Low-carbon slag cement and preparation method thereof

Abstract

The application provides a low-carbon slag cement and a preparation method thereof, and the low-carbon slag cement comprises the following components: 70-90 parts of mineral powder, 5-25 parts of Portland cement clinker, 5-15 parts of iron tailings, 1-5 parts of desulfurization gypsum, 0.0005-0.002 parts of a stand mill grinding aid component, 0.0005-0.002 parts of a grinding aid reinforcing component and 0.0005-0.002 parts of a dispersing component. Compared with the prior art, the application reasonably matches the types, dosages and particle sizes of the cementitious materials, optimizes the initial slurry structure, matches the hydration processes of the materials with each other, and obtains the low-carbon cement with low clinker dosage and good performance. The application stimulates the fine mineral powder particles with a small amount of clinker fine powder, avoids the problem of high water demand caused by the rapid hydration of a large amount of clinker fine particles, fully stimulates the hydration of the fine slag powder particles, and ensures the early strength of the low-carbon cement. In addition, the application reasonably utilizes a large amount of waste silica powder, slag and iron tailings, and is low-carbon and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of materials, specifically relating to a low-carbon slag cement and its preparation method. Background Technology

[0002] The building materials industry is a significant source of carbon emissions, with the cement industry accounting for 7.5% of global anthropogenic CO2 emissions. Therefore, the energy-intensive and high-emission cement industry will be a key focus in carbon reduction efforts. Cement industry carbon emissions are divided into direct and indirect emissions. Direct emissions include emissions from fuel combustion and emissions from the production process (carbonate decomposition). Indirect emissions include CO2 emissions from electricity consumption in cement production, as well as energy consumption in non-production processes such as power generation, heating, and transportation. The main source of CO2 emissions in the cement industry is the clinker production process. Carbonate decomposition accounts for approximately 60% of total carbon emissions; fuel combustion accounts for approximately 35%; and electricity consumption indirectly accounts for approximately 5%. Specifically, producing 1 ton of cement clinker requires approximately 1.2 tons of limestone and 0.3 tons of clay. Furthermore, the firing of silicate cement clinker typically requires a high temperature of around 1450℃, consuming approximately 105 kg of standard coal and producing approximately 0.8-1.0 tons of CO2 per ton of clinker.

[0003] Meanwhile, with rapid economic growth, the scale of industrial production in sectors such as steel, metallurgy, and photovoltaics has expanded unprecedentedly. While meeting the demand for large quantities of production materials, this has generated an astonishing amount of industrial waste. A large amount of industrial waste can be used as raw material or auxiliary cementitious material in cement production. This method reduces resource and energy consumption and CO2 emissions during cement production, while also lowering production costs. Simultaneously, it eliminates water and environmental pollution caused by waste accumulation and treatment, saves on waste treatment and accumulation costs, and reduces the large amount of land occupied by waste accumulation.

[0004] However, in some regions, the high alkali content of cement clinker due to the availability of limestone as a raw material significantly limits the utilization of limestone resources with high alkali content. my country's current national standard for cement, GB175 "General Portland Cement," stipulates that if reactive aggregates are used and the user requests low-alkali cement, the alkali content in the cement should not exceed 0.6%. Within the industry, clinker with an alkali content exceeding 0.8% is generally considered high-alkali clinker. Numerous studies have shown that excessively high alkali content in cement produced from high-alkali clinker poses a significant potential threat to the durability and safety of buildings.

[0005] Patent CN111606584A, published on September 1, 2020, discloses a type of slag cement. By weight percentage, it comprises the following components: 30-60% clinker, 20-40% mineral powder, 5-15% gypsum, 5-12% auxiliary materials, and 0.05-0.20% activator. The auxiliary materials are fly ash, titanium dioxide, and modified rubber particles, while the activator is a mixture of calcium sulfate, sodium metachlorite, and organic ammonium salts. The mineral powder content is relatively low, only 20%-40%.

[0006] Publication No. CN108623196A, published on October 9, 2018, discloses a lime-activated low-carbon cement with a large amount of industrial waste residue and its preparation method. The cement is composed of 5-25 parts cement clinker, 20-35 parts fly ash, 30-50 parts mineral powder, 6-12 parts lime, 5-9 parts gypsum, and 1-4 parts activator. The cement clinker and gypsum are mixed and ground together according to the specified proportions. After reaching the required fineness, they are then mixed and homogenized with fly ash, slag, lime, and activator. However, the excessive lime content affects the cement's stability. It releases a large amount of heat upon contact with water and absorbs water, causing the cement mortar or concrete to crack.

