RU2322511C1 - Sooty iron production method - Google Patents

Abstract

FIELD: metallurgy of iron.

SUBSTANCE: method comprises steps of mixing iron-containing components with carbon-containing reagents being technical carbon produced at process of thermal-oxidation decomposition or thermal decomposition of hydrocarbons; providing reaction of iron containing components heated and soaked in furnace with carbon-containing reagent for depositing finely dispersed carbon on surface and also in macro- and micro-pores of iron-containing component volume; creating in furnace protection atmosphere due to feeding nitrogen into furnace; cooling produced sooty iron in furnace. Invention allows shorten time period of production of sooty iron and increase by 2.9 - 4.5 times efficiency of said process.

EFFECT: improved efficiency of method, shortened duration of process for producing sooty iron.

1 tbl

Description

This invention relates to the metallurgy of iron, specifically to methods for producing soot iron, and can be used for the production of soot iron.

Known methods for producing soot iron by thermocatalytic decomposition of hydrocarbons on an iron sponge or in the process of their interaction with iron ore materials [1] with the deposition of finely dispersed carbon not only on the surface, but also in macro- and micropores in the bulk of the piece [2].

For the production of black carbon, not only gaseous, but also liquid hydrocarbons can be used [3], and iron powders, sponge, oxides, or part of the obtained product [4] can be used as the iron-containing base.

Among the disadvantages of these methods of producing soot iron should be attributed to its low productivity due to the long duration of the process.

Thus, when carbon black was produced with 40% carbon in it in a tube reactor with a diameter of 40 mm at 900 ° C, the process duration was 5 hours, and in the reactor ⌀ 150 mm, the product residence time in the reaction zone increased to 10 hours [2].

The productivity of a pilot continuous kiln, which includes a block of four carbofrax muffles, was 2.5–2.7 tons / day or 104–112 kg / hour according to design data [1].

The objective of the invention is to increase the productivity of the method for producing carbon black.

The problem is solved in that in the method for producing soot iron, including the deposition of finely dispersed carbon on the surface and in the pores, carbon black is used as carbon-containing reagent, carbon black is produced in a furnace with a protective atmosphere, which is created by feeding into the nitrogen oven.

Carbon black is a highly dispersed product of thermo-oxidative or thermal decomposition of hydrocarbons contained in natural and industrial gases, petroleum and coal oils. It mainly consists of 90-95% carbon and contains small amounts of impurities: hydrogen up to 0.5%, oxygen up to 1.3%, sulfur up to 1.0%, mineral impurities (ash) up to 0.5%. The carbon black particle size (average diameter) is 10-50 nm, the specific surface depending on the type of carbon black can be 10-1000 m ² / g.

The invention is illustrated by the following. Testing of the production of carbon black by the proposed method. As a carbon-containing reagent, we took carbon black (furnace soot) of grade P803 (GOST 7885-86), containing 0.04% ash and 0.3% sulfur, specific surface area - 15 m ² / g.

To obtain soot iron, the following types of iron-containing raw materials were used - reduced iron powder, air-sprayed raw powder, mill scale. These iron-containing components were mixed for 30 minutes in a two-cone mixer to obtain three mixtures, which contained 25% carbon black and 75% of the iron component of the corresponding type.

The resulting mixtures were loaded into quartz boats with a capacity of 250 g of the mixture and placed in a laboratory tube furnace SUOL - 0.4.4 / 12 - MG with an outer diameter of 40 mm, after which the furnace was turned on (heating rate - 11.7 ° / min) with simultaneous supply to the furnace of technical nitrogen of the 1st grade (GOST 9293-74), in which the content of N ₂ = 99.6%. The volume fraction of impurities - oxygen and water vapor is: not more than 0.4 and 0.009%, respectively. Impurities in nitrogen, as shown by the results of testing, - oxygen and water vapor do not affect the carbon content in soot iron. Upon reaching a temperature in the furnace of 1050 ° C, exposure was carried out at this temperature for 90 minutes, then the furnace was turned off and the obtained soot iron was cooled in a stream of nitrogen to room temperature. Next, carbon black was crushed, crushed and sieved into fractions.

