WO2022142136A1 - Sulfur-aluminum-iron cement, preparation method therefor, system thereof, and use thereof in marine engineering material - Google Patents

Abstract

Provided are a sulfur-aluminum-iron cement, a preparation method therefor, a system thereof, and the use thereof in a marine engineering material. Raw materials for the sulfur-aluminum-iron cement of the present invention comprise or consist of blast furnace slag, desulfurized gypsum, aluminum ash and steel slag, and the raw meal alkalinity coefficient is 0.81-0.9. The sulfur-aluminum-iron cement has performance advantages such as early strength, high strength, frost resistance, and impermeability, is particularly excellent in terms of seawater corrosion resistance, and is very suitable for serving as a marine engineering material. Moreover, in the present invention, the sulfur-aluminum-iron cement produced by using blast furnace slag has relatively low requirements regarding raw materials, the calcinating temperature is much lower than that of a traditional sulfoaluminate cement, and the cost can be reduced by about 30%.

Description

A kind of sulfur aluminum iron series cement, its preparation method, system and its application in marine engineering materials technical field

The invention relates to the field of solid waste utilization, in particular to a sulphur-aluminum-iron-based cement, a preparation method and system thereof and its application in marine engineering materials.

Background technique

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Nowadays, all countries in the world use general Portland cement or modified Portland cement in the construction of marine engineering. For example, various additives such as silica fume and ultra-fine mineral powder are added to enhance the durability of cement. Portland cement hydration products are mainly 3CaO·SiO ₂ , 2CaO·SiO ₂ , 3CaO·Al ₂ O ₃ and 4CaO·Al ₂ O ₃ ·Fe ₂ O ₃ , which are easily corroded and damaged by seawater, resulting in the failure of the cement. The poor corrosion resistance of seawater is the basic factor for the corrosion phenomenon of cement concrete in marine engineering. The durability of modified Portland cement with additives such as silica fume and ultra-fine mineral powder is slightly stronger than that of ordinary Portland cement, but the grinding of ultra-fine mineral powder consumes a lot of energy, and the addition of silica fume and additives will increase the The cost of cement, and the performance improvement of modified Portland cement is not obvious.

In the traditional production of sulfoaluminate cement, the main raw materials are high-quality bauxite, limestone and gypsum. The sulfoaluminate cement was prepared in a series of steps. _The main mineral phases _of sulfoaluminate cement clinker are calcium sulfoaluminate, dicalcium silicate and iron phase. To complete and generate effective ore phase, it is necessary to ensure high CaO content in the raw meal, but this also increases the quality requirements for raw materials and increases the cost.

SUMMARY OF THE INVENTION

In order to improve the deficiencies of the prior art, the present application provides a sulphur-aluminum-iron cement (high iron sulphoaluminate cement), its preparation method, system and its application in marine engineering materials.

In the first aspect of the present invention, the present invention provides a sulfur-aluminum-iron-based cement, the raw materials of which include or consist of blast furnace slag, desulfurized gypsum, aluminum ash and steel slag, and the raw meal basicity coefficient is 0.81-0.9.

In an embodiment of the present invention, the blast furnace slag is a solid waste formed from gangue in ore, ash in fuel and non-volatile components in solvent (generally limestone) during blast furnace ironmaking; it mainly contains Oxides and small amounts of sulfides of calcium, silicon, aluminum, magnesium, iron.

In some embodiments of the present invention, the blast furnace slag contains 44-54% wt CaO, 18-28% wt SiO ₂ and 8-16% wt Al ₂ O ₃ .

In a further embodiment, the main components of the blast furnace slag are: CaO: 48.84%wt, _SiO2 : 24.66%wt, _Al2O3 : 11.37%wt, _{Fe2O3 :} 0.49 _% wt, MgO: 11.4% wt.

In the embodiment of the present invention, in the sulphur aluminum iron cement raw meal, CaO accounts for 32-40 parts by weight, SiO ₂ accounts for 6-12 parts by weight, Al ₂ O ₃ accounts for 18-26 parts by weight, Fe ₂ O ₃ accounts for 18-26 parts by weight 10-15 parts by weight, SO ₃ 10-18 parts by weight, wherein the ratio of aluminum to sulfur is 1.0-1.8.

