Abstract: For the production of a product which can be dumped or utilized, the mineral substances are subjected in a rotary kiln to a thermal treatment at a temperature at which the charge of the rotary kiln is transformed to a pasty to liquid slag phase. The composition of the charge is so selected that a slag phase is produced in which the main components, which constitute a matrix, are in the range from 60 to 72% SiO.sub.2, 10 to 30% Al.sub.2 O.sub.3 and 5 to 25% CaO+MgO, of said matrix, wherein the total percentage of SiO.sub.2 +Al.sub.2 O.sub.3 +CaO+MgO equals 100, the total of the main components SiO.sub.2, Al.sub.2 O.sub.3, CaO and MgO amounts to more than 60% on a dry and ignition loss-free basis, of the mineral matter which is charged to the rotary kiln. The slag phase discharged from the rotary kiln is cooled and the exhaust gas from the rotary kiln is purified.

Abstract: Disclosed is a process for the production of reduced iron oxide-containing materials. Iron oxide and solid carbonaceous reducing agent are charged into a first expanded fluidized bed, which is supplied with an oxygen-containing fluidizing gas. The gas residence time selected is controlled in the reactor containing the first fluidized bed so that the reduction potential will result in a reduction of the iron oxide material not in excess of the FeO stage. A gas-solids suspension discharged from the first fluidized bed is supplied to a second expanded fluidized bed, which is supplied with a strongly reducing fluidizing gas. Strongly reducing gas and a major portion of the resulting devolatilized carbonaceous material are discharged from the upper portion of the second fluidized bed. Reduced material having a metallization of 50 to 80% and the remaining devolatilized carbonaceous material are discharged from the lower portion of the second fluidized bed.

Abstract: Disclosed is a process to effect a reduction to a desired, constant degree as exactly as possible and to achieve a low surplus of carbon. The reduction by treatment with carbonaceous reducing agents is effected in such a manner that fine-grained solids, which contain higher metal oxides, are calcined at 800.degree. to 1100.degree. C. with hot gases in which the solids are suspended. The calcined solids are reduced at a temperature in the range of from 800.degree. to 1100.degree. C. to form low metal oxides in a stationary fluidized bed, which is supplied with carbonaceous reducing agents and oxygen-containing gases. The carbonaceous reducing agents are supplied to the stationary fluidized bed at such a rate so as to reduce the higher metal oxides to low metal oxides, while maintaining the reduction temperature in the stationary fluidized bed and insuring that the discharged matter has the desired carbon content.

Abstract: 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.

Abstract: The melting operation is carried out in an elongated horizontal reactor, in which sponge iron is charged onto the molten material in an intermediate region of the reactor, carbonaceous fuel and high-oxygen gases are blown into the molten material and slag and sponge iron are tapped at opposite ends of the reactor.

Abstract: 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.

Abstract: 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.

Abstract: In a process of simultaneously producing fuel gas and process heat from carbonaceous materials wherein the carbonaceous materials are gasified in a first fluidized bed stage and the combustible constituents left after the gasification are subsequently burnt in a second fluidized bed stage the throughput rate and the flexibility are increased in that the gasification is carried out at a pressure of up to 5 bars and a temperature of 800.degree. to 1100.degree. C. by a treatment with oxygen-containing gases in the presence of steam in a circulating fluidized bed and 40 to 80% of the carbon contained in the starting material are thus reacted. Sulfur compounds are removed from the resulting gas in a fluidized state at a temperature in the range from 800.degree. to 1000.degree. C. and the gas is then cooled and subjected to dust collection.

Abstract: 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%.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An improved process for briquetting sponge iron-containing material wherein as binder there is employed dilute sulfuric acid and the sponge iron-containing material contains at least 40% by weight metallic iron.

Abstract: An improved process for the direct reduction of iron oxide-containing materials to form sponge iron which takes place in a rotary kiln by treatment with a solid carbonaceous reducing agent having a high content of volatile combustible constituents is disclosed. The charge is moved through the rotary kiln opposite to the direction of flow of the kiln atmosphere. Oxygen-containing gases are blown at controlled rates through nozzle blocks into the charge disposed over the nozzle blocks in the heating-up zone in that region thereof defined by the occurrence of ignitable particles of the solid reducing agent and ending before the reduction zone. Oxygen-containing gases are blown in at controlled rates through shell tubes into the free kiln space at least in that region. In accordance with the invention, at least a part of the solid carbonaceous reducing agent comprises disintegrated waste rubber. Preferably more than 80% of the solid carbonaceous reducing agent comprises waste rubber.

Abstract: 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.

Abstract: 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.

Abstract: A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in an oxidizing atmosphere in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with fuel from shell burners, is described. The invention resides in the use of different fuels which release different quantities of SO.sub.2 and SO.sub.3 per unit of calorific heat. The fuel which releases the larger quantity of SO.sub.2 or SO.sub.3 per unit value of calorific heat is supplied to the upper portion of the rotary kiln, and the fuel which releases the smaller quantity of SO.sub.2 and SO.sub.3 per unit of calorific heat is supplied to the lower portion of the rotary kiln.

Abstract: A process for directly reducing iron oxide-containing materials to provide sponge iron by heating said iron oxide-containing materials in a rotary kiln while employing a solid carbonaceous reducing agent having a high content of volatile combustible components, wherein oxygen-containing gases are injected into the rotary kiln at a controlled rate through shell pipes into the free kiln space and the charge is moved through the rotary kiln countercurrently to the flow of the kiln atmosphere, is described. The invention lies in injecting oxygen-containing gases at controlled rates through nozzle blocks into the charge disposed over said nozzle blocks and in injecting oxygen-containing gases at controlled rates through shell pipes into the free kiln space in that region of the heating-up zone defined by a point along the length of the heating-up zone where ignitable particles of the solid reducing agent first appear and a second point before the reducing zone.

Abstract: A process has been developed for directly reducing iron-containing oxidic materials to sponge iron by means of a moist solid carbonaceous reducing agent having a high volatile content in a rotary kiln in which the solid charge and a gaseous atmosphere move in counter-current flow through the kiln.