Apparatus for production of metal oxides

Claim 1

An apparatus according to claim 1 wherein said evaporator tank comprises a closed vessel having controlled outlet means adjustable to maintain pressure.

Claim 7

An apparatus for reducing a copper or zinc-rich ammonia carbonate pregnant solution to the corresponding copper or zinc oxide, said apparatus comprising: a dissolver tank containing copper or zinc source material and an ammonia carbonate solution initially containing few metal ions, means for recirculating said ammonia carbonate solution through said dissolver tank, an aerator for introducing and substantially uniformly distributing air or oxygen into said ammonia carbonate solution within said dissolver tank, whereby said copper or zinc and oxygen combine with said ammonia carbonate to form a cuprous/cupric or zinc pregnant solution, a closed evaporator tank having a generally conical bottom and a height at least one-third greater than its diameter, said tank being capable of withstanding an internal pressure of at least 15 p.s.i., said tank having a first outlet pipe adjacent the apex of said conical bottom for removal therethrough of said oxide, said tank having a second outlet pipe for removal therethrough of gases evaporated in said tank, said tank further having an inlet pipe for continuous injection of said pregnant solution into said tank, a portion of said tank being filled with a basic solution, means for transferring said pregnant solution to said evaporator tank inlet pipe, a heat exchanger external to said tank, pump means for forced recirculation of said basic solution through said heat exchanger and back to said tank below the liquid level therein, thereby maintaining the temperature of said basic solution between 214* and 218* F., throttle valve means controlling the flow of said evaporated gases through said second outlet pipe for maintaining a pressure within said tank of between 5 and 10 p.s.i., and a condenser communicating with said tank via said second outlet pipe, said condenser liquifying the ammonia, CO2 and water evaporated within said tank when said pregnant solution enters said basic solution, whereby pregnant solution injected through said inlet pipe will enter said heated basic solution, said oxide being formed in the resultant reaction.

Claim 12

A system for reducing metal oxide from a metal-rich ammoniacal liquor, said system comprising: a dissolver tank containing copper or zinc source material and an ammonia carbonate solution initially containing few metal ions, means for recirculating said ammonia carbonate solution through said dissolver tank, an aerator for introducing and substantially uniformly distributing air or oxygen into said ammonia carbonate solution within said dissolver tank, whereby said copper or zinc and oxygen combine with said ammonia carbonate to form a cuprous/cupric or zinc metal-rich ammoniacal liquor, a tank, a boiling ammonia hydroxide solution contained within said tank, a heat exchanger external to said evaporator tank and connected thereto by output and return pipes both terminating below the liquid level of said solution, pump means for forced recirculation of said solution through said heat exchanger to maintain said solution at a boiling temperature in the range of 212* to 225* F., controlled outlet means for maintaining the pressure within said evaporator tank at above about 5 p.s.i., injection means for continuously supplying said metal-rich ammoniacal liquor to said solution, the resultant reaction causing precipitation of said metal oxide, ammonia from said liquor replacing any evaporating from said solution so as to maintain the assay of said solution substantially constant during oxide reduction, an aeration tank, valved conduit means for transferring said metal-rich ammoniacal liquor from said dissolver tank directly to said injection means or via said aeration tank to said injection means, and a condenser communicating with said tank via said outlet means, said condenser liquifying the ammonia, CO2 and water evaporated within said tank when said metal-rich ammoniacal liquor is supplied to said solution.