Method for evaluating raw material suitability of steel slag-mineral slag-gypsum-based cementing material

Abstract

The invention relates to the field of comprehensive utilization of resources, in particular to a method for evaluating raw material suitability of a steel slag-mineral slag-gypsum-based cementing material. The method comprises the following steps: mixing to-be-identified steel slag powder and slag powder according to a mass ratio of 40: 45, and calculating the ternary alkalinity of the mixed powder; the method comprises the following steps: mixing to-be-identified steel slag powder, slag powder and gypsum powder according to a mass ratio of 40: 45: 15 to obtain a solid waste cementing material, mixing the solid waste cementing material with water according to a mass ratio of 1: 3, and measuring the ion concentration of Si < 4 + > in the early hydration process of the obtained mixing system; and evaluating the raw material suitability according to the ternary alkalinity and the ion concentration of Si < 4 + >. According to the method, the raw material suitability of the steel slag-slag-gypsum-based cementing material can be rapidly evaluated, and the detection efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of comprehensive resource utilization technology, and in particular to a method for evaluating the compatibility of steel slag-blast furnace slag-gypsum-based cementitious materials. Background Technology

[0002] Solid waste-based cementitious materials are hydraulic cementitious materials prepared primarily from various industrial solid wastes such as steel slag, blast furnace slag, fly ash, red mud, and industrial by-product gypsum. The development of this material relies on theories such as the double salt effect and the tetracoordination isomorphism effect of silicon, and has gone through development stages including geopolymers and low-clinker cement, demonstrating both theoretical and engineering feasibility. In this material system, blast furnace slag is the core component, combined with alkali-activating components (such as steel slag, carbide slag, and red mud, which mainly provide an alkaline environment to activate the slag's activity) and sulfate-activating components (usually desulfurized gypsum, phosphogypsum, and other solid wastes rich in calcium sulfate). Through the synergistic effect of these solid wastes, a new type of green building material with excellent mechanical properties and durability is ultimately formed.

[0003] Steel slag-blast furnace slag-gypsum-based solid waste cementitious materials, as the most representative synergistic combination in this system, have achieved fruitful results in the study of their mechanism of action and performance optimization. Several demonstration projects have been successfully carried out based on related research, achieving initial applications in the building materials field. However, their large-scale promotion is still relatively slow. The core bottleneck lies not only in the potential volume stability problem of steel slag itself, but also in the deeper constraint stemming from the inherent composition and phase fluctuations of industrial solid waste raw materials. This heterogeneity makes it difficult to stably control product performance. Due to the significant differences in composition and activity between steel slag and blast furnace slag from different sources and processes, the 28-day compressive strength of solid waste-based cementitious materials formulated from them can differ by as much as double. Existing research indicates that the activity index of steel slag and blast furnace slag in traditional cement systems cannot directly and accurately evaluate their true activity in solid waste-based cementitious material systems. Even methods like measuring the pH value of steel slag aqueous solutions are insufficient to directly determine the strength of their alkali-activating effect in complex synergistic systems. While microscopic analysis methods such as XRD and XPS can assess the activity of solid waste components to some extent, they often fail to yield quantitative indicators that can guide mix proportions. Traditional methods, such as mixing solid waste-based cementitious materials with fine aggregates, molding, curing to a specified age, and then testing their mechanical properties, while reliable, suffer from drawbacks such as long processing times and low efficiency. Therefore, to promote the further development and application of this material system, there is an urgent need to establish a rapid and quantitative activity assessment method. This method should be able to quickly determine the compatibility between the raw materials of solid waste-based cementitious materials, thereby efficiently evaluating and optimizing the comprehensive performance of steel slag-blast furnace slag-gypsum-based cementitious materials. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for evaluating the compatibility of raw materials for steel slag-blast furnace slag-gypsum-based cementitious materials.

