Gold Technology Carbon In Leach From Curtin University

Technology Carbon In Leach

Curtin University’s Gold Technology Grouph as designed and developed an automated “Carbon Meter" to continuously, reliably and accurately measure carbon concentrations in CIL tanks.

Currently, measuring the carbon to slurryratio involves taking a small sample from the tank, it’s time-consuming and has drawbacks interms of frequency, accuracy, and repeatability.

To optimising this process, you must precisely control the ratio of activated carbon to slurry.

Simply put, too much carbon is inefficient, while too little allows dissolved gold tobe lost to tailings.

But to control it, you first have to measure it. And this is true for the Carbon In Leachor CIL gold extraction process. Carbon-in-Leach accounts for about 75% of the world’s gold production.

Process Carbon In Leach

In this process, ground, gold-bearing ore is dissolved in a chemical slurry. Granules of activated carbon are added to absorb the dissolved gold, before further processing.

See Also :
Extracting Gold By Carbon In Pulp with Activated Carbon
Gold Processing With Method Carbon In Pulp 

This robust, self-contained unit takes sample sup to 20 times larger than the manual method, every 15 minutes, 24 hours per day, whichit feeds into a measurement cylinder that strains the larger carbon particles from the slurry before a laser beam accurately measures the amount of captured carbon.

This data, along with the well-established SIMCIL modelling tool, is used to optimise carbon management to a degree not previously possible.

The end result is less soluble gold lost to tailings. Gold producers are processing higher tonnages of lower grades of ore than ever before.

And along with fluctuating gold prices and increased costs, optimising processes is the key tolong-term profitability.

For many CIL operations, optimisations resulting in recovery a 100th of a gram more gold per tonne of slurry processed, can increase annual revenue by millions of dollars. And this is a significant benefit for any mining operation.

Activated  Carbon for Carbon In Leach

Video Gold Technology Carbon In Leach From Curtin University

Gold Leaching Process With Carbon In Pulp ( Video )

Gold processing techniques using activated carbon or Gold leaching process with Carbon In Pulp  in gold mining is a way to separate the gold metal or extraction of separation of minerals gold with other impurities. Where part of the processing of Carbon In Pulp using cyanide solution to separation. The processing of gold first time with using a Carbon In Pulp (CIP) introduced in gold mining in the early 1980s, and is considered as a process that is simple and cheap in the gold mining industry. But processing using cyanide in gold mining if not done correctly, would harm the surrounding environment.

For separation gold process by means of Carbon In Pulp needed an activated carbon which serves as metal absorbent material and activated carbon material mostly made from coconut shells. In addition to from that required cyanide to stage gold mineral dissolution process of the sludge. Before the  leaching process in Carbon In pulp, mineral rock must have a size that such as flour, which later on will used as a slurry.

Gold Processing With Method Carbon In Pulp

        Gold processing methods with the Carbon in pulp are often used in large-scale gold mining processing, where the active carbon in pulp method used for recovery of gold ore minerals in the washing tank. Tanks that are used are usually equipped with an agitator and air bubbles equipment and tools are designed to maintain solids in suspension in the slurry, and the achievement of leaching. In the process adsorption ore minerals in the soil material condition of the tank should be good enough to form a slurry that can flow under gravity or when pumped. To form a slurry, mineral ore in the mix with water and the reagent was added to the tank to get the gold leaching reaction

How to work the gold extraction process with carbon adsorption in the pulp can be explained by the following system

HOW TO WORK THE HEAP LEACHING MINING

Heap leach is a method developed by Henin and Lindstrom to process low-grade ore on a large scale with small production cost so that the levels below the cut-of grade can still be economical. Heap leach is the process of leaching of low grade gold rocks thrown, then the solution containing the metal particles are screened and separated by electrolysis. Heap leach done repeatedly and on a large scale.

There are several steps that are used in processing gold ores using heap leaching system

• Preparation of the foundation of leaching with an angle of 1 degree to 6 degrees. : The foundation of this leaching can be made by permanently using a hardening of the concrete floor or foundation and geo-coated membrane (High Density Polyethylene)

• Then the rock minerals that have been taken from the mine area was destroyed. Destruction of rock done to get smaller sized rocks. Size obtained usually ± ½ or up to 1 inch. machines used in the process of destruction is the engine or Stone Mill Hammer Crusher and Crusher Jaws.

• After the material to be crushed and refined, then placed into the foundation of leaching that has been provided

• Then through the spray in the spray solution of sodium sianide. And in general the use of sodium sianide NaCN. This process aims to take the gold extraction is formed in the chlorination process and transformed into compounds Dicyano Aurrat (Au (CN) 2). Because the compound that would be too absorption within the pores of activated carbon

In the cyanidation process consists of two important stages, namely the process of dissolution and separation of gold from the solution process. Solvents commonly used in the process cyanidasi is NaCN, KCN, Ca (CN) 2, or a mixture of all three. The solvent most often used is NaCN, being able to dissolve gold better than any other solvent. 

