Silicon fluoride-containing raw material composition and application thereof in Portland cement clinker production

Abstract

The invention discloses an application of silicon fluoride in preparation of Portland cement clinker. The application comprises the following steps: (1) preparing raw materials, wherein the preparation raw materials of the Portland cement clinker comprise sandstone obtained by mining and screening siliceous ores, yellow phosphorus slag, an iron material, fly ash, coal gangue, sludge, silicon fluoride waste residue and limestone; (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; and (4) carrying out high-temperature calcination. The problem that silicon fluoride waste residues are difficult to stack is effectively solved, the reaction activity of crystalline silicon is increased, clinker is promoted to be calcined and compounded completely, and the liquid phase appearing temperature and the clinker sintering temperature are reduced. The firing temperature range is expanded, the length of a firing zone is prolonged, and the reaction time of materials is prolonged. The viscosity of a liquid phase can be reduced, so that the diffusion of mass points in the liquid phase is facilitated, and the formation of tricalcium silicate is accelerated. As the firing range of the clinker is expanded, the harm caused by non-uniform temperature field in the kiln is greatly reduced, and the yield and quality of the clinker are improved. And as the calcining temperature is reduced, the NxO emission is correspondingly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of cement, and in particular to the application of silicon fluoride as a mineralizer in the preparation of silicate cement clinker. Background Art

[0002] Due to the limited and non-renewable nature of fluorite resources, a certain fluorine chemical plant has opened up a new way to obtain fluorine resources, which is of great strategic significance for the protection of fluorite resources. This process is based on the recovery of fluorine and silicon resources associated with phosphate ore, and has successfully explored a new process technology for producing anhydrous hydrogen fluoride products that is different from the fluorite method, realizing the industrial production of anhydrous hydrogen fluoride technology using fluorosilicic acid; through the industrial production of its own technology, it has made comprehensive use of fluorine and silicon resources associated with phosphate ore, realizing the transformation of waste into treasure, and is the main solution for the promotion of clean production technology in the phosphate fertilizer industry, which is beneficial to environmental protection.

[0003] Silicon tetrafluoride (Si F4) is obtained by wet-process phosphoric acid production using fluorine silicon associated with phosphate rock. It is an inorganic compound that will hydrolyze violently to produce silicic acid and hydrofluoric acid when it comes into contact with water. The chemical equation for its hydrolysis is: Si F4+2H2O=H2SiO3↓+HF↑. In this reaction, silicon tetrafluoride reacts with water to produce silicic acid (H2SiO3) and hydrofluoric acid (HF). The generated silicic acid (H2SiO3) is a white solid that is difficult to dissolve in water, forming a suspension, which is filtered to form silicon fluoride (SiF4). Factory-scale production is carried out through slurry filtering-slag pressing-air drying-water washing-slurry filtering-slag pressing-air drying to obtain extremely fine pure white powder.

[0004] After testing, the leaching toxicity test data of the silicon fluoride powder meets the standards and is not classified as hazardous waste, but as Class II general industrial solid waste. The heavy metal leaching and radioactivity both meet the requirements. However, the difficulty in storing the waste residue needs to be solved urgently.

[0005] Patent document CN104671267A discloses a multi-component sintering aid, which is composed of the following raw material formula components in mass percentage: 100-200 parts of sodium bicarbonate, 50-100 parts of hydrochloric acid, 100-150 parts of soda ash, 50-100 parts of nano-iron sulfate, 50-100 parts of nano-aluminum sulfate, 20-50 parts of nano-copper sulfate, 20-50 parts of nano-potassium sulfate, 20-50 parts of nano-calcium sulfate, 20-30 parts of citric acid, 20-30 parts of tartaric acid, 10-15 parts of silicon tetrafluoride, 10-15 parts of magnesium fluorosilicate, 10-15 parts of potassium silicate. It can also be applied to the production raw materials of other refractory materials or the production raw materials of aluminate cement. However, the technical solution has limited digestion level of silicon fluoride, but mainly processes other bauxite and waste resources. And there is no guidance and inspiration for the production of silicate cement clinker. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the prior art and provide an application of silicon fluoride in the preparation of silicate cement clinker, the steps comprising: (1) preparing raw materials: the raw materials for preparing silicate cement clinker include: sandstone screened from siliceous mines, yellow phosphorus slag, iron materials, fly ash, coal gangue, sludge, silicon fluoride waste residue, and limestone; (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; and (4) high-temperature calcining.