The invention utilizes blast furnace slag as a raw material of sulfoaluminate cement in large quantities, and through the control of key parameters such as the chemical composition of raw meal and aluminum-sulfur ratio, the basicity coefficient requirement in the traditional production process of sulfoaluminate cement can be broken through, and its It is reduced to 0.81-0.9; the reduction of alkalinity coefficient reduces the CaO content in the cement raw meal, thereby reducing the dependence on high calcium raw materials such as limestone.

In an embodiment of the present invention, the mineral composition in the cement clinker includes 50-70 wt% calcium sulfoaluminate, 0-20 wt% mayorite and 0-20 wt% calcium sulfoaluminate.

In some embodiments of the present invention, the mineral composition in the cement clinker includes 50-70 wt% calcium sulfoaluminate, 0.5-20 wt% mayorite and 0.5-20 wt% calcium sulfoaluminate

In some embodiments of the present invention, the mineral composition in the cement clinker includes 58 wt% calcium sulfoaluminate, 20 wt% mayorite and 8 wt% calcium sulfoaluminate.

In the embodiment of the present invention, the 3d compressive strength is greater than or equal to 49.7MPa, and the 3d flexural strength is greater than or equal to 6.9MPa. And, under the chloride ion solution immersion, the anti-corrosion coefficients of the 1d, 3d and 28d of the present invention are all greater than 1, indicating that the chloride ion solution can promote the slight growth of the sulphur-aluminum-iron cement produced from blast furnace slag.

High iron sulfoaluminate cement has the advantages of early strength, high strength, frost resistance, impermeability, especially excellent seawater corrosion resistance, which is very suitable for use as marine engineering materials, but due to the high price of raw materials, iron aluminate cement not widely applicable. The invention uses blast furnace slag as raw material, and the cost of high iron sulfoaluminate cement produced by using blast furnace slag is far lower than that of ordinary sulfoaluminate cement, and the 3d compressive and flexural strengths can reach 49.7 MPa and 6.9 MPa, which fully meet the The strength standard of ordinary 425 sulfoaluminate cement, so the high iron sulfoaluminate cement produced with blast furnace slag as raw material can be promoted as marine engineering materials.

In a second aspect of the present invention, the present invention provides a method for preparing the sulfur-aluminum-iron-based cement described in the first aspect, which comprises: mixing the ground blast furnace slag with dried desulfurized gypsum, aluminum ash and The steel slag is mixed and homogenized, and the homogenized raw meal is calcined.

In some embodiments of the present invention, the method includes: mixing and homogenizing the ground blast furnace slag with dry desulfurized gypsum, aluminum ash and steel slag, the basicity coefficient of the raw meal is 0.81-0.9, and the homogenized In the raw meal, CaO accounts for 32-40 parts by weight, SiO ₂ accounts for 6-12 parts by weight, Al ₂ O ₃ accounts for 18-26 parts by weight, Fe ₂ O ₃ accounts for 10-15 parts by weight, SO ₃ accounts for 10-18 parts by weight , the aluminum-sulfur ratio is 1.0-1.8; the homogenized raw meal is transported to a rotary kiln for calcination, the calcination temperature is lower than 1200 ℃, and the calcination time is 20-60min to obtain cement clinker.

In the production process of traditional sulfoaluminate cement, if the content of Fe ₂ O ₃ in the cement raw meal is too high, tetracalcium ferric aluminate will be formed, which cannot maintain the characteristics of early strength and high strength of sulfoaluminate cement. . In order to ensure the production quantity and quality of calcium sulfoaluminate, it is usually necessary to control the content of Fe ₂ O ₃ in the cement raw meal below 3%, that is, only a small amount of iron-containing minerals can be added to the cement raw meal. However, if the Fe content is too low, the calcination temperature will be seriously affected, resulting in the failure of the clinker ore phase to form normally and reducing the performance of cement.

In the embodiment of the present invention, the content of calcium and aluminum in the homogenized raw meal is lower than that of the conventional process, while the content of iron and sulfur is significantly higher than that of the conventional process. The preparation method of the present invention can make the content of Al ₂ O ₃ in the cement raw meal lower than that of the traditional production process, and the content of Fe ₂ O ₃ is higher than that of the traditional production process, and the calcination temperature is greatly reduced, and the applicable scope of the process is expanded.

