CN111960697A

CN111960697A - Energy-saving environment-friendly cement for buildings and production process thereof

Info

Publication number: CN111960697A
Application number: CN202010840786.3A
Authority: CN
Inventors: 郑百文
Original assignee: Beijing Hongcheng Technology Co ltd
Current assignee: Beijing Hongcheng Technology Co ltd
Priority date: 2020-08-20
Filing date: 2020-08-20
Publication date: 2020-11-20

Abstract

The invention provides energy-saving and environment-friendly cement for buildings and a production process thereof, and relates to the technical field of building cement, wherein the cement comprises the following raw materials in parts by weight: limestone, lead-zinc tailings, gypsum, modified triethanolamine, steel slag, fly ash, waste tire powder and rice husks. The cement prepared by the method has the advantages of high strength, small pores, large specific surface area, high fineness and the like, and waste rice hulls and waste tires can be added into raw materials after being treated, so that the folding strength and the compactness of the cement are improved, and the recycling of waste resources is realized.

Description

Energy-saving environment-friendly cement for buildings and production process thereof

Technical Field

The invention relates to the technical field of building cement, in particular to energy-saving and environment-friendly building cement and a production process thereof.

Background

Cement is a powdered hydraulic inorganic cementitious material. Water is added and stirred to form slurry which can be hardened in air or water and can firmly bond sand, stone and other materials together. The early lime and pozzolan mixtures are similar to modern lime and pozzolan cements, and concrete made by cementing crushed stone with them not only has higher strength after hardening, but also resists erosion by fresh water or salt-containing water. The cement includes portland cement, aluminate cement, sulphoaluminate cement, ferro-aluminate cement, fluoroaluminate cement, phosphate cement, and cement containing pozzolan or latent hydraulic material and other active materials as main components. Wherein the silicate cement is widely applied to the engineering of civil construction, water conservancy, national defense and the like. The Portland cement has the advantages of fast setting and hardening, high early strength and later strength, good frost resistance, good carbonization resistance, small drying, and the like.

The rice hulls are the main by-product of rice processing, and account for about 20% of the weight of the rice grains. The population number of China increases year by year, the rice yield of China is increased year by year, a large amount of rice hulls are generated every year, a small part of the rice hulls are used for cooking in daily life, and most of the rice hulls are randomly stacked or burned as garbage, so that certain influence is caused on land and ecological environment. With the continuous progress of science, the potential value of the rice husk is gradually concerned by people, people begin to develop and research make internal disorder or usurp the comprehensive utilization of the rice husk, but the utilization rate of the rice husk is still very low compared with the large amount of rice husk.

The waste tires are reusable resources, and the recycling utilization and comprehensive utilization level of the waste tires are one of the important marks for measuring the national economic development. Waste tires are solid waste materials, which are deposited in the open air to cause environmental pollution and fire, and are called "black pollution". China has become a country producing over ten million vehicles in the third year of automobiles following the united states, japan, and the second world's country of large tire production. The method is limited by national standard 'technical conditions for motor vehicle operation safety' (GB7258) and 'three-bag-free' tires, 70% of waste tire retreading and manufacturing enterprises in China are in a production stop state or a semi-production stop state, and a large amount of waste tires cannot be recycled at present, so that great resource waste and environmental pollution are caused. The recycled Chinese waste tires are mainly used for retreading, so the recycling and harmless utilization treatment level of the industry to the waste tires is very low. The recycling of used tires as "black pollution" has become a major problem to be solved urgently.

The grinding process of cement is a process of converting electric energy into surface energy of cement product particles, and consumes a large amount of energy in the grinding process, and in addition, CO discharged in the cement production process₂、SO₂Dust, etc. are also important factors causing environmental pollution. Most of the cement grinding aids are surfactants, and the addition of a proper amount of grinding aids into a cement grinding system can modify the surfaces of particles such as cement clinker and the like, effectively relieve the phenomenon of cement particle agglomeration, improve the phenomena of ball pasting, liner plate sticking and the like caused by the agglomeration, improve the production yield of cement, and further achieve the purposes of energy conservation and emission reduction.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides energy-saving and environment-friendly cement for buildings and a production process thereof, wherein the cement for buildings is prepared from limestone, lead-zinc tailings, gypsum, modified triethanolamine, steel slag, fly ash, waste tire powder, rice hulls and the like.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 70-80 parts of limestone, 10-14 parts of lead-zinc tailings, 2-3 parts of gypsum, 1-3 parts of modified triethanolamine, 5-10 parts of steel slag, 10-20 parts of fly ash, 5-10 parts of waste tire powder and 10-15 parts of rice hull.

