CN1381655A - Technology for making lime-sand brick cured by steam - Google Patents

Abstract

The invention relates to a production method of steam-cured lime-sand bricks, which uses a small amount of pozzolanic materials or granulated blast furnace slag; according to the quality of quicklime, sand, pozzolanic materials or granulated blast furnace slag, the mixing ratio of the three is optimized, and the formula range 8-15 parts by weight of fly ash, 6-10 parts by weight of quicklime and 75-85 parts by weight of sand. Mixing process: first grind the quicklime and pozzolanic materials or granulated blast furnace slag evenly, and then mix them evenly with sand and water. Steam curing process: Curing at constant temperature for 8 to 24 hours at a relative humidity of >95% and 80°C to 100°C. The invention can be realized by transforming a traditional lime-sand brick factory, thereby greatly reducing investment. The dosage of quicklime which is the most costly in the production is reduced, and the autoclaving process is canceled, which effectively reduces the production cost. And the product performance has reached the technical index of GB11945-1999 "Autoclaved Lime Sand Brick". The goals of energy saving, waste utilization, low cost and environmental protection are realized.

Description

A kind of production method of steam-cured lime-sand brick

technical field

The invention relates to the production technology of lime-sand bricks, in particular to a production method of steam-cured lime-sand bricks.

Background technique

Since the innovation of wall materials in our country, various new wall material industries have emerged one after another. However, due to some shortcomings in the product itself, or the traditional construction and usage habits, it is difficult to change for a while, resulting in a slow process of market acceptance of new wall materials. All kinds of bricks have the same shape as clay solid bricks and similar masonry methods, which conform to people's habits and are relatively easy to be accepted by the market. Especially in the 1950s and 1960s in our country, the autoclaved lime-sand bricks, which are now very mature, have stable product performance and mature production and application technology, and their brick shape is the same as that of clay solid bricks. The price is more reasonable, which is in line with people's traditional Construction and usage habits gradually occupy a stable market position, and the market demand is increasing, which has caused many companies to plan to invest in the construction of lime-sand brick factories or switch to lime-sand brick production.

However, traditional autoclaved sand-lime brick production requires bituminous coal or oil to provide energy for autoclave for autoclaving. The investment in autoclave equipment is large, and the burning of bituminous coal not only consumes a lot of energy, but also has high cost and pollutes the environment. At present, the Pearl River Delta region, such as Shunde, Nanhai, Foshan and other places, has banned new coal-fired boilers from the perspective of environmental protection, and the original lime-sand brick factories are gradually changing to fuel oil, otherwise they will face shutdown. If the fuel oil cost is used instead, it is very high. If the autoclave process can be canceled, the production cost of the original lime-sand brick factory can be reduced, and the investment of the new factory can also be greatly reduced. On the other hand, the imperfection of raw material mixing ratio and mixing process causes problems such as high cost and poor product performance. For example, in the existing production formula of autoclaved lime-sand bricks, the dosage of lime is generally 10-12%, and if the effective CaO content is low, the dosage can even reach 14%. Research has proved that, for the reaction, not all the lime mixed in is used for reaction, resulting in waste and increased cost; for the microstructure of lime-sand bricks, the mixed quicklime and water are not enough to fill the gaps in the sand, which is detrimental to performance . Since quicklime is the raw material with the highest cost in the production of lime-sand bricks, if a small amount of fly ash is added, the amount of quicklime is appropriately reduced, and the mixing ratio and mixing process are continuously improved, so that the lime can be fully utilized and the performance can be guaranteed. Production costs can be further reduced.