In the embodiment of the present invention, the alkalinity coefficient of the raw meal can be reduced to 0.81-0.9, which breaks through the alkalinity coefficient requirement in the traditional sulfoaluminate cement production process, and the reduction of the alkalinity coefficient reduces the content of CaO in the cement raw meal , thereby reducing the dependence on high calcium raw materials such as limestone. The spinel in blast furnace slag will not decompose within 1200 ℃ of calcination, and can play the role of aggregate in the process of cement hydration, thereby further improving the performance of cement.

However, if the calcium content in the raw material is too small, the reaction will be incomplete during the calcination process, and the amount of anhydrous calcium sulfoaluminate will not meet expectations, resulting in the formation of a large amount of anhydrous mayhemite, which will affect the performance of cement. After repeated experiments, the inventor found that reducing the content of aluminum in the raw meal during the batching process can realize that Fe replaces part of Al to generate tetracalcium ferric aluminate, which is used to replace part of the anhydrous calcium sulfoaluminate, which can also make cement have Early-strength, high-strength performance.

In some embodiments of the present invention, when calcining the cement raw meal prepared according to the present invention, the optimum calcination temperature is 1150°C-1180°C, which is much lower than the calcination temperature of traditional sulfoaluminate cement, which is beneficial to Energy saving and environmental protection.

In a third aspect of the present invention, the present invention provides a system for preparing the sulfur-aluminum-iron-based cement described in the first aspect, which includes: a drying system, a crushing system, a grinding system, a homogenizing system and a calcining system; According to the material processing sequence, the drying system is set before the crushing system or the grinding system, and the homogenization system is set after the crushing system or the grinding system and before the calcining system.

In some embodiments of the invention, the system includes a dryer, a crusher, a grinder, a homogenizer, and a rotary kiln.

In a fourth aspect of the present invention, the present invention provides a method for producing sulfur-aluminum-iron-based cement using the system described in the third aspect, comprising: drying the desulfurized gypsum by using a drying system; The gypsum enters the crushing system for crushing; the steel slag and blast furnace slag are ground in the grinding system; then the steel slag, blast furnace slag, desulfurized gypsum and aluminum ash after the above treatment enter the homogenization system for homogenization; after the homogenization treatment, the cement raw meal is obtained It is calcined in the calcination system to obtain cement clinker.

In a fourth aspect of the present invention, the present invention provides a marine engineering building material, which uses the sulfur-aluminum-iron-based cement described in the first aspect as a raw material.

In a fifth aspect of the present invention, the present invention provides the application of the sulfur-aluminum-iron-based cement described in the first aspect above as an offshore engineering building material or an application in the preparation of an offshore engineering building material.

As mentioned above, the 3d compressive and flexural strengths of the sulfur-aluminum-iron cement of the present invention can reach 49.7MPa and 6.9MPa, and the corrosion resistance coefficients of 1d, 3d and 28d are all greater than 1, and it has early strength, high strength, resistance to It has the advantages of corrosion and other advantages, and the raw materials are easy to obtain and cheap, and the calcination temperature is lower than 1200 ℃, which is especially suitable for promotion and use in the field of marine engineering construction.

Compared with the prior art, the advantages of the present invention are:

1. Compared with traditional Portland cement and modified Portland cement, the sulfur-aluminum-iron cement (ie high-iron sulfur-alumina cement) produced by using blast furnace slag as raw material has better corrosion resistance and erosion resistance. . Under the chloride ion solution immersion, the anticorrosion coefficients of 1d, 3d and 28d produced by blast furnace slag were all greater than 1, indicating that chloride ion solution can promote the slight growth of sulphur aluminum iron produced by blast furnace slag.

2. The sulfur-aluminum-iron cement of the present invention has the advantages of early strength, high strength, corrosion resistance, etc., and can be used in marine engineering projects to prolong the service life of buildings and make up for the shortcoming of insufficient durability of existing marine engineering materials.

3. The sulphur-aluminum-iron cement produced by using blast furnace slag has lower requirements for raw materials, and the calcination temperature is much lower than that of traditional sulphoaluminate cement, which can be as low as 1150 °C, which can reduce energy use and production cost, and the cost can be reduced by 30 %, reducing carbon dioxide emissions.

