DE3321899A1 - Process for the manufacture of masonry bricks - Google Patents

Abstract

In a process for the manufacture of masonry bricks from crushed granulated slag, fly ash as filler and hydrated lime as binder, in which the components are mixed, the moisture content of the mix is adjusted, the mix is pressed to form bricks and the bricks are hardened under steam pressure at an elevated temperature, it is proposed, for increasing the compressive strength, that 5-6% by weight of hydrated white lime, 10-12% by weight of filter ash from coal-fired power stations and 82-85% by weight of granulated slag from slag-tapping furnaces, relative to the solids content of the above components, are mixed with one another and the mix is adjusted to a moisture content of 4-8% by weight and pressed under a pressing force of at least 4000 kN. <IMAGE>

Description

Keyword: brick

Ref .: 664 Method for the production of bricks The invention relates to a process for the production of bricks from broken slag granulate, Fly ash as a filler and hydrated lime as a binder, in which the components are mixed, the moisture content of the mixture adjusted, the mixture pressed into stones and the stones are hardened under steam pressure at an elevated temperature.

From "Mitteilungen der VGB", 1955, pp. 779 - 780, especially illustration 19, such a process is known in which the hydrate is produced from carbide production is used as a binder. Information about the stone composition is not given made.

The applicant has her from Figure 12, page 778 of the above cited reference known method to the use of hydrate lime rearranged and set the task, compared to your procedure and the one above described method to improve the strength of the bricks.

This object is achieved in that 5 - 6 wt .-% white lime hydrate, 10-12% by weight of hard coal-fired power plant filter ash and 82-85% by weight of melting chamber granulate based to the solids content of the above components mixed together and the Mixture is adjusted to a moisture content of 4 - 8 wt .-% and the Mixture is pressed with a pressure of at least 4,000 kN.

It has surprisingly been found that within the above stated limits of the mixture composition compressive strengths up to approx. 350 kp / cm2 can be achieved and, if there is a deviation from the limits, a clearer one There is a drop in compressive strength.

When adjusting the humidity, the water must be taken into account that may stick to the melting chamber granulate, if this soon used after withdrawal from the granulation basin of the firing of a hard coal-fired power station will. The granulate is preferably transferred from the granulating basin to a drainage silo introduced, in which the moisture is reduced to around 5 wt .-%.

Preferably the moisture content of the mixture is 5 - 6% set.

The hardening is expediently carried out at 14-16 bar and at one Temperature from 180 - 2200C, with a pressure of 16 bar and a steam temperature of 1800C is preferred, Preferably the melting chamber granulate in itself known way broken by impact splitting, before or after the impact splitting Coarse fractions, e.g. B.

> 10 mm, must be screened off. In the known method according to the illustration 19 is also pre-screened, but only the coarse fractions in introduced the crusher, the fines directly into a Slag silo be introduced. There is a risk that the fine grain of the granulate will still be is not sufficiently relaxed.

It is useful if the curing time is 4 - 6 hours.

The method is to be described in more detail using the attached figure.

Raw granulate is fed into a feed hopper 1 and out of this A bucket elevator 3 is fed via a discharge belt 2. This comes from bucket elevator 3 Feed material into a screening machine 4, in the coarse fractions that are greater than. 10 mm are be screened off and discharged via a chute 5 as oversized grain. That on Oversized grain screened out in this way before impact splitting can be used with particular advantage Drainage material can be used. The grain size <10 mm is in an impact splitter 6 relaxed and introduced from there into a storage silo 7. via a metering device 8 and a belt conveyor 9, the processed granulate arrives in a scale 10 and from there in the desired amount into a mixer 11. Above the mixer 11 is a two-chamber silo 12 arranged, one chamber with white lime hydrate and one with another chamber with hard coal-fired power plant filter ash over charging devices, not shown be filled. These two components are dosed via the mixer 11 Scales 10 supplied by means of rotary feeders 13 and 14. The mixer 11 prepares with the addition of water, the mixture is then fed via a rubber belt conveyor 15 and a bucket elevator 16 is conveyed into a storage container 17.

Here takes place the complete hydration of the white lime hydrate and the unlocking of the pozzolanic properties of the fly ash. About a Volume 18 and a mixing screw 19 passes the material to press 20; on which, depending on the format set used in the press, different stone formats be pressed with a pressure of at least 4,000 kN.

The fresh pellets are loaded on a belt 21 of a hardening car 22 and automatically stacked on the hardening trolley. Before hardening kettles are 24 the hardening trolleys are put together to form autoclave-compatible batches on a parking space 23. The compacts then get into the hardening kettle 24 and are there by high tension Steam of 16 bar at a temperature of 2000C autoclave hardened in 4 - 6 hours. The finished bricks are then transferred to a final or loading point 25 transported and stacked here with a gantry crane 26. The empty hardship cars automatically roll back to the press.

That when discharging the stones from the press and when loading the Mixture falling from the hardening trolley is fed via a chute 22.1, a belt 22.2 Bucket elevator 22.3 and a belt 22.4 are fed back into the circuit.

If the stone factory is located on the site of the power plant, from which the filter ash and the granules are drawn off, the steam for the Hardening boiler 24 preferably withdrawn from the power plant, e.g. B.

as extraction steam.

Example 1,200 kg of granules with a grain size of -10 mm, 160 kg of filter ash and 80 kg of white lime hydrate are mixed together with the addition of a total of 68 l of water mixed and pressed with 4,000 kN. The compacts are steamed for 4 hours Hardened at 2000C and 16 bar.

Claims (6)

Keyword: Brick Az. 664 Process for the production of bricks Claims 1. A method for the production of bricks from broken slag granules, Fly ash as a filler and hydrated lime as a binder, in which the components are mixed, the moisture content of the mixture adjusted, the mixture pressed into stones and the stones are hardened under steam pressure at an elevated temperature, thereby characterized in that 5 - 6 wt .-% white lime hydrate, 10-12 wt .-% hard coal-fired power plant filter ash and 82-85 wt. melting chamber granules based on the solids content of the above Components are mixed together and the mixture adjusted to a moisture content of 4 - 8 wt .-% is set and the mixture with a pressure of at least 4,000 kN is pressed. 2. The method according to claim 1, characterized in that the moisture content the mixture is adjusted to 5-6 wt. 3. The method according to claim 1 or 2, characterized in that the Curing takes place at 14 - 16 bar and a steam temperature of 180 - 2200C. 4. The method according to any one of claims 1-characterized in that the granulate is broken in a manner known per se by impact gaps. 5. The method according to any one of claims 1 - 4, characterized in that that coarse fractions, preferably> 10 mm, are used as drainage means before breaking be screened. 6. The method according to any one of claims 1 - 5, characterized in, that the pressing takes place with a pressure in the range of 4,000 - 12,000 kN.