At present, the research on canceling the autoclave system at home and abroad is mainly in the aspect of changing raw materials and formulas. One is to add various activators to stimulate the activity of materials, thereby accelerating its reaction; the other is to use water such as cement and cement plant waste flue ash materials with high chemical activity; or use both at the same time. Then use the steam curing system or natural curing for 28 days to produce lime-sand bricks. Such as: "China Science and Technology Economic News Database", Southwest Economic Daily, 97, 5 (13) P3, reported that the cement steam-cured brick product developed by Wulong Zangde Building Materials Factory is a brick that adds cement and is produced by steam-curing process. "China Science and Technology Economic News Database" Building Materials Industry Information, 2000-00-05, Beijing Liulihe Huaxing Building Materials Factory uses the waste flue ash and fine sand of Liulihe Cement Factory as raw materials, mixes additives and then presses it into shape at one time. Natural curing for 28 days to produce sand-lime bricks. It solves the problem of canceling the autoclave system, but the activator is expensive, and the K ⁺ , Na ⁺ , Cl ^- , SO ₄ ^2- plasma in it is not good for the performance of the product; a large number of useful resources such as cement are used, and the product cost is high.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a production of steam-cured lime-sand bricks for the purpose of eliminating the autoclave process, reducing the amount of quicklime, and reducing production costs by optimizing the ratio of raw materials and process methods method.

The object of the present invention can be achieved through the following measures:

The present invention starts from the study of the influence of raw material quality, material mixing ratio and mixing process on the performance of lime-sand bricks. Through a large number of experiments and analysis, it finds out the use of a small amount of pozzolanic materials and granulated blast furnace slag. The pozzolanic materials include industrial waste slag powder. Coal ash or volcanic ash or tuff or zeolite or oil shale slag or burnt shale or burnt coal gangue or burnt clay or boiling slag, based on 100 parts by weight of all materials, the formula and process conditions are as follows:

(1) According to the porosity of the sand, the effective CaO content of quicklime, the quality of pozzolanic materials or granulated blast furnace slag, optimize the mixing ratio of the three within the following formula range:

   Pozzolanic material or granulated blast furnace slag 8-15 parts

6～10 parts of quicklime

Sand 75-85 parts

          Water is 12-14% of the above dry mix;

(2) Mixing process: Firstly, the pozzolanic material or granulated blast furnace slag and quicklime are ground together until the sieve residue on a 0.08mm square hole sieve is not more than 10%. To mix the ash, then mix the ash with sand and water and stir evenly;

(3) Curing process: the bricks are placed in the steam curing room, and under the condition of a relative humidity of 70% to 95%, the curing temperature is raised from room temperature to 80°C to 100°C after 4 to 6 hours; at the curing temperature, Keep the relative humidity > 95%, steam at a constant temperature for 8 to 24 hours and then cool naturally.

The dosage of pozzolanic materials or granulated blast furnace slag is related to the quality of pozzolanic materials or granulated blast furnace slag, the strength grade of lime-sand bricks produced, curing temperature and time. When other conditions are constant, the more the dosage, the higher the strength of the lime-sand brick.

The present invention aims at the essence of the above, by using a small amount of pozzolanic material or granulated blast furnace slag, its reaction with quicklime is accelerated under steam curing conditions, and the amount of ash is appropriately increased to fill the gaps in the sand; according to the effective CaO content of quicklime , the quality of pozzolanic materials or granulated blast furnace slag (mainly related to the loss on ignition), the void ratio of sand and the raw material quality, optimize the mix ratio of the three. When the mix ratio is adjusted within the formula range, sand with a void ratio of 0.40 Mix 80% and mix ash with 20% as the benchmark. When the porosity of the sand becomes larger, reduce the amount of sand and increase the amount of ash; when the porosity of the sand becomes smaller, increase the amount of sand and reduce the amount of ash to make the lime sand The brick microstructure is good, and the pozzolanic material or granulated blast furnace slag reacts fully with quicklime. Through the above measures, the amount of quicklime can be reduced, and the reaction between materials can be accelerated. At the same time, the autoclaved system can be replaced by the autoclaved system at 80-100°C. The curing temperature and time should be determined according to the actual production situation. To produce high-strength lime-sand bricks, the temperature must be high, or the time must be long; for lime-sand bricks of the same strength level, the curing temperature is increased and the curing time is shortened.

The present invention has the following advantages:

1. Starting from the existing problems in the production of autoclaved lime-sand bricks, only by optimizing the mixing ratio of raw materials and the mixing and steam curing process, the autoclaved process can be canceled and the amount of quicklime can be reduced without adding any activator The purpose, and the product performance reaches the technical index of GB11945-1999 "Autoclaved Lime-sand Brick". The data about raw material quality, mix ratio, curing conditions and strength of Lime-sand brick are shown in Table 1.

