Blast-furnace Shop Research Articles

Creation of software for blast-furnace workstations on the basis of up-to-date information technology

The design of software for blast-furnace workstations in the sinter and blast-furnace shop at OAO Magnitogorskii Metallurgicheskii Kombinat is considered. The system significantly reduces the time for preparation of accounting records and improves management decisions by the engineering staff.

Use of samplers of a new design to sample pig iron

The blast-furnace shop at the Magnitogorsk Metallurgical Combine has conducted an experiment involving the sampling of conversion pig iron with SA-E samplers made by the company Heraeus Electro-Nite. The new samplers ensure the acquisition of uniform and representative samples. The experiment established the optimum location for sampling the pig iron and the depth to which the sampler should be submerged in the iron. The improvement made in the sampling of pig iron makes the information obtained on the composition of the iron more reliable and reduces the amount of time needed to obtain the sample and prepare it for analysis.

Variation in coke properties within the blast-furnace shop

In active production at OAO Magnitogorskii Metallurgicheskii Kombinat (MMK), samples of melt materials were taken during shutdown and during planned repairs at furnaces 1 and 8. In particular, coke was taken from the tuyere zone at different distances from the tuyere tip. The mass of the point samples was 2-15 kg, depending on the sampling zone. The material extracted from each zone underwent magnetic separation and screening by size class. The resulting coke sample was averaged out and divided into parts: one for determining the granulometric composition and mechanical strength; and the other for technical analysis and determination of the physicochemical properties of the coke.

Evaluation of coal and its influence on coke quality and the coking process

The evaluation of coal batch is considered, along with its influence on coke quality and the coking properties. The quality of the coal available for coking at OAO Zapadno-Sibirskii Metallurgicheskii Kombinat is declining. Given the shortage of coking coal, coal ranks that are not of equivalent coking and enrichment characteristics are being added to the batch. In some cases, mixtures with energy coals are prepared. The ash content of the batch sent for enrichment is rising, and the concentrate yield is falling. With decrease in the content of bituminous coal in the coking batch, the strength of the coke is declining. Improving the performance of the coke-production and blast-furnace shops depends on access to coal of satisfactory structure and quality.

Phosphorus removal from high-phosphorus hot metal in the converter

The introduction of Korshunsk concentrate in the sintering batch at OAO Chelyabinskii Metallurgicheskii Kombinat (OAO ChMK) increased the mean phosphorus content in the hot metal from 0.10 to 0.17‐ 0.18% (in some periods, 0.20‐0.22%). This is due to the phosphorus content of 0.1% in such concentrate, which is an order of magnitude higher than in the batch materials previously employed, and also to the addition of converter slag to the batch (about 3% in the batch and the blast-furnace melt). On account of phosphorus accumulation in the converter slag, its content in the hot metal is constantly increasing. In view of the expanded production of continuous-cast billet, effective removal of phosphorus is required in order to produce converter steel with of required composition from high-phosphorus hot metal. In the oxygen-converter shop, most steel is smelted in three 160-t converters with a tar‐dolomite lining. Hot metal is supplied to the converter shop from the blast-furnace shop in portable ladles of capacity 100 and 140 t, decanted into two mixers in the mixer department, and then supplied through a special ladle to the converters. Oxygen is injected into the converter through a five-nozzle tuyere, with a nozzle aperture angle of 20 ° , at 400‐450 m 3 /min. Processing hot metal with up to 0.2% P increases the required duration of injection of the intermediate product in the converter, which considerably increases the loss of iron and the reducing-agent consumption and reduces the lining life. To determine the optimal phosphorus-removal parameters for oxygen-converter melt, an experimental series of 35 melts is considered, with three basicity values B = (CaO + MgO)/SiO 2 : less than 3.0, 3.0‐3.5, and more than 3.5. In the experimental melts, the chemical composition of the hot metal is as follows (wt %): 0.57‐ 1.07 Si (0.87, on average), 0.10‐0.24 Mn (0.15), and 0.10‐0.17 P (0.14). The hot-metal temperature fluctuates from 1323 to 1368 ° C (1345 ° C, on average). The proportion of hot metal in the metal batch is 80%. A single-slag smelting process is employed, with standard injection (mean rate 400‐450 m 3 /min); the height of the tuyere above the level of the quiescent bath is 1.1‐1.3 m during most of injection. The MgO content in the final slag is 4.9‐15.9% (8.9%, on average), and the FeO content is 11.3‐23.3% (16.2%). For some melts, at the end of injection, the tuyere is raised by 0.5 m, to increase slag oxidation. The end of injection is recorded visually in terms of the shape of the flame, the injection time, and the volume of oxygen consumed.

