CN117447108B - Composite cementing material and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of building materials, in particular to a composite cementing material and a preparation method thereof. The raw materials of the composite cementing material comprise 40-55 parts of carbide slag, 70-80 parts of seabed sludge, 10-20 parts of gamma-alumina and 15-20 parts of exciting agent in parts by weight. The invention simultaneously utilizes the carbide slag and the seabed sludge to realize the cooperative treatment of various solid wastes. In the preparation process, the gel material is subjected to thermal-mechanical-chemical combined excitation to achieve high hydration activity, and the system is promoted to produce more products with high Cl ^‑ adsorptivity by the directional design of hydration products, so that in-situ solid solution of Cl ^‑ is realized. The composite cementing material provided by the invention is suitable for producing concrete with different strength grades, has excellent adaptability and low electric flux, and shows good chloride ion permeation resistance.

Description

Composite cementing material and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to a composite cementing material and a preparation method thereof.

Background

Along with domestic economic development, various solid wastes are accumulated gradually, and a huge threat is formed to the ecological environment. Of these, carbide slag and marine sludge are two very representative ones.

The carbide slag is solid waste generated after acetylene gas is prepared from calcium carbide, and is one of main waste generated in the high-end petrochemical industry. The carbide slag contains trace carbon and sulfur impurities, is gray, has slight odor and is strong alkaline. At present, the reuse of carbide slag is often represented by using carbide slag as a production building material, chemical product or treating waste water, waste gas, etc. However, the added value and economic benefit of the products produced by the treatment methods are low, and the amount of the consumed carbide slag is limited, so that a large amount of carbide slag is still piled up or buried in the open air. The outdoor stacking or burying treatment mode not only occupies a large amount of land resources, but also can pollute the soil to alkalize the soil due to lack of anti-seepage treatment measures in the stacking and burying process; serious erosion to air, surface water and groundwater is generated; meanwhile, the carbide slag dust particles fly along with wind to cause serious pollution to the environment, and the normal life and physical health condition of the living community are endangered.

The seabed sludge is a natural solid waste formed by long-term erosion of seabed in natural conditions such as water flow erosion, ecological evolution and the like. In recent years, as we build up infrastructures such as ports and wharfs, the problem of sea mud accumulation is more serious, and treatment is needed. At present, the treatment modes of the seabed sludge are mainly four, one is to prepare the baked brick by using the seabed sludge, but the problems of salt impregnation, poor surface cohesiveness and the like of the baked brick are easily caused by a large amount of salt in the seabed sludge; secondly, preparing solidified soil by utilizing seabed sludge, wherein the components in sea sludge are complex and changeable, and the prepared solidified soil is unstable in quality; thirdly, a small amount of submarine sludge is used as a concrete mineral admixture, but the submarine sludge has low volcanic ash activity and is rich in chloride ions, so that the durability risk of the concrete is easily induced; fourthly, the seabed sludge is transported to a position far away from the shore to be thrown, but the method can have a great influence on the local environment.

In summary, the prior art still has the defects of various solid wastes, especially the treatment means of carbide slag and seabed sludge, and further causes environmental pollution. Based on this, there is a need in the art for a method that utilizes both carbide slag and subsea sludge to achieve the co-disposal of multiple solid wastes.

Disclosure of Invention

The invention aims to provide a composite cementing material and a preparation method thereof, and simultaneously, the method of carbide slag and seabed sludge is utilized to realize the cooperative treatment of various solid wastes.

In order to achieve the above object, the present invention provides the following technical solutions:

the composite cementing material is prepared from the following raw materials in parts by weight:

Optionally, the particle size of the seabed sludge is smaller than 150 mu m, and the seabed sludge comprises 40-55% of quartz, 20-25% of clay mineral, 15-25% of ground matter, 3-15% of organic matter and the balance of erosive inorganic salt according to mass percent;

the organic matter comprises CaCO ₃ and feldspar;

The aggressive inorganic salts comprise chloride salts and sulfate salts.

Optionally, the particle size of the carbide slag is less than 100 μm; the particle size of the gamma alumina is less than 100nm.

Optionally, the activator comprises sodium carbonate and sodium hydroxide.

Optionally, the mass ratio of sodium carbonate to sodium hydroxide in the excitant is 1:1.5 to 2.5.

The invention also provides a preparation method of the composite cementing material, which comprises the following steps:

1) Mixing carbide slag, seabed sludge and gamma-alumina as materials;

2) Calcining the material in the step 1);

3) Grinding the calcined material obtained in the step 2);

4) Mixing the ground material in the step 3) with an exciting agent to obtain the composite cementing material.

Optionally, the calcining temperature in the step 2) is 750-1000 ℃, and the calcining time is 45-90 min.

