piled up or put into the pool, the alkalinity should be adjusted to the pH of 111.

Dosage: The dosage of CNLITE gold dressing agent can refer to the dosage of sodium cyanide. Its dosage is about 0.5 to 1.0 parts per thousand (500-1000g of reagent/ton of ore). The actual dosage should be calculated based on the concentration of the slurry. Also the property, grade of the ore and pH of the slurry also can affect the dosage of CNLITE gold dressing agent.

Add Method: It can only be used after it is fully dissolved in normal temperature water. The rate of dissolution is usually accelerated in running water or after thorough agitation. Continuously dissolve CNLITE gold leaching reagent by flushing it into the agent pool (lean solution pool) or agent tank. If it is used in a heap leaching process, it can be added and sprayed at the same time.

Reagent Concentration: Because the pH and composition of different ores are different, the CNLITE gold leaching reagent should be dispensed according to the actual ore amount and the optimal concentration of the reagent obtained from the trail. The concentration of the reagent can be measured according to the method provided above.

In order to study the difference in gold leaching effects between sodium cyanide and CNLITE eco-friendly gold leaching reagent, we selected six kinds of gold ore samples. They are gold mine in Sultan Kush, oxidized gold ore in Tanzania (Busolwa Mining Ltd), oxidized gold gravity separation tailings in Tanzania (T5), oxidized gold ore in Mongolia, oxidized and mixed ore of gold mine(ie containing both primary ore and oxidized ore) in Tanzania (MMG GOLD LIMITED).Under the same conditions of other cyanide leaching conditions, this study focused on the difference in the dosage of leaching agent, leaching rate, and gold adsorption rate when using sodium cyanide or CNLITE as the leaching agent, and analyzed the economic benefits of similar projects. The results are shown in the following table.

process of cyanide gold extraction

process of cyanide gold extraction

Here I present an Process EXAMPLEof Gold Extraction Cyanide in which the cyanidation feed consists of a pyrite concentrate floated after the selective flotation of a copper-gold concentrate. The pyrite concentrate is reground to 90% minus 325 mesh and aerated in a high-lime solution prior to cyanidation. It contains 99% sulphides of which 10 to 20 percent is pyrrhotite and 0.3 to 0.7% chalcopyrite, the remainder being mostly pyrite. The gold content is 0.10 to 0.13 oz. per ton, none of which is free; the gold particles are attached to pyrite, and in general they are less than 1 micron in size. Cyanidation is conducted under conditions of intense aeration for a period of 6 to 8 hours. Residues run about 0.04 to 0.06 oz. gold perton. Cyanide consumption is about 2 lbs. NaCN per ton.

The conditions outlined by the authors for optimum gold dissolution and minimum cyanide consumption are: The pulp must be well aerated, the cyanide solution should be saturated with calcium sulphate, it should have at all times a minimum alkalinity of 1.0 lb. of CaO per ton, and the cyanide strength should not be more than 0.35 lb. NaCN per ton.

Here wecompared Pachuca aeration with bottle aeration and agitation; they also investigated the effects of various sulphates in solution on gold extraction and cyanide consumption. Pachuca aeration gave better gold extraction and lower cyanide consumption than bottle agitation. With the former more copper was found in solution, and less thiocyanate was formed; with bottle agitation the reverse was the case, in addition to which copper cyanogen complexes were found in the filter cake. From this it was concluded that gold dissolution depends not only on the presence of free cyanide but also on the concentration of copper cyanide complexes in the cyanide solution. Optimum results were obtained when the weight of total NaCN by distillation to copper varied between 2.0 and 2.6 to 1. An analysis of a mill pregnant solution is shownhere.

Mineral Processing engineersfound that the addition of ammonium sulphate improved the results obtained in the Pachuca; the residue was reduced by 0.005 oz. of gold per ton and cyanide consumption by about 0.3 lb. per ton. The degree of improvement derived from ammonium sulphate increased as the pyrrhotite content of the cyanidation feed increased. Less thiocyanate was formed although there was not much difference in the amount of copper dissolved. Other sulphates were tested, and proved that the beneficial effect was due to the sulphate radical; calcium sulphate was as effective as ammonium sulphate. For this reason the solution resulting from the regrinding and preaeration of the cyanidation feed in high lime solution was found to he beneficial in the cyanide circuit as it was saturated with calcium sulphate. In addition it contained 2 to 3 lbs. per ton of thiosulphate and had an initial oxygen content of less than 2 mg. per litre. The thiosulphate was inert as regards to this EXAMPLEpractice; at normal temperatures practically no reaction took place between thiosulphate and cyanide. The authors consider that the sulphate radical acts, to some extent, as a buffer against the oxygen demand of the pyrrhotite and pyrite and thus inhibits the reactions taking place between these minerals and cyanide in the presence of oxygen.

Suggestions that the copper cyanogen complex in the mill solutions atthis EXAMPLE PLANT is of the type Na2Cu(CN)3 and that this complex would be equal in dissolving effect to a cyanide solution containing about 0.004% NaCN. When the gold in an ore is very fine, as it is in the cyanidation feed at this EXAMPLE PLANT, and with no interfering factors, a solution of this type could be adequate for optimum extraction. Gold dissolution is possibly due to the relatively small amount of CN ions resulting from the dissociation of the sodium cuprocyanide. When other constituents of the ore besides gold are competing for the available CN ions, gold extractions would be affected adversely. By the reaction of such CN ions, to form thiocyanate for example, the ratio of total cyanide to copper would drop and the equilibrium of the sodium cuprocyanide would be affected. In order to restore equilibrium, either relatively insoluble copper cyanogen complexes such as NaCu(CN)2 or CuCN would be thrown out of solution, or more CN ions would have to be added to the solution. This would possibly explain the presence of cyanogen complexes in the filter cake when increased amounts of thiocyanate were present in solution, as they were with less intense aeration. As regards the decomposition of sulphide minerals such as pyrrhotite in cyanide solutions under various conditions of aeration, it wassuggested that this could take place by two series of reactions simultaneously. The first, in the stages pyrrhotite, alkaline sulphide, thiosulphate and sulphate, while the second would be pyrrhotite, alkaline sulphide and thiocyanate; intense aeration favors the former series of reactions with the result that less cyanide is wasted as thiocyanate and, therefore, more is available for copper and gold dissolution. (These reactions will be discussed in more detail in the next section.) Thus, there will be a greater reservoir of CN ions to draw on and, therefore, less possibility of copper cyanogen complexes being thrown out of solution. The presence of sulphate radical also prevents to some extent the formation of thiocyanate but its effect is much less marked than that of intense aeration.

extracting gold without cyanide - chemical engineering | page 1

extracting gold without cyanide - chemical engineering | page 1

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cyanide gold extraction process - jxsc machine

cyanide gold extraction process - jxsc machine

The cyanidation gold extraction process includes cyanide leaching, washing and leaching of the leaching slurry, extraction of gold from the cyanide or cyanide slurry, and smelting of the finished product.

The existing cyanide gold plant in Chinas gold mines basically adopts two types of gold extraction process, one is a so-called conventional cyanidation process for gold extraction by continuous countercurrent washing with a thickener, and the gold is replaced by zinc powder (CCD method and CCF). The other method is a non-filtered cyanide carbon slurry process (CIP method and CIL method) which does not require filtration and washing, and uses activated carbon to directly absorb and recover gold from cyanide pulp. The conventional cyanidation gold extraction process is divided into two types according to the treatment materials: one is a cyanide plant that processes flotation gold concentrate or treats amalgam and re-selects tailings. The other is to treat muddy oxidized ore, using a full mud mixing cyanide gold extraction process plant.

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