Full fly ash building brick and its manufacturing method and special additive

Abstract

A flyash brick for building is prepared from the flyash (90-96 wt.%) and the composite additive (4-10 wt%) containing water glass, alkaline oxide or the alkaline compounds, bentone, and iron oxide. Its advantages are high strength and low cost.

Description

technical field [0001] The invention relates to a building brick using fly ash as a raw material, a manufacturing method thereof and a special additive for producing the building brick. Background technique [0002] There are many mature technologies of using fly ash as raw material to produce building bricks, but most of the fly ash bricks in the prior art have a relatively low content, generally not more than 40%, and the rest of the raw materials are mostly high-quality clay with high plasticity, or crushed The clayey coal gangue or clayey shale (crushed), some of which are all of the above raw materials. Its production process is mainly based on wet production, that is, the amount of water added is more than 20%, and vacuum extrusion is formed. It requires the plasticity index of the blank to be greater than 7, so a series of large power equipment must be used to meet the technical requirements of raw material pretreatment, stirring and kneading. Therefore, a large amo...

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Problems solved by technology

Therefore, a large amount of money is occupied in equipment investment, and the inevitable result of high power consumption and high product cost is also brought about at the same time. Therefore, this product is difficult to be recognized by the market and is not enough to compete with clay bricks.

Second, the above-mentioned ratio of raw materials still requires a large amount of clay materials, which neither conforms to the national policy on the protection of cultivated land and natural ecology and the reform of wall materials, nor can it really meet the requirements of fly ash treatment

Third, most of the existing fly ash bricks are not strong enough, and they are mostly used as partition wall material bricks. However, after the country adopts the policy of restricting clay bricks, new load-bearing wall bricks are needed to replace clay bricks in low-rise buildings in the market

Converted by percentage, the maximum content of fly ash can only reach 86.36%, while the more expensive sodium-based bentonite and modified additives are at least 13.64%. The cost of the finished product is obviously high, and it is difficult to gain a foothold in the market

In addition, the fly ash brick production method adopts wet production, and the water content reaches 18-22%. The mixture must be pretreated by high-powered mud kneading and extrusion cutting. The investment of such equipment is relatively large. Moreover, the energy consumption is very high, and the cost of making bricks is also relatively high, so it is difficult to promote on a large scale, and its products also lack competitiveness

Moreover, due to its high water content, the drying time will inevitably increase, even if it is dried with hot air, it usually takes 8-14 hours

Third, since the basic composition of fly ash is silicon dioxide and aluminum oxide microbeads, both of which have relatively high hardness, it is difficult to crush most of the microbeads by ordinary rolling

[0004] Chinese patent 91110966.8 discloses a "fly ash brick and its production process". The fly ash content of the fly ash brick can reach more than 95%, and the remaining 3-5% water glass is used as a binder. Is the water glass content is too high

At present, the price of water glass in the market is 700 yuan per ton. According to the calculation of 5% blending, the cost of water glass equivalent to each standard brick is 0.07 yuan, which is almost the same as the price of clay bricks in the current market. Adding other costs, each brick The cost is about 0.15 yuan, making it difficult for the market to bear

In addition, the fly ash component of the brick is complicated in the production process and takes a long time, and the drying time is relatively long. In an artificial environment, it still takes 36-48 hours to dry with a drying medium.

The roasting time is about 17-20 hours, and the temperature needs to be increased stepwise during the roasting process, the process control is not easy to master, and the quality of the bricks is difficult to guarantee