Douglas P Laird

US Patent:

53624602, Nov 8, 1994

Filed:

Sep 24, 1993

Appl. No.:

8/125807

Inventors:

Douglas H. Laird - San Diego CA
Wendy K. Hanson - San Diego CA

Assignee:

Science Ventures Inc. - San Diego CA

International Classification:

C01F 500

US Classification:

4231574

Abstract:

Process for dissolving unwanted magnesium from phosphate ores by leaching with dilute sulfuric acid at automatically controlled pH. Minerals so treated are more easily converted by the conventional "wet" process into phosphoric acid, and yield better quality phosphoric acid. Magnesium So leached is precipitated with lime or dolime in a second conventional processing step to make byproduct magnesium hydroxide. An anion such as nitrate, acetate or formate is maintained in the recirculating leach solution in concentration sufficient that calcium sulfate does not precipitate with product magnesium hydroxide. Nearly pure carbon dioxide can be recovered as a second byproduct.

US Patent:

50664743, Nov 19, 1991

Filed:

Dec 13, 1989

Appl. No.:

7/450028

Inventors:

Douglas H. Laird - San Diego CA

Assignee:

Science Ventures, Inc. - San Diego CA

International Classification:

C01B 1750

US Classification:

423541R

Abstract:

A method for production of sulfur dioxide from calcium sulfate by high temperature thermal reduction. Calcium sulfate, preferably in the form of calcined phosphogypsum, is desulfurized using a fossil fuel as a heat source, the combustion products resulting therefrom being used as a reductant. The fuel and reductant may be coal, coke, liquid hydrocarbons or natural gas; high sulfur, medium or low rank coal is preferred. The fuel is combusted with air or oxygen-enriched air. The solid feeds are introduced as finely-divided particles entrained in reactant gases, and the temperature is sufficiently hot to cause residual processed materials to melt and drain from the reaction vessel in the form of a liquid slag, yet not hot enough to produce significant amounts of fine silicon oxide dust. Iron pyrite, sand and/or clay can be added to reduce the slag melting point and to control its viscosity.

US Patent:

63124998, Nov 6, 2001

Filed:

May 3, 2000

Appl. No.:

9/564330

Inventors:

Amirali G. Rehmat - Darien IL
Anil Goyal - Willowbrook IL
Douglas H. Laird - San Diego CA

Assignee:

Institute of Gas Technology - Des Plaines IL

International Classification:

C22C 700

US Classification:

75388

Abstract:

A method for stabilization of liquid mercury in which powdered copper particles are cleaned with a chemically reactive fluid suitable for removing surface oxidation from the surface. "Clean" powdered copper particles are mixed with liquid mercury to form a powdered copper/liquid mercury mixture. The mixture is then hardened to form an amalgam. Amalgams in which the amount of mercury is greater than 50% by weight of the total amalgam may be produced in accordance with the method of this invention.