Effect of Silica and Carbon-reducing Agents on Ni and Ti iImpurities During Silicon Production

The Ni and Ti contents of industrial silicon has a significantly affect the of organic silicon. On the basis of large specific production data, the chemical component of silica and the carbon-reducing agent effect of the Ni and Ti contents of silicon were investigated using statistical techniques. Two furnaces were also studied—an 8.5 MVA furnace and a 12.5 MVA furnace. The effects of TiO2 and NiO impurities on the power consumption of both furnaces were also evaluated using the correlation of the TiO2 and NiO impurities in raw materials with specific power consumption. The consumption of raw materials exhibited a high negative correlation with the TiO2 and NiO impurities in industrial silicon, as determined by linear regression—that is, 82% < |r| < 99%. The influence of Ni on industrial silicon production was also stronger than that of Ti. With an increase in Ni, the power consumption of the 8.5 MWA furnace significantly decreased, whereas that of the 12.5 MWA furnace is increased. Adjusting the content of Ni content can reduce the power consumption of industrial silicon production in the large furnace.

Technological modes of efficient metallization of iron-oxide-containing waste from metallurgical production

During the research, rolled scale and gas cleaning slimes from oxygen-converter workshop No. 1 of JSC “EVRAZ ZSMK” were used as iron-oxide-containing materials. Semi-coke from brown coals of the Berezovskoye deposit of the Kansko-Achinsk basin (temperature of semi-coking is 750 °C), coke fines of PJSC “Coke” and dust from coke dry-quenching plant of JSC “EVRAZ ZSMK” were used as carbon reducing agents. Total iron, FeO and Fe2 O 3 oxides amount to 73.3, 75.5 and 20.9 % in scale, 41.2, 4.7 and 53.7 % in sludge, respectively. Sludge also contains 4.3 % of total carbon and 20.6 % of CaO. Brown-coal semi-coke, coke fines and coke dust contains carbon and volatiles 94.05 and 9.5 %, 97.50 and 2.1 %, 97.47 and 1.6 % on dry ashless weight, respectively. For metallization of furnace charges with composition: scale, slime–semi-coke, coke fines, dust with addition of 10 % water-soluble binding–molasses, strong unroasted briquettes were pressed. Metallization modes of analyzed charge compositions were thermodynamically predicted and technologically determined. Metallization degree and metal iron content at usage of brown-coal semi-coke were found to be 97.5 and 90.2 % for scale, 97.5 and 71.3 % for sludge; of coke fines: 70.7 and 61.9 % for scale, 68.9 and 48.4 % for sludge; of coke dust: 72.1 and 62.6 % for scale, 69.2 and 48.2 % for sludge. The possibility of achievement the metallization degree of 97.0 – 98.0 % was established for briquetted charge from scale – brown-coal semi-coke with 92.0 – 93.0 % of total iron, 89.8 – 90.6 % of metallic iron, 2.8 – 3.2 % of FeO, 0.06 – 0.08 % of S, 0.016 – 0.018 % of P, 1.7 – 1.9 % of C, 1.0 – 1.2 % of CaO and 0.25 – 0.35 % of MgO at 1173 K and duration of 40 min.