Improved use of powder wire in steel metallurgy

Ladle treatment of hot metal by magnesium-bearing powder wire is in increasing use at metallurgical enterprises, since it does not involve large capital and operating expenses and it ensures effective desulfurization, stability of the results, and considerably reduced toxic emissions [1]. This technology is used today at OAO Mariupol’skii Metallurgicheskii Kombinat im. Il’icha, OAO Tulachermet, OAO Lipetskii Metallurgicheskii Zavod Svobodnyi Sokol (LMZSS), and elsewhere [2, 3]. At OAO LMZSS, ladle treatment of hot metal by magnesium-bearing powder wire is included in the production cycle for commercial cast iron and cast-iron pipe. In the blast-furnace shop, a push-rod system is installed in the region of the casting machines; both commercial iron cast in pigs and hot metal sent to the pipe-casting shop for further treatment in induction furnaces and pipe casting undergo desulfurization in 100-t ladles. In the mixer department of the pipe-casting ship, where necessary, the hot metal undergoes desulfurization in 30-t ladles to ensure a sulfur content of less than 0.012%. In the modification section, the hot metal is treated in 7-t ladles for 5‐10 min after discharge from the induction furnaces. After treatment, the ladle with the hot metal is sent on a trolley directly to the section for centrifugal pipe casting [4]. The technology ensures a stable residual-magnesium content of more than 0.025% throughout the pipe-casting cycle, permits considerably more efficient use of the magnesium, and significantly reduces the costs of modification; the pipe obtained meets all the standard requirements regarding microstructure and mechanical properties. Magnesium‐staurolite wire is used for desulfurization, and ferrosilicon‐magnesium wire is used for modification. The characteristics of ladle desulfurization of hot metal by magnesium‐staurolite/ferrosilicon‐magnesium wire in 30-, 100-, and 140-t ladles are shown in the table. (The data for 140-t ladles are taken from [4].) The results indicate that desulfurization is highly effective when using magnesium-bearing powder wire. Ladle treatment of hot metal by magnesium‐silicon alloy considerably improves the efficiency of magnesium utilization. The cost of removing 0.01% S is $0.5‐ 1.0/t if the initial content is ≥ 0.03% S, and $1.2‐1.6/t if the initial content is ≤ 0.02%. The degree of magnesium assimilation for the different groups of hot metal at OAO LMZSS is 90.2‐98%; the coefficient of magnesium utilization in sulfur removal K Mg‐S is 28.8‐46.4%; the magnesium consumption is 0.3‐0.5 kg/t. In steel production, treatment of the melt with calcium-bearing reagents is very effective and, in view of non-Russian experience, essential. In the production of high-quality metal for major gas and oil pipelines, shipbuilding, and the construction industry, ladle treatment with calcium-bearing powder wire is a key part of steel production and an effective means of improving the properties of liquid and solid steel. Calcium has a significant influence of the kinetics of steel reduction, refining, modification, and microalloying [2, 5]. At metallurgical enterprises where the melt is treated with calcium, the casting of steel reduced by aluminum is not a problem. The negative influence of alumina in the melt and in the final product is eliminated; the content of harmful impurities, oxides, and sulfides is reduced; and the composition and shape of the nonmetallic inclusions are modified. This improves the steel quality. The relative elongation is increased by 10‐15%, and the impact strength of thick rolled sheet is increased (by a factor of 1.5‐1.8), with simultaneous increase in strength (by 5‐10%) and decrease in the cold-brittleness threshold (by 15‐20 ° C). The surface

Furnaces and air heaters in blast furnace shop at OAO MMK

Furnaces and air heaters in blast furnace shop at OAO MMK

System for cleaning blast-furnace gas in the blast-furnace shop at the VSZh Koshitse combine

Experience has shown that the dust content of the gases leaving a blast furnace can be cut by 4 mg/m3 by using a simple and reliable gas-cleaning system that includes a dust catcher, wet scrubber, Venturi tues, valve group, and water separator. A wet-type gas-cleaning system can remove up to 60% of the zinc and lead in the flue gases of blast furnaces operated on a charge having a high concentration of nonferrous metals.

System for Continuously Monitoring Gas Composition over the Radius of the Top of Blast Furnaces

During a class-II overhaul of its 1719-m3 blast furnace, the blast-furnace shop at ISPAT-Karmet installed a system to continuously monitor the composition of the gases and their distribution over the top of the furnace. The information is sent to a computer monitor. A stationary gas-sampling beam was installed to sample the gas at the neutral line. The beam is connected to an EMG-20-1 gas analyzer by heated pulse lines. The data that is obtained makes it possible to correct the operation of the furnace in real time, which is particularly important when a multi-component charge is being used. Use of the system for continuous monitoring of gas composition has improved smelting conditions and increased furnace productivity by 263 tons/day while saving 5.0 kg of coke per ton of pig iron.

