Abstract: A process for cleaning undeslimed coal includes the steps of determining the scalar value of cross-correlation function of the measured values of the percent magnetics and the bulk specific gravity of a heavy media and coal slurry being fed to a cyclone, comparing the value to a set-point value determined after start-up when the recirculating suspension in the feed slurry is normally clean, and diverting at least a portion of the heavy media suspension that is separated from the underflow of the cyclone from being mixed with the feed coal slurry, to thereby correspondingly reduce the slime content of the feed slurry, and concurrently increasing the flow of cleaner heavy media suspension to the feed coal slurry until the cross-correlation function is brought up to the set-point value. Also disclosed is an embodiment of the process for cleaning coal, wherein the overflow from the cyclone is screened and screened solution is split between a first recycle loop for cleaning the suspension and the heavy media sump.

Abstract: A digestor includes a tank and an inverted dish-shaped cover, the lower end of which extends into sludge contained within the tank. The cover is ballasted by a number of ballast members which resemble tubs and which are integrally formed of concrete. Each ballast member is mounted with its cavity facing upwardly so that the ballast cavities automatically fill with sludge upon start-up of the digestor. When partially surfaced above the sludge, the predetermined total weight of sludge in the ballast members causes a substantial increase in the pressure exerted by the cover on the contained gas than would be exerted by the cover and unfilled ballast members.

Abstract: A device for moving filter plates from one end of a filter press to the other end, includes carriages which selectively couple to each of the plates and which are driven to slide along the frame members of the press by a hydraulic motor. A control means is provided to control the operation of the hydraulic motor.

Abstract: A system and process are provided for recovering copper from a contaminated copper-bearing source such as copper smelter flue dust. The copper-bearing source is leached in an acidic solution to produce a liquor containing dissolved copper and dissolved contaminants. Simple copper sulfides are precipitated from the liquor by reacting the liquor with chalcopyrite and sulfur dioxide. Copper is recovered from the precipitated sulfides.A novel process is provided for precipitating simple copper sulfides from a solution containing both dissolved copper and dissolved contaminants. The solution is combined with precipitation product such that substantially all ferric iron contained in the solution is reduced to ferrous iron. The ferric-free solution is reacted with chalcopyrite solids and sulfur dioxide to precipitate the dissolved copper as simple copper sulfides.

Abstract: A machine and process for washing paper stock pulp and similar free-filtering materials includes two or more horizontally-disposed wash drums mounted each in a tank. Two endless filter belts are trained to pass under each of said wash drums and through liquid contained in each of the tanks. A mat of pulp is formed between the two endless filter belts and carried under each of the wash drums for washing therein. Wash liquor passes through the pulp mat as it travels under each of the drums thereby washing the pulp mat, and the liquor passes between the drums and the tanks by gravity flow. After the pulp has been washed it is removed from between the two belts.

Abstract: A machine is disclosed for separating solids from feed liquor by gravity settling to form thickened subnatant. The machine includes a liquid-holding tank having an upstanding tubular column mounted therein for receiving the feed liquor. An inlet is formed in the upper portion of the column to admit clarified supernatant into the column for mixing with, and dilution of, the feed liquor. A plurality of subadjacent compartments include reagent introduction and mixing means to receive the feed liquor and to mix a chemical flocculating reagent thereinto. At the bottom of the column is an outlet to discharge the flocculated liquor directly into a pulp blanket stratum established within the tank.