OraPure Activated Carbon

Coconut Shell Carbon for Gold Cyanide Adsorption

OraPure is the coconut shell granular activated carbon engineered for gold recovery from cyanide leach solutions. The carbon is produced from selected coconut shell through controlled carbonisation and steam activation. The pore structure is tuned for the gold cyanide complex with iodine number above 1000 mg/g and BET surface 1000 to 1200 m2/g.

The granule is processed to reduce platelet formation that would otherwise restrict diffusion into the pellet over time. Hardness and attrition resistance hold through repeated acid wash and elution cycles.

Three Tier Pore Carries Gold Cyanide Into the Granule

A gold recovery carbon needs three pore size classes in series. Macro pores above 50 nm transport the gold cyanide complex from the bulk leach solution into the granule. Meso pores 2 to 50 nm branch off the macro pores and connect them to the active surface. Micro pores below 2 nm hold the adsorbed gold complex on a surface of 1000 to 1200 m2/g.

OraPure preserves the three tier architecture through reactivation cycles. K value (gold loading capacity at the pregnant solution gold concentration) holds across multiple operating cycles rather than degrading after the first elution.

Mesh Range Per Duty

• 8 x 16 mesh (1.18 to 2.36 mm): CIP and CIL slurries where the carbon contacts an abrasive solid load and granule attrition is the controlling constraint
• 6 x 16 mesh (1.18 to 3.35 mm): general CIL and CIC duty where balance of loading kinetics and granule retention is the priority
• 6 x 12 mesh (1.70 to 3.35 mm): CIC and heap leach columns where the higher granule size gives the lowest pressure drop and easiest carbon recovery

Acid Wash, Elution, Thermal Reactivation

Spent OraPure is acid washed to remove calcium carbonate scale. Elution strips the gold using hot caustic cyanide at 110 deg C for 24 to 36 hours, with the strip solution carrying the gold to downstream electrowinning. After 8 to 12 acid wash and elution cycles the carbon is thermally reactivated at 650 to 750 deg C in a rotary kiln in a controlled steam atmosphere, restoring activity to 90 to 95 percent of fresh.

Forms and Supply

Supplied as 8 x 16, 6 x 16, or 6 x 12 mesh granules in 25 kg bags or 1 metric tonne big bags. Low moisture and low ash at supply. COA per lot with iodine number, hardness, and K value verified. Available as media for new CIP and CIL plants, as makeup for existing operations, or inside a SorbiTech reactivation programme. For bulk supply, visit medaad.com/orapure. SorbiTech delivers OraPure across the gold CIP and CIL recovery application, the mining and metallurgy sector, and the parent activated carbon family.