DE3636659A1 - ACTIVATED ASH CEMENT AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

The invention relates to activated ash cement, which at Building instead of cement mortar and concrete is used, and Process for its production.

They are cements containing ash from thermal power stations up to 30% without activating chemical additive known. However, increasing the amount of ash leads to one substantial increase in duration for the beginning and the end of the setting time. Another proposal is known for activating cements with a high content of Ash from thermal power stations (DE-PS 27 40 114). This suggestion has not found any practical application since it does not ensures high early strengths that a normal Aftertreatment and thermal processing of the Concretes are required. There are other procedures too for the production of cements known (DE-PS 30 20 384 and 24 35 000), which, however, mainly the activation of cements treat with a high content of slag. It is also a process for making activated plasticized ash cement known where that Activation with a chemical supplement based on potassium Connections is carried out, but the deficiency are, the plasticizer is an unpleasant one Smell and sticking to the walls of the cement mill evokes. The processes for producing the above Cements are conventional processes.

The object of the invention is an activated ash To develop cement and process for its production, whereby the grinding process is improved and the setting and Curing time of the cement is controlled and the cement one  have normal time for setting and curing should and also increased strengths in the early and later hardening times compared to the known cements of this kind.

This task was as from the preceding claims obviously solved. The cement has the following composition: 40 to 55 parts by weight of Portland cement clinker, the latter being characterized by an allite content of awards over 50%; 1.5 to 5 parts by weight of natural gypsum - Gypsum stone or phosphogypsum; 35 to 55 parts by weight of ash of electrostatic precipitators in a thermal power station, distinguishes that the sum of silicon dioxide, dialuminium trioxide and total diferrotrioxide not less than 75% the sulfate content is not more than 5% and the Calcium oxide and magnesium oxide content is approx. 8%; chemical additive containing 0.5 to 2% by weight Dry substance water glass (aqueous potassium sodium silicate Solution); 0.25 to 1% by weight of dry substance monoethylene glycol; 0.2 to 1 part by weight of sodium nitrate; 0.2 to 0.8% by weight Parts of sodium carbonate and 3 to 6 parts by weight of cement dust.

A process for the production of activated ash cement is that the Portland cement clinker and the plaster in a manner known per se the first section the cement mill is fed, where as well as the one uniform product manufactured chemical aggregate is introduced while the ashes from the electrostatic precipitators the third section of the cement mill or is supplied together with the other products, whereby the duration of the grinding process is not greater than the duration of the Grinding process of ordinary Portland cement from the same clinker.

The advantages of the invention are as follows: The materials used are not difficult and call  no technological changes in production and application of the cements. They contribute to improvement of the grinding process and regulate the setting and curing times.

Compared to the known cements of this type the strengths in the early and later curing times elevated. By feeding the ashes into the third Chamber of cement mill becomes the performance of the latter increased up to 40%.

Example 1 Portland cement clinker

In a mixer with a stirrer, the activator is first Supplement made, the entrained cement the sodium carbonate and sodium nitrate in the dry Condition be homogenized. After that, use water glass and monoethylene glycol added and until complete Homogenize the mixture further stirred. It a slightly granular yellowish mixture is obtained.

To produce the activated ash cement, the first section of the clinker cement mill, the plaster  and the activating surcharge simultaneously fed and after this is ground to a necessary fineness the ash is the last section of the Cement mill fed, the duration of the grinding process is no greater than this for making one Ordinary Portland cement PZ 350 and 20 PZ 350. The cement grade 350 produced has the following Compressive strength on: the first day - not less than 5 MPa, on the third day - not less than 14 MPa, on seventh day - not less than 27 MPa and on the 28th day not less than 35 MPa. For quality class 450 are this data as follows: on the first day - not less than 8 MPa, on the third day - not less than 20 MPa, on seventh day - not less than 32 MPa and on day 28 - not less than 45 MPa.

Example 2

The method of preparation is the same as that given in Example 1. The cement produced also has the same grades on.

Example 3 for a higher strength cement.

The procedure of production is as in Example 1.

Table 1 shows data for one in industrial conditions manufactured activated ash-cement grade 350 indicated on the basis of clinker, with a chemical mineral composition, listed in Table 2 and ashes from the electrostatic precipitators of a thermal power station (Table 2), tested according to the Bulgarian state Standard 72-74.  

Table 1

Table 2

Table 3

Industrial trial

Table 3 (continued)

Claims (3)

1. Activated ash cement, containing 40 to 55 parts by weight of Portland cement clinker, characterized in that it also contains 1.5 to 4 parts by weight of gypsum or phosphor gypsum, 35 to 55 parts by weight of ash from the electrostatic precipitators Thermal power station, 1.5 to 2 parts by weight of water glass, 0.25 to 1.0 parts by weight of monoethylene glycol, 0.2 to 0.8 parts by weight of sodium carbonate, 0.2 to 1.0 parts by weight Contains sodium nitrate and 3.0 to 6.0 parts by weight of entrained cement. 2. Activated ash cement according to claim 1, characterized characterized in that the content of allite in Portland cement clinker is 50 to 70%. 3. Process for producing an activated ash cement according to claim 1, wherein the Portland cement  Clinker and the plaster the first section of the cement mill are fed, characterized, that the chemical aggregate and the ashes from the electrostatic precipitators sequentially fed, the duration the process of grinding that of ordinary Portland cement is the same, or the ashes from the electrostatic precipitators third section of the cement mill is fed, wherein the duration of the grinding process is shorter than that of the ordinary Portland cement is.