2. The production method of this steam-cured lime-sand brick is simple and feasible. Except for the use of a small amount of industrial waste slag fly ash with abundant sources and low price, the raw materials are the same as the traditional lime-sand brick; except for the change of the maintenance system, the rest of the production process is the same as the traditional limestone Sand bricks are the same, and the investment in plant construction can be greatly reduced by transforming the traditional lime-sand brick factory.

3. Cancel the autoclave process with high cost and environmental pollution, realize the steam curing process, reduce the lime consumption which is the most costly in production, and greatly reduce the production cost.

4. The cost of the steam-cured lime-sand brick produced by this method is reduced, the performance is excellent, and the market competitiveness of the product is greatly enhanced, which will accelerate the popularization and application of new wall materials. At the same time, the purpose of energy saving, waste utilization, low cost and environmental protection has been achieved in the production of wall materials, thereby promoting the technological progress of the new wall material industry.

Detailed ways

Example 1:

Fly ash from Guangzhou Huangpu Power Plant, quicklime for construction products, and quality requirements of Xijiang river sand in Shunde, Guangdong are shown in Table 1. First, 12 parts by weight of fly ash and 8 parts by weight of quicklime are ground and mixed uniformly, then 80 parts by weight of sand and water with a weight of 12% of the dry mixture are added and stirred evenly. After 4 hours of digestion, the secondary stirring is carried out. Press 70 tons of pressure to press into adobe. Put the adobe into the steam-curing room. Under the condition of relative humidity of 70%-95%, it will rise from room temperature to the curing temperature of 95°C after 4-6 hours. Cool and make lime-sand bricks. Test strength according to GB/T2542-92, see Table 1 for details, and reach the MU10 level in GB11945-1999.

Embodiment 2～5:

On the basis of Example 1, change the pozzolanic material, that is, use Guangdong Meixian volcanic ash, Guangdong Heping County zeolite, burnt clay, and Guangdong Shaogang slag instead of fly ash. The formula, molding, maintenance and strength testing are shown in Table 1. All have reached the MU10 level in GB11945-1999.

Embodiment 6～9:

Fly ash from Guangzhou Huangpu Power Plant, quicklime for building products, and sand from Xijiang river in Shunde, Guangdong are used. See Table 1 for the quality requirements of raw materials. First, 15 parts by weight of fly ash and 10 parts by weight of quicklime are ground and mixed uniformly, then 75 parts by weight of sand and 12% of the weight of the dry mixture are added and stirred evenly. After 4 hours of digestion, the secondary stirring is carried out. Press 70 tons of pressure to press into adobes, and the adobes are put into the steam curing room. In this embodiment, under the condition that the ratio of raw materials remains unchanged, the curing temperature and time are changed, see Table 1 for details, and the relative humidity is kept > 95% for constant temperature steam curing; then naturally cooled to make sand-lime bricks. Test strength according to GB/T2542-92, product testing results are shown in Table 1.

Example 10:

Adopt the same Guangzhou Huangpu Power Plant fly ash and building products quicklime with embodiment 1 and 9, adopt the sand of three kinds of different porosity namely embodiment 1,9,10 porosity is respectively 0.40,0.42,0.37, according to table 1 The formula changes the amount of mixed lime to ensure the microstructure and strength of lime-sand bricks. Molding and curing are carried out according to the process conditions of Example 1. The product testing results are shown in Table 1.

Example 11:

Adopt the same Guangzhou Huangpu Power Plant fly ash and Guangdong Shunde Xijiang river sand as example 1, the difference is to adopt different quicklime for building products, that is, the effective CaO content of quicklime in embodiment 1 is 73%, and the effective CaO content in quicklime in embodiment 11 is 80%. According to the formula in Table 1, the higher the effective CaO content in the quicklime, the lower the amount of quicklime, and the corresponding increase in the amount of fly ash to ensure the microstructure and strength of the lime-sand brick. Molding and curing are carried out according to the process conditions of Example 1. The product testing results are shown in Table 1.

Example 12:

Adopt quicklime for building products identical with embodiment 1 and sand from the river in Shunde, Guangdong, fly ash of different loss on ignition, see Table 1 for details, adopt two kinds of different fly ash of Guangzhou Huangpu Power Plant that is embodiment 1 and 12 The losses on ignition were 4.70% and 2.88%, respectively. According to Example 1 formula, molding, curing and testing strength, see Table 1. It can be seen from the data in Table 1 that for the same formula, the strength of lime-sand bricks made of fly ash with a small loss on ignition is one level higher than that of fly ash with a large loss on ignition.

Table 1 Example serial number Raw material and quality Fly ash: quicklime: sand mix ratio (%) Conservation conditions Flexural strength (MPa) Compressive strength (MPa) power level pozzolanic material or sand Quicklime (effective CaO content%) Sand (porosity) temperature(℃) time (h) average monoblock average monoblock 1 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.40 12:8:80 95 twenty four 3.0 2.4 14.8 11.5 MU10 2 Volcanic ash in Meixian, Guangdong 73 0.40 12:8:80 95 twenty four 2.6 2.0 13.5 10.3 MU10 3 Guangdong Heping County Zeolite 73 0.40 12:8:80 95 twenty four 2.8 2.3 14.2 11.0 MU10 4 burnt clay 73 0.40 12:8:80 95 twenty four 2.7 2.1 13.9 10.6 MU10 5 Guangdong Shaogang Slag 73 0.40 14:6:80 95 twenty four 3.0 2.6 14.8 11.7 MU10 6 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.42 15:10:75 80 twenty four 2.5 2.0 10.2 8.0 MU10 7 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.42 15:10:75 90 16 2.6 2.2 11.6 8.7 MU10 8 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.42 15:10:75 100 8 2.5 2.1 10.4 8.1 MU10 9 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.42 15:10:75 95 twenty four 3.8 3.5 20.2 16.5 MU15 10 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 73 0.37 8.5:6.5:85 95 twenty four 2.5 2.0 10.7 8.2 MU10 11 Guangzhou Huangpu Power Plant fly ash, loss on ignition 4.70% 80 0.40 13:7:80 95 twenty four 2.9 2.3 14.7 11.4 MU10 12 Guangzhou Huangpu Power Plant fly ash, loss on ignition 2.88% 73 0.40 12:8:80 95 twenty four 3.3 2.7 17.1 13.3 MU15

Claims (3)

1. A production method for steam-cured lime-sand bricks, which uses unslaked lime and sand as raw materials, and stirs with water evenly, through digestion, secondary stirring, molding, and produces lime-sand bricks after maintenance, which is characterized in that a small amount of volcanic ash is used quality material or granulated blast furnace slag, based on 100 parts by weight of all materials, the formula and process conditions are as follows: (1) According to the porosity of sand, effective CaO content of quicklime, pozzolanic material or granulated blast furnace   Slag quality and quality, optimize the ratio of the three within the following formula range:     Pozzolanic material or granulated blast furnace slag 8-15 parts 6～10 parts of quicklime 75～85 parts of sand         Water is 12-14% of the above dry mix; (2) Mixing process: First, the pozzolanic material or granulated blast furnace slag and quicklime are ground together until The 0.08mm square hole sieve residue is not more than 10%. The sieved and unsifted materials are mixed evenly. The uniform material is mixed ash, and then the ash is mixed with sand and water to mix evenly; (3) Curing process: the adobe is placed in a steam curing room, and the relative humidity is 70% to 95%. The temperature rises from room temperature to 80°C to 100°C after 4 to 6 hours is the curing temperature; at the curing temperature,   Keep the relative humidity > 95%, steam at a constant temperature for 8 to 24 hours and then cool naturally. 2. The production method of a kind of steam-cured lime-sand brick according to claim 1, wherein the pozzolanic material refers to industrial waste slag fly ash or volcanic ash or tuff or zeolite or oil shale slag or burned shale or burned shale. Coal gangue or burnt clay or boiling slag. 3. The production method of a kind of steam-cured lime-sand brick according to claim 1, characterized in that when the mixing ratio is adjusted within the formula range, 80% of the sand with a porosity of 0.40 and 20% of the ash are used as a benchmark , when the porosity of the sand becomes larger, reduce the amount of sand and increase the amount of ash mixed; when the porosity of the sand becomes smaller, increase the amount of sand and reduce the amount of ash mixed.