[0007] Further, the raw materials are 1-2 parts of sandstone screened from natural silica mines, 2-3 parts of yellow phosphorus slag, 0.5-1.5 parts of iron materials, 2-3 parts of fly ash, 2-3 parts of coal gangue, 0-0.5 parts of sludge, 0.7-1.5 parts of silicon fluoride waste residue, and 92-93 parts of limestone. Optionally, coal slag is also included.

[0008] Furthermore, the method also includes step (5) of forced cooling, preheating and crushing the recovered part before entering the clinker storage.

[0009] Furthermore, step (2) is to transport the raw materials to the raw material mill system for grinding, select the unqualified fineness materials through the powder selector, and return them to the mill for grinding again. The qualified raw materials are transported to the homogenization silo through the chute and bucket.

[0010] Furthermore, step (3) is to send the raw meal into a cyclone preheater through a homogenizing discharge device for preheating and decomposition.

[0011] Furthermore, step (4) is to send the product into a rotary kiln for high-temperature calcination.

[0012] Furthermore, the application is to increase the reactivity of crystalline silicon to promote the complete calcination of clinker, and reduce the temperature at which the liquid phase appears and the clinker sintering temperature.

[0013] Furthermore, the firing temperature can be reduced by 50-100℃, which expands the firing temperature range, prolongs the length of the firing zone, and increases the reaction time of the material. It can also reduce the liquid phase viscosity, which is beneficial to the diffusion of particles in the liquid phase and accelerates the formation of tricalcium silicate. Since the firing range of the clinker is expanded, the harm of uneven temperature field in the kiln is greatly reduced, and the clinker output and quality are improved.

[0014] Furthermore, the application is to improve the quality of clinker, reduce the content of free calcium (f-CaO), and thus reduce the heat consumption of clinker. As the calcination temperature is reduced, it is necessary to control the temperature of each point of the preheater to ensure the normal operation of the kiln, reduce the amount of pulverized coal feed, and correspondingly reduce NxO emissions.

[0015] Furthermore, the silicon fluoride waste residue comprises LoSS, SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, CaF4, etc. The sum of LoSS and SiO2 is greater than 90%, the CaF2 content of silicon fluoride is 2-3.5%, and also includes very small amounts of heavy metals Cu, Zn, Cd, Pb, Cr, Hg, Be, Ba, Na, Ag, As, Se.

[0016] The invention also provides a silicate cement raw material composition containing silicon fluoride, which comprises sandstone screened from siliceous ore mining, yellow phosphorus slag, iron material, fly ash, coal gangue, sludge, silicon fluoride waste residue and limestone.

[0017] Furthermore, the raw materials are 1-2 parts of sandstone screened from natural siliceous ore mining, 2-3 parts of yellow phosphorus slag, 0.5-1.5 parts of iron material, 2-3 parts of fly ash, 2-3 parts of coal gangue, 0-0.5 parts of sludge, 0.7-1.5 parts of silicon fluoride waste residue, and 92-93 parts of limestone.

[0018] Furthermore, the silicon fluoride waste residue comprises LoSS, SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, CaF4, etc. The sum of LoSS and SiO2 is greater than 90%, the CaF2 content of silicon fluoride is 2-3.5%, and also includes very small amounts of heavy metals Cu, Zn, Cd, Pb, Cr, Hg, Be, Ba, Na, Ag, As, Se.

[0019] At present, cement production has certain advantages in the treatment of solid and hazardous wastes, and has also made great breakthroughs, especially in the use of general solid wastes. With the tightening of solid waste discharge and storage policies and the staggered production of cement, the utilization rate of some solid and hazardous wastes cannot be guaranteed. Based on the characteristics of silicon fluoride components, the project uses silicon fluoride as a preparation method in silicate cement clinker, and its mechanism is as follows:

[0020] 1. Decomposition mechanism of silicon fluoride in silicate cement clinker

[0021] The main minerals C3S and C2S contained in cement clinker are both calcined products of CaO and SiO2. During the calcination of cement clinker, the diffusion rate of CaO in the SiO2 lattice is 4 times higher than that of SiO2 in the CaO lattice. ～ 5 times. Although the SiO2 content accounts for only about 14% of the total cement raw material, the diffusion rate of SiO2 particles is the main factor determining the reactivity of the raw material.

