ISSN:0003-8962    

DOI:10.1002/srin.198900881

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

A survey is given on the current state of direct reduction and smelting reduction processes. Several developments, such as coal injection, top‐gas recycling etc., contribute to decrease the coke consumption in the blast furnace. Coal‐based as well as gas‐based direct reduction processes have not succeeded in Western Europe. These processes have only attracted economical interest in locations where there is a cheap source of energy. Other developments to reduce iron ore are concerned with the direct production of liquid iron in a smelting reduction process with a substantial part of the reduction taking place in the liquid oxide phase. The ideal concept of a smelting reduction process with direct use of fine ore and coal as well as only liquid state reduction to a liquid product similar to steel has not yet been realized.

ISSN:0003-8962    

DOI:10.1002/srin.198900882

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Corex process is a smelting reduction process to produce hot metal of blast‐furnace quality. Coal is used instead of coke, and this replacement makes production costs of hot metal decrease. Iron ore reduction and melting is separated into two steps: in a melter gasifier reducing gas is generated and melting energy is produced by coal gasification; iron ore is reduced in a shaft furnace. Due to this separation, a great variety of untreated coals can be used.The Corex process is designed to operate under elevated pressure, up to 5 bar. Reducing gas is generated in a fluidized bed by partial oxidation of coal. After leaving the melter gasifier, the gas is mixed with cooling gas to obtain a temperature suitable for direct reduction, i.e. approximately 850–900°C.The fines captured in a hot cyclone are re‐injected into the gasifier. Reducing gas is fed into the reduction furnace and ascends through the iron burden according to the counterflow principle. The hot DRI having a temperature of 800–900°C is continuously charged into the melter gasifier, where further reduction is effected and melting occurs. Hot metal and slag drop to the bottom of the melter‐gasifier. Analogous to blast‐furnace practice hot metal and slag are discharged by conventional tapping.

ISSN:0003-8962    

DOI:10.1002/srin.198900883

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

A joint venture between Klöckner‐Werke and CRA was formed to work out the application of coal injection into the iron bath to smelting reduction. In the Hlsmelt process of CRA smelting reduction of prereduced fine ore is to be carried out directly in the iron bath. Post combustion, different coal grades, and metallurgical reactions were investigated in a pilot plant. Reduction of iron ore fines to wustite was tested in laboratory scale.

ISSN:0003-8962    

DOI:10.1002/srin.198900884

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The concept of a two‐stage smelting reduction process is presented. In the first stage highly metallized iron ore fines are produced in a circulating fluidized bed. In the second stage a hot metal is produced in a melter‐gasifier where – together with metallized ore – coal and oxygen are injected to generate the required heat and the CO‐rich reducing gas. The process was tested stepwise in pilot scale installations. Although only a reduction temperature of 830 °C instead of the required 880–900 °C could be realized in the pilot unit, test results make it very probable that a metallization of 90% can be reached with any fine ore without sticking problems, if the ore is covered with a carbon layer by CO decomposition in a pretreatment stage with the reduction offgas at 500–600 °C. The CO decomposition on the fresh ore leads to a high gas utilization which renders a CO2washing stage and gas recycling unnecessary.To prove the technical and economic feasibility of the combined process, the next development step should be the design and operation of a larger pilot plant with a capacity of at least 5 t hot metal/h for continuous and joint operation of both the melter/gasifier and the reduction stage.

ISSN:0003-8962    

DOI:10.1002/srin.198900885

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

On the basis of MIP development several process concepts for primary ironmaking technology were investigated. In the smelting reduction process described the reduction of iron ore occurs in three stages: in the first step the ore is preheated and prereduced in a cyclon‐heat exchanger system. In the second step it is melted. The final reduction of the partially reduced and melted ore to metallic iron takes place in the MIP reactor.

ISSN:0003-8962    

DOI:10.1002/srin.198900886

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

This paper briefly describes the history, the purpose and the present status of the “AISI Steel Initiative”. The American Iron and Steel Institute (AISI) started a cooperation between universities and steel industry to investigate new steelmaking processes. A concept for in‐bath smelting reduction has been developed.

ISSN:0003-8962    

DOI:10.1002/srin.198900887

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Iron produced with several of the “in‐bath smelting” technologies may differ from the output of conventional blast furnaces. Carbon content may be driven to below saturation, oxygen content will be high so that a) silicon may be near nil, and b) the sulfur content can reach upward of 10 times higher than achieved with the coke‐oven/blast‐furnace route. These conditions point to the need for new approaches for conversion of this intermediate liquid into steel.

ISSN:0003-8962    

DOI:10.1002/srin.198900888

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

A simulation model on bath smelting processes for the production of iron was developed which predicts the coal, flux, ore, and oxygen consumptions and the off gas volume, temperature and composition. The model is comprehensive in that it takes into account all of the important variables including coal composition, metal composition, ore composition, slag basicity, post combustion ratio, (PCR), prereduction degree (PRD), heat transfer coefficient (HTC), flux, scrap charge, and heat losses. Four basic cases were considered: I. 30% PRD–50% PCR; II. 90% PRD–0% PCR; III. 60% PRD–30% PCR; and IV. 0% PRD–50% PCR. Several different coals were considered and a sensitivity analysis of the critical variables was performed. The model also estimates the sulfur content of the metal. The major conclusions are:Post combustion siginificantly reduces coal consumption but above 20% PCR little reduction of FeO to Fe can be performed with the off gas.Prereducing to FeO (case I) and having as much post combustion as consistent with good heat transfer is an attractive process.This process only requires a simple prereducer, uses less coal, and is relatively insensitive to the type of coal used.High off‐gas temperatures may pose a potential problem. The off‐gas temperature can be reduced by using an O2–air mixture for post combustion, limiting post combustion or adding water to the gas.The use of CaCO3in place of CaO or of supplemental electricity does not appear attractive.The melting unit is theoretically an energy efficient scrap melter. For case I using 200 kg of scrap as part of the charge the coal consumption decreases by about 80 kg.With PCR>30% the FeO content of the slag is expected to be 2–5%, and the metal will not be saturated with carbon. These factors and the increased sulfur load since coal is the fuel indicate the sulfur content of the metal may exceed 0.25%.

ISSN:0003-8962    

DOI:10.1002/srin.198900889

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Comparing the four fundamental ironmaking processes the reasons for the development of smelting reduction were derived. Based on bibliographical references a fundamental classification of the main important smelting reduction processes is presented regarding the process engineering principle of both steps, prereduction and final reduction. According to fundamental considerations, the fluidized bed process seems to be optimal for prereduction.Experiments to investigate the influence of process parameters on sticking – the main problem of fluidized‐bed reduction – and their interactions were carried out. Optimal operating conditions to run a fluidized bed as the prereduction unit of smelting reduction process were derived.A special “Reduction‐SEM” to directly observe metallurgical reactions, like the precipitation behaviour of iron during iron ore reduction, is presented. With the results of such investigations it is possible to show the influence of precipitation behaviour on sticking and to assign the different types of precipitates to the Baur‐Glaessner‐Diagram. The influence of hydrogen addition on surface morphology is sketched out.

ISSN:0003-8962    

DOI:10.1002/srin.198900890

出版商:Wiley    

年代:2016

数据来源: WILEY