DD210675A1 - METHOD AND ARRANGEMENT FOR PRODUCING CEMENT ACCORDING TO THE BELIT TYPE - Google Patents

Abstract

The invention relates to a method and the corresponding circuit for the production of cement according to the Belit type, in particular the production and cooling of the cement clinker. Target u. The object of the invention is to produce an active Belit clinker whose strength development is close to the Portland cement, whereby the Abkuehlgradient required for the quenching is reduced by material influence. According to the invention this is achieved in that the cooling of the active Belit clinker is carried out in two stages such that in the first stage the rapid cooling (quenching), for example in a fluidized bed and / or a necessary grain size minimization to <equal to 10 mm diameter by impact crushing with simultaneous Kuehlg. and / or settings. of the silicate module or of the clay demodulator is achievable and the subsequent cooling in the second stage takes place with the usual Abkuehlgradienten.

Description

Process and assembly for the production of Belit-type cement

Field of application of the invention

The invention relates to a method and the corresponding circuit for the production of cement of the Belit type, in particular the production and cooling of the cement clinker.

Characteristic of the known technical solutions

It is known to produce active Belit cement. Corresponding processes are described, inter alia, in DD-VVP 138 197, DD-VVP 139 938 and DD-WP 142 704. It is this invention in each case that in a certain area To achieve cooling gradients> 500 K / min or to establish conditions in order to reduce these cooling gradients. This includes, in particular, the extraction of clinker with a grain size <10 mm, for example, by the burned clinker in total or only the oversize of a crushing or other use is supplied »

fi Οία 1982 * 03941

It has also been proposed that the rapid cooling takes place in a VVirbe Irinnenkühler · For this purpose, however, it is necessary that a simultaneous classification of the clinker should be made by a multiple subdivision of the air supply.

Another proposed solution provides to supply the hot clinker stream Zumahlstoffe with much lower temperature and abandon the entire material flow of a second cooling stage.

Another solution is to work with an increase in the Silikatraoduls of 2 in the direction of 4 with cooling gradient C 500 K / min.

Furthermore, it was proposed to increase the early strength of the active Belit cement by setting an optimal * content of non-sulphate bound alkalis in the Belit clinker.

The early strength of active belite cement can also be improved by grinding EGR dust, raw meal, limestone and the like. Ä. Increased and the overall cost of the process can be improved.

The technical realization of the high Abkühlgradienten can continue to be done in a chute cooler, which is fractionated by an air cross-flow of the clinker and the individual clinker fractions are flown according to their mean grain diameter. A disadvantage is the necessary high accuracy of the flow conditions in order to achieve sufficiently high residence times in the chute.

From DE-OS 26 32 691 and DE-OS 26 38 708 is known in the cooling area of a firing system (cooling zone in the oven tray, transition area between the oven and radiator

or · in the cooler) to add a marl raw material which is burned by the clinker heat and thereby achieves hydraulic properties itself ·

A disadvantage of the abovementioned solutions is the requirement that the rapid cooling process be achieved only with sufficiently small clinker grains.

To remedy this deficiency, the hot reduction of clinker was proposed starting at ^ 1300 ⁰ C with simultaneous rapid cooling in an impingement cooler. According to the invention, the primary clinker grain size plays no role in the actual rapid cooling. The disadvantage here is the extremely high stress of the material due to heat and abrasion.

Object of the invention

The aim of the invention is to produce an active Belit clinker whose strength development, in particular the early strength of the active Belit cement, comes close to the Portland cement and / or exceeds the late strength.

Explanation of the essence of the invention

The object of the invention is to reduce the cooling gradient required for the quenching zone by material influence by novel solutions in combination with known or already proposed detailed solutions, and at the same time favorable conditions for achieving high cooling gradients and for the subsequent comminution of the clinker, in particular with respect to Grain size to create ·

According to the invention the object is achieved in that the cement clinker with a lime standard of 75 to and one of the usual Portlandzementherstellung ent

Sintered sintering gradients at firing temperatures between 1350 C and 1450 ⁰ C and then subjected to a stepwise cooling · The cooling in the temperature range of 1350 ⁰ C to 1250 ⁰ C as the upper limit and 1000 ⁰ C to 800 ⁰ C as a lower limit with high Cooling gradients and the subsequent cooling with conventional cooling gradient.

The cooling in the first stage (rapid cooling) takes place, for example, in a fluidized bed. For example, a rotary tube cooler is used for cooling in the second stage.

At the same time a grain size minimization to a grain size s 10 mm is achieved. For this purpose, in the raw material, either the silicate module is increased from about 2.0 to 2.5 in the direction of 4.0, preferably 3.0, and / or the toner modulus is reduced to 1.

The coarse grain produced independently of this is separated from the clinker stream, comminuted and fed to the further process.

The method is further characterized in that the hot clinker stream before or in the first cooling stage, for example in the fluidized bed, is added to additives with substantially lower temperatures in a corresponding grain fraction.

Ausführungsbeispie1

The invention will be explained in more detail below with reference to an embodiment «In the drawing, an arrangement of the individual units for performing the method is shown schematically»

The fired Belit clinker is abandoned from the rotary kiln with a temperature of about 1300 ⁰ C a WirbelrinnenkUhler 2. The WirbelrinnekUhler is pressurized from below with air. In the WirbelrinneKUhler cooling of the Belitklinkers takes place in the temperature range 1350 ⁰ C to 1250 ⁰ C as upper limit temperature and 1000 ⁰ C to 800 ⁰ C as lower limit temperature with a Abkühlgradienten? 500th

The WirbelrinnekUhler is preferably the clinker with a particle size < 10 mm abandoned. Subsequently, the cooling of the clinker is carried out at usual Abkühlgradienten. In particular, a rotary tube cooler 5 or the like is used as the cooling unit.

