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US3789097A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for producing pelletized metal sulfide materials

Assignee: Kennecott Utah Copper LLC
•
Filing: 1971-08-02
•
Granted: 1974-01-29
•
Expires: 1991-08-02
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Abstract

Abstract A process of producing pelletized metal sulfide material bonded by reaction products of lime contacted by sulfur dioxide, so that the resulting pellets will have cohesive strength capable of withstanding the rough handling normally received in industrial smelting operations, comprises the steps of forming green pellets from a metal sulfide agglomerate prepared by mixing particulate metal sulfide material with lime in the presence of sufficient water to form a cohesive mixture, and of exposing the pellets to an effective amount of sulfur dioxide gas (which in the presence of moisture is converted to sulfurous acid) to react with the lime at temperatures ranging from room temperature to 100*C. to form calcium sulfite and calcium sulfate bonding agents. The hardness of the resulting pellets is increased many times over that achieved by the usual procedure of simple drying of metal sulfide material to form pellets which disintegrate prematurely when employed in commercial smelting operations. If a greater degree of hardness is necessary for some applications, the bonded pellets of the invention can be subjected to higher temperatures, imparting a degree of hardness to the pellets related to the temperature to which the pellets are exposed and the length of time of exposure.

Inventors

  • 👤 R Beck
  • 👤 D George
  • 👤 C Anderson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 19:14
CPC Classifications
C; C22; C22B; C22B1/00; C22B1/14; C22B1/24; C22B1/2406; B; B01; B01J; B01J2/00; B01J2/28

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 33 words
A process as set forth in claim 1, wherein the amount of moisture present in step (a) is such that the pellets formed contain from about 5 percent to about 20 percent water.
Claim 2
Dependent Claim 36 words
A process as set forth in claim 1, wherein the amount of lime-bearing material present in step (a) is such as to provide from about 3 - 6 percent calcium oxide by weight in the mixture.
Claim 3
Dependent Claim 16 words
A process as set forth in claim 1, wherein the lime-bearing material is slaked calcium oxide.
Claim 4
Dependent Claim 25 words
A process as set forth in claim 1, wherein the temperature of reaction is step (c) is between about 50* C. and about 90* C.
Claim 5
Dependent Claim 41 words
A process as set forth in claim 1, wherein the bonded pellets following the contact with sulfur dioxide, are additionally subjected to a heating step at a temperature above 100*C. for a period of time sufficient to further harden the pellets.
Claim 6
Dependent Claim 22 words
A process as set forth in claim 6, wherein the temperature of the heating step is from about 300*C to about 350*C.
Claim 7
Dependent Claim 21 words
A process as set forth in claim 1, wherein the metal sulfide material is made up of copper sulfide metallurgical concentrates.

References Cited (Backward Citations)

US1444467A Cited
GB702762A Cited
US3536475A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-01-28 1977-07-30 1978-01-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-01-28 1981-07-30 1982-01-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-01-28 1985-07-30 1986-01-29 $7700.00 Window Closed / Lapsed

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