DD153816A1 - METHOD FOR THE PRODUCTION OF CEMENT LINKERS - Google Patents

Abstract

The invention relates to a process for the production of cement clinker for the production of high-quality Portland cements with fast initial hardness and high compressive strength. According to the invention, in the rotary kiln, for example in the gypsum-sulfuric acid process, after the sintering zone at about 1200 degrees C, aqueous solutions or emulsions containing ammonium salts alone or mixed with phosphoric acid esters, wherein 1 to 5 parts by weight of ammonium salts or 1 to 5 parts by weight of ammonium salts and 0.1 to 0.5 parts by weight of phosphoric acid esters are added.

Description

VSB CHEMICAL COMPANY BITTERFELD Bitterfeld, 14. 8, 1980

2015 '

Process for the production of cement clinker

Field of application of the invention

The invention relates to a process for the production of cement clinker for the production of high-quality portlaad cements.

Characteristic of the known technical solutions

It is known to make Portland cement clinker after two technological crimes. One method starts with limestone (CaCO.,) And the other with anhydrite (CaSO ^) as the raw material. During the firing process, limestone and anhydrite are transformed into CaO, the main constituent of the cement. "For the quality of the cement, it is well known that the formation of tricalcium silicate is decisive." In addition, mineralogical constituents such as tricalcium aluminate and tetracalcium aluminate ferrite are important in the cement. As raw materials for the Zeiaentklinkerproduktion are therefore in addition to limestone or anhydrite and clay or slate gravel or Kiesabbrand sand 'required.

It is also known that the tricalcium silicate important for the hardening and compressive strength of the cement is at about 1400 ° C. in the sintering zone of the rotary kiln

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forms? regardless of whether one assumes limestone or anhydrite. Dwell time, aggregates and oxidizing or reducing gas atmosphere in the sintering zone at 1400 ^° C. play an essential role.

At temperatures below 1250 ^° C., the tricalcium silicate is metastable and decomposes into dicalcium silicate and free calcium oxide. "The slower the cooling process, the more the balance is shifted to free calcium oxide. Thus, it is in practice before that either deters the clinker shortly after the sintering zone with water or water vapor or the clinker at temperatures above 135 ° ⁰ C to be expelled from the oven and cool in the air "Both methods, however, are energetically uneconomical" · ·

In the application of anhydrite as a raw material brings the Abschreckverfahrec additionally considerable difficulties in the purification of the sulfur dioxide-containing exhaust gases before their catalytic η oxidation to sulfur trioxide.

It is known that the compressive strength is one of the most important properties of the cement and cements are divided into corresponding strength classes after the minimum compressive strength to be achieved after 28 days. But it is well known that rapid bonding of a cement has nothing to do with the development of a high initial strength. In contrast to the so-called Raschbindern have particularly valuable cements a normal binding time of 6 to 8 hours? but then sets in them a rapidly advancing hardening, so that such a cement reached after 24 hours high tensile and compressive strength.

Aim of the invention

The aim of the invention is to develop a process for the production of cement clinker, which allows j without large

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Effort to win high-quality Portiandzemente with fast initial hardness and high compressive strength.

Essence of the invention

This gave up "is inventively achieved in that one atomized in the rotary tube furnace of the sintering zone at about _E 1200 ⁰ C aqueous solutions or emulsions containing ammonium salts alone or in admixture with Phosphorsäureestern, wherein 1000 parts by weight of clinker from 1 to 5 parts by weight Ammoniuinsalze and 1 to As ammonium salts, for example, ammonium chloride, ammonium nitrate or ammonium sulfate may be added as mixtures of phosphoric acid are mixtures, such as those produced in the manufacture of various crop protection agents, such as mixtures of Thiophosphorsäureamiden , Trimethylthiophosphate and amidophosphoric acids or their salts »

The cement clinker produced by the process according to the invention are suitable for the production of high-quality Portland cements. Compared with the cements produced by known processes, the characteristic values "initial hardness and compressive strength are clearly improved". The residence time in the furnace j the "quenching process and the gas atmosphere play no significant role"

Execution Issues

In the following examples, the setting and compressive strength are determined by known standard methods. The beginning and end of solidification are determined by measuring the depth to which a needle loaded with an additional mass is placed in the plasticized according to a defined procedure Cement and water-based glue penetrate _β Cement, test sand are used to determine the compressive strength

and water in the ratio 1: 3 ί 0> 5 mixed in a Schaufelmiseher and. this mortar is compacted in the form of dimensions 4-0 mm χ 40 mm χ 160 mm by means of a shock table. One-day storage in humid air, the mortar prisms are demolded and stored under water. On the specified dates, the prisms are removed from the water and tested for compressive strength. ,

Examples 1 to 6 in the gypsum-sulfuric acid process compare cement clinker produced according to the invention with those which have been prepared by the previously customary process. The corresponding characteristic data (solidification time and compressive strength) are summarized in a table.

Example 1s.

In a rotary kiln with a length of 70 m and a free reaction chamber of 520 nr , 165 t of cement clinker are produced per day using the gypsum-sulfuric acid process. The temperatures in the sintering zone amount to 1450 ⁰ C. The clinker is cooled by air to about 700 ⁰ C in coolers before leaving the rotary kiln and stored in. An outdoor storage. After cooling to approx. 40 ⁰ G, the clinker is ground with 3 % gypsum to Portland cement. The following characteristics are achieved on a daily average

Solidification time Z ~ \ _7 compressive strength / ~ kpcm _7

3 days 7 days 28 days

.4.5 205 334 452

Example. zt

The conditions are analogous to Example 1. At about 1200 ⁰ G, an aqueous ammonium chloride solution is sprayed after the sintering zone. The ratio of clinker:. Ammonium ions is 1000 % 1 | 40 l of water are used per hour.

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Example 3: '. , ·

The conditions correspond to Examples 1 and 2, but only pure water is sprayed for comparison.

Example 4 $

The conditions are as in Example 1. At 1200 ⁰ O is sprayed · an industrial wastewater; j here is an aqueous emulsion of Ämmoniumchlorid and Phosphorsäureestern (mixture of trimethylthiophosphate and 0-methyl ~ amidophosphorsaurem .Ammoniumsalze The mass ratio clinker s ammonium ions: P is .1000: 1: 0.1, using 4Oi of water per hour.

Example 5?

The procedure is analogous to Example 4, but the mass ratio is clinker: ammonium ions: 'P now 1000; 5: 0.5 <> 180 1 of water are used per hour

Example 6:

The procedure is analogous to Example 4, but ammonium nitrate is used as the ammonium salt. * * The mass ratio of clinker ί ammonium ions: P is 1000 % 1.5 % .0.4.

Solidification time and compressive strength of the cements according to the invention in addition to comparative examples

setting time 2.5 Compressive strength / * ~ kpcm " 7 days 17 ' 4.4 3 days 365 28 days Example 2 2.2 225 337 534. , Example 3 2.0 200 380 455 Example 4 2.1 240 375 562. · Example 5 252 377 571 Example 6 244 567

Claims (1)

- 6 «2015 invention claim Verfahren.zur production of cement clinker for the production of high-quality Portland cements with fast initial hardness and high compressive strength, characterized in that in the rotary kiln roof of the sintering zone at about 1200 ⁰ C aqueous solutions or emulsions verdüstj the ammonium salts alone or in admixture with Phösphorsäureestern included 1 to 5 parts by weight of ammonium salts or 1 to 5 parts by weight of ammonium salts and 0.1 to 0.5 parts by weight of phosphoric acid ester are added to 1000 parts by weight of clinker.