[0022] f-CaO(1400℃)={0.343(LSF-93)+2.74(SM-2.3)}+

[0023] {0.83Q 45 +0.10 C 125 +0.39R 45}

[0024] Where: f-CaO (1400℃) - the content of free calcium oxide after raw material is calcined at 1400℃ for 30 minutes

[0025] LSF: limestone saturation factor,

[0026] LSF=(Ca0+Mg0) / (2.8S i02+l.18Al203+0.65Fe203)

[0027] SM: Silicate content SM = SiO2 / (Al2O3+Fe2O3)

[0028] Q 45 - >45μm coarse-grained quartz, expressed as a percentage of the total in the raw material sample;

[0029] C 125 ->125μm coarse-grained limestone, expressed as a percentage of the total in the raw material sample;

[0030] R 45 Other acid insoluble matter ->45μm, expressed as a percentage of the total in the raw meal sample.

[0031] The f-CaO formula indicates the role played by the chemical composition of the raw material. The higher the limestone saturation coefficient LSF and silica content SM, the higher the f-CaO value and the higher the calcination temperature. The second half of the formula indicates the role played by the fineness of different minerals in the raw material on the burnability. In particular, coarse particles SiO2 > 45μm and a small amount of acidic insolubles have a greater impact on the burnability.

[0032] When cement clinker is fired, the rate value of the clinker is basically emphasized, while the fineness of raw materials such as SiO2 that are difficult to fire is ignored. In the actual calcination process of clinker, the raw material contains SiO2 that is difficult to grind. Such coarse SiO2 is not easy to react with CaO to generate C2S and C3S, resulting in the generation of free calcium oxide (f-CaO). Industrial control is accustomed to controlling the amount of CaO. If coarse SiO2 is encountered, the firing temperature of the clinker must be increased to enhance the reaction ability of C2S and f-CaO to generate C3S, and also generate larger crystal C3S clinker particles, forming flying sand materials that are difficult to hydrate and have low strength. When the raw material contains some compounds with a low melting temperature, a "snowman" will be formed. Such clinker adheres to the high-temperature refractory brick wall or burner at the kiln mouth, affecting the normal calcination of the kiln and increasing safety risks. At this time, the amount of coal powder used during firing will be artificially increased, resulting in a reducing atmosphere in the kiln, which is not conducive to the firing of clinker and forms a vicious cycle. At the same time, large lattice C3S clinker crystals are formed, and the power consumption will also increase during grinding.

[0033] Therefore, the solution is to maintain the clinker rate and increase the fineness of raw meal grinding, but the power consumption of raw meal grinding will increase accordingly; a better way is to replace it with easy-to-grind SiO2 minerals, so that the raw meal is easy to grind and calcine, and the clinker strength can also be improved.

[0034] Generally, the fineness of raw material ground in cement plants is controlled at 0.08mm ≤18.0%, and 0.2mm dry screen ≤2.0%. The silicon fluoride used in the case has a 0.08mm sieve residue of 0.00%, and a 0.045mm sieve residue of only 2.0%. It has high dispersion. Because the particles are extremely small, they are heated faster and more evenly, and are more likely to react with CaO during calcination to generate C2S and C3S, which is beneficial to reduce free calcium (f-CaO), generate more silicate minerals, stabilize the clinker rate value and improve the clinker strength.

[0035] 2. Mineralization of silicon fluoride in the calcination of silicate cement clinker

[0036] In the case of raw materials containing high levels of alkaline minerals, adding extremely fine and fluorinated silicon fluoride can reduce the decomposition temperature and accelerate decomposition and volatilization. ～ At 1200℃, C3A can be decomposed into C 12 A7 and CaO, so that the precipitated CaO combines with C2S to form C3S to increase the content of A ore. Because limestone and sandstone have high crystalline silicon, fluorine-containing silicon fluoride can increase the reactivity of crystalline silicon, promote the complete calcination of clinker, and significantly reduce the temperature at which the liquid phase appears and the clinker burning temperature.