Crushing of soot iron cake was carried out on a jaw crusher, and grinding was carried out on a rod mill for 45 minutes at a ratio of the weight of the loaded material to the weight of the rods 1:10. The 0.2 mm fraction obtained after crushing on a jaw crusher and grinding in a core mill was combined, averaged, and considered to be a finished product. The chemical composition was determined on an averaged sample and the microstructure was studied. The table provides data on the chemical composition of soot iron.

Black carbon powder labeling Iron-containing raw materials used to produce carbon black The chemical composition of soot iron,% FROM S O ₂ SJ-I (prototype) Mill scale 24.2 0.018 1.84 SJ-2 (the proposed method) Reconstituted Iron Powder 24.1 0,026 0.46 SJ-3 (the proposed method) Air Spray Iron Powder 22.4 0,022 0.45 SJ-4 (the proposed method) Mill scale 21.0 0.024 0.59

As can be seen from the table, carbon black obtained by the proposed method has a lower oxygen content in its composition of 0.46-0.59% compared with 1.84% for the prototype.

The microstructure of the carbon black powder consists of perlite and cementite with carbon black particles distributed in the structure, and it is practically impossible to separate this carbon from the iron base by mechanical or magnetic methods, which is similar to the black carbon of the prototype.

As shown by the testing of the proposed method, to obtain carbon black with a carbon content of 21-24.1%, the residence time of the product in the reaction zone is 90 minutes. When the content of carbon black in the mixture with iron-containing raw materials was increased to 45%, carbon black was obtained with 38.9% carbon in the same 90 minutes in the reaction zone, while it took 5 to obtain carbon black with a prototype of carbon black hours, i.e. the duration of the process according to the proposed method is reduced by 3.3 times.

For the production of carbon black by the proposed method, you can use a conveyor furnace for annealing iron powders, in which nitrogen is used as a process gas [5]. The productivity of the conveyor furnace is 300-500 kg / h compared with 104-112 kg / h of a special furnace for the production of soot iron according to the prototype, i.e. 2.9-4.5 times higher.

Thus, the proposed method for producing soot iron can increase the productivity of the method by 2.9-4.5 times, but also simplify the process by carrying out the process in a conveyor furnace for annealing iron powders using nitrogen as a process gas, which eliminates the need for the design and manufacture of a special furnace for the production of black carbon.

Information sources

1. Sooty iron. Rukin V.V., Ostrik P.N., Dzeneladze J.I. M .: "Metallurgy". 1986, p. 4, 89.

2. B.A. Borok, V.V. Rukin, V.V. Keltsev, P.N. Ostrik, N.F. Kolesnik. Powder Metallurgy, 1973, No. 11, p. 11.

3. Copyright certificate No. 256789 (V. G. Voskoboinikov, B. A. Borok, V. G. Teplenko, Z. V. Solovyova, V. V. Rukin, V. P. Doronichev, V. V. Keltsev and X .D. Zybin). Bull. Inventions No. 10, 1980.

4. Copyright certificate No. 196910 (V. G. Voskoboinikov, B. A. Borok, V. G. Teplenko, Z. V. Solovyova, H. D. Zybin and V. V. Keltsev). Bull. Inventions No. 39, 1979.

5. O.D. Bunakov. Metal Technology, 2006, No. 5, p. 28.

Claims (1)

A method of producing soot iron, including the deposition of finely dispersed carbon on the surface, as well as in macro- and micropores in the volume of iron-containing components during the reaction of iron-containing components with a carbon-containing reagent in a furnace, characterized in that the iron-containing components are mixed with a carbon-containing reagent, which uses carbon black obtained in the process of thermo-oxidative or thermal decomposition of hydrocarbons, the deposition of finely dispersed carbon is carried out by heating by holding and holding the mixture in a furnace with a protective atmosphere, which is created by feeding nitrogen into the furnace, after which the soot iron obtained in the furnace is cooled.