Here is a method on how to conduct a cyanidation bottle roll test AKA Cyanide Gold Extraction Process:
Riffle out 400 grams of the ore.
Hobbyist Bottle Roller by https://www.actionmining.com/
Grind to pass 200 microns (“13-15 minutes for hard rock ores;” 10 minutes for oxidized ore) grind at 35% solids.
Wet screen. Retain and dry fractions. Settling overnight of – 45um will be required. Decant and dry. Perform cyclosiing on – 45um fraction. Ensure to include – 45um material dry screened from remaining size fractions. (20 minutes on Ro-tap screen shaker).
Reconstitute sample – add to bottle along with same weight of 0.1% (1 gram/litre) NaCN solution, to give 50% solids. Adjust pH to 10.0 – 10.5, with measured lime additions.
Put bottle on rolls (with variable speed setting set at zero – this is sufficient agitation) – if using two bottles, place caps away from each other, and start timing.
Connect up air lines such that air is bubbled through solution.
When a sample of the pregnant cyanide solution is required, decant 100 mls of pulp, into a beaker. Return to the bottle any previous filtrate, along with 50 ml of cyanide solution (0.1%). Return bottle to rolls.
Filter pregnant solution from pulp, retaining and labeling the solution. 40-50 mls of pregnant solution is required.
When final sample (72 hours usually) has been taken, the residual cyanide must be determined. Procedure for this determination is outlined elsewhere.
Wash solids with warm water and dry, setting aside for final residue.
Comments on this Cyanide Gold Extraction Process/Method:
Instead of cyanidation by bottle leaching on rolls, it may also be more convenient to bottle leach using magnetic stirrers with necessary air bubbled using flexible air lines. Alternatively, a flotation cell could be utilized.