From this it will spray cyanide in the extraction process produces a chemical reaction in the form:

 Au + NaCN + O2 + H2O = NaAu (CN) 2 + NaOH (from equation Elsener and Adamson)
 Au + NaCN + O2 + H2O = NaAu (CN) 2 + H2O2 + NaOH (from equation Adamson)

Gold extraction is generally effective at pH 9.5 to 11. Optimum near 10.5. The more acidic, hydrolysis to hydrogen cyanide had cyanide (HCN), the more alkaline reaction the more it will slow down. To speed up the process of gold dissolution in cyanide solution will be added to the catalyst. Namely lead Nitrate (PbNO3), because the catalyst can also increase the recovery of gold to be 95%. Generally cyanide complex solution containing between 1 ppm to 3 ppm.

• Once the cycle is completed the leaching process of leaching in the wash with water to remove residual cyanide is used peroxide. Decision-stop solution if the gold content down to 0.005 ounces of gold per ton of solution. Taking gold in the solution can be done by using activated carbon or by direct receipts using zinc cementation process (Merrill - Crowe Process). In addition to using the carbon and cementation, other techniques can be used is elektrorefining and ion exchange resins. Elektrorefining is the process of attachment of the metal contained in the solution on the cathode rod, in this process is stailess steel rod anode and cathode in the form of steel brush.

     In heap leaching using carbon adsorption techniques in coulumn Carbon (CIC) in which the solution containing the gold complex flows in tanks containing activated carbon in series and terraced. Activated carbon can absorb gold from 100 up to 400 ounces per ton of carbon, the efficiency will drop if content of the solution decreases. Precious metals in the capture of carbon by passing a hot solution of caustic soda and cyanide mixture (1% NaOH and 1% NaCN) Activated carbon can be reused by reactivation in advance using the rotary kiln at a temperature of 730 degrees Celsius for 20 minutes. In traditional mining usually carbon that has been filled with gold complexes directly in the fuel, the dust from the burning of carbon was then taken to be melted down. Contained metal can be purified directly. This is done because the aged and technological considerations.

Extracting Gold By Carbon In Pulp with Activated Carbon

       Carbon In Pulp is the absorption of compounds into carbon Dicyano Aurrat. In the process extracting gold by carbon in pulp with activated carbon occurs after the leaching of mineral ore slurry in a tank. And during the washing, the carbon-in-leach and adsorption occur simultaneously. In both processes mineral ore leaching slurry will be transferred from one tank into the recovery tank of carbon using a pumping machine.  

This is generally accomplished by passing the slurry through a series of adsorption vessels coupled with the periodic transfer of carbon, usually associated with pulp, and in the opposite direction. Column tanks are often used consists of a large carbon column (diameter 5 to 8 feet) and 15 to 20 feet in height, and filled with activated carbon. Minimum load of carbon rule of thumb is one pound of activated carbon per 0.1 ounces of gold are present in solution, and usually it's a few pounds per 1 / 10 ounce

         Two main methods Carbon In Pulp (CIP) and Carbon Columns may consist of the most widely used technique for extracting gold today. Both methods use a large tank in the column parallel step where gold is dissolved in the slurry (pulp) through a chemical process and combine agitation, oxygen and cyanide. In CIP, the carbon is mixed with a solution of cyanide leach and ore agitated in the Tank leaching, and the adsorption process will separate the gold. 

 This will bring together between carbon and gold cyanide solution which is attached to the carbon. Granular carbon is often hard to use in a variety of sizes between 10-16 mesh. Carbon is then filtered by using the screening, on-screen screening of carbon will settle and the liquid is finely ground ore (-100 mesh) will be screened out through the screen into the tank.CIP treatment system can be described simply as a picture diagram below:

Diagram of the processing of gold with carbon in pulp

Gold Cyanide Method

 Gold cyanide method is the process of dissolution of gold ore using cyanide chemicals, because every atom of gold requires dissolution of the mineral carrier or impurity with the stoichiometry of two cyanide-soluble compounds.

Gold cyanide process begins with Carl Wilhelm Scheele had discovered that the gold will be dissolved by cyanide in aqueous solution. And this gold cyanide process he discovered in 1783.

Gold cyanide method is a basic method of the gold dissolution process is often used in gold mining around the world, and gold cyanide process has been patented in 1887. The chemical reaction that occurs when the dissolution of gold cyanide is:

     4 Au + 8 NaCN + O 2 + 2 H2O → 4 Na [Au (CN) 2] + 4 NaOH

In the process of redox, oxygen removes electrons from the gold four simultaneous with the transfer of protons (H +) from water.
Mines that have used the cyanide process of gold mineral dissolution is: