CN106904848A - The method and its product of easy fired belite calcium sulphoaluminate sulphur calcium silicate cement - Google Patents

Abstract

The invention discloses a low-temperature firing method of belite-calcium sulfoaluminate-calcium sulfosilicate cement, comprising the following steps: step a, mixing industrial waste residue with industrial gypsum, adding water and mixing according to the water-cement ratio of 0.3-0.41 , After grinding for 15-60 minutes, pour the slurry into the mold, demould after molding, and obtain the sample. In step b, the above-mentioned sample is cured at a constant temperature, the curing temperature is 60-150° C., and the curing time is 3-9 hours; preferably, the curing temperature is 80-130° C., and the curing time is 3-4 hours. In step c, calcining at 750-1150° C. for 60-120 min, taking out the calcined sample from the high-temperature furnace, cooling rapidly, and obtaining the product after grinding. The present invention does not use limestone, does not generate a large amount of carbon dioxide, increases the environmental pressure, and on the other hand, has a low calcining temperature and low energy consumption. Therefore, the present invention is a low-carbon, green preparation method.

Description

A low-temperature burning method of Belite-calcium sulfoaluminate-calcium sulfosilicate cement and its products

technical field

The invention belongs to the field of material technology, and relates to a preparation method of Belite-calcium sulfoaluminate-calcium sulfosilicate cement and its products, in particular to a low-temperature fired Belite-calcium sulfoaluminate-sulfur silicon Calcium acid cement method and products thereof.

Background technique

Today's world is developing rapidly. While people's material life is being improved, people are more and more concerned about the earth on which we live. As the most widely used building material—cement, it plays an important role in the progress of human society and social and economic development. It also produces high energy and resource consumption and greenhouse gas emissions. Usually, ordinary Portland cement has a calcium oxide content of about 66%, which accounts for 50-70% of the alite mineral in the clinker, that is, the formation of tricalcium silicate The temperature is about 1450°C. The mineral contains calcium oxide up to 73.7%, and the energy consumption of CaCO ₃ decomposition accounts for about 46% of the theoretical heat consumption of clinker, resulting in high energy consumption for general-purpose Portland cement clinker firing; Belite mineral, that is, dicalcium silicate , It can be formed quickly at a temperature higher than 1250°C, so it can be formed at a lower kiln temperature. In addition, the CaO content in Belite is 65.1%, which is lower than the 73.7% CaO content in Alite, and the required limestone The amount of calcium sulphoaluminate anhydrous (3CaO·3SiO ₂ ·CaSO ₄ ), the resulting energy consumption and carbon emissions are also reduced accordingly, and the early hydration rate is low; The formation temperature is low (1300°C), and like C ₂ S, it has the characteristics of energy saving and low CO ₂ emission, and the mineral has the characteristics of improving early strength. The hydration has the characteristics of "small at both ends and large in the middle". In the initial period of 0-6h, the hydration reaction is slow and the AFT content is low. In the middle period of 6h-3d, the hydration rate is the fastest, and most of the hydration reactions are concentrated in this stage. Reaction, but the rate is greatly slowed down. Calcium sulfosilicate, also known as Tesinite, has always been considered an inert material, but it is actually an active material, which can usually be formed at 950-1200 ° C and can be formed on the second day of hydration It can be quickly hydrated to form ettringite. In order to reduce energy consumption and carbon dioxide gas emissions in the cement production process, research on low-alumina or high-silicon sulfur-aluminate cement has been launched on a large scale at home and abroad.

The existing method for preparing calcium sulfosilicate, such as the Chinese patent application with application number 201510066039.8, discloses a sulfoaluminate cement, which requires secondary calcination according to the set calcination temperature and holding time; application number is 201510066040.0 The Chinese patent application disclosed a preparation method of calcium sulfosilicate, the calcination temperature is 1100 ~ 1250 ℃, heat preservation 2 ~ 8h. The above method has the following disadvantages (1) secondary calcination is required, the procedure is complicated, and the temperature of the first calcination is high; (2) the required holding time is long and the energy consumption is large. Whether it is possible to develop a cement containing calcium sulfosilicate synthesized at one time at low temperature, which can not only overcome the above-mentioned deficiencies of complex process and high energy consumption in the prior art, but also realize effective treatment of waste residue, is a topic worthy of research in this field .

