In situ roasting and leaching of sulfide minerals
AssigneeOccidental Research Corporation
InventorsClyde V. Johnson, Wilhelmus G. J. Huijnen
Life of this patent
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Abstract
There is provided a process for recovery of metal values from an ore body containing sulfide minerals. The ore body is fractured for increasing its permeability. The fractured ore body is then roasted in situ to increase the permeability and porosity of ore body to liquid leach solutions. The roasted sulfide minerals in the ore body are thereafter contacted with a leach solution to extract metal values therefrom and the extracted metal values are recovered.
Claims15
A process for increasing the permeability of an ore body containing iron-copper sulfide minerals comprising the steps of:
- fracturing an ore body containing iron-copper sulfide minerals for forming ore surfaces within the ore body and for increasing the permeability of the ore body sufficiently to allow passage of gases therethrough;
- roasting the fractured ore body in situ for forming a combustion gas comprising sulfur dioxide, the roasting being continued for a sufficient time for forming an iron-rich oxide crust on such ore surfaces and for concentrating copper values remote from such ore surfaces;
- removing such a combustion gas from the ore body;
- shocking the roasted ore body for releasing such an iron-rich oxide crust from the ore surfaces for exposing the concentrated copper values;
- and
- contacting the copper values with a leach solution comprising mineral acid for leaching said copper values from the ore body.
A process for the recovery of copper values from an ore body comprising iron-copper sulfide minerals, the process comprising the steps of:
- (a) drilling at least one borehole into the ore body and placing at least one explosive charge into such a borehole;
- (b) detonating such an explosive charge for fragmenting at least a portion of the ore body forming a fragmented mass comprising iron-copper sulfide mineral particles;
- (c) inserting a casing into said borehole and cementing the casing in place;
- (d) lowering a fluid transport pipe having a diameter less than the diameter of the casing downwardly through said casing, the fluid transport pipe extending below said casing and into a lower region of the fragmented mass of iron-copper sulfide mineral particles;
- (e) roasting such a fragmented mass by:
- (i) introducing a mixture of fuel and an oxygen-supplying gas downwardly through the fluid transport pipe and into the fragmented mass;
- (ii) igniting the mixture of fuel and oxygen-supplying gas to heat at least a portion of the iron-copper sulfide minerals to above the ignition temperature of said iron-copper sulfide minerals;
- (iii) discontinuing introduction of the fuel while continuing introduction of the oxygen-supplying gas for roasting the fragmented mass at a temperature between about 250.degree. C. and about 1500.degree. C. for forming a combustion gas comprising sulfur dioxide, for migrating iron values toward an outer region of each roasted iron-copper sulfide mineral particle, the iron values combining with oxygen to form an iron-rich oxide crust surrounding each roasted iron-copper sulfide mineral particle, and for migrating copper values toward a center region of each roasted iron-copper sulfide mineral particle;
- (f) detonating an explosive charge in a region of the ore body to remove at least a portion of the iron-rich oxide crust surrounding each roasted iron-copper sulfide mineral particle for exposing the center region of each roasted iron-copper sulfide mineral particle;
- (g) leaching copper values from the center region of each roasted iron-copper sulfide mineral particle by introducing a leach solution into the fragmented mass of roasted iron-copper sulfide mineral particles and contacting the center region of each roasted iron-copper sulfide mineral particle with the leach solution for forming a pregnant leach solution comprising copper values;
- and
- (h) recovering copper values from the pregnant leach solution.
A process for the recovery of copper values from an ore body which comprises iron-copper sulfide minerals, the process comprising the steps of:
- fragmenting an ore body comprising iron-copper sulfide minerals to form a fragmented mass comprising iron-copper sulfide mineral particles;
- roasting the fragmented mass comprising iron-copper sulfide mineral particles in situ for concentrating copper values in a center region of such a roasted iron-copper sulfide mineral particle and for forming an iron-rich oxide crust surrounding such a center region;
- removing the iron-rich oxide crust to expose the center region of such an iron-copper sulfide mineral particle;
- and thereafter
- leaching copper values from such roasted iron-copper sulfide mineral particles.
Dependencies are inferred from the claim text.