Optionally, the grinding in the step 3) is to grind the calcined material to a specific surface area of 350-450 m ²/kg.

From the aspect of element correction, the seabed sludge contains a large amount of siliceous and aluminous components, and the contained clay components have larger potential activities, so that the potential activities are reasonably released through scientific means. The carbide slag can be used as a high-calcium solid waste, can be used as an excellent calcium correction component, and can be used for constructing a reasonable CaO-Al ₂O₃-SiO₂ ternary system for the system. The system products are guided directionally by other small amount of ionic compounds, so that the synergistic improvement of high hydration activity and low durability risk is realized.

The invention takes carbide slag as a main calcium source, seabed sludge as a main silicon source, nano alumina as a main aluminum source, and uses an excitant obtained by compounding sodium carbonate and sodium hydroxide to supplement a certain amount of carbonate ions, so as to directionally guide hydration products to generate hydrotalcite phases and calcium aluminosilicate gel. The resulting hydrotalcite phase can largely adsorb Cl ^-、SO₄ ^2- by interlayer ion exchange. The generated calcium aluminosilicate gel not only has higher cementation performance, but also has larger specific surface area, and can provide more Cl ^- adsorption points. In addition, the designed high-alumina system can convert harmful ions SO ₄ ^2- in the system into trisulfide type hydrated calcium sulfoaluminate (AFt) and monosulfide type hydrated calcium sulfoaluminate (AFm) and further generate F salt with Cl ^-, SO that the gel material is endowed with higher hydration activity, and meanwhile harmful elements in sea mud are strongly adsorbed, and the generation of durability risks is avoided.

In the invention, inert substances in raw materials are modified through thermal-mechanical-chemical coupling treatment, so that the purpose of high activity is achieved, and excellent physical and chemical properties are provided for the cementing material;

The clay minerals in the sea mud are calcined to remove hydroxyl groups, so that certain hydration activity is generated. Meanwhile, under the actions of thermal activation, mechanical activation and polarization of Ca ²⁺, a large amount of quartz components in the raw materials can better complete the vitrification process. The existence of Al ₂O₃ can be used as a cosolvent to reduce the breaking bond energy, and can be inserted into a silicon chain to prevent the silicon chain from repolymerization, so that compared with the traditional activation method, the silicon chain has higher dismemberment degree, and the conversion from Q ⁴ to Q ⁰ is more thorough, so that the hydration activity of the cementing material is further improved.

Compared with the prior art, the invention has the following beneficial effects:

the main raw materials of the carbide slag/sea mud-based composite cementing material provided by the invention are industrial solid wastes, so that the cooperative treatment of 'treating wastes with wastes' and various solid wastes is realized, and the social environmental benefit is remarkable;

According to the invention, through reasonable ingredients, the hydration product of the cementing material is regulated and designed, so that the in-situ solid solution of aggressive substances such as chloride salt, sulfate and the like in the cementing material system is realized, and the durability threat to a final product is avoided;

The composite cementing material provided by the invention is suitable for producing concrete with different strength grades, has excellent adaptability and low 28d electric flux, and shows good chloride ion permeation resistance;

the preparation method of the carbide slag/sea mud-based composite cementing material is simple and feasible, and has industrial value.

Detailed Description

The invention provides a composite cementing material which is prepared from the following raw materials in parts by weight:

in the present invention, the weight parts of the carbide slag may preferably be 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts;

The particle size of the carbide slag is less than 100 μm, preferably less than 95 μm, more preferably 90 μm, still more preferably 80 μm;

According to the mass percentage, the carbide slag contains 85-95 percent of Ca (OH) ₂、1～10％CaCO₃, 1-3 percent of unreacted carbon particles and the balance of silicon-containing compounds;

The Ca (OH) ₂ content in the carbide slag is preferably 87 to 93%, more preferably 88 to 92%, still more preferably 89 to 90%;

the CaCO ₃ content in the carbide slag is preferably 2-8%, more preferably 4-7%, even more preferably 5-6%;

The content of unreacted carbon particles in the carbide slag is preferably 1 to 2%, more preferably 1.5 to 1.7%.

In the present invention, the weight parts of the subsea sludge may preferably be 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts;

the particle size of the subsea sludge is less than 150 μm, preferably less than 140 μm, more preferably less than 130 μm, still more preferably less than 120 μm;

The seabed sludge comprises, by mass, 40-55% of quartz, 20-25% of clay minerals, 15-25% of ground substances, 3-15% of organic matters and the balance of aggressive inorganic salts;

the organic matter comprises CaCO ₃ and feldspar;

the aggressive inorganic salts comprise chloride salts and sulfate salts;

The quartz in the seabed sludge is preferably 44-52%, more preferably 44.3-50%, even more preferably 45-48%;

the clay mineral is preferably 21 to 24%, more preferably 22 to 23%, still more preferably 22.3 to 22.5%;

The geologic material is preferably 16 to 24%, more preferably 18 to 21%, still more preferably 19 to 20%; the geological matter comprises CaCO ₃ and feldspar in any proportion, and the CaCO ₃ and the feldspar are not 0 at the same time;

The organic matter is preferably 5 to 13%, more preferably 9 to 12.5%, still more preferably 10 to 12%;

The aggressive inorganic salts comprise chloride and sulfate salts in any proportion.

