RU2129093C1 - Method of preparing calcium carbide - Google Patents

Abstract

FIELD: chemical industry, more particularly production of acetylene and melting of steel. SUBSTANCE: coke-ash residue resulting from thermal processing of oxidized brown coals comprises (wt %): CaO 47.5; C, 35.4; Fe₂O₃, 6.6; SiO₂, 5.0; Mg, 3.3; Al₂O₃, 1.6; S, 0.1 and the balance, 0.5, is mixed with 12.9-28.3% calcium carbonate based on mixture weight. The whole is subjected to high-temperature melting at 2000-2100 C, then cooled to separate CaC₂ and ferrosilicium. Method does not require expensive products. CaC₂ content is 275-285 l/kg and ferrosilicium content is 0.1-0.2 wt %. EFFECT: more efficient preparation method. 2 cl, 3 ex

Description

 The invention relates to chemical technology, in particular to the production of calcium carbide.

 A known method of producing calcium carbide / Kuznetsov L.A. Calcium carbide production. M., 1954, p. 32, 33 /, including the melting of a mixture consisting of lime and carbon, while up to 30% of thermally processed production waste - sludge of "dry" acetylene generators, which is a source of calcium oxide, silicon and iron, is added to fresh lime, which reduces the cost of calcium carbide and improves the environmental situation, as part of the harmful waste going to landfills is recycled.

 The disadvantage of this method is the use of expensive products / metallurgical coke, anthracite, calcined lime / as part of the main charge / 70% /, as well as the cost of anthracite, electricity, steam during thermal processing of sludge.

 A known method of producing calcium carbide / USSR copyright certificate N 664476, C 01 B 31/32, class. C 01 B, 1976 /, by electrothermal smelting of lime and a carbon reducing agent with a periodic supply of corrective material, which is used as the coke oven residue for thermal processing of carbonate-containing oil shale in an amount up to 10% of the charge weight, while the coke oven residue is a source of calcium oxides / 24 0 - 31.0% /, silicon / 14 - 20% /, iron / 2.3 - 3.5% / and carbonaceous reducing agent / 16 - 18% /.

 This reduces the cost of calcium carbide, increases the content of the main substance in the product and allows the use of production waste / coke residue /.

 The disadvantage of this method is the consumption of expensive products / electrode graphite, calcined lime / in the main part of the charge / 90 - 99% /.

 A known method of producing calcium carbide / USSR copyright certificate N 1168508, class. C 01 B 31/32, 1983 /, including the melting of a mixture consisting of lime and carbon, cooling the melt and separation of the reaction products - calcium carbide and ferrosilicon, while the mixture is melted in the presence of limestone or shale ash coke in an amount of 12.9 - 28.3% of the mass of the charge. To adjust the ratio of silicon to iron in the charge, the missing amount of iron is introduced in the form of chips, providing a weight ratio of silicon to iron of 1: 2, while obtaining calcium carbide with a quality mark / acetylene displacement - up to 300 l / kg carbide /.

 The disadvantage of this method is the use of expensive products in the main composition of the mixture / lime and carbon material /.

 The basis of the invention is the task of producing calcium carbide using waste from the mining industry in the main composition of the charge, which reduces the cost of calcium carbide and improves the environmental situation through the processing of dumps.

 The problem is solved in that in the method of producing calcium carbide, which includes melting the mixture from a material containing oxides of calcium, silicon, iron and carbon, cooling the melt and separation of the reaction products - calcium carbide and ferrosilicon, while the mixture is melted in the presence of limestone in an amount 12.9 - 28.3% by weight of the charge, according to the invention, coal wastes are used as the specified material, in particular the coke-ash residue from the thermal processing of oxidized brown coals of the composition, wt.%: Calcium oxide 47.5; carbon 35.4; iron oxide 6.6; silica 5.0; magnesium oxide 3.3; alumina 1.6; sulfur 0.1; phosphorus - traces, the rest is 0.5.

 The use of coal wastes - the coke-ash residue of the thermal processing of oxidized brown coals with the average composition given above, allows to reduce the cost of calcium carbide, since these wastes are transported to dumps, occupying arable land. Currently, under heaps only in the Kansk-Achinsk coal basin there are 6,000 hectares of arable land, giving up to this a grain yield of 25 centners per hectare / Gavrilin K.V., A.Yu. Ozersky. Kansk-Achinsk coal basin. M .: Nedra, 1996, p. 93, 152, 154 /, while the raw material base only in the Berezovsky section of Cabassa is 1 billion tons of off-balance coal with a high content of calcium oxide in the coke ash residue / up to 50% /.

