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:
Oct. 01, 1996
Filed:
May. 04, 1995
Claude Boulanger, Shipshaw, CA;
Andrew N Carruthers, Beaconsfield, CA;
Robert L Clegg, Chicoutimi-Nord, CA;
Kwat I The, Gladstone, AU;
Alcan International Limited, Montreal, CA;
Abstract
A process for producing strong, essentially dust-free agglomerates from dust created by an industrial operation carried out, for example, on an ore or mineral, e.g. during the thermal conversion of a material containing predominantly gibbsite to sub-alpha alumina by a multistage thermal process having at least one intermediate stage. The process comprises grinding particles of binder material containing undercalcined alumina to a median particle size of less than 30 microns and to a specific surface area in the range of 90-300 m.sup.2 /g; combining about 1-4 parts by weight of the dust with one part by weight of the ground binder material to form combined solids; mixing the combined solids with water to produce agglomerates, the total amount of added water being about 0.8-1.2 parts by weight for every part by weight of the ground binder material, plus about 0.08 to 0.12 parts by weight for every part by weight of the dust; and optionally aging the resulting agglomerates in a closed environment at a temperature of at least 80.degree. C. for at least one hour in at least 50% humidity. The water is mixed with the combined solids by intensive mixing in a mixer equipped with a mixing motor, the water being added according to the following scheme: (a) 40-80% of the total amount of water is added to the combined solids at a rate such that no more than 10 minutes are required for complete addition; (b) optionally allowing a period of time to pass after the addition of the water in step (a) before proceeding further while continuing the intensive mixing; (c) commencing the addition of the remainder of the water and measuring a characteristic of said mixture corresponding to its viscosity and using the measurement as a reference value; and (d) continuing the addition of the remainder of the water while continuing to measure the characteristic of the mixture, the water being added at such a rate that the characteristic of the mixture remains the same as the reference value during the addition or varies by less than .+-.5%.