In the present invention, the weight part of the gamma alumina is preferably 12 to 19 parts, more preferably 14 to 18 parts, still more preferably 15 to 16 parts;

The particle size of the gamma-alumina is less than 100nm, preferably less than 90nm, more preferably less than 80nm, and even more preferably less than 70nm.

In the present invention, the weight part of the activator is preferably 16 to 19 parts, more preferably 17 to 18 parts;

the excitant comprises sodium carbonate and sodium hydroxide;

the mass ratio of sodium carbonate to sodium hydroxide in the excitant is 1:1.5 to 2.5, preferably 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4.

The invention also provides a preparation method of the composite cementing material, which comprises the following steps:

1) Mixing carbide slag, seabed sludge and gamma-alumina as materials;

2) Calcining the material in the step 1);

3) Grinding the calcined material obtained in the step 2);

4) Mixing the ground material in the step 3) with an exciting agent to obtain the composite cementing material.

In the present invention, the temperature of the calcination in step 2) is 750 to 1000 ℃, preferably 800 to 950 ℃, and more preferably 850 to 900 ℃;

the calcination time is 45 to 90 minutes, preferably 50 to 80 minutes, more preferably 55 to 70 minutes, still more preferably 60 to 65 minutes;

The grinding in the step 3) is to grind the calcined material to a specific surface area of 350-450 m ²/kg, preferably 360-446 m ²/kg, more preferably 380-420 m ²/kg, still more preferably 387-400 m ²/kg;

The mixing in step 1) and step 4) may be accomplished by mixing in a planetary ball mill for a period of 7 to 15 minutes, preferably 8 to 13 minutes, more preferably 9 to 12 minutes, and even more preferably 10 to 11 minutes.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Taking carbide slag and seabed sludge as raw materials.

The carbide slag comprises 90.4 percent of Ca (OH) ₂、7.0％CaCO₃, 1.7 percent of unreacted carbon particles and the balance of silicon-containing compounds according to mass percent;

the seabed sludge comprises, by mass, 44.3% of quartz, 22.3% of clay minerals, 19.0% of ground substances, 12.5% of organic substances and the balance of aggressive inorganic salts.

55 Parts of carbide slag, 70 parts of seabed sludge and 15 parts of gamma-alumina are weighed and uniformly mixed in a planetary ball mill to be used as materials, and then the materials are calcined at 900 ℃ for 1h, and are rapidly cooled by an air cooling machine. Grinding the cooled material to a specific surface area of 387m ²/kg, and then adding 15 parts of sodium carbonate and sodium hydroxide composite material as an exciting agent, wherein the mass ratio of the sodium carbonate to the sodium hydroxide is 1: and 2, uniformly mixing to obtain the carbide slag/sea mud-based composite cementing material A.

Example 2

The composition of the carbide slag and the seabed sludge is the same as that of the embodiment 1;

40 parts of carbide slag, 80 parts of seabed sludge and 20 parts of gamma-alumina are weighed and uniformly mixed in a planetary ball mill to be used as materials, and then the materials are calcined at 900 ℃ for 1h, and are rapidly cooled by an air cooling machine. Grinding the cooled material to a specific surface area of 446m ²/kg, and then adding 20 parts of sodium carbonate and sodium hydroxide composite material as an exciting agent, wherein the mass ratio of the sodium carbonate to the sodium hydroxide is 1: and 1.5, uniformly mixing to obtain the carbide slag/sea mud-based composite cementing material B.

Application examples 1 to 2

Mortar was prepared using the carbide slag/sea mud-based composite cement material a prepared in example 1 and the carbide slag/sea mud-based composite cement material B prepared in example 2, respectively, and the strength grade of the mortar was determined with reference to GB/T175-2007 cement standard vibration and test analysis standard.

Table 1 Standard mortar prepared from composite cementing material A, B and compressive strength thereof

As shown in Table 1, the 28d compressive strength of the standard mortar test pieces prepared in application examples 1 and 2 is 49.2MPa and 51.1MPa respectively, and is greater than 42.5MPa, and the compressive strength requirement of the standard mortar test pieces for 42.5-grade ordinary Portland cement in relevant regulations is met, so that the carbide slag/sea mud-based composite cementing material disclosed by the invention is excellent in hydration activity and can be used for preparing mortar.

