New Patents iii

type of ore to thiourea leaching in the presence of carbon instead of subjecting the slurry to cyanidation leaching.

4902429

GAS ASSISTED FLOTATION PROCESS

Robert Carpenter, Harrison F Lyman assigned to Redux Corporation

This invention relates to a gas assisted flotation process and apparatus useful in the separation of solids from liquids in a slurry, such as treated waste waters, paper pulp solution etc. The gas as- sisted flotation process may be operated on a continuous basis. The upper portion of the main chamber of the apparatus is tapered inward to terminate in an apex which has an opening through which the floated and compressed solids and gas are removed. The apparatus also has a fluid discharge line through which the separated fluids may be removed which also contains a fluid discharge valve which may be opened and constricted intermittently to control the flow of slurry through the system.

4904373

FOSSIL RESIN FLOTATION FROM COAL BY SELECTIVE

COAGULATION AND DEPRESSION OF COAL

Jan D Miller, Qiang Yu, Ye Yi assigned to University of Utah

disclosed is a process for separating resin from a mixture of resin-bearing coal particles by in- creasing the pH of a froth flotation process to a value of at least 12. Particles of reduced size resin-bearing coal are preferably mixed with water to from a slurry. The pH of the slurry is then adjusted with a chemical agent to about 12. The slurry is then subjected to froth flotation. The coal particles aggregate to one another al- lowing the remaining resin-rich particles to attach to the bubbles formed during the flotation process. A much improved separation efficiency for resin flotation from coal is observed.

4904374

FROTH FLOTATION

Haimi Singer, Amor Jordaan, Johannesburg, South Africa assigned to Sentrachem Limited

49027~

POLYMERIC SULFIDE MINERAL DEPRESSANTS

Alan S Rothenberg, David W Lipp, Samuel Wang, Donald P Spitzer assigned to American Cyanamid Company

A novel polymer composition comprising recur- ring units of the formula: See Patent for Chem- ical Structure wherein each R1 is, individually, hydrogen or C 1-C4 alkyl; each R5, individually, is hydrogen or a C1-C4 lower alkyl group; X is OH or SH; Y is OR2, SR2, NR22, or NR2- NR22; R2 is hydrogen, a C1-C4 lower alkyl or a C 1-C4 substituted lower alkyl, no more than one of Y and X being hydroxyl, and M is hydrogen, an alkali metal cation or an ammonium ion; x represents a residual mole percent fraction; y is a mole percent fraction ranging from about 0.5% to about 25%; z is a mole percent fraction ranging from about 0% to about 25%; and the molecular weight of the polymer is between ab- out 1,000 and 500,000.

A method of selectively recovering an ar- senopyrite, pyrrhotite or like mineral from a material containing such a mineral and pyrite which includes the steps of providing a slurry of the material, adding a dialkyl (C3-8)- dithiophosphate to the slurry, passing a gas through the slurry to cause the mineral to be car- ded to the surface of the slurry and report in a first float concentrate, removing this concentrate from the slurry, activating the mineral remaining in the slurry by adding a suitable water-soluble copper salt to the slurry, adding a monoalkyl (C3-10)-dithiocarbamate to the slurry, passing a gas through the slurry to cause mineral to be car- ded to the surface of the slurry and form a second float concentrate, removing the second concentrate from the slurry and combining the first and the second float concentrates.

4904375

SODIUM SILICATE AS A PHOSPHATE FLOTATION

MODIFIER

Robert Snow assigned to IMC Fertilizer Inc