Contents of the invention

Purpose of the invention: In order to meet the requirements of sustainable development, the present invention provides a low-temperature fired belite-calcium sulfoaluminate- Calcium sulfosilicate cement method and its products, the method only needs to be calcined once, the holding time is short, the calcining temperature is low, and the comprehensive utilization of waste is realized

Technical solution: The method for one-time low-temperature firing of Belite-calcium sulfoaluminate-calcium sulfosilicate cement according to the present invention comprises the following steps:

Step a: Mix industrial waste residue with industrial gypsum, add water and mix according to the water-cement ratio of 0.3-0.41, grind for 15-60 minutes, pour the slurry into a mold, demould after molding, and obtain a sample.

In step b, the above-mentioned sample is cured at a constant temperature, the curing temperature is 60-150° C., and the curing time is 3-9 hours; preferably, the curing temperature is 80-130° C., and the curing time is 3-4 hours.

In step c, calcining at 750-1150° C. for 60-120 min, taking out the calcined sample from the high-temperature furnace, cooling rapidly, and obtaining the product after grinding. The preferred calcination temperature is 1050°C and the calcination time is 120min.

There is also an alternative in the present invention, that is: replace the above steps a and b with: mix industrial waste residue, industrial gypsum and hydration product waste, add water to mix at 0.1-0.2, mix uniformly, and obtain a sample , and then proceed to step c.

Specifically, for the above two schemes, the industrial gypsum is desulfurized gypsum or phosphogypsum.

The industrial waste slag includes silicon-aluminum raw materials, aluminum raw materials, and calcareous raw materials; wherein the silicon-aluminum raw materials are calcium-increased liquid slag and coal gangue; the aluminum raw materials are tailings bauxite; the calcium raw materials are calcium carbide slag, Sugar filter sludge or lime dried sludge.

The hydrated product waste is silicon-calcium-aluminum raw material. Such as pipe pile residual slurry and waste concrete fines.

More specifically, the ratio of raw materials in the above steps is: silicon-aluminum raw material or silicon-calcium raw material: aluminum raw material: industrial gypsum: calcium raw material = 10.77-54.12%: 5.67-30.97%: 5.95-15.28%: 18.73-61.26%.

For the grinding in the above steps, the specific surface area is 350-420 m ² /kg.

It is found in the research that the hydrothermal precursor used in the present invention has a great influence on the mechanical properties of the cement product. The hydrothermal reaction described in the present invention is to carry out constant temperature maintenance on the sample after demoulding. The best curing conditions are: The curing temperature is 80-130°C, and the curing time is 3-4 hours. The optimum calcination conditions are: the calcination temperature is 1050°C, and the calcination time is 120min.

The product prepared by the preparation method described in this application, the product contains C ₂ S: 33-62%; 30-42%; 8-25%.

Beneficial effect: the method of firing Belite-sulfoaluminate-calcium sulfosilicate cement at one time of the present invention reduces the performance of Belite-sulfoaluminate-calcium sulfosilicate cement through a suitable hydrothermal precursor. The firing temperature reduces energy consumption, and the performance of Belite-sulfoaluminate-calcium sulfosilicate cement is improved through proper proportioning and process, realizing the preparation of low-carbon Belite-sulfoaluminate at low temperature Salt-calcium sulfosilicate cement.

