TH36728A - Method for treating effluent from gas leaching systems of iron ore reduction plants - Google Patents

Abstract

DC60 (09/03/42) describes a procedure for dealing with wash water from the gas washing system of an iron ore reduction plant. The wash water is in direct contact with the gas in two gas washers (1 to 4) located adjacent to the gas side, forming a two-stage washing process that is combined, one behind and the other removed from the gas washers after solid material separation. It is then returned through the process and cooled and returned to the gas washers. Thus, the wash water is removed separately from the two washing stages, and only the wash water from the first stage is desolidated significantly from solids in a concentrater (6) and then passed on to the hot water tank (8). The wash water from the second stage is passed directly into the return tank (10), where it is depressurized and enriched with carbon dioxide gas, which is then passed into the hot water tank to further enrich the wash water within it with carbon dioxide. The wash water from the hot water tank is cooled in a heat exchanger (19) and then returned with the wash water from the first stage. The hot water return tank (10) is passed to the gas washing machine of the two-stage washing stage, in order to enrich the wash water in the hot water tank with carbon dioxide. Alternatively, a portion of the washed gas is enriched with carbon dioxide, or a portion of the water enriched with carbon dioxide in the return water tank can be passed into the hot water tank (Figure). A practice described is the procedure for washing water from the gas washing system of an iron ore oxygen reduction plant, in which the wash water is in direct contact with the gas in two gas washing machines (1 to 4) located adjacent to the gas side, forming two combined washing stages, one behind the other. The wash water is removed from the gas washing machine after solid material separation, is returned through processing and cooling, and returned to the gas washing machine. Thus, the wash water is removed separately from the two washing stages, and only the wash water from the first washing stage is desolidated significantly from solids in the concentrate (6) and then passed on into the hot water tank (8). The wash water from the second washing stage is passed directly into the return water tank (10), where it is released with compressed gas enriched with carbon dioxide. This water is passed into the hot water tank to enrich the wash water inside with carbon dioxide. The wash water from the hot water tank is cooled in the heat exchanger (19) and then returned with the wash water from the return hot water tank (10) to the two-stage washing gaseous unit, in order to enrich the wash water in the hot water tank with carbon dioxide. Alternatively, a portion of the carbon dioxide-enriched wash gas or a portion of the carbon dioxide-enriched water in the return water tank can be passed into the hot water tank.

Claims (12)

1. Treatment Method of Wastewater from the Gas Washing System of an Iron Ore Reduction Plant: The wash water is in direct contact with the gas in two gas washers (1 to 4) in a two-stage washing configuration, one behind the other, adjacent to the gas side. The wash water is removed from the gas washers (1 to 4) and, after solid separation and cooling, is returned to the gas washers (1 to 4). Specifically, the wash water is removed separately from the two-stage washing, and only the wash water from the first stage is primarily desolidified in the concentrate (6) and passed into the hot water tank (8). There, the wash water from the second stage is passed directly into the return water tank (10), where it is depressurized and enriched with carbon dioxide. This gas is then passed into the water tank (8) to further decompose the carbon dioxide. The flush water is abundant there, and in the section where the flush water from the hot water tank (8) is cooled in the heat exchanger (19) and further together with the flush water from the return flush tank (10) is sent back to the gas washing machines (1 to 4) of the two-stage flushing process. 2. The method under claim 1 is characterized by an iron ore oxygen reduction plant consisting of a chimney furnace and a pulverizing gasifier, and by the presence of gas washers at each washing stage for the top gas (1,4) of the chimney reduction furnace and the gas from the gasifier (2, 3) of the pulverizing gasifier; multiple gas washers (1, 2, 3, 4) of each washing stage for wash water flow are combined in parallel with each other. 3. The method under claim 1 or 2 is characterized in which the rinse water from the concentrate (6) is delivered to the hot water tank (8) in a controlled manner in which the water level in the concentrate's overflow pipe (6) is adjusted to a high level. 4. The method under any of the claims in Claims 1 through 3 is characterized by the washing water located in the hot water tank (8) being completely purified with carbon dioxide by the feeding of the purging gas which exits the second washing stage. 5. The method under any of the claims in Claims 1 through 4 is characterized by a portion of the rinse water in the return tank (10) being passed into the hot water tank (8) in order to enrich the rinse water inside with carbon dioxide. 6. The method under any of the claims in Claims 1 through 5 is characterized by a portion of the rinse water contained in the hot water tank (8) being passed without being cooled in the rapid cooling zone (24, 25) of the gas washing machine (1, 2) of the first washing stage. 7. The method under any of the claims in Claims 1 through 6 is characterized by a portion of the wash water from the gas washing cone (1) for the tower top gas in the first washing stage being returned to the rapid cooling zone (24) of this gas washing machine (1). 8. The method under any of the claims in Claims 1 through 7 is characterized in which the washing water of the washing gas (27) for the gaseous equipment after the first washing stage is introduced into the rapid cooling zone (25) of the washing gas (2) for the gaseous equipment in the first washing stage. 9. One of the methods under Reputations 1 through 8 is characterized by the wash water from the second washing stage being supplemented with steam carried by gases exiting the first washing stage and condensed in the second washing stage. 10. The method under any of the claims in Claims 1 through 9 is characterized by the flush water in the return water tank (10) being supplemented by the addition of fresh water. 11. The method under any of the claims in Claims 1 through 10 is characterized by the release pressure gases which exit the wash water in the hot water tank (8) being passed to the wash gases which exit the second washing stage or to the flare-burning system. 12. The method under any of the claims in Claims 1 through 11 is characterized by the fact that the wash water from the hot water tank (8) is cooled by water, not directly/water or water/air heat exchange. (Claims 12, 2 pages, 1 figure)