Description of drawings

The accompanying drawings that form a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation to the present application. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein:

Fig. 1 is the production flow chart of blast furnace slag to produce iron-based sulfoaluminate cement;

FIG. 2 is a line graph of the resist coefficient of Example 2 and Comparative Examples 3 and 4. FIG.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In the following examples, the experimental methods without specific conditions are usually in accordance with conventional conditions or in accordance with the conditions suggested by the manufacturer.

Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in a conventional manner in the art or in accordance with product instructions. In addition, any methods and materials similar or equivalent to those described can be used in the methods of the present invention. Methods and materials for preferred embodiments described herein are provided for illustrative purposes only.

Blast furnace slag is a solid waste formed from gangue in ore, ash in fuel and non-volatile components in solvent (usually limestone) during blast furnace ironmaking. Mainly contain calcium, silicon, aluminum, magnesium, iron oxides and a small amount of sulfide. In an embodiment of the present invention, the blast furnace slag composition includes CaO: 44-54% wt, SiO ₂ : 18-28% wt, and Al ₂ O ₃ : 8-16% wt. Unless otherwise specified, the main components of blast furnace slag in the following embodiments of the present invention are: CaO: 48.84%wt, _SiO2 : 24.66%wt, _Al2O3 : 11.37%wt, _{Fe2O3 :} 0.49 _% wt, MgO : 11.4% wt.

Example 1

As shown in Figure 1, a system for producing sulfoaluminate cement using blast furnace slag includes a dryer, a crusher, a grinder, a homogenizer and a rotary kiln; the dryer is used for drying desulfurized gypsum ; The desulfurized gypsum after drying is crushed in the crusher; the steel slag and blast furnace slag are ground in the grinder; then the steel slag, blast furnace slag, desulfurized gypsum and aluminum ash are mixed according to the set ratio and then enter the homogenization equipment for homogenization ; The cement raw meal after homogenization is calcined in the rotary kiln to obtain cement clinker.

The alkalinity coefficient of the homogenized cement raw meal here is 0.81. In the homogenized raw meal, CaO accounts for 37 parts by weight, SiO ₂ accounts for 8 parts by weight, Al ₂ O ₃ accounts for 23 parts by weight, and Fe ₂ O ₃ accounts for 37 parts by weight. 13 parts by weight, SO ₃ accounts for 12 parts by weight. Afterwards, the homogenized material was transported to a rotary kiln for calcination. The calcination temperature was 1160° C. and the calcination time was 30 minutes to obtain cement clinker. The main mineral composition of the cement clinker is shown in Table 1. Add 3% gypsum to the cement clinker, enter into a cement pulverizer for grinding, and obtain sulfoaluminate cement. The mechanical properties of the obtained sulfoaluminate cement are shown in Table 4. The strength inspection standard is carried out according to GB20472-2006 "Sulfoaluminate Cement".

Table 1 Main mineral composition (wt%) in cement clinker

component	calcium sulfoaluminate	mayorite	calcium sulfoaluminate
Cement clinker	58	20	17

Comparative Example 1

The difference from Example 1 is that the calcination temperature is 1120° C., and others are the same as in Example 1. The main mineral compositions in the prepared cement clinker are shown in Table 2, and the properties of the prepared sulfoaluminate cement are shown in Table 4.

Table 2 Main mineral composition in cement clinker (wt%)

component	calcium sulfoaluminate	mayorite	calcium sulfoaluminate
Cement clinker	48	28	8

Comparative Example 2

The difference from Example 1 is that the calcination temperature is 1200° C., and others are the same as in Example 1. The main mineral compositions in the prepared cement clinker are shown in Table 2, and the properties of the prepared sulfoaluminate cement are shown in Table 4.

Table 3 Main mineral composition in cement clinker (wt%)

component	calcium sulfoaluminate	mayorite	calcium sulfoaluminate
Cement clinker	56	19	15

Table 4

Example 2

The difference from Example 1 is: the finished cement product is made into a mortar block and placed in a 5% ^Cl- solution for curing.

