Metallgesellschaft Aktiengesellschaft

Mannesmann Aktiengesellschaft

Wolfram Schnabel

Harry Serbent

Gerhard Reuter

Martin Hirsch

Lothar Formanek

Heribert Koenig

Gerd Elsenheimer

Herbert Lausch

Klaus-Dietrich Fritzsche

Lothar Reh

Gero Rath

Heinz Eichberger

Harald Sauer

Hans-Werner Schmidt

Georg Daradimos

Detlev Schlebusch

Detmar Arlt

Karl-Heinz Fischer

Kurt Meyer

Ernst Scheu

Gunter Kossek

The charge is moved through a rotary kiln countercurrently to the gas atmosphere. Solid carbonaceous reducing agent having a high content of volatile constituents is charged into the rotary kiln at its charging end. Solid carbonaceous reducing agent having a high content of volatile constituents is blown into the rotary kiln at its discharge end and is distributed over the charge in part of the length of the kiln. Oxygen-containing gases are supplied to the rotary kiln through its shell at a plurality of locations. In order to provide optimum operating conditions in the final zone of the kiln, solid carbonaceous material having a high content of volatile constituents is separated into a coarser fraction and a finer fraction, a part of the coarser fraction and a part of the finer fraction are mixed. The resulting mixture is blown by a blowing device into the rotary kiln at its discharge end, said mixture consists of an amount of 10 to 40% of the finer fraction and of an amount of 90 to 60% of the coarser fraction and is blown at a rate of up to 50% of the total feed rate of solid carbonaceous material. The blown mixture is distributed over up to 50% of the length of the kiln, and the remaining solid carbonaceous material is charged into the rotary kiln at its charging end.

Process for a direct reduction of iron oxide containing materials in a

Sponge iron is produced by a direct reduction of iron oxide containing materials in a rotary kiln, the material discharged from the rotary kiln is separated into sponge iron and material which contains surplus carbon, the carbon-containing material is burnt in a fluidized bed reactor containing a circulating fluidized bed, and the heat generated by the combustion is recovered and utilized to produce electric power. To ensure a utilization of the surplus energies of the rotary kiln process and to minimize the contents of SO.sub.2, NO.sub.X, and CaS, the dust-containing exhaust gas from the rotary kiln is supplied to the fluidized bed reactor and is afterburnt therein, at least a major part of all oxygen-containing gases supplied to the fluidized bed reactor is supplied as a fluidizing gas to the lower portion of the fluidized bed reactor, the combustion of the combustible constituents is effected with an over-stoichiometric oxygen content, and the solids entrained by the gases discharged from the fluidized bed reactor are recycled to the fluidized bed reactor in such a manner that the weight of solids circulated per hour is at least 5 times the weight of the solids contained in the fluidized bed reactor.

Process for generating heat and producing sponge iron

Sponge iron is produced by a direct reduction with solid carbonaceous reducing agents. In order to permit a melting of the sponge iron, particularly of that part thereof which is inferior in metallurgical properties, in a process which is as simple and economical as possible, the exhaust gas from the direct reduction process is used to produce electrical energy, which is supplied to the electric reducing furnace, and sponge iron at a rate corresponding to the electrical energy that is produced is charged to the electrical reducing furnace and comprises at least part of the sponge iron which is inferior in metallurgical properties.

Process of producing liquid carbon-containing iron

A process for afterburning and purifying process exhaust gases, which contain combustible constituents, wherein the process exhaust gases and the oxygen-containing gases required for a combustion are separately supplied to a fluidized bed reactor of a circulating fluidized bed. In the fluidized bed reactor, the gas velocity is adjusted to 2 to 10 m/s (empty pipe velocity), the mean suspension density is adjusted to 0.1 to 10 kg/m.sup.3, the temperature is adjusted to 700.degree. to 1100.degree. C., and the stoichiometric ratio of gas-purifying agent having a particle size d.sub.p 50 of 30 to 200 .mu.m to pollutant contained in the process exhaust gas or formed by the combustion is adjusted to 1.2 to 3.0, calculated as Ca:S. The entrained solids in the gases from the fluidized-bed reactor are recycled to the reactor at a rate of at least 5 times the weight of solids contained in the fluidized bed reactor per hour.

Process of afterburning and purifying process exhaust gases

Sponge iron produced by direct reduction is melted in an electric arc furnace, in which a pool of liquid metal is maintained. To ensure that liquid carbon-containing iron for forming the pool is available in adequate quantities and that the process can be carried out with the highest possible economy, the sponge iron is reacted in an electric arc furnace on a bath of liquid carbon-containing iron (hot metal), which has been produced from sponge iron or from partly reduced ore in an electric reducing furnace, and in dependence on the electric load changes which are due to the operation of the electric arc furnace the operation of the electric reducing furnace is so controlled that a virtually constant load on the electric power supply system is maintained.

Process of making steel by melting sponge iron in an electric arc furnace

In the operation of the rotary kiln provided at its charging end with a central burner, solid reducing agents having a high content of volatile constituents are used and the charge and the gas atmosphere are conducted in cocurrent streams. To avoid a high heat load per unit of volume in the heating-up zone and yet to increase the heating-up rate, a solid carbonaceous reducing agent having a high content of volatile constituents is charged together with the iron oxide-containing material into the charging end of the rotary kiln, oxygen-containing gases are blown through nozzle blocks into the free gas space and into the charge in the heating-up zone, and oxygen-containing gases are blown through nozzle blocks into the free kiln space in the reducing zone.