[0007] Therefore, it is essential to provide a slag cement with high mineral powder content, stability, and excellent performance. Summary of the Invention

[0008] The purpose of this invention is to provide a low-carbon slag cement and its preparation method. The low-carbon slag cement prepared by the combined treatment of slag and silicon waste from the photovoltaic industry results in a low-carbon slag cement with high slag content, high cement strength, and qualified stability.

[0009] The specific technical solution of this invention is as follows:

[0010] A low-carbon slag cement comprises the following raw materials in parts by weight:

[0011] 70-90 parts mineral powder, 5-25 parts silicate cement clinker, 5-15 parts iron tailings, 1-5 parts desulfurized gypsum, 0.0005-0.002 parts vertical mill grinding aid, 0.0005-0.002 parts grinding aid reinforcing component, and 0.0005-0.002 parts dispersing component.

[0012] The silicate cement clinker is a high-alkali clinker.

[0013] Preferably, the alkali mass fraction in the silicate cement clinker is: 0.80% ≤ (Na2O + 0.658K2O) ≤ 1.5%.

[0014] The desulfurized gypsum has an attached water content of no more than 12%, a calcium sulfate dihydrate (CaSO4·2H2O) content of no less than 90%, and a calcium sulfite hemihydrate (CaSO4·1 / 2H2O) content of no more than 0.5%.

[0015] The grinding aid component of the vertical mill consists of sucrose monolaurate, polypropylene glycol, and water.

[0016] Preferably, the grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.1-0.5:1-5.

[0017] Preferably, the molecular weight of the polypropylene glycol is between 200 and 600.

[0018] The grinding aid and strengthening component is composed of alkanolamine, phosphate and humic acid;

[0019] The mass ratio of the alkanolamine, phosphate, and humic acid is 1:0.5-2:1-5.

[0020] The alcoholamine is selected from monoethanol diisopropanolamine.

[0021] The phosphate is selected from sodium dihydrogen phosphate.

[0022] Preferably, the grinding aid component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate, and humic acid in a weight ratio of 1:0.5-2:1-5.

[0023] Preferably, the dispersed component is propylene glycol diacetate or glyceryl monolaurate.

[0024] The present invention provides a method for preparing low-carbon slag cement, comprising the following steps:

[0025] 1) Add the formulated mineral powder, desulfurized gypsum and vertical mill grinding aid to the vertical mill, and grind them in the vertical mill to obtain V400 mineral powder.

[0026] 2) Add V400 mineral powder and the dispersing component into an ultrafine air jet mill and grind them to obtain V800 mineral powder and V1000 mineral powder respectively;

[0027] 3) Add the silicate cement clinker and grinding aid / reinforcing components to a ball mill according to the formula, and ball mill to obtain specific gravity values ​​of 320±10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2 / kg of cooked powder;

[0028] 4) Add the prescribed amount of iron tailings to a ball mill and ball mill to obtain a specific surface area of ​​320±10m. 2 / kg of iron tailings powder;

[0029] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 320±10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2Low-carbon slag cement is obtained by uniformly mixing clinker powder and iron tailings powder at a ratio of / kg.

[0030] In step 1), the mineral powder includes blast furnace slag and waste silicon powder;

[0031] Preferably, the weight ratio of blast furnace slag to waste silicon powder is 10-30:1.

[0032] The waste silicon powder refers to silicon waste generated during the silicon wafer cutting process in the photovoltaic industry.

[0033] Preferably, the waste silicon powder has a particle size between 0.4 and 0.6 μm, and the content of silicon and silicon dioxide in the dry basis material (W) is... Si+SiO2 ≥98%.

[0034] In step 3), the ratio is 320 ± 10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2 The weight ratio of clinker powder is 1-5:1.

[0035] In step 5), the weight ratio of V400 mineral powder, V800 mineral powder and V1000 mineral powder is 5-10:1-5:1.

[0036] The specific gravity of the V400 mineral powder is 400±10m. 2 / kg; the specific gravity of the V800 mineral powder is 800±10m 2 / kg; the specific gravity of the V1000 mineral powder is 900±10m 2 / kg.