[0037] 3. Effect of Silicon Fluoride on Clinker Quality during Calcination of Portland Cement Clinker

[0038] The CaF2 content of silicon fluoride is between 2.45% and 3.02%, which can reduce the firing temperature by 50%. ～ 100℃ expands the firing temperature range, prolongs the length of the firing zone and increases the reaction time of the material. It can also reduce the liquid viscosity, which is beneficial to the diffusion of particles in the liquid phase and accelerates the formation of tricalcium silicate. The expansion of the clinker firing range greatly reduces the harm of uneven temperature field in the kiln and improves the clinker output and quality.

[0039] 4. Effect of silicon fluoride on coal consumption and CO2 emissions in the calcination of silicate cement clinker

[0040] Silicon fluoride can promote tricalcium silicate to burn into silicate cement clinker at about 1300-1350℃. The clinker composition contains C3S, C2S, C3A, C 11 A7xCaF2, C4AF and other minerals can generate clinker with good quality and qualified stability, which can significantly improve the quality of clinker and reduce the content of free calcium (f-CaO), thereby reducing the heat consumption of clinker. Due to the reduction of calcination temperature, it is necessary to control the temperature of each point of the preheater to ensure the normal operation of the kiln, reduce the amount of coal powder feed, and correspondingly reduce NxO emissions. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0042] Example 1

[0043] Silicon fluoride waste residue is used as a mineralizer in the preparation method of silicate cement clinker. The steps include: (1) by weight, the raw materials for preparing the silicate cement clinker include: 1.18 parts of sandstone screened from natural siliceous ore, 2.63 parts of yellow phosphorus slag, 0.54 parts of iron material, 2.50 parts of fly ash, 1.80 parts of coal gangue, 0.02 parts of sludge, 1.35 parts of silicon fluoride waste residue, 0.29 parts of coal slag, and 93.18 parts of limestone. (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; (4) high-temperature calcining. Step (5) forced cooling and recovery of the preheated and crushed parts into the clinker storage for storage.

[0044] Steps (2) to (5) are as follows: the materials are metered and then conveyed to the raw material mill system for grinding; after grinding to the required fineness, the qualified raw materials are conveyed to the raw material warehouse through the powder selector, and the unqualified raw materials are returned to the raw material mill system for re-grinding.

[0045] The raw material in the raw material storehouse is sent to a cyclone preheater for preheating and pre-decomposition, and then sent to a rotary kiln for high-temperature calcination, and then cooled and crushed to obtain cement clinker.

[0046] The high-temperature cement clinker discharged from the rotary kiln is cooled by a cooler, and the waste heat of the high-temperature cement clinker is recovered at the same time.

[0047] Example 2

[0048] Silicon fluoride waste residue is used as a mineralizer in the preparation method of silicate cement clinker. The steps include: (1) by weight, the raw materials for preparing the silicate cement clinker include: 1 part of sandstone screened from natural siliceous ore mining, 2 parts of yellow phosphorus slag, 0.5 parts of iron material, 2 parts of fly ash, 2 parts of coal gangue, 0.7 parts of silicon fluoride waste residue, and 92 parts of limestone. (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; (4) high-temperature calcining.

[0049] Example 3

[0050] Silicon fluoride waste residue is used as a mineralizer in the preparation method of silicate cement clinker. The steps include: (1) by weight, the raw materials for preparing the silicate cement clinker include: 2 parts of sandstone screened from natural siliceous ore mining, 3 parts of yellow phosphorus slag, 1.5 parts of iron material, 3 parts of fly ash, 3 parts of coal gangue, 0.5 parts of sludge, 1.5 parts of silicon fluoride waste residue, and 93 parts of limestone. (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; (4) high-temperature calcining.