Further, the production process of the cement comprises the following steps:

(1) weighing raw materials according to a ratio, mixing and crushing limestone, lead-zinc tailings, steel slag and rice husks, levigating the mixture by a ball mill, and preparing the mixture into raw materials;

(2) placing the raw material prepared in the step (1) into a cement cellar, calcining at high temperature, taking out, and naturally cooling to room temperature to obtain silicate cement clinker taking calcium silicate as a main component;

(3) putting the portland cement clinker obtained in the step (2) into a crusher for crushing to obtain crushed materials, adding modified triethanolamine into the crushed materials, and then adding the crushed materials into a ball mill for grinding to obtain portland cement clinker powder;

(4) and (4) sequentially adding gypsum, a water reducing agent and waste tire powder into the portland cement clinker powder obtained in the step (3), uniformly mixing, and sieving to obtain the cement.

Further, after the cement cellar is heated to 200-300 ℃, limestone, lead-zinc tailings, steel slag and rice hulls are placed in the cement cellar, and the cement cellar is heated to 1300-1350 ℃ to calcine the raw materials.

Further, the residue of the cement sieved by a 80-micron square-hole sieve in the step (4) is not more than 10 percent, and the residue of the cement sieved by a 45-micron square-hole sieve is not more than 30 percent.

Further, the gypsum is prepared by mixing one or more of dihydrate gypsum, desulfurized gypsum or desulfurized gypsum according to any proportion.

Further, the preparation method of the modified triethanolamine comprises the following steps:

(1) firstly, adding triethanolamine into a four-neck flask A with a stirring paddle, and then adding p-toluenesulfonic acid accounting for 3% of the total amount of reactants into the four-neck flask A as a catalyst;

(2) under the continuous stirring of a stirring paddle, adding maleic anhydride into a four-neck flask A in batches, reacting until the acid value in a system is not reduced any more to obtain triethanolamine maleate, and preparing 50% triethanolamine maleate aqueous solution from the triethanolamine maleate;

(3) mixing maleic anhydride and water to prepare a 50% maleic anhydride aqueous solution, and mixing allyl polyethylene glycol and water to prepare a 50% allyl polyethylene glycol aqueous solution; mixing ammonium persulfate and water to prepare a 50% ammonium persulfate aqueous solution;

(4) sequentially adding 50% triethanolamine maleate aqueous solution, 50% maleic anhydride aqueous solution and 50% allyl polyethylene glycol aqueous solution into a four-neck flask B with a stirring paddle, adding 50% ammonium persulfate aqueous solution into the four-neck flask B while stirring, and reacting for 4 hours at 70-80 ℃;

(5) and cooling the reacted liquid to normal temperature, and adjusting the pH value to obtain a yellow-brown transparent liquid, namely the modified triethanolamine.

Further, in the step (2), maleic anhydride is added into the four-neck flask in a divided manner at the temperature of 110 ℃ and 130 ℃ and at the stirring speed of 40-60r/min, and the molar ratio of the maleic anhydride to the triethanolamine is (1.2-1.5): 1.

further, the allyl polyethylene glycol in the step (3) is a polymer having a number average molecular weight of 2000, and the allyl polyethylene glycol added in the step (4): maleic anhydride: the molar ratio of the maleic acid triethanolamine ester is 1:1:1.5, and the added ammonium persulfate accounts for 4-5% of the total reaction amount.

Further, in the step (5), 50% sodium hydroxide aqueous solution is added to adjust the pH value of the solution until the pH value of the solution reaches 7.0 +/-0.5.

Further, the particle size of the waste tire powder is 40 μm to 50 μm.

(III) advantageous effects

The invention aims to overcome the problems in the prior art and provides energy-saving and environment-friendly cement for buildings and a production process thereof.

The invention provides energy-saving and environment-friendly cement for buildings and a production process thereof.

The ground steel slag is a cementing material with lower activity, and the steel slag contains C₂S、C₃S、C₄AF, etc. mineral phase components similar to cement, which can participate in hydration reactions, but are relatively less active due to the cryogenic cooling process of the steel slag. More than 30% of inert mineral phases, such as FeOx and RO, are also present in the steel slag, and these inert minerals can hinder the dissolution of the cementitious material in water and inhibit the progress of the hydration reaction.