[0037] Preferably, the particle size of the V400 mineral powder particles is between 10-11 μm, the particle size of the V800 mineral powder particles is between 4.5-5.5 μm, and the particle size of the V1000 mineral powder particles is between 2.5-3.5 μm.

[0038] Preferably, the V400 mineral powder has a 3-day activity index between 50-60%, a 7-day activity index between 80-90%, and a 28-day activity index between 95-105%; the V800 mineral powder has a 3-day activity index between 100-110%, a 7-day activity index between 115-125%, and a 28-day activity index between 125-135%; and the V1000 mineral powder has a 3-day activity index between 120-130%, a 7-day activity index between 135-145%, and a 28-day activity index between 140-150%.

[0039] The waste silica powder used in this invention has a particle size between 0.4-0.6 μm. The small particle size of the waste silica powder allows it to fill the gaps between other material particles, increasing the density of the slurry and improving cement strength. The high moisture content and fine particle size of the waste silica powder allow it to fill the gaps between slag particles, stabilizing the material layer. Furthermore, the waste silica powder contains a small amount of cutting fluid, whose main component is a surfactant, which provides some dispersion after drying, improving the efficiency of the classifier at the top of the vertical mill. The synergistic effect of sucrose monolaurate and polypropylene glycol stabilizes the material layer and improves grinding efficiency during the grinding of slag in the vertical mill. In cement clinker, allite has an average size of approximately 65 μm, and belite approximately 55 μm. Sodium dihydrogen phosphate adsorbs onto the surface of clinker particles, reducing the crystallinity of the crystal lattice, thereby improving grinding efficiency. It also causes amorphization of the particle surface layer, lattice defects, lattice distortion, and changes in surface energy, placing the particles in a metastable high-energy state and increasing the activity of the clinker powder. Diisopropanolamine monoethanol is polar, structurally asymmetrical, and contains positive and negative charge centers. It readily adsorbs onto cement powder, and the Ca-O ionic bonds on the fractured surface break, causing Ca... 2+ Active sites, saturated broken valence bonds shield the aggregation forces between particles to prevent aggregation, thus exhibiting a promoting effect on the grinding process, and reacting with Al in cement paste solutions. 3+ and Fe 3+ Complexation, forming soluble complexes, promotes the hydration of C4AF to generate AFt, altering the amount of Ca(OH)2 present in the cement stone hydration process, thereby accelerating the hydration of silicate minerals, stimulating the reactivity of cementitious materials, resulting in accelerated hydration rate, improved cement stone pore structure, optimized morphology of hydration products, stimulated cementitious material reaction, and reduced ettringite crystal size, thus increasing cement stone strength. Humic acid complexes with metal ions, increasing the metal ion diffusion rate, promoting the dissolution of slag glass, shortening the latency period in the hydration reaction, and accelerating the formation of hydration products. The synergistic effect of these three factors not only aids in clinker grinding but also promotes subsequent hydration reactions, increasing cement strength. Propylene glycol diacetate and glyceryl monolaurate have good surface activity and can be adsorbed on the particle surface, improving particle dispersibility. OH- produced by clinker hydrolysis... - It can penetrate the surface of the silica glass of slag powder and enter the interior, promoting the disintegration of the glass structure and thus promoting the hydration reaction of slag.

[0040] The intrinsic activity and particle size of cementitious materials affect their hydration rate. Fine-grained silicate cement clinker particles (<10 μm) have a high water demand, rapid early hydration, high early strength, and low later strength. Medium-grained silicate cement clinker particles (10-32 μm) have a lower water demand, faster hydration rates in the middle and later stages, and higher early and later strength. In this invention, a specific surface area of ​​320 ± 10 μm is used. 2 / kg and the ratio is 380±10m2 / kg of clinker powder balances the clinker particle content in different particle size ranges. 380±10m 2 The clinker powder per kg contains a significant amount of fine clinker powder. This fine clinker powder stimulates the hydration of fine mineral particles, thus avoiding the high water demand caused by the rapid hydration of a large number of fine clinker particles. Simultaneously, it fully stimulates the hydration of fine slag powder particles, ensuring the early strength of low-carbon cement. (320±10m) 2 The clinker powder contains a high proportion of medium-sized particles per kg, which improves the efficiency of the clinker powder. The auxiliary cementitious material particles (mineral powder, iron tailings powder, quartz sand powder) in the medium-to-coarse-fine range (>10 μm) have a very slow hydration rate. This invention uses particles with a specific particle size of 320 ± 10 μm. 2 Iron tailings powder (relatively low price) per kg is the main component of this part, mainly serving to optimize the particle composition of the system and improve the density of the system, with a specific surface area of ​​320±10m. 2 A portion of the clinker powder per kg also falls within this particle size range, ensuring long-term strength growth in the cement. Finer slag particles exhibit higher activity, but grinding costs also increase. Considering the relationship between cost and performance, the formulation of this invention was chosen. Based on the hydration rates of different raw materials at different particle sizes in this low-carbon slag cement, this invention optimizes the particle size distribution of low-carbon slag cement by rationally combining the amounts and particle size ranges of mineral powder, cement clinker powder, and iron tailings powder. This improves its bulk density, reduces cement water demand, and decreases the number of harmful pores formed during hydration. This not only enhances cement strength but also effectively improves the durability of cement-based materials.