 Obtaining calcium carbide from coal waste reduces its cost by 30%, since the raw material component of the cost is up to 1/3 of the cost of calcium carbide (Production of calcium carbide in the USSR and abroad. Series "Production of phosphorus and calcium carbide." -M .: NIITEKHIM , 1973).

 Moreover, the thermal processing of waste does not require expensive products / anthracite, steam, electricity /, since the coke-ash residue of the thermal processing of oxidized brown coal is the product of incomplete combustion using the thermal energy of this process.

 Example 1

The mixture is prepared from the coke-ash residue of the thermal processing of oxidized brown coal composition, wt.%: Calcium oxide 47.5; carbon 35.4; iron oxide 6.6; silica 5.0; magnesium oxide 3.3; alumina 1.6; sulfur 0.1; the rest is 0.5; phosphorus - traces. The weight ratio of silicon to iron in the charge is 1: 2. The average particle size of the charge of 2 to 3 mm The resulting mixture is subjected to high-temperature melting in a graphite crucible at 2000 - 2100 ^o C for 15 minutes, then the melt is cooled to room temperature. The resulting melt consists of 96.5 parts by weight of calcium carbide / containing 75% CaC ₂ / and 3.5 wt.h. ferrosilicon in the form of independent immiscible phases. The displacement of calcium carbide is 275 l / kg. The content of ferrosilicon in calcium carbide is 3.4%.

 Example 2

The mixture is prepared from the coke-ash residue of the thermal processing of oxidized brown coal (of the same composition as in example 1) and calcium carbonate is introduced in the form of limestone / containing 96 - 98% CaCO ₃ / in the amount of 12.9% of the mass of the mixture. The particle size of the mixed components is 2 to 3 mm. The resulting mixture is subjected to high-temperature melting at 2000 - 2100 ^o C for 15 minutes, then the melt is cooled to room temperature and the products of melting are separated. After phase separation, 93.3 parts by weight are formed. calcium carbide and 6.7 wt. including ferrosilicon. The displacement of the carbide obtained is 284 l / kg, with a ferrosilicon content of 0.2%.

 Example 3

A mixture is prepared from the coke-ash residue of the thermal processing of oxidized brown coals (of the same composition as in Example 1) and calcium carbonate is introduced in the form of limestone / containing CaCO ₃ 96 - 98% / in the amount of 28.3% of the mass of the mixture. The particle size of the mixed components is 2 to 3 mm. The resulting mixture is subjected to high-temperature melting at 2000 - 2100 ^o C for 15 minutes, then the melt is cooled to room temperature and the products of melting are separated. After phase separation, 93.2 parts by weight are formed. calcium carbide and 6.8 wt. including ferrosilicon. The displacement of the carbide obtained is 285 l / kg, with a ferrosilicon content of 0.1%.

 The application of the proposed method allows to obtain high quality carbide from coal waste going to the dump. Ferrosilicon is also used for the deoxidation of steel in the steel industry. The presence of insignificant amounts of sulfur and traces of phosphorus allows the use of industrial furnaces to produce carbide in this way, and an unlimited raw material base (17% of the total brown coal mined by the open method) suggests the possibility of large-tonnage production, which eliminates the growth of dumps, since coal waste can be processed into valuable a product whose cost is currently estimated at $ 500 per tonne and is not enough.

Claims (2)

 1. The method of producing calcium carbide, including melting the mixture from a material containing oxides of calcium, silicon, iron and carbon, cooling the melt and separation of the reaction products - calcium carbide and ferrosilicon, the melting is carried out in the presence of calcium carbonate in the form of limestone in an amount of 12, 9 - 28.3% of the mass of the charge, characterized in that as the specified material using a coke-ash residue from the thermal processing of oxidized brown coal. 2. The method according to claim 1, characterized in that the coke oven residue of the thermal processing of oxidized brown coal has the following composition, wt.%:
Calcium Oxide - 47.5
Carbon - 35.4
Iron Oxide - 6.6
Silicon Oxide - 5.0
Magnesium Oxide - 3.3
Alumina - 1.6
Sulfur - 0.1
The rest is 0.5