00/02107 Resources for increased operation efficiency of blast-furnace shops

00/02107 Resources for increased operation efficiency of blast-furnace shops

The Blast-Furnace Shop at the Magnitogorsk Metallurgical Combine from Congress to Congress

The Blast-Furnace Shop at the Magnitogorsk Metallurgical Combine from Congress to Congress

Refractory concrete lining for a hot-blast valve

This paper gives a brief description of the composition, technology and main properties of a high-alumina concrete that has been used for making the lining of the disk and rings of a hot-blast valve. The tenon and honeycomb types of concrete reinforcement have been tested in the linings of experimental valves. The results of the tests of the experimental valves in the blast-furnace shop of the Azovstal' Integrated Works have demonstrated that the lining with the tenon-type reinforcement is in fairly good condition. Due to the use of the concrete lining, the heat losses through a valve have been decreased by a factor of 1.5 – 2, the hot-blast temperature increased by 10 – 12°C, and the average service life of valves, by a factor of two.

Performance of a tuyere with a combination blast

Blast furnace shop No. 1 at the Novolipetsk Metallurgical Combine studied tuyere parameters on an oxygen-enriched blast in changing the consumption of natural gas. Recording devices and resistance thermometers were installed to record continuously the temperature drop of the water. It was determined that there is an inverse proportional relationship between the consumption of natural gas and the temperature drop that makes it possible to develop a system to monitor the thermal state of the hearth by measuring the temperature drop of the coolant water on all tuyeres, and, after isolating external factors affecting the temperature drop, to determine the pattern of change in the thermal state about the periphery of the hearth.

Determination of the demand for natural gas and optimization of its distribution among blast-furnace shops under the Ukrainian Ministry of Ferrous Metallurgy

Determination of the demand for natural gas and optimization of its distribution among blast-furnace shops under the Ukrainian Ministry of Ferrous Metallurgy

Design solutions for improving the efficiency of slag transfer from blast-furnace and hot-metal ladles in converter shops

The converter shop, with two 350-ton converters, was built in 1977 to make steel for large-diameter oil- and gas-line pipe. The method used previously to remove the slag before the pig iron was added to the mixer did not ensure the removal of slag from all of the incoming ladles because of the heavy freight traffic. Thus, the plant used the Ukrgipromez design to build a special slag-handling section. Its construction has improved slag removal and increased the capacity of the mixer section. The new section for removing slag from blast-furnace pig-iron ladles is housed in a separated building 30 m wide and 60 m long. The crane track is at the +17.0-m elevation. The building is located inside the mixer section in the path of the pig-iron flow from the blastfurnace shop. The building contains two through railroad tracks for transporting the pig and one siding for the slag ladles. The section is equipped with two foundry cranes of 180 + 63/20 tons capacity and two MSSh-I slag-pumping units designed by VNllmekhchermet. The units are installed on the working platform at the +8.2-m elevation and are operated by attendants. The work plan in the section is as follows: the iron, after desulfurization or directly from the blast-furnace shop, arrives in the section in a train made up of 4-5 140-ton hotmetal-car ladles. The foundry crane then places the pig-filled ladles near the slag-pumping unit. The inclination ofi~the ladle is regulated by raising the crane a small amount. The slag is pumped into a 16-m 3 slag ladle set on a stand. An exhaust hood located above the slag ladle helps remove impurities from the air by means of fans, the exhausted air later being cleaned in cyclones. The section pumps off 60-80% of the slag. To keep the surface of the metal from cooling, a device is provided which covers the surface of the pig iron with fine llme. In the charging bay of the converter section, slag is pumped off from the hot-metal ladles by another MSSh-I unit into a 16-m 3 slag ladle set on a special stand. After the ladle is filled, it is transferred to one of two self-propelled cinder cars, moved under the converters, and taken on to the slag pier. However, the efficiency with which the slag was pumped off by the lISSh-i was too low. Therefore the "~qllmekhchermet" institute designed the MSSh-2, based on the first design. Results of trials of the new machine confirmed its reliability and greater efficiency in pumping slag from 350-ton ladles. Plans called for the installation of two MSSh-2 units in the charging bay to continuously remove slag from all of the hot-metal ladles even in the case of shutdown of one of the machines for repairs or malfunction.

Processing and use of welding slag in blast-furnace and sinter shops

Processing and use of welding slag in blast-furnace and sinter shops

Blast-furnace production reserves ? Into action!

In the fourth year of the Tenth Five-Year Plan, we must significantly increase the output of pig iron nationally, improve pig quality, and improve the regularity of deliveries to steel making shops. Plants must make maximum use of internal reserves in order to successfully fulfill the State Plan and the socialist obligations for the year. This isspecially true of reserves that might be uncovered during the course of socialist competition presently involving the blast-furnace shops of 27 plants in the sector. These collectives concluded an agreement to compete to fulfill the plan and obligations for 1978 for the production of high-quality pig iron at minimal material and labor costs.

Labor Protection in Blast-Furnace Shops (From the Materials of a Scientific-Technical Conference)

Labor Protection in Blast-Furnace Shops (From the Materials of a Scientific-Technical Conference)

Improvement of coke screening and separation of large fractions from the screened material in the blast-furnace shop

Improvement of coke screening and separation of large fractions from the screened material in the blast-furnace shop

Mechanization and automation at the blast-furnace shop

Mechanization and automation at the blast-furnace shop