[0041] Compared with existing technologies, this invention rationally designs the combination of types, amounts, and particle sizes of cementitious materials in low-carbon slag cement, optimizing the initial slurry structure and matching the hydration processes of each material to obtain low-carbon cement with low clinker content and good performance. This invention uses a small amount of fine clinker powder to activate fine mineral powder particles, avoiding the high water demand caused by the rapid hydration of large amounts of fine clinker particles, while fully activating the hydration of fine slag powder particles, ensuring the early strength of low-carbon cement. Furthermore, this invention makes extensive and rational use of waste silica fume, slag, and iron tailings to produce high-performance low-carbon slag cement, turning waste into treasure, reducing environmental burden, and decreasing resource and energy consumption and CO2 emissions during cement production, thus achieving low-carbon goals. The method of this invention fully utilizes high-alkali clinker for production grinding, thereby effectively improving the utilization rate of limestone resources with high alkali content. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0043] Example 1

[0044] A low-carbon slag cement is composed of the following components in parts by weight: 70 parts mineral powder, 25 parts silicate cement clinker, 15 parts iron tailings, 5 parts desulfurized gypsum, 0.0005 parts vertical mill grinding aid, 0.002 parts grinding aid reinforcing component, and 0.0005 parts dispersing component.

[0045] The mineral powder is obtained by grinding a mixture of blast furnace slag (dry basis) and silicon waste (waste silicon powder) generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 10:1. The particle size of the waste silicon powder is between 0.4-0.6 μm, and the (silicon + silicon dioxide) content (W) in the dry basis material is... Si+SiO2 ≥98%. The mineral powder prepared according to the following method has a specific gravity of 400±10m. 2 / kg of V400 mineral powder, with a specific gravity of 800±10m 2 / kg of V800 mineral powder and a specific gravity of 900±10m 2 / kg of V1000 mineral powder is compounded in a weight ratio of 10:1:1.

[0046] The alkali content in the silicate cement clinker is 0.60%.

[0047] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.1:5; the molecular weight of the polypropylene glycol is 200.

[0048] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:2:1.

[0049] The dispersed component is propylene glycol diacetate.

[0050] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0051] 1) Add the blast furnace slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components to the vertical mill according to the formula, and grind the materials in the vertical mill according to the control parameters to obtain V400 mineral powder.

[0052] 2) Add V400 mineral powder and the formula dispersion components into an ultrafine air jet mill, control the parameters of the air jet mill to grind, and obtain V800 mineral powder and V1000 mineral powder respectively;

[0053] 3) Add the silicate cement clinker and grinding aid / reinforcing components to the ball mill according to the formula. By controlling the speed of the air supply and the classifier, the ball mill grinds the materials to obtain a specific gravity of 320±10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2 / kg of clinker powder; specific gravity is 320±10m 2 / kg of clinker powder and a specific gravity of 380±10m 2 The weight ratio of clinker powder per kg is 1:1;

[0054] 4) Add the iron tailings to the ball mill and grind them by controlling the speed of the air and the classifier through the control system to obtain a specific surface area of ​​320±10m. 2 / kg of iron tailings powder;

[0055] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 320±10m. 2 / kg of clinker powder, with a specific gravity of 380±10m 2 Low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0056] Example 2

[0057] A low-carbon slag cement is composed of the following components in parts by weight: 90 parts mineral powder, 5 parts silicate cement clinker, 5 parts iron tailings, 1 part desulfurized gypsum, 0.002 parts vertical mill grinding aid, 0.0005 parts grinding aid reinforcing component, and 0.002 parts dispersing component.

