Method for recovering trace elements from coal
AssigneeRobert W. Halliday
InventorBruce E. Minter
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Abstract
The present invention is directed to a method for the recovery of one or more trace elements including gold and one or more platinum group elements from coal. More particularly, the present invention may specify parameters for the selection of coal for combustion, the parameters for combustion of the pre-selected coal, the parameters for the preparation and mixing of a charge for a furnace including ash from the combustion of the coal with an inquart and a fluxing agent, the parameters for the heating of the charge and casting of a dore bar and the parameters for the production of an anode slime from the dore bar. The method of the present invention may also specify parameters for the recovery of silver, gold and one or more trace platinum group elements from the anode slimes.
Claims22
A method for recovering trace elements from coal including the steps of:
- mixing a charge including an ash formed by the combustion of a pre-selected coal, the ash including gold and one or more platinum group elements, an inquart including gold and one or more platinum group elements and a fluxing agent;
- charging a furnace with the charge;
- heating the charge in the furnace to a pre-selected temperature forming a molten charge including a molten inquart;
- absorbing a portion of the gold and one or more platinum group elements of the ash into the molten inquart;
- discharging a molten slag from the furnace;
- casting a dare bar by discharging the molten inquart including an absorbed portion of the gold and one or more platinum group elements of the ash to a mold;
- digesting the dore bar in an electrowinning process wherein the dore bar is introduced into an acidic bath as an anode and an electrical potential is maintained between the anode and a metallic plate cathode:
- reducing silver ions from the dore bar onto the metallic plate cathode;
- and
- precipitating and dissolving trace elements in the electrolytic solution producing an anode slime.
Dependencies are inferred from the claim text.