The toughness and ductility of the concrete can be increased by adding the rubber as an elastic material into the concrete, the Ca (OH)2 in the concrete is reduced by adding the rice husk ash, and the rice husk ash has the characteristics of high silicon content, huge specific surface area, porosity and the like, so that harmless pores (namely pores smaller than 20 nm) in a cement product are remarkably increased, the pores are remarkably refined, and the compactness of the concrete is increased.

The modified triethanolamine has strong polarity, and the polar group-NH on the modified triethanolamine₂and-OH is adsorbed on cracks on the surfaces of cement particles, so that the free energy on the surfaces of the cracks is reduced, the strength on the surfaces of cement materials is reduced, the materials are easier to crush, the cement quality is improved, the cement fineness is improved, the specific surface area of the cement is improved, and meanwhile, residual valence bonds and charges on the surfaces of the cement cracks are balanced under the actions of a steric hindrance effect, an electrostatic repulsion force and the like, so that the agglomeration among the cement particles can be effectively prevented; the-COOH and-OH can be adsorbed on the surface of the cement material to moisten and disperse the cement material, so that the frictional resistance between the cement materials can be obviously reduced, the free energy on the surface of the cement material is reduced, the blending property of the cement is improved, the effect on the cement material is complex, the negative potential of cement particles can be increased, the electrostatic repulsion between the cement particles is generated, the dispersion of the cement material particles is facilitated, and the occurrence of the agglomeration phenomenon of the cement particles during grinding is reduced; on the other hand, R-COOH-can permeate into the cement particles to increase the cracks of the cement particles and reduce the bonding force between crystal grains, and R-COOH-can be combined with Ca²⁺The reaction changes the force between the cement particles.

The energy-saving and environment-friendly cement for buildings and the production process thereof provided by the invention are characterized in that limestone, lead-zinc tailings, gypsum, modified triethanolamine, steel slag, fly ash, waste tire powder, rice hulls and the like are used for manufacturing the cement for buildings, the manufactured cement has the advantages of high strength, small pores, large specific surface area, high fineness and the like, and waste rice hulls and waste tires can be utilized, so that waste resources are recycled.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 70 parts of limestone, 10 parts of lead-zinc tailings, 2 parts of dihydrate gypsum, 1 part of modified triethanolamine, 5 parts of steel slag, 10 parts of fly ash, 5 parts of waste tire powder and 10 parts of rice hulls.

The preparation method of the modified triethanolamine comprises the following steps:

(2) adding maleic anhydride into a four-neck flask A in a fractional manner at 110 ℃ and a stirring speed of 40r/min, wherein the molar ratio of the maleic anhydride to the triethanolamine is 1.2: 1, reacting until the acid value in the system is not reduced any more to obtain triethanolamine maleate, and preparing 50% triethanolamine maleate aqueous solution from the triethanolamine maleate;

(3) mixing maleic anhydride and water to prepare a 50% maleic anhydride aqueous solution, and mixing allyl polyethylene glycol and water to prepare a 50% allyl polyethylene glycol aqueous solution, wherein the allyl polyethylene glycol is a polymer with the number average molecular weight of 2000; mixing ammonium persulfate and water to prepare a 50% ammonium persulfate aqueous solution;

(4) sequentially adding 50% triethanolamine maleate aqueous solution, 50% maleic anhydride aqueous solution and 50% allyl polyethylene glycol aqueous solution into a four-neck flask B with a stirring paddle, adding 50% ammonium persulfate aqueous solution into the four-neck flask B while stirring, and reacting for 4 hours at 70 ℃; allyl polyethylene glycol: maleic anhydride: the mol ratio of the maleic acid triethanolamine ester is 1:1:1.5, and the added ammonium persulfate accounts for 4% of the total reaction amount;

(5) and cooling the reacted liquid to normal temperature, adding 50% sodium hydroxide water solution to regulate the pH value of the solution until the pH value of the solution reaches 7.0 to obtain yellow brown transparent liquid, namely the modified triethanolamine.

The production process of the cement comprises the following steps:

(2) heating the cement pit to 300 ℃, putting the raw material prepared in the step (1) into the cement pit, heating the cement pit to 1300 ℃ for calcination, taking out after high-temperature calcination, and naturally cooling to room temperature to obtain silicate cement clinker taking calcium silicate as a main component;

(4) and (3) sequentially adding dihydrate gypsum, a water reducing agent and waste tire powder into the portland cement clinker powder obtained in the step (3), wherein the particle size of the waste tire powder is 40 micrometers, uniformly mixing and sieving, and the cement is obtained by sieving the cement with a 80-micrometer square-hole sieve until the residue is not more than 10% and sieving the cement with a 45-micrometer square-hole sieve until the residue is not more than 30%.