[0058] The mineral powder is obtained by grinding blast furnace slag and waste silicon powder generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 30:1. The mineral powder is composed of V400 mineral powder with a particle size between 10-11 μm, V800 mineral powder with a medium particle size between 4.5-5.5 μm, and V1000 mineral powder with a medium particle size between 2.5-3.5 μm at a weight ratio of 5:5:1, and is prepared according to the following method. The waste silicon powder has a particle size between 0.4-0.6 μm, and the dry basis material contains (silicon + silicon dioxide) content (W... Si+SiO2 ≥98%.

[0059] The alkali content in the silicate cement clinker is 1.2%.

[0060] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.5:1; the molecular weight of the polypropylene glycol is approximately 400.

[0061] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:0.5:5.

[0062] The dispersed component is propylene glycol diacetate.

[0063] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0064] 1) Add the mass fractions of blast furnace slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid to the vertical mill, control the parameters, and obtain V400 mineral powder;

[0065] 2) Add V400 mineral powder and the formula dispersion components into an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0066] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 320±10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2 / kg of clinker powder, with a specific gravity of 320±10m 2 / kg of clinker powder and a specific gravity of 380±10m 2 The weight ratio of clinker powder per kg is 1:1;

[0067] 4) Add the iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​320±10m. 2 / kg of iron tailings powder;

[0068] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 320±10m. 2 / kg of clinker powder, with a specific gravity of 380±10m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0069] Example 3

[0070] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 23 parts silicate cement clinker, 8 parts iron tailings, 4 parts desulfurized gypsum, 0.001 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.001 parts dispersing component.

[0071] The mineral powder is obtained by mixing and grinding blast furnace slag and waste silicon powder generated from the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 20:1. The particle size of the waste silicon powder is between 0.4-0.6 μm, and the content of (silicon + silicon dioxide) in the dry basis material is (W Si+SiO2 ≥98%; the pulverized mineral powder has a specific gravity of 400±10m. 2 / kg of V400 mineral powder, with a specific gravity of 800±10m 2 / kg of V800 mineral powder and a specific gravity of 900±10m 2 V1000 mineral powder per kg is compounded in a weight ratio of 10:2:1.

[0072] The activity of the slag powder was determined according to the method for determining the activity index of slag powder in Appendix A of GB / T 18046-2017 "Granulated Blast Furnace Slag Powder for Cement, Mortar and Concrete". The activity index of V400 slag powder was 60% at 3 days, 82% at 7 days, and 102% at 28 days; the activity index of V800 slag powder was 108% at 3 days, 124% at 7 days, and 133% at 28 days; and the activity index of V1000 slag powder was 128% at 3 days, 141% at 7 days, and 148% at 28 days.

[0073] The alkali content in the silicate cement clinker is 0.93%.

[0074] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.3:3.

[0075] The molecular weight of the polypropylene glycol is approximately 300.

[0076] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:3.

[0077] The dispersed component is glyceryl monolaurate.

[0078] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0079] 1) Add the formula amount of slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components into the vertical mill, control the parameters, and obtain V400 mineral powder;

[0080] 2) Add V400 mineral powder and the formula dispersion components into an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0081] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 320±10m. 2 / kg of clinker powder and a specific gravity of 380±10m 2 / kg of clinker powder, with a specific gravity of 320±10m 2 / kg of clinker powder and a specific gravity of 380±10m 2 The weight ratio of clinker powder per kg is 2:1;

[0082] 4) Add the iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​320±10m. 2 / kg of iron ore powder;

[0083] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder. The table shows a concentration of 320±10m.2 / kg of clinker powder, with a specific gravity of 380±10m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0084] Example 4

[0085] A low-carbon slag cement is composed of the following components in parts by weight: 80 parts mineral powder, 20 parts silicate cement clinker, 12 parts iron tailings powder, 3.5 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.0008 parts grinding aid reinforcing component, and 0.0013 parts dispersing component.

[0086] The preparation method of Example 4 was carried out in accordance with that of Example 3.

[0087] Example 5

[0088] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0089] The mineral powder is obtained by grinding a mixture of blast furnace slag and waste silicon powder generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 15:1. The particle size of the waste silicon powder is between 0.4-0.6 μm, and the (silicon + silicon dioxide) content (W) in the dry basis material is... Si+SiO2 ≥98%; the mineral powder has a specific gravity of 409m 2 / kg of V400 mineral powder, with a specific gravity of 796m 2 / kg of V800 mineral powder and a specific gravity of 901m 2 / kg of V1000 mineral powder is compounded in a weight ratio of 8:3:1.