[0005] When preparing solid waste-based cementitious materials by combining steel slag, blast furnace slag, and gypsum from different sources, there are common problems such as significant differences in product performance due to fluctuations in raw material sources and difficulty in accurately identifying the activity of raw materials. This invention discovers that in the steel slag-blast furnace slag-gypsum solid waste-based cementitious system, in addition to the basic chemical composition affecting its hydration activity, the ion concentration in the hydration solution is also a core indicator reflecting the essential characteristics of the hydration process. Changes in ion concentration are directly related to the hydration behavior and structural evolution of each component within the cementitious system. Therefore, accurate measurement of ion concentration in the early hydration stage is one of the key entry points for evaluating the reaction characteristics of this system in this invention. Further research in this invention shows that in the early hydration stage (<3h) of the steel slag-slag-gypsum-based cementitious material system, the steel slag components play a decisive role in the changes in the concentration of various ions in the solution. The amount of silicon and aluminum dissolved in the solution can directly reflect the structural stability of the core hydration active phases such as calcium silicate, calcium aluminate, and calcium aluminosilicate in the steel slag. However, this kind of key information cannot be accurately obtained simply by measuring the pH value of the steel slag solution or testing its activity index after mixing with cement. For example, when steel slag with a high free calcium oxide content is ground and mixed with water, the free calcium fine powder hydrates rapidly, which leads to an increase in the pH of the solution, but cannot represent the hydration activity of other components in the steel slag. In addition, the activity index exhibited by steel slag after mixing with cement is not necessarily related to its own hydration activity, because the contribution of this activity index also comes from multiple effects such as the micro-aggregate effect, the alkali activation effect, and the micro-expansion effect. Therefore, directly testing the ion concentration in the early hydration environment is the most direct and effective method for assessing the hydration status of steel slag-blast furnace slag-gypsum-based cementitious materials.

[0006] Specifically, the present invention provides a method for evaluating the compatibility of steel slag-blast furnace slag-gypsum-based cementitious materials, comprising: 1) Mix the steel slag powder to be tested with the slag powder at a mass ratio of 40:45 and calculate the ternary basicity of the mixed powder.

[0007] 2) Steel slag powder, blast furnace slag powder, and gypsum powder to be identified were mixed at a mass ratio of 40:45:15 to obtain a solid waste cementitious material. The solid waste cementitious material was then mixed with water at a mass ratio of 1:3. The Si content during the early hydration process of the resulting mixture was measured. 4+ The ion concentration.

[0008] 3) Based on ternary alkalinity and Si 4+ Ion concentration is used to assess the compatibility of raw materials.

[0009] This invention constructs a two-dimensional rapid determination system combining stoichiometric parameters and ion dissolution characteristics, providing an efficient technical means for the rapid screening and compatibility optimization of raw materials for solid waste-based cementitious materials. This system is developed by analyzing the ternary basicity TA and Si... 4+ The comprehensive verification of two criteria—ion concentration and compatibility—allows for rapid determination of the suitability of solid waste raw materials within 1-3 hours, significantly improving detection efficiency compared to traditional methods for assessing the mechanical properties of mortar after molding. This invention sets a specific evaluation standard for the ratio of steel slag to slag, primarily based on practical operability considerations in actual production. Studies have shown that as the steel slag content in solid waste-based cementitious materials increases (typically exceeding 20%), their mechanical properties exhibit an overall downward trend; the decline is particularly significant when the steel slag content exceeds 40%, making this approach unsuitable for practical use. Therefore, this invention fixes this ratio at 40:45 and further blends it with gypsum powder at a mass ratio of 40:45:15. This blending ratio enables effective performance evaluation while ensuring a high steel slag content, accurately determining the early hydration process of solid waste cementitious materials and the Si content in the liquid phase. 4+ Ion concentration, thereby significantly improving the reliability, safety and applicability of the evaluation results.

[0010] In this invention, the specific raw material mass ratio and the mass ratio of solid waste cementitious material to water enable more convenient and accurate early hydration and liquid-phase Si of the solid waste cementitious material. 4+ Ion concentration determination; by quantifying the chemical characteristics of the core components of the cementitious material and the early ion release behavior during hydration, the compatibility of raw materials in the solid waste cementitious material can be rapidly determined. Under the specific parameter conditions mentioned above, the Si content in the liquid phase at this stage can be obtained more accurately. 4+ Ion concentration.

[0011] Preferably, in step 2), the specific surface area of ​​the steel slag powder, blast furnace slag powder, and gypsum powder is 350~450 m². 2 / kg. Before determining the ion concentration, this invention preferably involves grinding steel slag, mineral slag, and gypsum to a specific surface area of ​​350-450 m². 2 / kg, under this preferred fineness condition, the experimental results are more representative.

