Shungite in metallurgy
Shungite rocks are a very promising raw material for metallurgy. This is due to several factors. The ratio of the main components of the rock – carbon (30%) and silicon (55%) – is close to the stereochiometric ratio necessary for the implementation of reduction processes in the Si – C—O system and the synthesis of metallic silicon and silicon carbide.
Shungite carbon has an amorphous structure, is resistant to graphite and retains a high reactivity over the entire temperature range of real metallurgical processes. The specific structure of shungite rocks has an exceptionally beneficial effect on the kinetics and energy of reduction reactions in the Si – C—O system. The structure of the Zazhoginsky shungite is a uniform distribution of silicate minerals with a particle size of less than 10 microns in a carbon matrix.
Thus, a close and developed (up to 20 m2/g) contact between silicates and carbon is created. This circumstance, in turn, increases the role of solid-phase reactions in the reduction process and creates a number of technological advantages when using shungites to replace metallurgical coke and silica raw materials in the process of obtaining silicon carbide, smelting siliceous cast iron and ferroalloys.
Shungite rock has high mechanical strength (800-1200 kg/cm2), low abrasion resistance. The high density of shungite rock (2.2–2.4 t/m3) creates prerequisites for a more economical use of the furnace unit volume when it replaces the traditional carbon-silica charge. Thermal and petrographic studies have shown that at 1250 ° C, reduction processes begin to take place in shungite rocks, and in the range of 1500-1700 ° C, silicon carbide is intensively synthesized. At 1800 °C, the weight loss is 57%, and the proportion of SiC in the composition of products exceeds 80%.
These results determined the direction of industrial and semi-industrial experiments with shungite rocks: 1) in blast furnace melting to increase the silicon content in cast iron by loading shungite into the blast furnace instead of ferrosilicon;
2) in gutters and fly masses as a strengthening additive instead of metallurgical coke and silicon carbide; 3) for smelting blast furnace ferroalloys;
4) for smelting ferroalloys (ferrosilicon, silicomanganese, silicocalcium, ferrosilicochrome, etc.) in electric furnaces; 5) for the production of SiC for the purpose of subsequent processing of the latter into refractory and chemically resistant structural materials, as well as for use as a filler in refractory masses and as a reducing agent.
The industrial use of shungite in the smelting of cast iron is carried out at Tulachermet, JSC Kosogorsky Metallurgical Plant. It was found that the coefficient of coke replacement with shungite is on average 1 t/t. The proportion of silicon shungite passing into cast iron is 88.5%. With an increase in the silicon content in cast iron, the coke replacement coefficient increases. When smelting cast iron, the optimal consumption of shungite is 20 kg per 1 ton of cast iron, when smelting cast iron, the consumption of shungite was up to 100 kg per 1 ton of cast iron. The coefficient of coke replacement with shungite during blast furnace smelting of ferroalloys is estimated at an average of 1 t/t.
During the smelting of silicomanganese in electric furnaces, the consumption of shungite was 200 kg per 1 ton of alloy. The use of shungite in pyrometallurgical processes for the production of nickel, cobalt, copper, the shungite of the Zazhoginsky deposit is a rock unique in composition, structure and properties. It consists of 30% shungite carbon, which does not contain volatiles, and is not inferior to coke in reactivity. The ash (mineral) part (70%) consists of silicates, in which SiO2 is 85%.
In pyrometallurgy, the following properties of shungite are positively evaluated: 1) high electrical resistance, which allows melting with increased carbon; 2) high density (2.3–2.4 g /cm3), due to which shungite sinks deeper into the melt and is less oxidized by oxygen from furnace gases; 3) shungite does not contain a noticeable amount of impurities that degrade the quality of commercial nickel (zinc, lead, tellurium and etc.). In 1980-1981. laboratory and enlarged laboratory technological experiments on the use of shungites as a reducing agent and flux were carried out in Gipronickel, including on slag from the Pechenganikel combine with the addition of 20% matte. Large-scale laboratory smelting was carried out on two types of furnaces – furnaces with indirect arc and furnaces with slag conductivity.
Conclusions from the experiments:
The use of shungite rock as a complex flux reducing agent instead of coke and quartzite during depletion of converter slags makes it possible to increase the extraction of cobalt into enriched matte by 23.7%, nickel by 5.2%, copper by 8% abs. 2. The distribution coefficient improves for cobalt by 4.8 times, for nickel by 3.3 times, copper by 1.5 times. 3. Losses per 1000 kg of iron are reduced: cobalt by 3.45 times nickel by 3.25 times copper by 2 times.
