DE3305868A1 - Method for producing cement clinker - Google Patents

Description

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Process for the manufacture of cement clinker

The manufacturing process of cement consists in adding the raw materials to form a homogeneous mass, the Burning this mixture in a kiln to form cement clinker and grinding this clinker into a fine powder. Small amounts of Means used to control the setting of the cement. One of these means can be plaster of paris. Two procedures that known as wet milling and dry milling,

are used depending on whether the raw materials are dry or when wet, be ground and mixed. There is another variant of these procedures, the so-called Semi-dry milling process in which the raw materials are dry milled and then with water

are ground to form granules that are contained in the kiln be fed in.

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ι Kilns for the production of cement clinker have come from the first discontinuous i'.ott lchkilns (vat kilns) over ring kilns and rotating kiln no. developed that nowadays be used.

A twisting piece is put together - /. B a \ .s a long tube, in the generally made of steel with a refractory lining, which has various mechanisms for rotation about its axis and which is inclined at an angle to the horizontal so that the higher end of the kiln feed in raw material slowly to the lower one! - Hikes downhill at the end of the kiln. The inclination of the pipe is 2 ° to 6 ° and the speed of rotation can 30 to 180 seconds for each revolution. The diameter is more than 7 m and lengths of up to 250 m can be achieved. The kiln is placed on the ground by means of a arranged burner using fossil fuel, such as coal, oil or gas, heated. That Material introduced into the kiln migrates down and up the kiln against the flow of the remaining combustion gases on its way to the bottom of the kiln, the material is dried, preheated, calcined and burned to form clinker, which is cooled in a cooler at the end of the kiln by means of air, which is then used as combustion air or secondary air is sucked in. At the head end of the kiln there are usually various devices for Support of the heat transfer of the kilng gases to the raw materials attached.

The temperature at which the cement clinker is manufactured in rotary kilns, varies depending on the raw materials of 1300 ⁰ C to 15SO ⁰ C. your time of passage through a rotary kiln beträft 1 to 4 hours, depending on the length of the kilns and production capacity. These long residence times of the materials in conventional rotating kilns are due to those in the kilns

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the reactions taking place, namely drying, preheating, calcining and clinker formation, caused by the The temperature of the solids are very dependent. This temperature in turn depends on the heat transfer from the remaining Combustion gases to these solids. The heat transfer between the remaining combustion gases and the raw materials is slow and not very satisfactory. He makes it necessary to construct large kilns, where the raw materials can reach the minimum temperatures suitable for the formation of cement. All these measures require high investment costs.

If the mixture of raw materials used to manufacture cement clinker could be heated up very quickly, almost instantly, to very high temperatures above those found in conventional rotating kilns are found, the residence times of the raw materials in the kiln could be considerably shortened, thereby shorter ones Kilns would be needed for the same production capacity.

In addition, the speed increases as the temperature rises the chemical reactions that take place in the kiln are considerable. This increase the speed of the chemical Reactions with temperature would further reduce the residence time of the materials in the kiln Have consequence.

The invention provides a method for manufacturing cement clinker in a reactor in which high temperatures can be reached and which enables a large Perform number of reactions, many of them so far were not feasible or were only possible in theory.

Method and reactor both use radiation as a heat source ³ ^ and keep the reactions within a liquid ßchutzabschirmung isolated which they contact by a

with the inner surfaces of the reactor.

In conventional reactors, the Reactions required heat passed through convection and / or conduction to the reagents. This makes two essentials Creates problems which limit the nature and scope of the reactions that can be carried out. The first problem is the limitation of the reaction temperatures caused by the resistance to high temperatures the materials of which the wall of the reactor is made. Second, the wall is a conventional one Reactor at the highest temperature of the system and is therefore the ideal place of conversion of the system and in the Majority of! • 'all accumulate the reaction products the wall. This build-up reduces the system's capacity to carry heat to the reagents, thereby making it necessary the temperature of the heat source is gradually increased to maintain the initial level of reaction which will eventually increase the capacity of the thermal resistance of the reactor wall material can exceed.