[0012] Further preferably, in step 2), the early hydration time is controlled to be 1-3 hours, preferably 1 hour; the Si content of the middle liquid phase of the mixing system is measured. 4+ The ion concentration.

[0013] Further preferred, step 1) further includes drying and grinding the steel slag and ore slag to be identified to a specified fineness, providing uniform powder material for subsequent hydration and ion concentration determination. The mass fractions of CaO, SiO2, and Al2O3 in the steel slag powder and ore slag powder are determined using X-ray fluorescence spectroscopy. The ternary basicity is calculated based on the ratio of the mass fraction of CaO to the sum of the mass fractions of SiO2 and Al2O3.

[0014] As a preferred option, the selected steel slag is converter steel slag discharged from the converter smelting process or steel slag sludge discharged after wet grinding and magnetic separation, and is determined to have no poor stability issues according to the test methods in "Steel Slag Powder for Cement and Concrete" (GB / T20491).

[0015] As a preferred option, the selected slag is granulated blast furnace slag with TiO2 < 2% and a glass content greater than 95% after water quenching and rapid cooling.

[0016] Preferably, the selected gypsum is desulfurized gypsum, phosphogypsum, titanium gypsum, or fluorogypsum, with desulfurized gypsum having a CaSO4·2H2O content greater than 92% produced in the wet flue gas desulfurization process being the most preferred. When desulfurized gypsum resources are insufficient, phosphogypsum, titanium gypsum, or fluorogypsum with a CaSO4·2H2O content greater than 90% or anhydrous calcium sulfate content greater than 90% may also be used.

[0017] Preferably, the selected steel slag and slag raw materials are all from the same batch of furnace products, and a multi-point mixed sampling method is used for sampling, with no fewer than 8 sampling points and a sample size of no less than 500g at each sampling point. All samples are then mixed evenly and reduced to 500g using the quartering method, awaiting subsequent testing. Before reduction, the steel slag and slag particles must be crushed to below 4.75mm. Preferably, the determination of the mass fraction of CaO, SiO2, and Al2O3 in the steel slag and slag raw materials should be performed according to the fused plate method specified in GB / T 175. When preparing samples, the steel slag, slag, and gypsum raw materials are first dried to constant weight at 100±5℃, and then ground to pass through a 200-mesh (75μm) sieve.

[0018] As a preferred option, the selected water meets the Class II water standard in GB / T 6682.

[0019] Preferably, in step 2), the solid waste cementitious material is mixed with water and stirred at a speed of 250~350 r / min for 1~3 min, and then subjected to a hydration reaction at a temperature of 18~22℃; preferably, it is stirred at a speed of 300±20 r / min for 2±0.5 min, and then subjected to a hydration reaction in a constant temperature water bath environment of 20±1℃.

[0020] Preferably, in step 2), the middle liquid phase of the mixing system is used, and after filtration, the Si content in the filtrate is quantitatively determined by inductively coupled plasma atomic emission spectrometry. 4+ The ion concentration.

[0021] Preferably, in step 3), when the ternary basicity is ≥1.0 and Si 4+ When the ion concentration is ≥1.2 mg / L, the raw material compatibility of the steel slag-blast furnace slag-gypsum-based cementitious material is considered good; when the ternary basicity is <1.0, and / or Si 4+ When the ion concentration is <1.2 mg / L, the raw material compatibility of the steel slag-blast furnace slag-gypsum-based cementitious material is considered poor. The above-mentioned preferred ternary basicity and Si... 4+ The ion concentration determination threshold can more accurately determine the raw material compatibility and causes of problems in steel slag-blast furnace slag-gypsum-based cementitious materials.

[0022] In this invention, the compatibility of raw materials in steel slag-blast furnace slag-gypsum-based cementitious materials is comprehensively determined by using both ternary basicity and ion concentration as dual indicators: when the ternary basicity TA of the mixed powder is ≥1.00, and the Si concentration in the liquid phase of the mixing system is low... 4+ When the concentration is ≥1.2 mg / L, the compatibility of each raw material in this group of cementitious materials can be judged as good; if any of the above indicators are not met, the compatibility of each raw material is judged as poor. Among them, when the ternary basicity TA <1.00, the core problem is that the existing ratio of steel slag and blast furnace slag is poor, resulting in insufficient synergistic effect of components. 4+ When the concentration is <1.2mg / L, the core problem is that the selected steel slag itself has low activity and weak hydration reaction capacity. The ternary basicity TA <1.00 and the ion concentration does not meet the standard, which means that there are two problems: poor activity of the steel slag itself and improper steel slag-slag ratio.