[0051] Comparative Example 1

[0052] The raw materials for preparing the silicate cement clinker of Comparative Example 1 include: by weight, the raw materials for preparing the silicate cement clinker include: 2.09 parts of sandstone screened from natural siliceous mines, 3.00 parts of yellow phosphorus slag, 0.56 parts of iron materials, 2.66 parts of fly ash, 1.72 parts of coal gangue, 0.02 parts of sludge, 0.0 parts of silicon fluoride waste residue, 0.18 parts of coal slag, and 92.84 parts of limestone.

[0053] The other steps and methods are exactly the same as those in Example 1.

[0054] The following comparative analysis was performed on Example 1 and Comparative Example 1:

[0055] 1. Control of three rates of raw material and clinker before and after using phosphogypsum

[0056] Table 1 Comparison of raw material composition and three rate value control between Example 1 and Comparative Example 1

[0057]

[0058] It can be seen from the results in Table 1 that when 1.35% of silicon dioxide waste slag is added to the raw material ingredients, the three rates of raw material and clinker do not change much, and the chloride ion content of the raw material increases by 0.002%, which has little effect.

[0059] Table 2 Comparison of clinker composition and three rate value control between Example 1 and Comparative Example 1

[0060]

[0061] From the statistical comparison data in Table 1 and Table 2, after using silicon fluoride to prepare the raw materials, the chemical composition and physical properties of the clinker are stable, and all indicators meet the national standards; at the same time, after adding silicon fluoride, due to the action of a small amount of fluoride ions and extremely fine silica, the burnability of the raw materials is improved and the calcination rate of the clinker is accelerated, and the decomposition rate is increased by 0.15%.

[0062] II. Table 3 Comparison of raw material batching cost changes between Example 1 and Comparative Example 1

[0063]

[0064]

[0065] From the perspective of raw material proportion, the proportion of material addition did not fluctuate much. The addition of silicon fluoride was 1.35%, the addition of mining siliceous materials decreased by 0.91% year-on-year, and the addition of yellow phosphorus slag decreased by 0.37% year-on-year. The cost of raw material ingredients decreased by 0.44 yuan / ton.

[0066] 3. Effect of silicon fluoride on clinker quality before and after use

[0067] Table 4 Effect of Example 1 and Comparative Example 1 on free calcium in clinker, liter weight, small grinding time and consistency

[0068]

[0069] After using silicon fluoride, the free calcium of clinker is 0.84%, which is 0.08% lower than that of not using silicon fluoride, and the qualified rate is 100.0%; the weight per liter is 1345g / L, which is 5g / L higher than that of not using silicon fluoride, and the qualified rate is 100.0%; after using silicon fluoride, the small grinding time is 1800 seconds, which is 216 seconds lower than that of 2016 seconds without using silicon fluoride, which is a significant decrease, indicating that the grindability of clinker has improved. The standard consistency of small grinding clinker is 24.9%, which is unchanged compared with the previous year.

[0070] Table 5 Effect of Example 1 and Comparative Example 1 on clinker setting time and strength

[0071]

[0072]

[0073] After using silicon fluoride, the initial setting time of clinker is 132min, which is 7min longer than before silicon fluoride is added, and the final setting time is 180min, which is 4min longer than before silicon fluoride is added. The 3-day strength of clinker is 33.7MPa, which is 0.5MPa higher than before silicon fluoride is added. The 28-day strength is 56.8MPa, which is 0.6MPa higher than before silicon fluoride is added. This is mainly due to the addition of trace elements such as CaF2 and the finer siliceous crystals. Silicon and calcium are better combined under the action of flux minerals, and the calcination rate is accelerated.

[0074] 5. Comparison of main parameters of kiln calcination before and after using silicon fluoride

[0075] Table 6 Comparison of pipe crusting between Example 1 and Comparative Example 1

[0076]

[0077] It can be seen from Table 6 that by comparing the crusting of the preheater C5 slide tube, the inner diameter of the slide tube without using silicon fluoride is 65-67cm, and no obvious crusting is found at the elbow position. After using silicon fluoride, the slide tube crusting inspection shows that the crusting thickness is about 1-2cm, and there is not much overall crusting. The inner diameter of the slide tube is 66cm. After comparing the on-site slide tube crusting inspection and temperature measurement, after using silicon fluoride, the slide tube crusting has not been significantly aggravated. The temperature at point 2# of C5A slide tube has dropped by 22°C, and the temperature at point 3# of C5B slide tube has dropped by 33°C. There is no obvious change in the slide tube temperature at other positions.