[0090] The V400 mineral powder has a particle size of 10.45 μm, the V800 mineral powder has a particle size of 4.91 μm, and the V1000 mineral powder has a particle size of 2.69 μm.

[0091] The alkali content in the silicate cement clinker is 1.06%.

[0092] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.3:2.

[0093] The molecular weight of the polypropylene glycol is approximately 400.

[0094] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:4.

[0095] The dispersed component is propylene glycol diacetate.

[0096] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0097] 1) Add the formula amount of blast furnace slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components into the vertical mill, control the parameters, and obtain V400 mineral powder;

[0098] 2) Add V400 mineral powder and the formula dispersion components into an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0099] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 318m. 2 / kg of clinker powder and a specific ratio of 386m 2 / kg of clinker powder; specific gravity is 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The weight ratio of clinker powder per kg is 3:1;

[0100] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0101] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 318m. 2 / kg of clinker powder, with a specific gravity of 386m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0102] Comparative Example 1

[0103] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0104] The mineral powder is made by mixing blast furnace slag and silicon waste generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 15:1 and grinding them to a specific surface area of ​​796m. 2 / kg was obtained, with a particle size of 4.91μm.

[0105] The alkali content in the silicate cement clinker is 1.06%.

[0106] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol, and water in a weight ratio of 1:0.3:2. The molecular weight of the polypropylene glycol is approximately 400.

[0107] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:4.

[0108] The dispersed component is propylene glycol diacetate.

[0109] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0110] 1) Add high-speed iron slag, desulfurized gypsum, waste silica powder, and grinding aid components to the vertical mill, control the parameters, and obtain a specific surface area of ​​400±10m. 2 / kg of mineral powder;

[0111] 2) Take the 400±10m obtained in step 1) 2 / kg of mineral powder and dispersion components were added to an ultrafine air jet mill, and the specific surface area was controlled to obtain a value of 796m. 2 / kg of mineral powder;

[0112] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 318m. 2 / kg of clinker powder and a specific ratio of 386m 2 / kg of clinker powder; specific gravity is 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The weight ratio of clinker powder per kg is 3:1;

[0113] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0114] 5) Compare the table 796m 2 / kg of mineral powder (only V800 mineral powder is used) The specific value is 318m. 2 / kg of clinker powder, with a specific gravity of 386m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0115] Comparative Example 2

[0116] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0117] The mineral powder is obtained by grinding blast furnace slag. Its ratio is 400±10m 2 / kg of V400 mineral powder, with a specific gravity of 800±10m 2 / kg of V800 mineral powder and a specific gravity of 900±10m 2 The V1000 mineral powder is compounded at a weight ratio of 8:3:1 per kg, and the preparation method is as follows.

[0118] The alkali content in the silicate cement clinker is 1.06%.

[0119] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.3:2.

[0120] The molecular weight of the polypropylene glycol is approximately 400.

[0121] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:4.

[0122] The dispersed component is propylene glycol diacetate.

[0123] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0124] 1) Add slag, desulfurized gypsum, and grinding aid components to the vertical mill, control the parameters, and obtain V400 mineral powder;

[0125] 2) Add V400 mineral powder and dispersing components to an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0126] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 318m. 2 / kg of clinker powder and a specific ratio of 386m 2 / kg of clinker powder; specific gravity is 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The weight ratio of clinker powder per kg is 3:1;

[0127] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0128] 5) Mix V400 mineral powder, V800 mineral powder, V1000 mineral powder, and 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0129] Comparative Example 3

[0130] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0131] The mineral powder is obtained by grinding a mixture of blast furnace slag and silicon waste generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 15:1. The specific gravity is 409m. 2 / kg of V400 mineral powder, with a specific gravity of 796m 2 / kg of V800 mineral powder and a specific gravity of 901m 2 It is composed of V1000 mineral powder in a weight ratio of 8:3:1 per kg.

[0132] The V400 mineral powder particles have a particle size of 10.45 μm, the V800 mineral powder particles have a particle size of 4.91 μm, and the V1000 mineral powder particles have a particle size of 2.69 μm.

[0133] The alkali content of the silicate cement clinker powder is 1.06%.

[0134] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.3:2.

[0135] The dispersed component is propylene glycol diacetate.