Comparative Example 3

The difference from Example 2 is: put the mortar in clear water for maintenance, and other things are the same as in Example 2. The properties of the prepared mortar block are shown in Tables 5 and 6.

Comparative Example 4

The 425 sulfoaluminate cement was made into a mortar block and placed in a 5% Cl ^- solution for curing. The properties of the prepared mortar block are shown in Tables 5 and 6.

Comparative Example 5

The 425 sulfoaluminate cement was made into a mortar block and placed in clean water for curing. The properties of the prepared mortar block are shown in Tables 5 and 6.

Comparative Example 6

The 425 Portland cement was made into a mortar block and placed in a 5% Cl ^- solution for curing. The properties of the prepared mortar block are shown in Tables 5 and 6.

Comparative Example 7

The 425 Portland cement was made into a mortar block and placed in clean water for curing. The properties of the prepared mortar block are shown in Tables 5 and 6.

table 5

The corrosion resistance coefficient K is defined as the ratio of the flexural strength of the mortar test block immersed in the erosive solution to the flexural strength of the mortar test block immersed in clean water at the same age. Relative erosion resistance.

Table 6

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand the foregoing embodiments. The technical solutions described are modified, or some technical features thereof are equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A sulfur-aluminum-iron series cement, the raw material of which comprises or consists of blast furnace slag, desulfurized gypsum, aluminum ash and steel slag, and the raw meal basicity coefficient is 0.81-0.9.
2. The sulfur-aluminum-iron-based cement according to claim 1, wherein the blast furnace slag is a solid formed from gangue in the ore, ash in the fuel and non-volatile components in the solvent during the blast furnace ironmaking process. waste;

   Preferably, the components of the blast furnace slag include 44-54%wt CaO, 18-28%wt SiO ₂ and 8-16%wt Al ₂ O ₃ .
3. The sulphur-aluminum-iron-based cement according to claim 1 or 2, wherein in the sulphur-aluminum-iron-based cement raw meal, CaO accounts for 32-40 parts by weight, SiO ₂ accounts for 6-12 parts by weight, and Al ₂ O ₃ 18-26 parts by weight, Fe ₂ O ₃ 10-15 parts by weight, SO ₃ 10-18 parts by weight, wherein the ratio of aluminum to sulfur is 1.0-1.8.
4. The sulfoaluminate cement according to claim 1 or 2, wherein the mineral composition in the cement clinker comprises 50-70wt% calcium sulfoaluminate, 0-20wt% mayorite and 0-20wt% sulfur Calcium aluminum ferrite.
5. The sulfur-aluminum-iron-based cement according to claim 1 or 2, characterized in that its 3d compressive strength ≥ 49.7 MPa, and its 3d flexural strength ≥ 6.9 MPa.
6. A method for preparing the sulfur-aluminum-iron-based cement according to any one of claims 1 to 5, comprising: mixing and homogenizing the ground blast furnace slag with dry desulfurized gypsum, aluminum ash and steel slag; The homogenized raw meal is calcined, the calcination temperature is lower than 1200 DEG C, and the calcination time is 20-60 min to obtain cement clinker.
7. A system for preparing the sulfur-aluminum-iron-based cement according to any one of claims 1 to 5, comprising: a drying system, a crushing system, a grinding system, a homogenizing system and a calcining system; according to the material processing sequence, the drying system is set Before the crushing system or the grinding system, the homogenization system is arranged after the crushing system or the grinding system and before the calcining system.
8. A method for producing sulphur-aluminum-iron-based cement by using the system described in claim 7, comprising: drying desulfurized gypsum by using a drying system; the dried desulfurized gypsum is broken into a crushing system; steel slag and blast furnace slag are Grinding in the grinding system; then the steel slag, blast furnace slag, desulfurized gypsum and aluminum ash treated above enter the homogenization system for homogenization; after the homogenization process, the cement raw meal obtained is entered into the calcination system for calcination to obtain cement clinker.
9. An offshore engineering building material, which uses the sulfur-aluminum-iron-based cement according to any one of claims 1 to 5 as a raw material.
10. The application of the sulfur-aluminum-iron-based cement according to any one of claims 1 to 5 as an offshore engineering building material or in the preparation of an offshore engineering building material.

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