Liquid purification or separation – Processes – Separating
Patent
1990-02-13
1991-03-05
Fisher, Richard V.
Liquid purification or separation
Processes
Separating
210386, 210400, 210526, 210805, C02F 1112, B01D 2124, B01D 33052
Patent
active
049975790
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a procedure for the draining of sludge, especially of Flocculent flotation sludge, whereby the water-mud cloudiness is introduced into a settling tank with a water overflow.
2. Prior Art
With the use of increasingly productive output machinery in the coal mining industry, the fine and finest granular portion of the raw coal has inevitably increased.
The separation of fine-granular portion of the raw coal is widely effected by flotation. The sludge recovered during the flotation process must be drained to the point that it can be eliminated, i.e, deposited.
The mechanical drainage of the recovered sludge, for example, by swivel filter presses, is connected with high investments and high operating costs.
Therefore, in most cases, the flotation sludge is first thickened by chemical flocculation compounds and the resulting pre-drained sludge is deposited in sink ponds. These ponds provide ample time for the sludge to settle, so that mud-free water flows from the overflow. When the usable space of the sinking pond is filled with mud, a new sinking pond must be constructed.
An essential disadvantage of this procedure is the large area required for the construction of sinking ponds, whereby suitable areas are not always available as needed.
It is, therefore, the task of the presented invention to provide for a simple and economic process for the draining of sludge, especially flocculent flotation sludge, so that it can subsequently be deposited in high containers.
SUMMARY OF THE INVENTION
Based on the invention stated at the beginning, this task is solved in that the sediment sludge constantly removed from the settling tank is transferred onto a slanted conveyer, that horizontal grooves for the canalization of the water extracted from the sludge are molded into the sludge layer on the slanted conveyor, and that the water flowing back in the horizontal grooves is accepted and removed by water drainage systems arranged over the slanted conveyor and tilted towards the front side of the horizontal grooves.
This results, appropriately, in the syphoning and draining of the back-flowing water over several rows of water channels arranged successively in conveyor direction.
The horizontal grooves molded into the sludge layer on the slanted conveyor effect, on the one hand, short draining passages diagonally to the conveyor direction, and on the other hand, they drain the released back-flowing water. This water can be removed and, if necessary, immediately returned to the settling tank on several successive levels in conveyor direction. Because of the short flow passages of the water extracted from the sludge a relief on the sludge layer on the following conveyor area and a good drainage of the sludge is achieved.
The invented procedure effects, in an especially simple manner, the reduction of the water contents in refined sludge to the point that, if necessary, by introducing a dry medium as, for example, flue ash, it can also be stored in high depositories.
To improve the drainage, the sludge can be shifted between the groove rows, whereby the newly formed horizontal grooves may present a distance different from the other conveyor sections. It could also be practical to plan, in addition, a pressure drainage by means of several pressure rollers.
The forming of the horizontal grooves can immediately be effected by pressing into the water lines on the sludge layer or, on the other hand, by another suitable device. Appropriately, however, the horizontal grooves are pressed in by profile rollers distributed across the width of the slanted conveyor, for example, section rollers of a roller diagonally provided for over the slanted conveyor. If the section rollers are not operated by the sludge layer itself, but, for example, by conveyor rollers constructed on the side of the conveyor, a supportive effect for the pressing in is achieved by means of the forced relative speed between the sludge layer and the roller surface. To achieve a better draina
REFERENCES:
patent: 3630358 (1971-12-01), Ralph
patent: 3891549 (1975-06-01), Carmel et al.
patent: 4192747 (1980-03-01), Wykoff
patent: 4858769 (1989-08-01), DeVries
Gros Norbert
Padberg Werner
Stahl Werner
Creighton Wray James
Fisher Richard V.
McCarthy Neil M.
Saarbergwerke Aktiengesellschaft
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