[0078] Each shift provides feedback on the cleaning of the kiln tail crust. After using phosphogypsum, there is no obvious increase in the shrinkage crust, and the slope accumulation has not changed much. Compared with the drum sweep, there are no sulfur, alkali, and chlorine circles at 35-74 meters, and there is no obvious change in the drum temperature before and after use.

[0079] Table 7 Comparison of kiln feed amount between Example 1 and Comparative Example 1

[0080] project Comparative Example 1 Example 1 contrast Kiln feed rate 400-420 400-420 0 Clinker power consumption 27.6 27.6 0

[0081] It can be seen from Table 7 that there is no significant change in the output and process power consumption before and after the use of silicon fluoride.

[0082] By comparing the quality data, after using silicon fluoride in the raw material stage, the free calcium, weight per liter, initial setting time and final setting time of the clinker out of the kiln did not change much as a whole, and the clinker strength increased by 0.5MPa and 0.6MPa in 3 days and 28 days respectively; the clinker grinding time was reduced by 136 seconds compared with before use, and the grindability of the clinker was significantly improved; the comprehensive performance of the clinker was improved to a certain extent, indicating that silicon fluoride in the raw material batching significantly reduces the raw material batching cost, and does have a mineralization effect in the clinker calcination process.

[0083] 1. Calculation of energy saving effect

[0084] From Table 8 below, it can be calculated that adding 1.1-1.6% silicon fluoride to the raw material can save 0.275kg of standard coal per ton of clinker. Based on the production of 1.84 billion tons of clinker in 2023, it can save about 506 tons of standard coal, achieving energy conservation and environmental protection.

[0085] Table 8 Energy saving effect calculation table Calculation basis: 1kg clinker

[0086]

[0087] According to the above, adding 1.1%-1.6% silicon fluoride can save 0.275kg of standard coal, and the CO2 emission coefficient of standard coal is 0.67. It can be inferred that adding 1% silicon fluoride can reduce 0.275kg of CO2 generated by coal combustion per ton of clinker. Based on the production of 1.84 billion tons of clinker in 2023, 5.06 million tons of CO2 emissions can be reduced throughout the year. The reduction of CO2 emissions effectively alleviates the pressure on the control of carbon emissions.

[0088] 2. Cost

[0089] Table 9 Ingredient cost comparison table

[0090]

[0091] It can be concluded from Table 9 above that after adding 1% of silicon fluoride waste slag, the raw material batching cost is reduced by 0.44 yuan. Based on the calculation that 1.53 tons of raw material is consumed per ton of clinker, the batching cost per ton of clinker can be reduced by 0.67 yuan.

[0092] 3. Economic Benefits

[0093] According to the above, adding 1% silicon fluoride to the calcination of silicate cement clinker can save 0.175kg of standard coal. If the unit price of raw coal is calculated at 940 yuan / t, the addition of silicon fluoride can save 0.26 yuan per ton of clinker in coal cost.

[0094] The annual plan is to produce 2.92 million tons of raw materials and 1.9 million tons of cement clinker. The subsidy per ton of silicon fluoride is -85 yuan. Based on the minimum dosage of 1.0%, the following is true:

[0095] Cost savings per ton of clinker production = cost savings of raw material ingredients * material consumption + cost savings of coal + subsidy income diluted to clinker cost = 0.44*1.53+0.26+(292*1.00 / 100)*85 / (292 / 1.53)) = 2.24 yuan

[0096] 4. Social Benefit Analysis

[0097] According to the actual output of 1.84 billion tons of cement clinker in 2023, the demand for raw materials is close to 2.97 billion tons. If the average dosage of silicon fluoride in raw materials reaches 1.0%, the consumption of silicon fluoride can be increased by 29.7 million tons per year. In Hubei, Guizhou, Yunnan, Anhui and Shandong, where phosphorus chemical industry is relatively concentrated, it plays an active leading role in the effective utilization of silicon fluoride.