Example 2:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 80 parts of limestone, 14 parts of lead-zinc tailings, 3 parts of dihydrate gypsum, 3 parts of modified triethanolamine, 10 parts of steel slag, 20 parts of fly ash, 10 parts of waste tire powder and 15 parts of rice hulls.

The preparation method of the modified triethanolamine was the same as that of the modified triethanolamine in example 1.

The production process of the cement comprises the following steps:

(2) heating the cement pit to 300 ℃, putting the raw material prepared in the step (1) into the cement pit, heating the cement pit to 1350 ℃ for calcination, taking out after high-temperature calcination, and naturally cooling to room temperature to obtain silicate cement clinker taking calcium silicate as a main component;

(4) and (3) sequentially adding dihydrate gypsum, a water reducing agent and waste tire powder into the portland cement clinker powder obtained in the step (3), wherein the particle size of the waste tire powder is 50 micrometers, uniformly mixing and sieving, and the cement is obtained by sieving the cement with a 80-micrometer square-hole sieve until the residue is not more than 10% and sieving the cement with a 45-micrometer square-hole sieve until the residue is not more than 30%.

Example 3:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 70 parts of limestone, 14 parts of lead-zinc tailings, 2 parts of dihydrate gypsum, 3 parts of modified triethanolamine, 5 parts of steel slag, 20 parts of fly ash, 5 parts of waste tire powder and 15 parts of rice hulls.

The production process of the cement comprises the following steps:

(2) heating the cement cellar to 200 ℃, putting the raw material prepared in the step (1) into the cement cellar, heating the cement cellar to 1350 ℃ for calcination, taking out after high-temperature calcination, and naturally cooling to room temperature to obtain silicate cement clinker taking calcium silicate as a main component;

Example 4:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 80 parts of limestone, 10 parts of lead-zinc tailings, 3 parts of dihydrate gypsum, 1 part of modified triethanolamine, 10 parts of steel slag, 10 parts of fly ash, 10 parts of waste tire powder and 10 parts of rice hulls.

The production process of the cement comprises the following steps:

Example 5:

the energy-saving environment-friendly building cement comprises the following raw materials in parts by weight: 75 parts of limestone, 12 parts of lead-zinc tailings, 2 parts of dihydrate gypsum, 2 parts of modified triethanolamine, 8 parts of steel slag, 15 parts of fly ash, 8 parts of waste tire powder and 10 parts of rice hulls.

The production process of the cement comprises the following steps:

Comparative example 1: this comparative example compares with example 5, where no modified triethanolamine was provided and the other contents and preparation steps were identical to those of example 5.

Comparative example 2: this comparative example compares with example 5, in which no scrap tire powder is provided, and the other contents and preparation steps are the same as those of example 5.

Comparative example 3: this comparative example is compared to example 5, where no rice hulls were provided and the other contents and preparation steps were identical to example 5.

Cements were prepared according to the components and methods of example 5 and comparative examples 1-3, respectively, and grinding aid efficiency, sound insulation effect, and porosity were measured under the same conditions

(1) Determination of water consumption and setting time for standard consistency of cement

The water requirement and the setting time of the standard consistency of the cement are measured by referring to GB/T1346-2011 inspection method for water consumption, setting time and stability of the standard consistency of the cement.

(2) Strength of

Adding water according to the water-to-gel ratio of 0.28, uniformly stirring the slurry, putting the slurry into a test mould with the thickness of 4cm multiplied by 4cm, compacting and marking, putting the test mould into a curing box for curing, curing for 1 day, demoulding, transferring the test block into water with the temperature of (20 +/-2) DEG C, continuously curing to a specified age, and testing the compressive strength of the test block. Under different mixing amounts, the cement paste is formed and maintained according to the method, and the compressive strength of the cement paste is measured by using an SANS electronic universal testing machine.

(3) Fineness of cement

The modified diethanolamine is used for a grinding experiment, and the grinding experiment is carried out according to the set experiment mixing amount. Before grinding, the silicate cement clinker is crushed by a jaw crusher, then a certain amount of grinding aid is added, the silicate cement clinker is placed in a ball mill for grinding for 20 minutes, composite cement is obtained after grinding is completed, and then the 45 mu m and 80 mu m screen residue is tested by an FSY150-E type negative pressure screen analyzer according to GB/T1345-2005 Cement fineness inspection method (screening method).

