DD289036A5 - METHOD OF CEMENT LINKERS AND SO LOW 2-STROKEN GASES - Google Patents

Abstract

The invention relates to a process for the production of cement clinker and SO2-containing gases in gypsum sulfuric acid Prozesz from raw meal. As a substitute for anhydrite in the raw meal CaSO3-containing waste products from the spray absorption of flue gas desulfurization are used. 5 to 80% waste product is used. {Gypsum-sulfuric acid process; raw meal; Anhydrite substitute; flue gas desulfurization; waste product; CaSO3-sustainably}

Description

Field of application of the invention

The invention relates to a process for the production of cement clinker and SO ₂ -containing gases for the production of Portland cement and sulfuric acid in gypsum-sulfuric acid process.

Characteristic k of the known technical solutions

It is known to produce cement clinker from natural raw materials such as anhydrite, clay, Fe ₂ O ₃ carriers (ζ B. Kiesabbrand), quartz sand or other SiOy-containing correction materials and reducing coke by the gypsum-sulfuric acid method

(Z. Angewandte Chemie 38.794-795 [1925]; 39.169-174 [1926]; Chem. Ing. Techn. 21.227-229 [1949]).

Numerous methods for the desulfurization of flue gases have become known in which waste products of different composition are incurred, which can only be partially recycled economically. Particularly in the case of spray absorption processes (SAV), CaSO ₃ -containing waste products are formed which, according to the current state of the art, are not used and have to be disposed of in a costly manner (ZKG 11/88, pp. 576-582). The waste product from the SAV is essentially free of ash fractions and contains as its main constituent CaSO _{3 in} addition to CaSO ₄ .

Also known is a process for recycling the waste products of the dry flue gas desulphurisation for the production of cement clinker by the gypsum sulfuric acid method according to DD 241891. The waste product described therein contains CaSO _{2 in} addition to large amounts of ash and is due to the AI ₂ O ₃ - and SiO ₂ -containing ash as aggregate use.

Object of the invention

The aim of the invention is to develop a process for the production of cement clinker and usable SO ₂ -containing gases, which takes place with reduced total expenditure in the gypsum-sulfuric acid process using previously difficult to use waste products.

Darlegu ..; · the essence of the invention

The object of the invention is to replace natural anhydrite in the gypsum sulfuric acid process as CaO and SO ₂ carrier so by waste that high quality cement clinker and usable SO ₂ -containing gases can be produced. According to the invention the object is achieved in that in existing plants of the gypsum sulfuric acid process, a raw mixture for clinker production is used, the CaSO ₃ -containing waste products from the spray absorption of flue gas desulfurization in amounts of 5 to 80% as a substitute for anhydride. As CaSO ₃ -containing waste products find REA products with 35 to 80% CaSO ₃ and 5 to 20% CaSO ₄ use.

An advantage of the method according to the invention, in which high-quality cement clinker are obtained, consists in a reduced total energy input for the stages raw meal production and the firing process, since the SO _{2 is released} from the Ca sulfite easier than from anhydrite. As a result, the clinker throughput can be increased and the SO ₂ deficit in the raw meal can be equalized.

Furthermore, the method results in a waste-free use of calcium sulfide-containing accumulation materials, whereby a landfill of these materials is avoided.

embodiment

To contrast the solution according to the invention with the previously used raw mixture cement clinker and SOj-containing gases were prepared from the following raw mixtures:

1. Conventional raw mixture of anhydrite, lignite filter ash (BFA), sand and coke according to the prior art.

2. Raw mixture according to the invention, in which 50% of the anhydrite after mixture 1 has been replaced by a waste product containing predominantly CaSO ₃ .

3. Inventive raw mixture in which the anhydrite of the mixture 1 has been completely replaced by a CaSO ₃ -containing waste product.

The chemical analysis of the raw materials and the CaSOj-containing waste product are listed in Table 1.

-2- 289 Table 1: Raw material analyzes

Salary in% Al ₂ O ₃ Fe ₂ O ₃ CaO sulfate sulfite component SiO ₂ SO ₃ SO ₃ - - 40.4 58.8 - anhydrite _ 1.9 0.9 0.8 - - sand 95.0 14.8 9.7 16.9 - - BFA 41.4 - - 50, u 1.0 27.0 waste product 1.0

Under specification of the target values of lime standard KSt = 100 and silicate module SM = 2.4, from clinker mixtures corresponding to 3. clinker are fired, which were ground to Portland cement under reproducible laboratory conditions. The composition of the three crude mixtures and the calculated according to Bogue content of clinker phases are compared in table.

Table 2: Composition of raw mixes and proportion of clinker phases calculated according to Bogue (KSt = 100, SM = 2.4)

raw mix Portions in the crude mixture (%) Anhydrite Sand 8FA 3.6 3.5 3.4 16.1 18.0 19.7 waste product Silicates (%) C ₃ S C ₂ S 1 2 3 80.0 39.3 39.3 76.9 71.8 71.7 71.7 4.9 5.0 5.0

A comparison of the strength development is shown in Table

The raw meal mixture 3 is produced without dry and grinding process by simple mixing. This results in an additional energy advantage.

Table 3: Strength development of the cements made from the three clinker Test batch of compressive strength (MPa)

1 day 3 days 28 days

1 14.8 30.8 50.4

2 15.2 29.5 50.6

3 15.0 30.4 49.8

Table 4: Primary energy consumption of brown coal fuel rod for the clinker fire

(kJ / kg clinker)

From raw mixture 1 8800 From raw mixture 2 8U00 Pipe Mix3 7200

Claims (2)

1. A process for the production of cement clinker and SO ₂ -containing gases for the production of Portland cement and sulfuric acid in the gypsum sulfuric acid process using flue gas desulfurization products, characterized in that in the raw meal CaSO ₃ -containing waste products from the spray absorption process of flue gas desulfurization as a substitute for Anhydrite is used with 5 to 80%. 2. The method according to claim 1, characterized in that CaSO ₃ -containing waste products with 35 to 80% CaSO ₃ and 5 to 20% CaSO ₄ find use.