Process of producing sponge iron by a direct reduction of iron

Fine-grained material which contains iron oxide is prereduced in a fluidized bed and is subsequently completely reduced in a rotary kiln. In order to avoid agglomeration and incrustation in the rotary kiln, the prereduction is carried out to effect a metallization of 50 to 80%.

In order to avoid incrustation and an excessively strong thermal attack on the afterburning chamber, the exhaust gases which contain gaseous and solid constituents which are combustible are afterburned in a plurality of stages, which are connected in series. The rate at which oxygen is supplied to each stage is so controlled that part of the combustible constituents is afterburned in each stage. The gas which is about to enter each succeeding stage is cooled by injected water.

Process of afterburning combustible constituents of exhaust gases from

In the treatment of bulk materials with hot gases below the melting point of the charge component it is desired to prevent a formation of undesired crusts during normal operation and when the rotary kiln is operated at a reduced speed during short-time trouble. For this purpose, a controlled dissipation of heat is effected in several sections of the rotary kiln in that the shell of the kiln and the refractory lining are cooled so that the temperature of that portion of the inside surface of the rotary kiln which is submerged below the charge is always maintained at or up to 50.degree. C. below the temperature of the charge disposed thereover.

Process of thermally treating bulk materials in a rotary kiln

Before iron oxide-containing materials is reduced in a rotary kiln by a treatment with solid carbonaceous reducing agents below the melting point of the charge, the iron oxide containing material and carbonaceous reducing agent are preheated in a multiple-hearth furnace, in which the reducing agent is subjected to an at least partial coking or an at least partial low-temperature carbonization. To prevent a partial reduction and sintering, the iron oxide-containing material is preheated in the upper part of the multiple-hearth furnace and the solid carbonaceous reducing agent is separately preheated in the lower part of the multiple-hearth furnace. At least part of the gases produced by the low-temperature carbonization in the lower part of the multiple-furnace is caused to flow in the upper part of said furnace in a countercurrent to the iron oxide-containing material to supply the heat required in said upper part.

Process of directly reducing iron oxide containing materials in a rotary

A process is disclosed for producing quicklime by a calcining treatment with a hot gas in a rotary kiln, wherein solid carbonaceous fuel for producing hot gas is fed into the charging end of the rotary kiln and an oxygen-containing gas is blown through nozzle blocks into the charge disposed over nozzle blocks in the heating-up zone beginning at the point where ignitable particles of the solid fuel first appear, the improvement wherein:

Process of producing quicklime by calcining in a rotary kiln

Residual materials which become available in metallurgy and contain oxides and volatilizable non-ferrous metals or compounds thereof are treated in a rotary kiln with solid carbonaceous reducing agents and are thus directly reduced in a high proportion to sponge iron whereas a substantial part of their non-ferrous metal content is volatilized. The solids discharged from the rotary kiln are sieved with a parting size of about 3 to 10 mm, depending on the feed grading of the residual materials and their disintegration characteristics, so that a major part of the unmagnetic material is included in the fine fraction. The coarse fraction is subjected to an electro-slag resistance process. The fine fraction is subjected to an electro-magnetic separation. The magnetic fraction is subjected to the resistance slag-refining process. The unmagnetic fraction is incorporated in and bonded to the feed mixture for the rotary kiln by a tumbling or pelletizing operation.

Steel making process

A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with solid carbonaceous fuel, is described. The invention resides in introducing an oxygen-containing gas into a horizontal region across the rotary kiln defined by a point along the length of the kiln where ignitable particles of said solid fuel first appear and a second point along the length of said rotary kiln which is spaced from the charging end of said kiln not more than 50% of the length thereof. The oxygen-containing gases are injected through nozzle blocks in said rotary kiln, and oxygen-containing gas is introduced into the free space of said kiln.

Process of calcining limestone in a rotary kiln

When in the direct reduction of iron-oxide-containing materials in a rotary kiln solid, carbonaceous reducing agents having a high content of volatile constituents are charged to the rotary kiln at its charging end, a reoxidation of the sponge iron can readily occur in the final portion of the reduction zone unless a definite surplus of solid reducing agent is there maintained. To reduce the required surplus while still positively avoiding reoxidation, reducing gases and/or liquid hydrocarbons are introduced in said final portion by means of tubular air nozzles at least partially into the charge located above the air nozzles beginning with at least 75 percent metallization.

Process of directly reducing iron oxide-containing materials

In a Waelz process of volatilizing zinc and lead from iron-containing and oxide-containing material in an inclined rotary kiln, which is charged at its upper end with the material together with solid carbonaceous reducing agent having a high content of volatile combustible constituents, wherein the reduction and volatilization are effected below the softening point of the charge, metallic iron-containing material is discharged from the lower end of the rotary kiln, combustion air is sucked into the lower end of the rotary kiln, and the exhaust gases are sucked from the upper end, the improvement which comprises blowing oxygen-containing gases through tubular air nozzles into the charge disposed over said tubular air nozzles in that region of the heating-up zone which begins where ignitable particles of the solid reducing agent begin to occur and which terminates at up to 50 percent of the length of the kiln.

Growing community of inventors

Hattersheim, Germany

Wolfram Schnabel