Process for extracting with liquids soluble substances from subdivided solids
OwnerBarnard Stewart Silverinventor
Life of this patent
Estimating the term…
Abstract
Small particles and fines included along with larger subdivided solids are treated with liquid to extract soluble solids therein in a process using milli-screens with milli-sized openings of less than about 0.095 inches across. The milli-screen openings may be kept open for the passage of liquids with specially-designed wipers and/or back-flushing from a liquid compartment and/or rotation of the milli-screen past the matrix of subdivided solids, the subdivided solids themselves acting as a screen cleaner. The invention is useful in batch or continuous diffusers for extracting soluble solids from subdivided solids containing small particles and fines.
Claims42
A process for extracting soluble substances from subdivided solids containing small particles and fines, said process employing at least one tank having first and second portions, at least one discharge outlet for the withdrawal of enriched extraction liquid from the at least one tank, at least one milli-screen, said at least one milli-screen having an upstream face and a downstream face with respect to the flow of liquid medium when the liquid medium is withdrawn through said at least one discharge outlet, a plurality of discrete milli-openings extending from the upstream side to the downstream side of said at least one milli-screen, said milli-openings comprising sizes less than about 0.095 inches across on the upstream side of the said at least one milli-screen, said process comprising the steps of:
- introducing subdivided solids into a first portion of the at least one tank;
- said subdivided solids containing fines;
- said fines containing substances that can be extracted with a liquid medium;
- introducing liquid extraction medium into a second portion of the at least one tank;
- contacting the subdivided solids with the upstream face of said at least one milli-screen;
- pushing the subdivided solids including small particles and fines toward the second portion of the at least one tank with said at least one milli-screen so that said subdivided solids move countercurrent to the flow of the liquid extraction medium;
- separating at least some of said fines from the liquid extraction medium with said at least one milli-screen;
- and
- withdrawing the enriched extraction liquid from the first portion of the at least one tank;
- and
- withdrawing the spent subdivided solids from said second portion of the at least one tank.
A process for extracting soluble substances from subdivided solids containing small particles and fines, said process employing at least one tank, at least one discharge outlet for the at least one tank for the withdrawal of enriched extraction liquid, at least one milli-screen in the at least one tank, said at least one milli-screen having an upstream face and a downstream face with respect to the flow of liquid medium when the liquid medium is withdrawn through said at least one discharge outlet, a plurality of discrete milli-openings extending from the upstream side to the downstream side of said at least one milli-screen, said milli-openings comprising sizes less than about 0.095 inches across on the upstream side of said at least one milli-screen, said process comprising the steps of:
- introducing subdivided solids into the at least one tank, said subdivided solids containing at least about 5% by weight of fines,
- said fines containing substances which can be extracted with a liquid extraction medium;
- introducing liquid extraction medium into the at least one tank for extracting substances from the fines;
- providing contact between said subdivided solids and said at least one milli-screen;
- separating at least some of said fines from the liquid extraction medium with said at least one milli-screen;
- withdrawing the enriched extraction liquid medium from said at least one tank;
- and
- removing spent subdivided solids together with the small particles and fines from the at least one tank.
A process for extracting soluble substances from subdivided solids containing small particles and fines, said process employing at least one tank, at least one milli-screen in the at least one tank, said at least one milli-screen having an upstream face and a downstream face with respect to the flow of liquid medium when the liquid medium is withdrawn through the discharge outlet, a plurality of discrete milli-openings extending from the upstream side to the downstream side of said at least one milli-screen, said milli-openings comprising sizes less than about 0.095 inches across on the upstream side of said at least one milli-screen, at least one compartment located downstream from said at least one milli-screen, at least one discharge outlet in the said at least one compartment for the withdrawal of enriched extraction liquid, said process comprising the steps of:
- introducing subdivided solids into at least one tank, said subdivided solids containing more than about 3% by weight of fines,
- said fines containing substances which can be extracted with a liquid extraction medium;
- introducing liquid extraction medium into the at least one tank for extracting substances from the fines;
- providing contact between said subdivided solids and said at least one milli-screen;
- conducting at least a portion of the extraction liquid medium into said at least one compartment;
- separating at least some of said fines from the liquid extraction medium with said at least one milli-screen;
- withdrawing the enriched extraction liquid medium from said at least one compartment;
- and
- removing spent subdivided solids together with the small particles and fines.
Dependencies are inferred from the claim text.