The present invention directly uses industrial waste residue and industrial gypsum as raw materials. The industrial waste residue contains CaO, SiO ₂ , Al ₂ O ₃ and SO ₃ , so the raw material does not need modification or other treatment, which saves the processing cost and improves the raw material utilization rate. The initial cost is greatly reduced, and the environmental problems caused by industrial waste residues are solved at the same time. Moreover, the present invention does not use limestone, does not generate a large amount of carbon dioxide, increases environmental pressure, and on the other hand, has a low calcining temperature and low energy consumption. Therefore, the present invention is a low-carbon, green preparation method.

detailed description:

The present invention will be further described below in conjunction with specific examples. The components of the raw materials used in this example are shown in Table 1.

Table 1 Main chemical composition of raw materials (%)

raw material CaO coal gangue 1.44 58.00 17.66 1.70 Carbide slag 65.57 4.27 2.56 1.20 sugar filter mud 46.67 1.96 1.09 1.76 lime dried sludge 50.48 6.10 1.45 —— Desulfurization gypsum 30.90 2.50 2.73 44.00 Phosphogypsum 28.67 4.11 0.62 40.53 Tailings bauxite 0.48 8.3 39.05 —— Calcium-enriched liquid slag 15.00 35.00 18.00 —— Pile residual slurry 28.93 21.38 3.00 ——

Example 1

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 2.

Table 2 Embodiment 1 raw material ratio and water consumption

Example 1 coal gangue Tailings bauxite Desulfurization gypsum sugar filter mud water Mass/g 203.6 118.4 65.4 612.6 373

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the ratio and place them in a planetary mill, add water, grind for 15 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Hydrothermal synthesis: put the above sample in a digital display constant temperature stirring circulation curing box that has been heated to a set temperature of 60°C, take it out and cool it after constant temperature curing for 9 hours;

3) Calcination: After the cooled block sample is crushed, it is placed in a high-temperature furnace, calcined at 950°C for 90 minutes, taken out for rapid cooling, and ground by a ball mill until the specific surface area is 350m ² /kg to obtain Belite-sulfur Calcium aluminate-calcium sulfosilicate cement.

The measured properties of the cement are shown in Table 3.

Table 3 Example 1 prepared Beilite-calcium sulfoaluminate-calcium sulfosilicate cement performance table

Example 2:

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 4.

Table 4 embodiment 2 raw material ratio and water consumption

Example 2 Pile residual slurry Tailings bauxite Phosphogypsum Carbide slag water Mass/g 538.4 205.1 69.2 187.3 150

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the ratio and place them in a planetary mill, add water, grind for 15 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Calcination: put the block sample in a high-temperature furnace, calcinate at 750°C for 80 minutes, take it out for rapid cooling, and grind it with a ball mill until the specific surface area is 370m ² /kg to obtain Belit-calcium sulfoaluminate-sulfosilicate calcium cement.

The measured properties of the cement are shown in Table 5.

Table 5 Example 2 prepared Beilite-calcium sulfoaluminate-calcium sulfosilicate cement performance table

Example 3:

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 6.

Table 6 embodiment 3 raw material ratio and water consumption

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the ratio and place them in a planetary mill, add water, grind for 20 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Hydrothermal synthesis: Place the above sample in an autoclave that has been heated to a set temperature of 130°C, and take it out to cool after constant temperature curing for 4.5 hours;

3) Calcination: After the cooled block sample is crushed, it is placed in a high-temperature furnace, calcined at 1050°C for 120 minutes, taken out for rapid cooling, and ground by a ball mill until the specific surface area is 390m ² /kg to obtain Belite-sulfur Calcium aluminate-calcium sulfosilicate cement.

The measured properties of the cement are shown in Table 7.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 7 embodiment 3 makes

Example 4

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 8.

Table 8 embodiment 4 raw material ratio and water consumption

Example 4 Pile residual slurry Tailings bauxite Desulfurization gypsum Carbide slag water Mass/g 541.2 206.2 64.1 188.5 110

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in the planetary mill, add water, grind for 20 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Calcination: put the block sample in a high-temperature furnace, calcinate at 900°C for 60 minutes, take it out for rapid cooling, and grind it with a ball mill until the specific surface area is 400m ² /kg to obtain Belit-calcium sulfoaluminate-sulfosilicate calcium cement.

