Search

The article presents the results of studies on the influence of time, the amount of steel shavings and coke on the electric melting of ferrosilicon manganese dusts to obtain a ferroalloy. The research was carried out by the method of rotational planning of the second order (Box-Hunter plans) and by electric smelting of dust in laboratory ore-thermal arc furnace. Dust from the production of ferromanganese by LLP Taraz Metallurgical Plant, coke and steel shavings were used during the research. It was determined that to achieve αSi≥70%the process must be carried out in the presence of 25% coke and 8.1-9% steel shavings from the mass of dust for 55.8-60 minutes, to achieve αMn in an alloy of 80-85% the process must be carried out in the presence of 25% coke, 5.7-9.0% steel shavings for 41.2-54.4 minutes. When melting the charge containing 75.2% of dust, 18.8% of coke, 6% of steel shavings, within 60 minutes the weight of the ferroalloy was 258 g (38.8% of the weight of the charge or 51.6% of the weight of dust). The degree of extraction of manganese into the alloy was 82.3%, silicon - 66.1%. The resulting ferroalloy belongs to ferrosilicon manganese of the FeMnSi12 grade.

The article contains the research results of obtaining a ferroalloy from a carbon ferrochrome dust containing 30,2% of Сr2O3, 23.4% of SiO2, 32.7% of MgO, 5.0% of FeO, 1.6% of CaO, 4.5%of Al2O3, 2.3%of C, and 0.3 %-others. The studies were carried out by a thermodynamic modeling method using the HSC-5.1 software package (Outokumpy) based on the principle of the Gibbs energy minimum, the Box-Hunter rototable planning technique and electric melting of the dust in an arc furnace. It was found that the interaction of the dust with carbon under equilibrium conditions and in the presence of iron leads to formation of Cr4C(T>10000C),Cr3C2, Cr7C3,Cr (T>11000C), FeSi (T>13000C), SiC (T>14000C), SiOg and Si(T>15000C). In the temperature range of 1745-19000C and in the presence of 18-34% of carbon and 8% of iron of the dust mass, the resulting ferroalloy contained 18.5-25.2% of Si and 46.8-49.4% of Cr (in this case the silicon extraction degree into the alloy was 60.0-64.4%, the chromium one–99.8%). When the electrosmelting the granulated dust together with coke and steel shavings, the chromium extraction degree into the alloy was 98-99%, the silicon one–53-57%; the obtained ferroalloys containing 18.3-21.9% of silicon and 45.6-53.6%of chromium meet the requirements to FeCrSi23-grade ferrosilicochromium.

The article presents the results of studies on the production of ferrosilicon from iron ore (magnetite) concentrate and quartzite. The studies were carried out by thermodynamic simulation using the HSC-5.1 software package, based on the principle of Gibbs minimum energy and electric smelting of the concentrate together with coke and quartzite in a single-electrode arc furnace. Based on the studies, it was found that, under equilibrium conditions, the interaction of magnetite concentrate with silicon oxide (IV) and carbon is accompanied by the formation of FeSi (> 1200 0C), Fe3Si (> 1100 0C), FeSi2 (> 500 0C), Zng (> 800 0C) Pbg (> 1200 0C); the degree of silicon extraction into the ferroalloy depends on the ratio in the SiO2 / Fe3O4 mixture, decreasing from 85.6 to 66.1 (for example, at 17000С) with an increase in the SiO2 / Fe3O4 ratio from 0.42 to 1.25. When melting a mixture containing 70% concentrate, 11% quartzite, 19% coke, a ferroalloy containing 15-18% Si. The resulting ferroalloys are graded from FeSi15 to FeSi45.

The use of concrete in building allows obtaining reliable and long-lasting operation of buildings, but such conditions require concrete with specified characteristics. Today hardly one can produce a concrete structural mix of high quality without any additives. To control actively the structure and properties of a concrete mix and concrete, along with chemical additives, mineral additives are used. The mineral additives are the powders of various mineral nature, obtained from natural or man-made raw materials: ground slag, rocks, etc. The article introduces the method of obtaining a mineral additive for a structural mix, in particularly for concrete. Qualitative characteristics of the additive obtained were studied as follows: the index of the degree of grinding to be equal to 1, standard consistency (normal density) – (180±5) mm with a mass ratio of «additive: water») – 100: 70, setting time – beginning 20 min, water absorption 0.27%, water content 9.65%, the proportion of insoluble residue in hydrochloric acid solution is 1.70%. Implementation of the additive in the concrete composition has shown that the quality of the product does not fall, and the actual strength is 250.7 kgf/cm2, which is slightly higher than the strength of the concrete sample without an additive. It was determined that the quality of concrete products with a mineral additive corresponds to GOST as follows: density 1775 kg/m3; mass humidity 0.3%; volume humidity 0.5%. The introduction of a structural mix will significantly improve the properties of a concrete structural mix and will also reduce the fuel resources consumption for production of the concrete structural mix, products and constructions of its basis.

The article covers the results of researches on thermodynamic modeling of ferroalloy and calcium carbide obtaining from basalts of deposit Dubersay. The software package HSC-5.1, based on the principle of Gibbs energy minimum uses in the study. The influence of temperature (from 500 to 2500 °C) and the amount of carbon (from 40 to 60 % of the basalt mass) in the basalt–Fe–nC system was determined. It has been established that iron silicides are formed at T ≥ 1300 °C, Si at T ≥ 1400 °C, CaSi and Al at T> 1700 °C and CaC2 – at T ≥ 1800 °C. An increase of the amount of carbon from 40 to 60 % allows rise the degree of distribution of Si in the alloy up to 94 %, calcium in CaCl2 – up to 62.3 %, aluminum – to alloy up to 93.9 %. An increase of the amount of carbon allows increase the silicon concentration in alloy up to 55 % (at 1800 °C), aluminum – up to 17 % (at 2000 °C) and calcium carbide capacity – up to 350 dm3/kg. The method of rototable planning of the second order allows find equations of regressions of the influence of temperature and amount of carbon on the equilibrium distribution of silicon, aluminum, and calcium between the ferroalloy and calcium carbide. On the basis of this equations were determined, that within the temperature range 1956-1996 °C from the Dubersay deposit basalt, the ferroalloy with a content of ΣSi and Al 60.8-65.4 % (including 12- 15 % Si) and calcium carbide with a capacity of 250-300 dm3/kg are formed. Wherein degree of recovery into the alloy for silicon is 91-91.4 % and for aluminum is 63-75.1 % and calcium – into CaC2 is 60-60.7 %. The resulting ferroalloy by the content of silicon and aluminum can be attributed to the complex ferroalloy – ferrosilicoaluminium, calcium carbide – to the industrial product of grade from 3 and up to the highest.