[0136] The molecular weight of the polypropylene glycol is approximately 400.

[0137] The grinding aid and strengthening component is triethanolamine.

[0138] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0139] 1) Add the blast furnace slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components to the vertical mill according to the formula, control the parameters, and obtain V400 mineral powder.

[0140] 2) Add V400 mineral powder and the amount of dispersed components in the formula to an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0141] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 318m. 2 / kg of clinker powder and a specific ratio of 386m 2 / kg of clinker powder, with a specific gravity of 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The weight ratio of clinker powder per kg is 3:1;

[0142] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0143] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 318m. 2 / kg of clinker powder, with a specific gravity of 386m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0144] Comparative Example 4

[0145] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0146] The mineral powder is obtained by grinding a mixture of blast furnace slag and silicon waste generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 15:1. The mineral powder has a specific gravity of 409m 2 / kg of V400 mineral powder, with a specific gravity of 796m 2 / kg of V800 mineral powder and a specific gravity of 901m 2 / kg of V1000 mineral powder is compounded in a weight ratio of 8:3:1.

[0147] The V400 mineral powder particles have a particle size of 10.45 μm, the V800 mineral powder particles have a particle size of 4.91 μm, and the V1000 mineral powder particles have a particle size of 2.69 μm.

[0148] The alkali content in the silicate cement clinker is 1.06%.

[0149] The grinding aid component of the vertical mill is triethanolamine.

[0150] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:4.

[0151] The dispersed component is propylene glycol diacetate.

[0152] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0153] 1) Add the formula amount of slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components into the vertical mill, control the parameters, and obtain V400 mineral powder;

[0154] 2) Add V400 mineral powder and the formula dispersion components into an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0155] 3) Add silicate cement clinker and grinding aid / reinforcing components to a ball mill, and control the speed of the air supply and classifier by controlling the speed of the system to obtain a specific gravity of 318m. 2 / kg of clinker powder and a specific ratio of 386m 2 / kg of clinker powder, with a specific gravity of 318m 2 / kg of clinker powder and a specific ratio of 386m 2 The weight ratio of clinker powder per kg is 3:1;

[0156] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0157] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific gravity of 318m. 2 / kg of clinker powder, with a specific gravity of 386m 2 The low-carbon slag cement is obtained by mixing clinker powder and iron tailings powder in a certain proportion.

[0158] Comparative Example 5

[0159] A low-carbon slag cement is composed of the following components in parts by weight: 75 parts mineral powder, 18 parts silicate cement clinker, 10 parts iron tailings, 4 parts desulfurized gypsum, 0.0015 parts vertical mill grinding aid, 0.001 parts grinding aid reinforcing component, and 0.0008 parts dispersing component.

[0160] The mineral powder is obtained by grinding a mixture of blast furnace slag and silicon waste generated during the silicon wafer cutting process in the photovoltaic industry at a weight ratio (dry basis) of 15:1. The specific gravity is 409m. 2 / kg of V400 mineral powder, with a specific gravity of 796m 2 / kg of V800 mineral powder and a specific gravity of 901m 2 / kg of V1000 mineral powder is compounded in a weight ratio of 8:3:1.

[0161] The V400 mineral powder particles have a particle size of 10.45 μm, the V800 mineral powder particles have a particle size of 4.91 μm, and the V1000 mineral powder particles have a particle size of 2.69 μm.

[0162] The silicate cement clinker powder has a specific ratio of 386m. 2 / kg, the alkali content in its clinker is 0.46%.

[0163] The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.3:2.

[0164] The molecular weight of the polypropylene glycol is approximately 400.

[0165] The grinding aid and strengthening component is composed of monoethanol diisopropanolamine, sodium dihydrogen phosphate and humic acid in a weight ratio of 1:1:4.

[0166] The dispersed component is propylene glycol diacetate.

[0167] The above-mentioned method for preparing low-carbon slag cement includes the following steps:

[0168] 1) Add slag, desulfurized gypsum, waste silica powder, and vertical mill grinding aid components into the vertical mill, control the parameters, and obtain V400 mineral powder;

[0169] 2) Add V400 mineral powder and dispersing components to an ultrafine air jet mill, and control the parameters to obtain V800 mineral powder and V1000 mineral powder respectively;

[0170] 3) Add silicate cement clinker and grinding aid / reinforcing components to the ball mill, and control the air and classifier speeds by controlling the system. The ratio obtained was 386m. 2 / kg of cooked powder.