The measured properties of the cement are shown in Table 9.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 9 embodiment 4 makes

Example 5

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 10.

Table 10 Embodiment 5 raw material proportioning and water consumption

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in the planetary mill, add water, grind for 45 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Hydrothermal synthesis: Place the above sample in an autoclave that has been heated to a set temperature of 100°C, take it out and cool it after constant temperature curing for 6 hours;

3) Calcination: After the cooled block sample is crushed, it is placed in a high-temperature furnace, calcined at 850°C for 90 minutes, taken out for rapid cooling, and ground by a ball mill until the specific surface area is 340m ² /kg to obtain Belite-sulfur Calcium aluminate-calcium sulfosilicate cement.

The measured properties of the cement are shown in Table 11.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 11 embodiment 5 makes

Example 6

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 12.

Table 12 embodiment 6 raw material ratio and water consumption

Example 6 Pile residual slurry Tailings bauxite Desulfurization gypsum Carbide slag water Mass/g 309.1 309.7 126.2 255 200

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in a planetary mill, add water, and grind for 60 minutes. After taking it out, pour the slurry into the mold, and demould after molding to obtain a block sample;

2) Calcination: put the block sample in a high-temperature furnace, calcinate at 900°C for 120 minutes, take it out for rapid cooling, and grind it with a ball mill until the specific surface area is 360m ² /kg to obtain Belit-calcium sulfoaluminate-sulfosilicate calcium cement.

The measured properties of the cement are shown in Table 13.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 13 embodiment 6 makes

Example 7

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 14.

Table 14 embodiment 7 raw material ratio and water consumption

Example 7 Calcium-enriched liquid slag Tailings bauxite Phosphogypsum Carbide slag water Mass/g 210.7 248.5 152.8 388 320

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in a planetary mill, add water, grind for 5 hours, take out and pour the slurry into the mold, demould after molding, and obtain a block sample;

2) Hydrothermal synthesis: Place the above sample in an autoclave that has been heated to a set temperature of 120°C, and take it out to cool after constant temperature curing for 3.5 hours;

3) Calcination: After the cooled block sample is crushed, it is placed in a high-temperature furnace, calcined at 1000°C for 60 minutes, taken out for rapid cooling, and ground by a ball mill until the specific surface area is 360m ² /kg to obtain Belite-sulfur Calcium aluminate-calcium sulfosilicate cement.

The measured properties of the cement are shown in Table 15.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 15 embodiment 7 makes

Example 8

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 16.

Table 16 embodiment 8 raw material ratio and water consumption

Example 8 Pile residual slurry Tailings bauxite Desulfurization gypsum Carbide slag water Mass/g 502.2 191.3 59.5 247 130

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in a planetary mill, add water, and grind for 60 minutes. After taking it out, pour the slurry into the mold, and demould after molding to obtain a block sample;

2) Calcination: put the block sample in a high-temperature furnace, calcinate at 1000°C for 90 minutes, take it out for rapid cooling, and grind it with a ball mill until the specific surface area is 360m ² /kg to obtain Belit-calcium sulfoaluminate-sulfosilicate calcium cement.

The measured properties of the cement are shown in Table 17.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 17 embodiment 8 makes

Embodiment 9:

The ratio of raw materials and water consumption designed in this embodiment are as shown in Table 18.

Table 18 Embodiment 9 raw material ratio and water consumption

Example 9 coal gangue Tailings bauxite Phosphogypsum lime dried sludge water Mass/g 212.3 123.4 74 590.3 329

The specific implementation steps are as follows:

1) Mixing: Weigh the raw materials according to the proportion and place them in the planetary mill, add water, grind for 20 minutes, take out the slurry and pour it into the mold, demould after molding, and obtain a block sample;

2) Hydrothermal synthesis: put the above sample in a digital display constant temperature stirring circulation curing box that has been heated to a set temperature of 80°C, take it out and cool it after constant temperature curing for 9 hours;

3) Calcination: After the cooled block sample is crushed, it is placed in a high-temperature furnace, calcined at 1150°C for 120 minutes, taken out for rapid cooling, and ground by a ball mill until the specific surface area is 390m ² /kg to obtain Belite-sulfur Calcium aluminate-calcium sulfosilicate cement.

