Carbon Adsorption In Recovery Of Gold

It has been known that gold in a cyanide leach solution would adsorb to activated carbon for over 70 years, and many papers have been written on the subject. Carbon, as a media of recovery for gold from leach solutions, did not gain wide acceptance in the gold industry until the 1970's, with the explosion of heap leaching of vast quantities of low grade gold ores, and subsequent production of many gallons of pregnant leach solution. It is now the most common method used for the recovery of gold from a cyanide leach solution.

Two primary methods, Carbon In Pulp (CIP) and Carbon Columns probably comprise the most widely utilized techniques for extracting gold, now days. In CIP, the carbon is mixed with the cyanide leach solution, and agitated in the leach tanks, and agitated with the ore while the gold is being dissolved. This assures a rapid interface between the carbon and the gold loaded cyanide solution. Granular, hard carbon is used, in the size range of 10-16 mesh. The carbon is then removed by screening, across a carbon screen, allowing the liquid and finely ground ore (-100 mesh) to pass through easily, and retaining the carbon on the screen. The carbon is then generally subjected to a heated solution (200 deg to 250 deg F) of (1%) sodium hydroxide and (0.1%) cyanide and the gold is re-dissolved and removed from the carbon surface. At this point, the NaOH/CN solution is sent to electrowinning cells, where the gold is plated onto stainless steel cathodes. The gold is removed from the cathodes by either using a high pressure water spray, sometimes shaking the cathode, and in some cases, the stainless steel cathode is placed into a melting furnace and heated to 2,000 degrees F, to melt the gold from the cathode. The stainless steel cathode, of course, does not melt at this temperature, but such temperatures reduce the life of the cathodes, and most will wash the gold "sponge" from the cathodes. The fine, powdered gold is then melted and poured into dore bars.

The carbon in pulp method is only used where tank leaching is utilized for the recovery of gold from the ores and this is not the case in most large gold mines today, since heap leaching is the lowest cost method for recovering gold from ores containing from a few grams to 5 or 6 grams per ton. If the ore is a high grade, it may be feasible to tank leach it. By high grade, it would probably be in the range of ¼ ounce per ton (Au) range or greater. The cost of leaching by tank is considerably greater than leaching in a heap. This is due to the requirement to crush the ore to -100 mesh (at least), and to provide mechanical equipment to store and agitate the ore for extended periods of time (4-6 hours). Occasionally, carbon columns will be used with tank leaching operations, also, especially if the mine has a dual leach system, heap leach of low grade and tank leach of high grade.

Carbon columns consist of large columns (5 to 8 ft diameter) and 15 to 20 feet in height, charged with activated carbon. The minimum load of carbon rule of thumb is one pound of activated carbon per 0.1 ounce of gold present in the solution. Usually, it is several pounds per 1/10 ounce, though, as the cost of carbon is relatively insignificant compared to timely recovery of gold.

The pregnant cyanide solution flows through the carbon columns, which are generally situated in step fashion, so that the overflow from the highest column will gravity flow to the next column, alleviating the requirement for pumping. The gold adsorbs onto the surface of the carbon. The loaded carbon is periodically removed from the columns, and sent to the stripping circuit. The carbon is then generally subjected to a heated solution (200 deg to 250 deg F) of (1%) sodium hydroxide and (0.1%) cyanide and the gold is re-dissolved and removed from the carbon surface. At this point, the NaOH/CN solution is sent to electrowinning cells, where the gold is plated onto stainless steel cathodes. The gold is removed from the cathodes by either using a high pressure water spray, sometimes shaking the cathode, and in some cases, the stainless steel cathode is placed into a melting furnace and heated to 2,000 degrees F, to melt the gold from the cathode. The stainless steel cathode, of course, does not melt at this temperature, but such temperatures reduce the life of the cathodes, and most will wash the gold "sponge" from the cathodes. The fine, powdered gold is then melted and poured into dore bars.