Shungite carbon has an amorphous structure, is resistant to graphite and retains a high reactivity over the entire temperature range of real metallurgical processes. The specific structure of shungite rocks has an exceptionally beneficial effect on the kinetics and energy of reduction reactions in the Si – C—O system. The structure of the Zazhoginsky shungite is a uniform distribution of silicate minerals with a particle size of less than 10 microns in a carbon matrix.
Thus, a close and developed (up to 20 m2/g) contact between silicates and carbon is created. This circumstance, in turn, increases the role of solid-phase reactions in the reduction process and creates a number of technological advantages when using shungites to replace metallurgical coke and silica raw materials in the process of obtaining silicon carbide, smelting siliceous cast iron and ferroalloys.
Shungite rock has high mechanical strength (800-1200 kg/cm2), low abrasion resistance. The high density of shungite rock (2.2–2.4 t/m3) creates prerequisites for a more economical use of the furnace unit volume when it replaces the traditional carbon-silica charge. Thermal and petrographic studies have shown that at 1250 ° C, reduction processes begin to take place in shungite rocks, and in the range of 1500-1700 ° C, silicon carbide is intensively synthesized. At 1800 °C, the weight loss is 57%, and the proportion of SiC in the composition of products exceeds 80%.
These results determined the direction of industrial and semi-industrial experiments with shungite rocks: 1) in blast furnace melting to increase the silicon content in cast iron by loading shungite into the blast furnace instead of ferrosilicon;
2) in gutters and fly masses as a strengthening additive instead of metallurgical coke and silicon carbide; 3) for smelting blast furnace ferroalloys;
4) for smelting ferroalloys (ferrosilicon, silicomanganese, silicocalcium, ferrosilicochrome, etc.) in electric furnaces; 5) for the production of SiC for the purpose of subsequent processing of the latter into refractory and chemically resistant structural materials, as well as for use as a filler in refractory masses and as a reducing agent.
The industrial use of shungite in the smelting of cast iron is carried out at Tulachermet, JSC Kosogorsky Metallurgical Plant. It was found that the coefficient of coke replacement with shungite is on average 1 t/t. The proportion of silicon shungite passing into cast iron is 88.5%. With an increase in the silicon content in cast iron, the coke replacement coefficient increases. When smelting cast iron, the optimal consumption of shungite is 20 kg per 1 ton of cast iron, when smelting cast iron, the consumption of shungite was up to 100 kg per 1 ton of cast iron. The coefficient of coke replacement with shungite during blast furnace smelting of ferroalloys is estimated at an average of 1 t/t.
During the smelting of silicomanganese in electric furnaces, the consumption of shungite was 200 kg per 1 ton of alloy. The use of shungite in pyrometallurgical processes for the production of nickel, cobalt, copper, the shungite of the Zazhoginsky deposit is a rock unique in composition, structure and properties. It consists of 30% shungite carbon, which does not contain volatiles, and is not inferior to coke in reactivity. The ash (mineral) part (70%) consists of silicates, in which SiO2 is 85%.
In pyrometallurgy, the following properties of shungite are positively evaluated: 1) high electrical resistance, which allows melting with increased carbon; 2) high density (2.3–2.4 g /cm3), due to which shungite sinks deeper into the melt and is less oxidized by oxygen from furnace gases; 3) shungite does not contain a noticeable amount of impurities that degrade the quality of commercial nickel (zinc, lead, tellurium and etc.). In 1980-1981. laboratory and enlarged laboratory technological experiments on the use of shungites as a reducing agent and flux were carried out in Gipronickel, including on slag from the Pechenganikel combine with the addition of 20% matte. Large-scale laboratory smelting was carried out on two types of furnaces – furnaces with indirect arc and furnaces with slag conductivity.
Conclusions from the experiments:
The use of shungite rock as a complex flux reducing agent instead of coke and quartzite during depletion of converter slags makes it possible to increase the extraction of cobalt into enriched matte by 23.7%, nickel by 5.2%, copper by 8% abs. 2. The distribution coefficient improves for cobalt by 4.8 times, for nickel by 3.3 times, copper by 1.5 times. 3. Losses per 1000 kg of iron are reduced: cobalt by 3.45 times nickel by 3.25 times copper by 2 times.
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The site was created by IP Senyukov Artem Nikolaevich (INN - 100603631961)
with the support of the My Business center of the Republic of Karelia.
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