BG63006B1 - Composition and method for the preparation of a binder - Google Patents

Abstract

The method and the composition are used in the cement industry for the manufacture of all types of cement. Waste gypsum products are used for making the binder. It has increased specific surface and activity. The method results in higher output in grinding of the binder and reduced energy consumption of the comprehensive production and technological process. The binder has the following composition, in %: clinker from 90 to 100, gypsum and the ditramine grinding intensifier being a mixture of ethanolamines, 0.01- 1.0. Waste gypsum products from 2 to 6% are added as gypsum containing over 98% calcium sulphate dihydrate. According to the method the gypsum waste is crushed, mixed with clinker after which the components are fed to grinding and mixing with ditramine. The latter is injected over the gypsum waste in the initial phase of grinding, before their mixture with the clinker. 2 claims

Description

Field of application

The invention relates to a composition and method for making a binder and are used in the cement industry for the production of all types of cement.

BACKGROUND OF THE INVENTION

A composition for the preparation of a binder consisting of a clinker, gypsum and a grinder is known. The grinder is a mixture containing in%: phenol -31, triethanolamine - 49, water - 19.5, chelating agent - 0.25 and coloring agent - 0.25 (1).

The disadvantages of the known composition are that it contains phenol, which has carcinogenic properties affecting the health of the staff in the production of cement, as well as those living in buildings constructed with such cement.

There is also a method of preparing a binder in which a mixture of the constituents of the substance is milled by injecting an intensifying substance, the melamine-formaldehyde condensation product, which, at a temperature of T - 150 ° C and a 20% solution, reduces the temperature of the fine fraction of the binder to 120 ° C, during which time the water is evaporated from the mixture to give a binder with the desired fineness of milling (2).

The disadvantages of the known method are that it is complicated by the need to use an additional injection device for grinding the intensifier during the final grinding phase and precision in adjusting the dosage of the fed intensifier.

SUMMARY OF THE INVENTION

The problem that solves the invention is to provide a composition for the preparation of a binder in which gypsum molding material is to be involved as a waste product, to have an increased specific surface area with increased activity, and to create a method for its preparation which method to have increased productivity in grinding the binder and with reduced specific energy intensity of the entire production and technological process.

According to the invention, the binder composition consists of a clinker in an amount of 90 to 100%, gypsum and a grinding intensifier, dithramine. Ditramine is a mixture of ethanolamines in an amount of 0.01 to 1% with the addition of gypsum waste products, 2 to 6%, which contain calcium sulphate dihydrate above 98%.

The method of preparing the binder consists in crushing the gypsum waste which is mixed with the clinker, after which the components are ground and mixed with ditramine. Dithramine is sprayed onto gypsum waste in the initial grinding phase before mixing with clinker.

The advantages of the composition and the method of producing a binder are that a cement clinker of ordinary chemical and mineral composition is used, as a plaster regulator, waste gypsum products are used, the cement obtained is time bound within the standard requirements, the specific surface of the cement is increased by over 15% and its activity reaches from 48 to 58 MPa.

An exemplary embodiment of the invention

The invention is further explained by the exemplary embodiments of binder preparation compositions shown as follows.

In the present composition, an existing gypsum waste product from the foundry and porcelain faience industries is used as a regulator of cement bonding. These are molds or parts thereof obtained by mixing with water molding gypsum and / or a mixture of α and β-forming gypsum. After a number of cycles of use, gypsum molds lose their ability to reproduce exactly f

the size of the molding article, which makes them unusable and is disposed of as waste product that is used successfully according to the invention. The molds contain calcium sulphate dihydrate above 98%.

Example 1. Composition containing in%: clinker-98, gypsum waste-2 and ditramine 0.01 as a grinding intensifier, which is a mixture of ethanolamines.

This composition is suitable when using a clinker with a sulfur content of more than 1%. The resulting cement has a bonding time of 1 h and 25 min - beginning and end of 3 h and 50 min. The compressive strength after 28 days is 44.8 MPa. The fineness of grinding with a specific surface area of 3,370 cm ² / g is improved.

Example 2. Composition containing in%: Clinker - 94, gypsum waste - 6 and dithramine 0.25.

The composition is suitable using a low sulfur trioxide clinker - about 0.6%. The resulting cement has a bonding time of 2 h and 55 min - beginning and end of 4 h and 40 min. The compressive strength is 43.4 MPa and the grinding value with a specific surface area is improved - 3420 cm ² / g.

Example 3. Composition containing in%: Clinker - 95, gypsum waste - 5 and dithramine 0.015.

The clinker used contains about 0.9% sulfur trioxide. The resulting cement has a bonding time of 2 h and 35 min - start and end - 4 h and 10 min. The compressive strength is 55.4 MPa and the grinding fineness is the best specific surface area - 4802 cm ² / g.

The amount of the digestion intensifier - ditramine, can reach up to 1% using a very dense clinker that defines it as difficult to digest.

In addition, the resulting cements are of a high brand, making them preferred for use in various construction activities.

In some practical cases it is possible to use compositions containing clinker - 95% and gypsum waste - 5%, which after grinding show good practical properties and properties, despite the absence of dithramine. In this case, the connection time is 1 h and 55 min - start and end - 4.0 h. The compressive strength is 42.8 MPa, the grinding fineness is 3160 cm ² / g. The specific surface area obtained is lower than that of the compositions using dithramine, which results in a decrease in the compressive strength of the cement.

The essence of the binder preparation method is as follows.

The gypsum waste used is crushed in a crusher to a size of pieces of 0 to 50 mm, and then transported for grinding in a cement mill. At the outlet of the mill hopper there is a dispenser through which the crushed particles of gypsum waste are mixed with the other clinker materials and hydraulic additives and resubmitted for joint grinding, resulting in Portland cement with certain properties.

According to the invention, the used grinding intensifier - ditramine, is sprayed onto the crushed particles of gypsum waste after the dispenser under the cement mill hopper. Due to the high porosity of the crushed gypsum particles from the molding gypsum molds, the liquid milling intensifier absorbs in these particles, reducing and even stopping its evaporation and take-off, since all milling intensifiers are volatile liquids. Thus, it was of particular importance in the implementation of the method that the dithramine be sprayed onto the gypsum wastes in the initial grinding phase before mixing with the clinker.

In this way, the proposed method achieves an increase in the specific surface of the ground cement, respectively. increases its activity from 48 to 58 pH, increases the productivity of the cement mill, reducing the specific consumption of electricity for grinding cement.

Claims (2)

A composition for the preparation of a binder consisting of a clinker in an amount of 90 to 100%, gypsum and a grinding intensifier - ditramine, characterized in that ditramine is a mixture of ethanolamines in an amount of from 0.01 to 1.0 and gypsum waste in the amount of 2 to 6% containing calcium sulphate dihydrate exceeding 98% was added as gypsum. 2. A process for preparing a binder in which gypsum waste is crushed, mixed with clinker, after which the components are fed for grinding and mixed with dithramine, characterized in that the dithramine is sprayed onto the gypsum waste in the initial grinding phase , before mixing them with the clinker.