[0098] According to the above, adding 1.1%-1.6% silicon fluoride can save 0.275kg of standard coal, and the CO2 emission coefficient of standard coal is 0.67. It can be inferred that adding 1% silicon fluoride can reduce 0.275kg of CO2 generated by coal combustion per ton of clinker. Based on the production of 1.84 billion tons of clinker in 2023, 5.06 million tons of CO2 emissions can be reduced throughout the year. The reduction of CO2 emissions effectively alleviates the pressure on the control of carbon emissions.

[0099] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0100] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments is illustrative rather than restrictive. A person skilled in the art may modify the technical solutions described in the embodiments, or replace some of the technical features by equivalents, based on reading the specification of the present invention; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An application of silicon fluoride in the preparation of silicate cement clinker, characterized in that: The steps include: (1) Raw material preparation: The raw materials for preparing silicate cement clinker include: sandstone screened from siliceous ore mining, yellow phosphorus slag, iron materials, fly ash, coal gangue, sludge, silicon fluoride waste residue, and limestone; (2) crushing and homogenizing the raw materials; (3) preheating and decomposing; (4) high-temperature calcining.

2. The use according to claim 1, characterized in that: The raw materials are 1-2 parts of sandstone screened from natural siliceous ore mining, 2-3 parts of yellow phosphorus slag, 0.5-1.5 parts of iron material, 2-3 parts of fly ash, 2-3 parts of coal gangue, 0-0.5 parts of sludge, 0.7-1.5 parts of silicon fluoride waste residue, and 92-93 parts of limestone; optionally, coal slag is also included.

3. The use according to claim 1, characterized in that: The step also includes a step (5) of forced cooling, preheating the recovered part, crushing it and then storing it in a clinker warehouse.

4. The use according to claim 1, characterized in that: Step (2) is to transport the raw materials to the raw material mill system for grinding, select the unqualified fineness materials through the powder selector, and return them to the mill for grinding again; the qualified raw materials are transported to the homogenization silo through the chute and bucket lift; Step (3) is to send the raw meal into the cyclone preheater through the homogenizing discharge device for preheating and decomposition; Step (4) is to send the product into a rotary kiln for high-temperature calcination.

5. The use according to claim 1, characterized in that: The application is to increase the reactivity of crystalline silicon, promote the complete calcination and combination of clinker, and reduce the temperature at which the liquid phase appears and the clinker sintering temperature and / or Lowering the firing temperature by 50~100℃ expands the firing temperature range, prolongs the length of the firing zone and increases the reaction time of the material; it also reduces the liquid viscosity, which is beneficial to the diffusion of particles in the liquid phase and accelerates the formation of tricalcium silicate; because the firing range of the clinker is expanded, the harm of uneven temperature field in the kiln is greatly reduced, and the clinker output and quality are improved; and / or The application is to improve the quality of clinker, reduce the content of free calcium, and thus reduce the heat consumption of clinker; because the calcination temperature is reduced, it is necessary to control the temperature of each point of the preheater to ensure the normal operation of the kiln, reduce the coal powder feed amount, and correspondingly reduce NxO emissions.

6. The use according to claim 1, characterized in that: The silicon fluoride waste slag components include LoSS, SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, and CaF4; the sum of LoSS and SiO2 is greater than 90%, and the CaF2 content of silicon fluoride is 2-3.5%.

7. A silicate cement raw material composition containing silicon fluoride, characterized in that: Including sandstone screened from siliceous ore mining, yellow phosphorus slag, iron materials, fly ash, coal gangue, sludge, silicon fluoride waste residue, and limestone.

8. The composition according to claim 7, characterized in that The raw materials are 1-2 parts of sandstone screened from natural siliceous ore mining, 2-3 parts of yellow phosphorus slag, 0.5-1.5 parts of iron material, 2-3 parts of fly ash, 2-3 parts of coal gangue, 0-0.5 parts of sludge, 0.7-1.5 parts of silicon fluoride waste residue, and 92-93 parts of limestone.

9. The composition according to claim 7, characterized in that The silicon fluoride waste residue comprises LoSS, SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, CaF4, etc. The sum of LoSS and SiO2 is greater than 90%, and the CaF2 content of silicon fluoride is 2-3.5%.

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