[0171] 4) Add iron tailings to the ball mill, and control the speed of the air and classifier by controlling the system to obtain a specific surface area of ​​321m. 2 / kg of iron ore powder;

[0172] 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder. 386m 2 / kg of clinker powder The low-carbon slag cement is obtained by mixing it evenly with iron tailings powder in a certain proportion.

[0173] The low-carbon slag cements obtained in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests. The standard consistency water requirement and setting time were tested in accordance with GB / T 1346-2011 "Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement", and the strength was tested in accordance with GB / T 17671-2021 "Test Methods for Strength of Cement Mortar (ISO)". The results are shown in Table 1 below.

[0174] Table 1. Performance results of low-carbon slag cement in each embodiment and comparative example.

[0175]

[0176]

[0177] The above detailed description of the present invention with reference to the embodiments is illustrative rather than limiting. Several embodiments may be listed according to the defined scope. Therefore, changes and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A low-carbon slag cement, characterized in that, The low-carbon slag cement comprises the following raw materials in parts by weight: 70-90 parts mineral powder, 5-25 parts silicate cement clinker, 5-15 parts iron tailings, 1-5 parts desulfurized gypsum, 0.0005-0.002 parts vertical mill grinding aid, 0.0005-0.002 parts grinding aid reinforcing component, and 0.0005-0.002 parts dispersing component; The mineral powder includes blast furnace slag and waste silicon powder; the weight ratio of the blast furnace slag to waste silicon powder is 10-30:

1. The alkali mass fraction in the silicate cement clinker is: 0.80% ≤ (Na₂O + 0.658K₂O) ≤ 1.5%; The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water; The grinding aid and strengthening component is composed of alkanolamine, phosphate and humic acid; The waste silicon powder refers to silicon waste generated during the silicon wafer cutting process in the photovoltaic industry; The alcohol amine is selected from monoethanol diisopropanolamine; The phosphate is selected from sodium dihydrogen phosphate.

2. The low-carbon slag cement according to claim 1, characterized in that, The grinding aid component of the vertical mill is composed of sucrose monolaurate, polypropylene glycol and water in a weight ratio of 1:0.1-0.5:1-5.

3. The low-carbon slag cement according to claim 1, characterized in that, The mass ratio of the alkanolamine, phosphate, and humic acid is 1:0.5-2:1-5.

4. The low-carbon slag cement according to claim 1, characterized in that, The dispersed component is propylene glycol diacetate or glyceryl monolaurate.

5. A method for preparing low-carbon slag cement according to any one of claims 1-4, comprising the following steps: 1) Add the formulated mineral powder, desulfurized gypsum and vertical mill grinding aid to the vertical mill, and grind them in the vertical mill to obtain V400 mineral powder; 2) The V400 mineral powder and the dispersing component were added to an ultrafine air jet mill and milled to obtain V800 mineral powder and V1000 mineral powder, respectively. The specific surface area of ​​the V400 mineral powder was 400±10 m². 2 / kg; the specific surface area of ​​the V800 mineral powder is 800±10 m². 2 / kg; the specific surface area of ​​the V1000 mineral powder is 900±10 m². 2 / kg; 3) Add the silicate cement clinker and grinding aid / reinforcing components to a ball mill according to the formula, and ball mill to obtain specific surface areas of 320±10 m². 2 / kg of clinker powder and a specific surface area of ​​380±10 m² 2 / kg of cooked powder; 4) Add the prescribed amount of iron tailings to a ball mill and ball mill to obtain a specific surface area of ​​320±10 m². 2 / kg of iron tailings powder; 5) Mix V400 mineral powder, V800 mineral powder, and V1000 mineral powder with a specific surface area of ​​320±10 m². 2 / kg of clinker powder and a specific surface area of ​​380±10 m² 2 / kg of clinker powder and a specific surface area of ​​320±10 m² 2 Low-carbon slag cement is obtained by uniformly mixing / kg of iron tailings powder.

6. The preparation method according to claim 5, characterized in that, In step 3), the specific surface area is 320±10m². 2 / kg of clinker powder and a specific surface area of ​​380±10 m² 2 The weight ratio of clinker powder is 1-5:

1.

7. The preparation method according to claim 5, characterized in that, In step 5), the weight ratio of V400 mineral powder, V800 mineral powder and V1000 mineral powder is 5-10:1-5:1.

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