SU497338A1 - The method of processing iron-containing sludge - Google Patents

Description

(54) METHOD FOR PROCESSING IRON-CONTAINING SLUDGE

The invention relates to a technique for the agglomeration of iron ore materials and can be used for the disposal of high-moisture slimes of gas cleaning of metallurgical furnaces.

A known method for treating iron-containing sludge is that the sludge is supplied through a pipeline from the sludge basin S Condenser. The thickened sludge is loaded into the rotating tumble dryer through a hopper and adheres with a thin layer to the inner surface of the drum. The hot gases from the reducing drum are introduced into the rotating dryer drum in order to evaporate the moisture contained in the sludge and increase the thickness of the sludge layer adhering to the drum wall. Chains attached to the inner wall of this drum shake the layer and accelerate the evaporation of moisture. The drum contains scrapers that rip off a layer of dried sludge. The sludge is sorted with a vibrating screen on the granules and dust, after which the granules are fed into the recovery drum, and the dust is fed back into the hopper by means of a conveyor, the granules are mixed with the reducing agent coming from the hopper and pelletized in a rotating reducing drum heated by a burner.

The disadvantages of this method are the high cost of the process due to the low heat utilization factor; the duration of the drying process and, as a result, the productivity of installations is low; high yield trivia.

The purpose of the invention is to intensify the granulation and increase the strength of the granules. This is achieved by the fact that sludge with a solid content of 300-1100 g / l is blown in the direction of movement of the material into successive zones, with the temperature of each subsequent zone more than the previous one by 20-100 ° C, and the amount of sludge introduced is reduced by 4-10% per nm of gas.

FIG. 1 shows a sludge treatment circuit; in fig. 2 and 3 - the direction of injection of sludge into the fluidized bed chamber.

Pipeline sludge enters the thickener, from where it is supplied by pneumatic forks to a rectangular elongated fluidized bed apparatus, where it is dried in an atmosphere of hot flue gases and simultaneously granulated on the germinal particles of any iron ore material of a fraction of 1-8 mm, the liquefaction rate is 2- 6 times the boiling velocity of a particle of equivalent diameter. The slurry is blown in the direction of movement of the solid, granular material (Fig. 2) and against the movement of the fluidizing agent (Fig. 3) at a speed exceeding the speed of the onset of fluidization 1.2-2.0 times. In the first zone along the material, the temperature is maintained at 105-110 ° С, in the second, narrower zone adjacent to the discharge window, 180-200 ° С, for this purpose, the flow of pulp to the nozzles in the second zone is reduced by 10% for each nm of the heat transfer fluid . The finished granules are discharged from the bed to the screen where the 10-25 mm fakery is screened out, which is sent directly to the open-hearth furnace or to the converter, and the fraction of 10 mm passed through the sieve returns to the fluidized bed furnace, to its opposite part, to as germs.

Experience has shown that the proposed method of supplying sludge to a layer on the one hand reduces the entrainment of the sprayed material from the layer to 1-1.5%, on the other hand, creates good conditions for the movement of the nourishing granules to be unloaded. Increasing the temperature of the fluidized bed in the loading direction reduces the likelihood of raw granules escaping, improves the liquefaction conditions of the largest granules and the unloading end of the up-take.

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parata. In laboratory reactors, circular and rectangular sections are obtained from open-hearth sludge with a solid content of 500-750 g / l and a solid fraction less than 10

micron 25-60% strong dehydrated granules with a size of 5-25 mm. The strength of the granules 5-18 kg / granule. Residual moisture 0.01-0.5%. When the contents in the pulp of the fine fractions less than 30% of schlama granulate poorly, the ash increases to 30-40%.

Subject invention

A method for treating iron-containing sludge, including thickening it, feeding pneumatic nozzles into the fluidized bed chamber from returning and treating with hot flue gases in countercurrent, characterized in that, in order to intensify granulation and increase the strength of granules, the sludge with solid content 300 -1100 g / l is blown in the direction of movement of the material into successive zones, with the temperature of each subsequent zone being greater than the previous one by 20-100 ° C, and the amount of sludge introduced is reduced by 4-10% for each nm gas, respectively but.

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