Daniel W Lewis
Broker in Salt Lake City, UT

4256553, Mar 17, 1981

Jan 23, 1980

6/114476

Frank A. Baczek - Sandy UT
Bruce C. Wojcik - Kearns UT
Alexander A. Jueschke - Salt Lake City UT
Daniel M. Lewis - Salt Lake City UT
Jack C. Otto - Magma UT
Lawrence L. Tuttle - Sandy UT

Envirotech Corporation - Menlo Park CA

C25C 112, C25C 700

204106

A process and system are provided for recovering copper from chalcopyrite concentrate. The chalcopyrite is ground to a mean particle size of about 1. 5-5 microns. The ground chalcopyrite is then divided into a first stream and a second stream. The first stream is leached in a leach solution containing at least about 100 gpl sulfuric acid and about 10-30 gpl ferric iron to produce a copper sulfate solution containing about 40-75 gpl dissolved copper and less than about 5 gpl ferric iron. The second stream of ground chalcopyrite is combined with the copper sulfate solution and with sulfur dioxide such that the combination reacts to precipitate dissolved copper from the copper sulfate solution as simple copper sulfides and to produce a liquor containing dissolved ferrous iron. The simple copper sulfides are then separated from the ferrous iron liquor. Sulfuric acid is added to the ferrous iron liquor to precipitate the ferrous iron as ferrous sulfate and the produce a recycle solution containing about 400-600 gpl sulfuric acid.

4359376, Nov 16, 1982

May 11, 1981

6/262373

Frank A. Baczek - Sandy UT
Bruce C. Wojcik - Kearns UT
Alexander A. Jueschke - Salt Lake City UT
Daniel M. Lewis - Salt Lake City UT
Jack C. Otto - Magma UT
Lawrence L. Tuttle - Sandy UT

Envirotech Corporation

C25C 700

204242

A system and process are provided for recovering copper from a contaminated copper-bearing source such as copper smelter flue dust. The copper-bearing source is leached in an acidic solution to produce a liquor containing dissolved copper and dissolved contaminants. Simple copper sulfides are precipitated from the liquor by reacting the liquor with chalcopyrite and sulfur dioxide. Copper is recovered from the precipitated sulfides. A novel process is provided for precipitating simple copper sulfides from a solution containing both dissolved copper and dissolved contaminants. The solution is combined with precipitation product such that substantially all ferric iron contained in the solution is reduced to ferrous iron. The ferric-free solution is reacted with chalcopyrite solids and sulfur dioxide to precipitate the dissolved copper as simple copper sulfides.

4290865, Sep 22, 1981

Jan 23, 1980

6/114477

Frank A. Baczek - Sandy UT
Bruce C. Wojcik - Kearns UT
Alexander A. Jueschke - Salt Lake City UT
Daniel M. Lewis - Salt Lake City UT
Jack C. Otto - Magma UT
Lawrence L. Tuttle - Sandy UT

Envirotech Corporation - Menlo Park CA

C25C 112

204106

A system and process are provided for recovering copper from a contaminated copper-bearing source such as copper smelter flue dust. The copper-bearing source is leached in an acidic solution to produce a liquor containing dissolved copper and dissolved contaminants. Simple copper sulfides are precipitated from the liquor by reacting the liquor with chalcopyrite and sulfur dioxide. Copper is recovered from the precipitated sulfides. A novel process is provided for precipitating simple copper sulfides from a solution containing both dissolved copper and dissolved contaminants. The solution is combined with precipitation product such that substantially all ferric iron contained in the solution is reduced to ferrous iron. The ferric-free solution is reacted with chalcopyrite solids and sulfur dioxide to precipitate the dissolved copper as simple copper sulfides.