With a clinker content with a grain = 10 mm, this is eliminated from the clinker stream. For this purpose, the clinker is fed to a separator 3, from which the pebble is supplied to the WirbelrinnenkUhler and the coarse grain an impact crusher k . In accordance with the cooling effect in the impact crusher 4, which is also supplied with cooling air, the comminuted clinker is fed to the Wirbelrinnenktihler 2 or directly to the second cooling stage, the rotary tube cooler. As cooling air the rotary kiln cooler 5 fresh air is supplied. From the exhaust air from the rotary tube cooler 5 is a part of the WirbelrinnenkUhler and / or an exhaust duct 6 the impact crusher 4 abandoned via an exhaust duct. At the same time both units to the extent required via the lines 8 and 9 also supplied fresh air.

The exhaust air from the first cooling stage is led wholly or partially, bypassing the leaning stage, into the sintering stage, the rotary kiln.

An essential feature of the invention is, at the same time by material influence the proportion

keep the clinker as small as possible with a diameter = 10 mm without mechanical comminution

It is already known that a lifting of the silicate module from 2.0 to 2.5 in the direction preferably 3, 4 contributes to increase the early strength and to reduce the Abkühlgradienten required for Belitklinker.

Surprisingly, however, it has been found that with the same silicate module and the values for the lime standard typical for active belitzement, a reduction of the clay modulus to = 1 has a positive effect both on the early strength of the cement and the cooling gradient can be lowered and, at the same time, on the formation of smaller clinker grains, as known from Portland cement leads.

"A" belite raw meal with the moduli of the lime 80, module silicate and alumina 2.8 0.75 module and at a Sinterteraperatur of 1350 ⁰ C, the proportion of clinker particles> 10 mm will in this case be less than 10%. The further embodiment of the method provides that with the addition of additives with substantially lower temperatures in the first cooling stage or in the field of impact crushing, in addition to the supply of colder air, the required Abkühlgradient is achieved.

The overall effect achieved by cooling with a high cooling gradient of self-comminution of the granules has an advantageous effect. This applies to the size of the granules in the further cooling process and also to the improvement of the subsequent clinker transport and the clinker grinding » ^x

In the drawing, the material guide in each case by closed lines and the air ducts by dashed lines.

Claims (9)

Erfinrtungsanspruch 1. A process for the production of cement by dem'Bellt type having a lime standard of Rohmehles of 75 to 85 and one of the Portland cement production corresponding heating gradient, firing temperature zwlsohen 1350 ⁰ C and H50 ⁰ C as well as a stepped cooling or quenching at high cooling gradients, preferably in the temperature range 1350 ⁰ C to 1250 ⁰ G as the upper limit temperature and 1000 ⁰ C to 800 ⁰ C as the lower limit temperature, characterized in that the cooling in two stages takes place such that in the first stage, the rapid cooling (quenching), for example, in a fluidized bed and / or a necessary grain size minimization to ^ 10 mm diameter by impact crushing with simultaneous cooling and / or adjustment of the silicate module or the clay demodulator is achievable and the subsequent cooling in the second stage is carried out at conventional Abkühlgradienten. S
-X- 2. Method naoh point 1, characterized in that before and / or in the first cooling stage », for example, in the fluidized bed and / or the impact crusher additives are supplied at significantly lower temperatures in an adapted grain fraction. 3. Method naoh point 1, characterized in that only the oversize = 10 mm diameter is separated from the clinker stream and the impact dissipation is supplied. 4. The method according to item 1 to 3, characterized in that the silicate module of 2.0 to 2.5 in the direction of 4.0 preferably increased 3 and / or the toner modulus is reduced to <1. 5. The method according to item 1 to 4, characterized in that the area of the fluidized bed cooling and the area of the impingement cooling cooler exhaust air of the second Kühlstufe and / or fresh air are supplied as cooling air and the hot cooling air of the second stage, bypassing the first stage wholly or partially the Sintering process is supplied. 6. Arrangement for carrying out the method according to item 1 to 5, characterized in that a rotary kiln (1) an impact crusher and / or a Wir'be Irinnenkühler (-2) and the Wirbelrinnenkühler a second cooler, for example, a rotary kiln cooler, is connected downstream , 7. Arrangement for carrying out the method according to item. 1, to 5, characterized in that the rotary kiln (1) is followed by a separating member (3) for the oversize of the clinker, the Wirbelrinnenkühler (2) is connected via a line for the fine grain with the separator (3) and by means of an adjusting or directly to the rotary kiln (1), from the Absoheideorgan (3) leads a line for oversize to impact crusher (4), via material lines are the Worm chillers (2) and / or the impact crusher (4) connected to the downstream DrehrohrkUhler (5). 8. Arrangement according to item 6 and 7, characterized in that exhaust ducts connect the material inlet of the rotary tube cooler (5) with the Wirbelrinnenkühler (.2) and / or with the impact crusher (4) and are connected to the exhaust ducts via control elements Prischluftleitungen. 9. Apparatus for carrying out the method according to item 1, to 5, characterized in that the air-permeable bottom of the Wirbelrinnenkühlers (2) is arranged in the conveying direction of the material up to 20 °, preferably 5 to 15 ° to the horizontal rising. - For this 1 sheet drawings -