In this process for the production of cement clinker at high temperature, an annular protective cover is made of a inert liquid which is substantially transparent to radiation is generated; the protective cover has a essentially axial length. Then the mixture of raw materials is passed through the core of the protective cover guided a predetermined path which substantially coincides with the axis of the protective sheath, and the raw materials remain trapped in the latter. Once the flow of raw materials has started, it becomes radiant energy high intensity directed through the protective cover in order to use at least part of the wejres of the raw materials to collapse. The core absorbs sufficient radiant heat around the temperature of the raw materials to increase the level which o for the beginning of the

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Reactions is required that lead to the formation of cement clinker.

In the case of raw materials, self-opposed to radiant energy are permeable, an absorbent material is introduced into the flow of raw materials. This material absorbs sufficient radiant energy to raise the temperature of the core to the desired level. However, it can occur that in the case of raw materials transparent to radiation, one or more reaction products reduce the radiation energy absorb. In these cases, after the start of the reaction, the absorbent material can be removed from the flow of raw materials separated and the reaction can be continued.

The high-temperature reactor according to the invention essentially converts to the raw materials all the heat required by radiation. This reactor or reactors are protected by some patents. The reactor contains a tube with an inlet end and an outlet end which the Define the interior of the tube as a reaction chamber in which the reactions can be carried out. middle to introduce an inert liquid into the reaction chamber create an annular protective housing for the in- nenflache of the reaction tube. Means of introducing the Raw materials through the inlet end direct these raw materials along a predetermined path axially towards the reactor tube. The annular protective sheath made of inert liquid limits the raw materials within the reactor on the center and out of contact with the reactor tube. Radiant energy of high intensity is generated and directed into the interior of the reactor chamber to at least partially coincide with the route of raw materials, sufficient radiation energy is absorbed to keep the temperature of the raw materials extremely high Increase temperatures. The inventive method

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for the production of cement clinker is based on the coupling of radiation for heat transport to the flow of raw materials.

The first consideration about heat transfer in this process is the radiation absorption coefficient of the raw materials. The ring-shaped protective cover made of inert liquid, which protects the reactor wall should be substantially transparent to radiation and thus very transparent low value for the radiation absorption coefficient own.

This enables the transfer of radiant energy through the annular protective sheath to the flow of raw materials with little or no loss of energy. Of the Heat transfer occurs almost instantaneously and is subject to rapid and precise control. In this way, in the reactor and in the process according to the invention, the temperature of the core or the reactor chamber to extremely high Temperatures can be increased while the ring-shaped protective cover remains relatively cold. This procedure can be a Provide power density in the core or in the reactor chamber of more than 10000 watt / cm, whereby for industrial Purposes more suitable values on the order of up to

400 watts / cm.
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The invention creates a method for the production of cement clinker, which means for breaking raw materials, means for dispensing, pre-homogenizing, grinding and homogenizing the raw materials in the wet milling process, dry milling process or semi-dry milling process, and means for transferring heat from the hot gases exiting the reactor to the raw materials prior to their introduction into the reactor.

The high temperature reactor comprises a tube having an inlet end and an outlet end, the interior being the

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Rohrs defines a reactor chamber in which reactions can be carried out, means for introducing a inert liquid ii the reactor chamber to create an annular protective sheath for the inner surface of the Reactor tube, it being desirable that this inert liquid be substantially transparent to radiation is, means for introducing the raw materials into the reaction chamber through the inlet end such that the materials be directed to a path which runs predominantly axially to the reactor tube, means for heat transfer the flow of raw materials with coupling of the radiation such that the radiation energy generates high intensity and is directed to the interior of the reactor chamber so that it is at least part of the route of the raw materials can coincide.

At the outlet end of the high temperature reactor means are provided for cooling and / or quenching the cement clinker, that during the passage of the raw materials through the core or the reaction chamber of the high temperature reactor means of transportation and storage the cooled cement clinker, means for mixing and dispensing the cement clinker with other compounds, such as plaster of paris, and finally means for grinding the cement clinker with the aforementioned compounds, one of which can be plaster of paris, to the desired grain size.

In this method for manufacturing cement clinker, the raw materials in the core or of the reactor chamber can reach the high temperature reactor temperatures in excess of 3000 ⁰ C. Since the heat transfer also takes place almost immediately, this method allows the time for the transfer of the raw materials from the inlet end of the high-temperature reactor to the outlet end of the reactor to be chosen to be significantly shorter than in rotating kilns, this time being between 0.1 seconds and 600 seconds.