Any silver present in the ore, will also be leached in the cyanide solution, and will be present in the dore bar, as well. Most mines do not have the refining capacity to separate the silver from the gold and the bars are sent to a commercial refinery for producing the 99.99% gold and silver ingots that are sold on the commercial gold market.

Once the carbon has been stripped, it can be reused after recharging it in a kiln, by heating it to around 1300 degrees F. The carbon is then cooled, screened to remove fines and is ready for reuse. Fines are not desirable in carbon circuits, since they will escape through the carbon screens and end up in the leach, capturing gold that will not be recovered. For this reason, high quality and hard carbon is generally utilized for these applications. Generally, the size range of the carbon is 10 mesh to 16 mesh and almost always no finer than 20 mesh. Coconut shell carbon and Coal Based Carbon is generally the preferred carbon for use in recovering gold from leach solutions

Wastewater Treatment

We provide very high quality wastewater and water treatment Chemicals which cannot be availed anywhere else. Our wastewater recycling techniques are quite exclusive as well. We also provide our services at quite affordable prices so that everyone can avail them easily. We have also gained the position of the most prominent water treatment services providers.

Brand Name	Purpose	Speciality
IU-TECH-2001	Boiler & Cooling Tower	Blended with 'MCI' to Resist metal loss
IU-TREAT-2002	Boiler Antiscalent + Oxyscavenger	Blended with Corossion Inhibitor along with Tube
IU-TREAT-2003	Cooling Tower Antiscalent + Oxyscavenger	Blended with Corossion Inhibitor along with Tube
IU-TECH-2005	Cooling Tower Biocide + Fungiside	Single Dose
IU-BIOCHEM	ETP water Recycling Chemical	To minimize Opwrational Cost
RESI FRESH+VE	Cationic Resine Cleaner	To increase Resin Life
RESI FRESH-VE	Anionic Resine Cleaner	To increase Resin Life
RESI FRESH (S)	Softening plant Cleaner	To increase Resin Life
VA-TREAT-5002	Vapour absorptions Machine Anti scalent	Antiscalent singke Dose effective in chilled water also

Air Pollution Control Services

We provide one of the best air pollution control services which are of high optimum quality. Our air pollution controlling techniques are unique and are available with no one else. We are highly famous for air pollution prevention as it is highly effective. We also supply our services at quite genuine prices for everyone to avail them easily.

Granular Activated Carbon

We supply one of the best quality granulated activated carbon(Coal Based, Wood Based and Hard sell based) which can be availed through us only. Our activated granular carbon is highly famous and is highly demanded by all. We also supply our granular activated carbon at quite affordable prices for everyone to avail them easily. We are also one of the highly renowned granular carbon manufacturers and suppliers in India.

Application of G.A.C.

Effluent Treatment Plant. Waste Water Treatment for Reduction in the level of BOD & COD. Catalyst in Chemical-Metallurgical industrial Gases. Swimming pools and soft Drink Plants For Determination. Purifications of Drinking Water Industrial Gases. Solvent and Gold Recovery. Absorption of Dissolved Recovery. Absorption of Dissolved Organic Matter. Water and Mask Filter. Breweries and Distilleries.

Appearance	Black Granules	Black Granules	Black Granules	Black Granules	Black Granules	Black Granules
Particle	Any Sieve size 4/8, 8/16 .12/30, 4/16, 8/30, 16/30	>>	>>	Any Sieve size 4/8, 8/16 .12/30, 4/16, 8/30, 16/30	>>	Any Sieve size 4/8, 8/16 .12/30, 4/16, 8/30, 16/30
Iodine					95	1
Ad sorption	400+/-25	500+/-25	750+/-25	850+/-50	0+/-50	100+/-50
mg/gm
pH	9to10	9to10	9to10	9to10	9to10	9to10
Moisture%
>>	5	5	5	5	5	5
Total Surface area
sq.mtrs. /gm	400	500	750	850	950	1100
Bulk Density gm/cc					0.5	0.4
>>	0.55+/-0.1	0.55+/-0.1	0.53+/-0.1	0.51+/-0.1	0+/-0.1	8+/-0.1
Ball Pan Hardness no.	85	85	85	90	90	95
Ash Content%					5	5
>>	27%Max	27%Max	27%Max	10%Max	3%Max	3%Max

Powdered Activated Carbon

We are one of the most prominent activated carbon manufacturers and suppliers in India. Our powdered activated carbon is of the best quality and is available with us only. We also supply our activated powdered carbon at affordable prices for everyone to avail them easily. Our activated carbon can also be availed within the stipulated time avoiding all delays.