Application examples 3 to 6

C30 and C60 grade concrete was prepared by using the carbide slag/sea mud based composite cementing materials A, B prepared in examples 1-2, respectively, and the formulations used are shown in Table 2.

Table 2 formulations/kg for preparing concrete according to application examples 3 to 6

Comparative examples 1 to 2

The concrete with the grade of C30 and C60 is prepared by using the commercial P.O42.5R cement. The specific formulation is shown in table 3.

TABLE 3 formulation/kg of commercial P.O 42.5R Cement to concrete

Numbering device	Concrete grade	Cement and its preparation method	Mineral powder	Fly ash	Sand and sand	Stone	Water and its preparation method	Additive agent
									Comparative example 1	C30	200	80	60	810	1040	160	8.8
Comparative example 2	C60	380	100	80	640	1050	150	15.1

The compressive strength of the concrete prepared in application examples 3 to 6 and comparative examples 1 to 2 was measured with reference to GB/T50081-2019 Standard for test method of physical mechanical Properties of concrete, and the chloride ion resistance of the concrete prepared in application examples 3 to 6 and comparative examples 1 to 2 was measured with reference to GB/T50082-2009 Standard for test method of long-term Performance and durability of ordinary concrete, and the results are shown in Table 4.

Table 4 Properties of the concrete obtained as a result of the comparative test of examples 3 to 6 and comparative examples 1 to 2

The C30 grade concrete is concrete with the compressive strength grade of 30 MPa. As can be seen from Table 4, the 28d compressive strength of the concrete prepared in application examples 3 and 4 was 35.8MPa and 34.1MPa, respectively, which all satisfied the strength requirements of C30 grade concrete. The 28d electric flux of the C30 concrete prepared in application examples 3 to 4 was significantly smaller than that of the commercial C30 concrete shown in comparative example 1, compared with comparative example 1.

The C60 grade concrete is a concrete with a compressive strength grade of 60MPa, and as can be seen from Table 4, the 28d compressive strengths of the concrete prepared in application examples 5 and 6 are 68.8MPa and 64.2MPa, respectively, which satisfy the strength requirements of the C60 grade concrete. The 28d electric flux of the concretes produced in examples 5 to 6 is significantly less than that of the commercial C60 commercial concrete compared with comparative example 2.

According to the embodiment, the carbide slag/sea mud based composite cementing material provided by the invention has excellent adaptability to materials such as market main flowing sand, stone and additives, and can be used for preparing a concrete material with lower 28d electric flux and excellent chloride ion resistance. And the hydration product contains hydrotalcite and aluminosilicate phase, so that a large amount of chloride ions in sea mud and outside invasion can be adsorbed, and the anti-chloride ion performance is excellent. Therefore, the carbide slag/sea mud based composite cementing material provided by the invention can be widely applied to the production of concrete with different strength grades, and has a huge application prospect.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (4)

1. The composite cementing material is characterized by being prepared from the following raw materials in parts by weight:

40-55 parts of carbide slag;

70-80 parts of seabed sludge;

10-20 parts of gamma-alumina;

15-20 parts of an exciting agent;

the excitant comprises sodium carbonate and sodium hydroxide;

The mass ratio of sodium carbonate to sodium hydroxide in the excitant is 1: 1.5-2.5;

The preparation method of the composite cementing material comprises the following steps:

1) Mixing carbide slag, seabed sludge and gamma-alumina as materials;

2) Calcining the material in the step 1);

3) Grinding the calcined material obtained in the step 2);

4) Mixing the ground material in the step 3) with an exciting agent to obtain the composite cementing material;

The particle size of the submarine sludge is smaller than 150 mu m, and the submarine sludge comprises, by mass, 40-55% of quartz, 20-25% of clay minerals, 15-25% of ground substances, 3-15% of organic matters and the balance of aggressive inorganic salts;

the organic matter comprises CaCO ₃ and feldspar;

the aggressive inorganic salts comprise chloride salts and sulfate salts;

and 2) calcining at 750-1000 ℃ for 45-90 min.

2. The composite cementitious material of claim 1, wherein the carbide slag has a particle size of less than 100 μm; the particle size of the gamma alumina is less than 100nm.

3. The method for preparing the composite cementing material according to any one of claims 1 to 2, which is characterized by comprising the following steps:

1) Mixing carbide slag, seabed sludge and gamma-alumina as materials;

2) Calcining the material in the step 1);

3) Grinding the calcined material obtained in the step 2);

4) Mixing the ground material in the step 3) with an exciting agent to obtain the composite cementing material.

4. The method for preparing the composite cementing material according to claim 3, wherein the grinding in the step 3) is to grind the calcined material to a specific surface area of 350-450 m ²/kg.