The measured properties of the cement are shown in Table 19.

Belit-calcium sulfoaluminate-calcium sulfosilicate cement performance table that table 19 embodiment 9 makes

comparative example

The conventional method in the prior art is adopted to prepare Belite sulfoaluminate cement with fly ash, limestone and gypsum. The specific composition of each raw material is shown in Table 20.

Table 20 Chemical Composition of Raw Materials

name Loss on ignition CaO MgO limestone 42.76 1.17 0.66 0.025 53.42 1.3 —— 0.24 plaster 20.75 6.83 2.77 0.57 30.10 0.98 36.84 0.24 fly ash 4.27 52.30 36.05 3.87 1.36 0.94 —— ——

Weigh the raw materials according to the designed ratio, mix, press and shape, calcinate, keep warm at 1300°C for 60 minutes, and cool in the air to obtain clinker.

The measured physical and mechanical properties of the cement are shown in Table 21.

Table 21 Physical and Mechanical Properties of Cement

From Examples 1 to 9 and the comparative examples, it can be seen that the present invention has great advantages. Compared with the conventional preparation process in the prior art, the present invention is a low-carbon, green The preparation method of Belite sulfoaluminate cement, especially utilizes the hydrothermal precursor, which contains calcium silicate hydrate and calcium sulfoaluminate hydrate, reduces the calcining temperature, and reduces the advantages of energy consumption; moreover, the present invention uses industrial Waste slag is used as raw material, without using mineral raw materials such as limestone and clay, and does not generate carbon dioxide, which reduces environmental pressure, saves resources, and promotes the sustainable development of cement.

Claims (9)

1. a method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement, it is characterised in that comprise the following steps：

Step a, industrial residue is mixed with industrial gypsum, is added water mixing for 0.3~0.41 by the ratio of mud, grinds 15~60min Slurry is poured into mould afterwards, the demoulding after shaping obtains sample；

Step b, by said sample thermostatic curing, curing temperature is 60~150 DEG C, and curing time is 3~9h；

Step c, then at 60~120min is calcined at 750~1150 DEG C, the sample after calcining is taken out from high temperature furnace, rapidly Cooling；Product is obtained after grinding.

2. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1, it is special Levy is to replace with described step a, step b：Industrial residue, industrial gypsum are mixed with waste material containing hydrated product, by 0.1 ~0.2 adds water mixing, is well mixed shaping, obtains sample, then subsequent steps c.

3. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its It is characterised by that described industrial gypsum is desulfurated plaster or ardealite.

4. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its It is characterised by that described industrial residue includes sa raw material, aluminum raw material, calcareous raw material；Wherein sa raw material is increasing calcium liquid State slag, gangue；Aluminum raw material is mine tailing bauxite；Calcareous raw material is carbide slag, sugared filter mud or lime dewatered sludge.

5. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its It is characterised by that described waste material containing hydrated product is silico-calcium aluminum raw material.

6. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its It is characterised by that described silico-calcium aluminum raw material is residual slurry of tubular pile or discarded concrete fines.

7. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its The proportioning of the raw material being characterised by above-mentioned steps is：Sa raw material or silicon calcareous raw material：Aluminum raw material：Industrial gypsum：Calcium Matter raw material=10.77~54.12%：5.67~30.97%：5.95~15.28%：18.73~61.26%.

8. the method for easy fired belite-calcium sulphoaluminate-sulphur calcium silicate cement according to claim 1 and 2, its The grinding in above-mentioned steps is characterised by, specific surface area is milled to for 350~420m²/kg。

9. the product that the methods described of claim 1 or 2 is prepared, it is characterised in that contain C in the product₂S：33~62%；