Activated Carbon Powder - Washed Grades

TEST	SPPA	SPPA (S)	PHARMA	PHARMA (s)	PHARMA (ssp)	P (ssp)	SP (ssp)
Methylene Blue mg/g	200	240	280	320	360	4700	450
KmnO4 % min	45	50	60	75	85	90	92
Ash % max	4	4	3	2.5	2	1.5	1.0
Iron ppm max	250	250	200	150	100	50	50
Acid Solubles % max	1.5	1.5	1.5	1.5	1.5	1.5	<1
Water Solubles % max	1	1	1	1	1	1	1
PH	6 to 7.5	6 to 7.5	6 to 7.5	6 to 7.5	6 to 7.5	6 to 7.5	6 to 7.5
Moisture % max	10	5	5	5	5	5	5
Chloride Ppm max	1200	1200	1000	1000	100	100	100
Standard	IP	BP	USP	USP	USP	USP	USP

Activated Carbon Powder - Unwashed Grades

TAST	SP	SP (U)	SP (U-1)	SP (U-2)	SP (U-3)	SP (U-4)	SP (U-5)	SP (U-6)	SP (U-7)	SP (U-8)
Methylene blue mg/g	100	150	180	240	270	300	340	360	400	450
KmnO4 % min	25	35	40	45	60	70	75	80	85	90
Ash % min	60	30	11	11	10	8	8	8	8	8
Iron ppm max	1000	800	600	600	600	600	600	600	600	600
Acid Solubles % max	12	10	7	5	5	5	5	5	5	5
Water Solubles % max				1-4	1-4	1-4	1-4	1-4	1-4	1-4
PH	10	10	10	7	Adjustable between 7 to 11	Adjustable between 7 to 11	Adjustable between 7 to 11	Adjustable between 7 to 11	Adjustable between 7 to 11	Adjustable between 7 to 11
Moisture % max	11	11	11	10	10	10	10	10	10	10

Products

We offer one of the best quality services and products to our customers which are available nowhere else. Our exclusive services comprise of business consultancy services, manpower training, water and waste water treatment services, air pollution control services etc. We have a highly efficient team of professionals which handles our tasks related to our services in a very effective way and provide one of the best services possible. Our products include very high quality granulated activated carbon and powdered activated carbon.

Granular Activated Carbon Size 4 x 8 mm.

Granuals Activated Carbon Size 2 x 4 mm and .05 x 2 mm.

Company Profile

Our company was established in the year of 2005 and in just a short span of time it has made a prominent position for itself. Our company is a highly reliable service provider and a manufacturer as well. Our range of services and products is quite exclusive and comprises of air pollution prevention, HR manpower training, water and wastewater treatment services, business consulting services, granular activated carbon and powdered activated carbon. We also check the quality of our products through stringent quality checks before their supply.

We have scores of qualified quality analysts to inspect our products. Alongside, we are also equipped with the latest machinery which is available for manufacturing. We also boast a highly dedicated and skilled work force. With our significant experience of serving our customers around the India, we have committed ourselves to provide quality products and services at competitive prices.

Name of CEO	Mr. Saheb Ali & Maksood Ahamad
Year of Estd.	2005
Primary Business Type	Manufacturer & Service Provider
Sale Tax Number	TIN No. 22143202845 (CST&VAT) W.E.F. 17.11.2005
Product/Service We Offer	Granular Activated Carbon, Powdered Activated Carbon, Air Pollution Control Services, Manpower Training, Business Consulting Services & Wastewater Treatment