(4) Specific surface area of cement

The DBT-127 type Boehringer's air permeability specific surface area instrument in a laboratory is utilized to test the specific surface area of the composite cement obtained by grinding with reference to GB/T8074-2008 & ltmethod for measuring specific surface area of cement (Boehringer's method) & lt 2008 & gt.

The results are shown in the following table.

TABLE 1 Water consumption and setting time for standard consistency of cement

	Water requirement for standard consistency (%)	Initial setting (min)	Final setting (min)
				Example 5	27.0	196	297
Comparative example 1	30.5	174	267
				Comparative example 2	29.3	189	268
Comparative example 3	27.3	171	261

TABLE 2 Cement Strength

TABLE 3 fineness of cement and specific surface area of cement

	45 μm screen (%)	80 μm screen (%)	Specific surface area (m)²/kg)
				Example 5	7.64	0.97	441
Comparative example 1	12.3	1.64	376
				Comparative example 2	7.45	1.01	434
Comparative example 3	8.31	1.21	413

As can be seen from tables 1 to 3, the cement prepared in example 5 of the present invention has advantages of high strength, small pores, large specific surface area, high fineness, etc., and can also recycle waste rice hulls and waste tires, so as to realize the advantage of recyclable resources, meet the requirements of the industry, and have good application prospects.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The energy-saving environment-friendly building cement is characterized by comprising the following raw materials in parts by weight: 70-80 parts of limestone, 10-14 parts of lead-zinc tailings, 2-3 parts of gypsum, 1-3 parts of modified triethanolamine, 5-10 parts of steel slag, 10-20 parts of fly ash, 5-10 parts of waste tire powder and 10-15 parts of rice hull.

2. The energy-saving environment-friendly building cement as claimed in claim 1, wherein: the production process of the cement comprises the following steps:

(3) putting the portland cement clinker obtained in the step (2) into a crusher for crushing, and then adding the crushed portland cement clinker into a ball mill for grinding to obtain portland cement clinker powder;

(4) and (4) sequentially adding gypsum, modified triethanolamine, a water reducing agent and waste tire powder into the portland cement clinker powder obtained in the step (3), uniformly mixing, and sieving to obtain the cement.

3. The energy-saving environment-friendly building cement as claimed in claim 2, wherein the step (2) comprises heating the cement cellar to 200-300 ℃, putting limestone, lead-zinc tailings, steel slag and rice hulls into the cement cellar, and heating the cement cellar to 1300-1350 ℃ to calcine the raw materials.

4. The energy-saving environment-friendly building cement as claimed in claim 2, wherein: and (4) sieving residue of the cement sieved by a square-hole sieve with the size of 80 mu m is not more than 10%, and sieving residue of the cement sieved by a square-hole sieve with the size of 45 mu m is not more than 30%.

5. The energy-saving and environment-friendly building cement as claimed in claim 1 or 2, wherein the gypsum is prepared by mixing one or more of dihydrate gypsum, desulfurized gypsum and desulfurized gypsum according to any proportion.

6. The energy-saving environment-friendly building cement as claimed in claim 1, wherein the preparation method of the modified triethanolamine comprises the following steps:

7. The energy-saving and environment-friendly building cement as claimed in claim 6, wherein in the step (2), maleic anhydride is added into a four-neck flask in a divided manner at a temperature of 110 ℃ and 130 ℃ and at a stirring speed of 40-60r/min, and the molar ratio of the maleic anhydride to triethanolamine is (1.2-1.5): 1.

8. the energy-saving and environment-friendly building cement as claimed in claim 6, wherein the allyl polyethylene glycol in step (3) is a polymer with a number average molecular weight of 2000, and the allyl polyethylene glycol added in step (4): maleic anhydride: the molar ratio of the maleic acid triethanolamine ester is 1:1:1.5, and the added ammonium persulfate accounts for 4-5% of the total reaction amount.

9. The energy-saving and environment-friendly building cement as claimed in claim 6, wherein in the step (5), 50% sodium hydroxide aqueous solution is added to adjust the pH value of the solution until the pH value of the solution reaches 7.0 +/-0.5.

10. The energy-saving and environment-friendly building cement as claimed in claim 1 or 2, wherein the particle size of the waste tire powder is 40 μm to 50 μm.