Minerals Engineering, Vol. 3, No. 6, pp. i - i v , 1990 0892-6875/90 $3.00 + 00 Printed in Great Britain Pergamon Press plc

NEW PATENTS

This Section contains abstracts and, where appropriate, illustrations of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH ® online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH ® can be obtained from Pergamon Orbit InfoLine Inc., 8000 Westpark Drive, McLean, Virginia 22102 U.S.A.

Copies of complete patents announced in this Section are available from Pergamon Orbit InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon Orbit InfoLine only.

4892631

R E C O V E R Y O F P R E C I O U S M E T A L S F R O M C O M P L E X O R E S

Merwin G White

Precious metals are resolved and recovered from complex ores by a repetitious process of (1) heating in an electric arc furnace, a source con- taining complex ore values with fluxes and a base metal, to which a precious metal inquart has pre- ferably been added, thereby smelting the pre- cious metal values into the base metal; (2) transferring the base metal in an acid-proof bag to an electrolytic cell where the base metal becomes the anode and subjecting the cell to a direct positive current causing the base metal and unresolved complex values to be dissolved from the anode and plate out on a cathode leaving the precious metal inquart and resolved precious metals in the acid-proof bag in the form of an anode mud; (3) charging the cathode and any undissolved anode back to the smelting operation and repeating the smelting and elec- trolysis operations as many times as necessary to resolve the complex values in the source and col- lecting them in the anode mud. Anode mud from a series of cycles is collected, combined and sub- sequently smelted and electrolyzed, thereby recovering a rich anode mud which is commer- cially salable, or from which gold, silver and metals from the platinum group may be separated.

4892648

P R O C E S S F O R B E N E F I C I A T I O N O F C O A L A N D A S S O C I A T E D

A P P A R A T U S

Amol Kulkarni assigned to Viking Systems International Inc

A process for removing mineral matter from coal is disclosed. The process involves creating ultrafine coal by pulverizing the coal feed material and mixing it with an aqueous amine solution. The coal/amine solution is fed into a flotation cell and gaseous carbon dioxide is char- ged into the cell. The carbon dioxide reacts with the amine solution to form bubbles which carry the clean coal componentof the coal feed material to the top of the cell for subsequent removal from the cell. The bubbles are reduced in size as they move up within the cell. The mineral matter, which is heavier than the clean coal, stays at the bottom of the cell and can be removed spearately. The amine and the carbon dioxide used in the process can be recycled. An associated apparatus is also disclosed.

~ 9 2 ~ 9

C A L C I U M C A R B O N A T E B E N E F I C I A T I O N

Joseph Mehaffey, Thomas C Newman assigned to Akzo America Inc

A process for purifying calcium carbonate ore by the removal of silicate impurities from the ore by reverse flotation. The process achieves high yields and low acid insoluble content of the cal- cium carbonate product by employing novel col- lectors. These novel collectors which characterize the invention comprise organo- nitrogen compounds including propoxylated quaternary ammonium compounds, unsym- metrical dialkyl dimethyl quaternary am- monium compounds and dialkyl hexahydropyrimidine compounds.