The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 16, 1983
Filed:
Feb. 26, 1982
Ralph K Iler, Wilmington, DE (US);
Paul B Queneau, Golden, CO (US);
Mark W Cooperrider, Arvada, CO (US);
Abstract
A method is provided for inhibiting the formation of silica scale on flash-pot surfaces during the multi-stage flashing of sulfuric acid pressure-leach slurry obtained following the continuous autoclave leaching of nickel lateritic ore at elevated temperature and pressure during which silica is dissolved, wherein the leach slurry is subjected to a high-temperature flash stage such that the slurry at the flash temperature is supersaturated in soluble silica, and wherein the slurry is thereafter subjected to at least one additional flash at an intermediate-temperature flash stage at which silica precipitates and tends to form a scale accompanied by a decrease in said supersaturation. The improvement resides in recycling a substantial portion of the slurry to the intermediate-temperature stage following flashing to the intermediate-temperature flash stage, the portion recycled being sufficient to effect a dilution in silica concentration of the slurry being flashed into the intermediate-temperature flash stage from the high-temperature stage, and continuing the recycling of flashed slurry to the intermediate-temperature flash stage, whereby silica scale formation at the intermediate-temperature flash stage is greatly inhibited. The pH of the recycling stream may be adjusted to further minimize silica deposition.