초록 ▼

Small particles and fines included along with larger subdivided solids are treated with water base liquid extraction medium 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

Small particles and fines included along with larger subdivided solids are treated with water base liquid extraction medium 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.

대표청구항 ▼

[ I claim:] [1.] A method for extracting soluble substances from subdivided solids containing small particles and fines with water base liquid extraction medium, said process employing at least one tank having first and second portions, at least one discharge outlet for the withdrawal of enriched ex

[ I claim:] [1.] A method for extracting soluble substances from subdivided solids containing small particles and fines with water base liquid extraction medium, 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having an upstream face and a downstream face with respect to the flow of liquid medium when the liquid medium is withdrawn through said at least one discharge outlet, a plurality of discrete milli-openings extending from the upstream side to the downstream side of said at least one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 small particles and fines;said small particles and fines containing substances that can be extracted with a water base liquid medium;introducing water base liquid extraction medium into a second portion of the at least one tank;contacting at least some of the subdivided solids with the upstream face of said at least one milli-screen;pushing the at least some of subdivided solids including small particles and fines toward the second portion of the tank with said at least one milli-screen countercurrent to the flow of the water base liquid extraction medium; andseparating at least some of said small particles and fines from the liquid extraction medium with said at least one milli-screen;withdrawing the enriched extraction liquid from the first portion of the at least one tank; andwithdrawing the spent subdivided solids from said second portion of the at least one tank.