Method of recovering precious metals
AssigneeKrupp Polysius AG
InventorJohann Knecht
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Abstract
The invention relates to a method of recovering precious metals from oxidic or refractory or semi-refractory ore material containing precious metal. This recovery of precious metal takes place with optimal comminution work and with more efficient and more reliable leaching also of non-oxidic ore material in such a way that the ore material is subjected to material bed comminution in the grinding gap between two rollers which are pressed against one another under high pressure and revolve in opposite directions and afterwards the comminuted ore material is preferably leached using a stirring movement in a container.
Claims15
A method of recovering precious metal from oxidic, refractory, or semi-refractory ore material containing said metal, said method comprising comminuting said ore material in a material bed comminuting zone under pressure sufficient to form particles from said ore material and to form cracks in at least some of said particles, each of said particles having a surface area, each of those particles having cracks therein having its surface area increased by the presence of such cracks;
- discharging comminuted particles from said comminuting zone;
- classifying the particles discharged from said comminuting zone into relatively coarse and relatively fine fractions;
- returning the relatively coarse fraction particles to said comminuting zone for further comminution;
- oxidizing the relatively fine fraction particles in an oxidizing zone if the ore material is refractory or semi-refractory;
- diverting the relatively fine fraction particles away from the oxidizing zone if the ore material is oxidic;
- delivering the relatively fine fraction comminuted particles to a mixing zone containing a leaching fluid capable of dissolving the precious metal, thereby forming in said mixing zone a mixture of said relatively fine fraction particles and said leaching fluid;
- agitating the mixture at said mixing zone with such intensity as to maintain at least the majority of said relatively fine fraction particles in suspension in said leaching fluid and separated from one another so that said leaching fluid contacts the entire surface area of at least said majority of said relatively fine fraction particles;
- leaching at least some of the precious metal from said relatively fine traction particles into said leaching fluid in said mixing zone;
- separating the relatively fine fraction particles from said mixture following leaching of precious metal from said relatively fine fraction particles into said leaching fluid;
- and extracting the leached metal from said leaching fluid.
The method according to any one of the preceding claims wherein the comminuting of said ore material in said comminuting zone is performed in the absence of the addition of binding material.
A method of recovering precious metal from oxidic, refractory, or semi-refractory ore material containing said metal, said method comprising comminuting said ore material in a material bed comminuting zone under pressure sufficient to form particles from said ore material and to form cracks in at least some of said particles, each of said particles having a surface area, each of those particles having cracks therein having its surface area increased by the presence of such cracks;
- discharging comminuted particles from said comminuting zone;
- classifying in a classifying zone at least a portion of the particles discharged from said comminuting zone into relatively coarse and relatively fine fractions;
- returning the relatively coarse fraction particles to said comminuting zone for further comminution;
- oxidizing the relatively fine fraction particles in an oxidizing zone if the ore material is refractory or semi-refractory;
- diverting the relatively fine fraction particles away from the oxidizing zone if the ore material is oxidic;
- delivering the relatively fine fraction comminuted particles to a mixing zone containing a leaching fluid capable of dissolving the precious metal, thereby forming in said mixing zone a mixture of said relatively fine fraction particles and said leaching fluid;
- agitating the mixture at said mixing zone with such intensity as to maintain at least the majority of said relatively fine fraction particles in suspension in said leaching fluid and separated from one another so that said leaching fluid contacts the entire surface area of at least said majority of said relatively fine fraction particles;
- leaching at least some of the precious metal from said relatively fine fraction particles into said leaching fluid in said mixing zone;
- separating the relatively fine fraction particles from said mixture following leaching of precious metal from said relatively fine fraction particles into said leaching fluid;
- and extracting the leached metal from said leaching fluid.
Dependencies are inferred from the claim text.