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The cement clinker is produced, as previously stated, by burning a framework of raw materials, one of which is basically composed of calcium carbonate and the other of aluminum silicates. Typical materials that correspond to this description are limestone and clay, both of which are found in nature in a large number of variants. The variety of raw materials used can be wide; r, o marl composed of a mixture of clay and limestone of organic origin, clay slate or slate, which are also common raw materials, can be used. In addition to naturally occurring materials, artificial products are also used as raw materials. Examples are fan furnace slag, coal smuts, and alkaline residues from the ammonium sulfate and alkaline product manufacturing industries. Other materials, such as soil, quartzite, bauxite residues and iron oxides, which are examples of many others, are used to adjust the composition of the mixture of raw filaments.

This invention, which provides a process for the manufacture of cement clinker in a high temperature reactor such as the one previously described and protected by several patents, includes all mixtures of raw materials, be they naturally occurring or artificial, such as those described above which are incorporated into one Kiln can be fed in for the production of cement clinker. In particular and also under this patent is a process for the production of cement clinker in a high-temperature reactor for Verfüp; un | - provided, v / o, the mixture of raw materials from which the cement clinker is formed, as a further component <\ it genannen mixture the waste from a laundry to a coal mine either as a partial erscitz or in its entirety for manufacture on the basic of clay or as a one

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1 more component of the mixture of raw materials, from which the cement clinker p; eferti, "" t will contain. This Kohlberp; factory laundry waste contains certain amounts of organic material, which is part of the

5 dunr of the cement clinker provides the necessary energy.

Claims (1)

Dr. rer. ns ». DIETER OlpL-Phyt hy KESStERPLATI 1 SC * NORNBERG Empresa Nacional Hulleras Del Horte ö.A. Avd. de Galicia 4Ί Oviedo / Spain Process for the manufacture of cement clinker Claims Λί Process for the production of cement clinker, characterized by means for breaking the raw materials, means for processing Q _{0 of} the raw materials before they are introduced into the high-temperature reactor, be it a dry milling process, semi-dry milling process or wet milling process, which can include, for example, dispensing, pre-homogenization, comminution and homogenization of the raw materials using the aforementioned methods, means for heat transfer from the hot gases which the Leaving the reactor, proceeding to the raw materials Γ - 2 - -η their introduction into the reactor, a high temperature reactor, and means for introducing the raw materials into the reactor chamber through the inlet end such that these raw materials are directed in a path which runs predominantly axially to the reactor tube, means for cooling the cement clinker which is produced in the reactor chamber has been and is located at the outlet end of the reactor, means for mixing and dispensing the Cement clinker with other compounds, such as gypsum, and means for breaking up the above Mixture to the desired grain size. c. Process according to Claim 1, characterized in that the inert liquid which is introduced into the reactor chamber in order to produce an annular protective housing is essentially transparent to radiation. 3. The method according to claim 1, characterized in that the heat overrides the raw materials in the reactor chamber of the high temperature reactor by coupling with Strahüunr is promoted, wci «i in the case when the raw materials are themselves permeable to radiant energy, the introduction of a material which is opposed to radiant energy acts absorbing, in the flow of raw materials is considered. 4. The method according to claims 1 and 3 »characterized in that radiation energy generates high intensity and is directed towards the interior of the reactor chamber so that it is with at least part of the route of the raw materials coincides. 5. The method according to any one of claims 1 to 4, characterized marked that the reactor number of the high temperature reactor with a radiation density above 10,000 watts / cm are provided k.-mn and preferably with values on the order of 400 watts / cm. L. J "I ^: ··; ··;. ·· ■:" :. ·: 3305368 Γ ■ - * - ■ 6. The method according to any one of claims 1 to f>, characterized in that that the raw materials inside the reactor chamber of the high-temperature reactor can reach temperatures above 300 ° C. and preferably temperatures of up to 25OO ° C. 7. Method according to one of Claims 1 to 6, characterized in that that the passage time of the raw materials through the high-temperature reactor is between 0.1 and 600 Seconds. 8. The method according to claim 1, characterized in that the raw materials comprise all those materials natural and artificial, both alone and mixed, used in a kiln for the manufacture of cement clinker can be fed in. 9. The method according to claims 1 and 8, characterized in that the mixture of Kohmuteriii] ien as one Another component of the mixture is the waste from a coal mine wash either as a toilet-wise replacement or a total replacement of the clay fraction of the mixture or as another component of the mixture of raw materials contains.
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