Dust, blast furnace

Gicht gas, n. gas from the top of a blast furnace, blast-furnace gas top gas, exit gas, mittel, n. remedy for gout. rauch, m. top smoke (of a blast furnace). -rose, /. peony, rhododendron, -riibe,/. bryony, -schwamm, m. incrustation near a furnace top (Zinc) tutty. staub, m. blast-furnace dust flue dust. 

At some plants the blast furnace dust is recycled as feedstock to the sinter plant. At plants without sintering operations, blast furnace dust is sometimes mixed with other byproduct residues, briquetted, and recycled back to the blast furnace. In other plants, the dust is landfilled or stockpiled.1 Several techniques are available for removing the zinc and lead. The majority of blast furnace sludge is land disposed as solid waste or stockpiled. Because of the similarity between wastewater sludges generated by sinter plants and blast furnaces, these streams are commingled and cotreated.1 The blast furnace slag is cooled and processed to be reused for various applications such as onsite in-land reclamation and landfill construction. 

Blast-furnace Dust(Gichtstaub in Ger). It was used in some expl compns Ref Kast-Metz(1944), 46 7... 

Sinter plant dusts Blast furnace dusts BOS grits and sludges... 

Apart from lead, blast furnace dusts are often enriched in cadmium, zinc and indium, and can be a source for recovery. Again separation before recycle may be necessary to provide an outlet and prevent the development of heavy circulating loads. 

As part of the quality control programme and to support accreditation according to the EN lEC/ISO 17025 2005 [6], each batch of samples should contain a reference material to validate the results. As there are currently no suitable and traceable certified reference materials available, several in-house reference materials (RMs) were developed. One iron ore and one sinter dust were selected to be developed as RMs for the alpha spectrometry method and the same sinter dust along with a blast furnace dust were selected for the gamma spectrometry method. When analysing stack emission samples, one blank filter was spiked with a known amount of a certified Pb standard solution (R22-02, National Physical Laboratory, UK) and used as a reference for result validation. 

Fig. 2. Cement 2ones in the CaO—AI2O2—Si02 system (5) where B represents basic blast-furnace slag D, cement compositions which dust on cooling E, compositions showing no tendency to set G, aluminous cement and PC, Pordand cement.

Typical applications in the chemical field (Beaver, op. cit.) include detarring of manufactured gas, removal of acid mist and impurities in contact sulfuric acid plants, recovery of phosphoric acid mists, removal of dusts in gases from roasters, sintering machines, calciners, cement and lime Idlns, blast furnaces, carbon-black furnaces, regenerators on fluid-catalyst units, chemical-recoveiy furnaces in soda and sulfate pulp mills, and gypsum kettles. Figure 17-74 shows a vertical-flow steel-plate-type precipitator similar to a type used for catalyst-dust collection in certain fluid-catalyst plants. 

Steel mills Blast furnaces charging, pouring CO, fumes, smoke, particulates (dust) Good maintenance, seal leaks use of higher ratio of pelletized or sintered ore CO burned in waste-heat boilers, stoves, or coke ovens cyclone, scrubber, and baghouse... 

Reverberatory and blast furnaces Pot furnaces Reverberatory furnaces Blast and electric furnaces Basic O2 and electric arc furnaces Dust-handling equipment Sludge incineration Dryer... 

Gases from the sintering process contain SO2, dust, and metal oxide fumes. The blast furnace gases contain similar particulates plus SO2 and CO. Table 30-10 indicates the expected SO2 emissions. 

Reduce dust emissions at furnaces by covering iron runners when tapping the blast furnace and by using nitrogen blankets during tapping. 

In the blast furnace, the reaction of the nitrogen in the blast with coke leads to the formation of poisonous chemicals such as hydrogen cyanide and cyanogens, and each cubic meter of the blast furnace gas contains from 200 to 2000 mg of these compounds. The blast furnace gas is scrubbed with water in the dust collection system the cyanide compounds dissolve in the water, which is then discharged after the compounds have been destroyed. Another poisonous emission in blast furnace operations is hydrogen sulfide. The sulfur present in the coke is converted into calcium sulfide in the slag, the water-quenching of... 

Solid effluents arising from metallurgical operations occur principally in two forms fine particulate solids or dusts, and solid wastes. As an example, blast furnace gas may contain up to 170 kg of dust per ton of pig iron produced. Suitable methods must be devised for processing the solid effluents for two reasons (i) to prevent pollution of the environment and (ii) to recover their valuable content, if any. As far as the latter is concerned, reference may be drawn, as an example, to the recovery of rhenium from the exit gas from molybdenite roasting in a multiple-hearth furnace. 

The rising cost of scrap and waste disposal, the scarcity of onsite landfill space, and potential environmental liabilities make it an economic necessity to recover iron units from dust and sludge. However, recycling to the blast furnace raises the hot metal phosphorus content to undesirable levels. 

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