[0023] Preferably, for steel slag-slag-gypsum solid waste-based cementitious materials determined to have good raw material compatibility, the steel slag content in the solid waste cementitious material in the application system can be arbitrarily selected between 20% and 40%. For steel slag-slag-gypsum-based cementitious materials determined to have poor raw material compatibility, their usability must be assessed in conjunction with the mechanical properties of the mortar, and the steel slag content in the solid waste cementitious material in the application system should not exceed 30%. In this invention, for solid waste-based cementitious materials composed of raw materials determined to have good compatibility, the steel slag content can be arbitrarily selected between 20% and 40% during use, while the steel slag content in solid waste-based cementitious materials with poor raw material compatibility cannot exceed 30%, and must pass the traditional mortar mechanical property assessment before use.

[0024] Further optimization is needed. For solid waste-based cementitious materials composed of raw materials with poor compatibility, ultrafine grinding or the addition of activators can be used to compensate for their weak activity, depending on the actual situation. A solid waste-based cementitious material composed of raw materials determined by the method of this invention to have good compatibility (ratio of steel slag: blast furnace slag: gypsum = 40:45:15, raw material specific surface area controlled at 400±20m²) 2 / kg), the 28-day compressive strength of the mortar test block, measured according to the method in GB / T 17671, can reach more than 30MPa.

[0025] As a preferred embodiment, the method for rapidly assessing the compatibility of raw materials in steel slag-blast furnace slag-gypsum-based cementitious materials achieves rapid determination of the compatibility of each raw material in the solid waste cementitious material by quantifying the chemical characteristics and early hydration ion release behavior of the core components of the cementitious material. Figure 1 As shown, it includes the following steps: 1) Select steel slag and ore slag raw materials to be identified, and after drying and grinding, determine the mass fractions of CaO, SiO2 and Al2O3 in the two raw materials by X-ray fluorescence spectrometry (XRF); 2) Steel slag powder and slag powder are mixed at a mass ratio of 40:45 to obtain a basic mixed powder; based on the oxide content measured in step 1), the ternary basicity TA of the mixed powder is calculated. The ternary basicity TA is the ratio of the mass fraction of CaO to the sum of the mass fractions of SiO2 and Al2O3, i.e., TA=w(CaO) / [(SiO2)+(Al2O3)].

[0026] 3) Weigh steel slag powder, blast furnace slag powder, and gypsum powder at a mass ratio of 40:45:15 and mix them to form a solid waste cementitious material. Add this cementitious material to water that meets the GB / T 6682 Class II water standard at a mass ratio of 1:3 in a mixing device and mix. After the hydration reaction has proceeded for 1 hour, take a sample of the liquid phase from the middle of the mixing system, filter it, and determine the Si content. 4+ The ion concentration.

[0027] 4) Using the aforementioned ternary alkalinity TA and Si 4+ The compatibility of raw materials in steel slag-slag-gypsum-based cementitious materials is comprehensively judged by the dual index of ion concentration: when the ternary basicity TA of the mixed powder is ≥1.00, and the Si concentration in the liquid phase of the mixing system is low... 4+ When the concentration is ≥1.2 mg / L, the compatibility of each raw material in this group of cementitious materials can be judged as good; if any of the above indicators are not met, the compatibility of each raw material is judged as poor. Among them, when the ternary basicity TA <1.00, the core problem is that the existing ratio of steel slag and blast furnace slag is poor, resulting in insufficient synergistic effect of components. 4+When the concentration is <1.2mg / L, the core problem is that the selected steel slag itself has low activity and weak hydration reaction capacity, while the ternary basicity TA <1.00 and the ion concentration does not meet the standard. Therefore, the two problems of poor steel slag itself and improper steel slag-slag ratio coexist.

[0028] The beneficial effects of this invention are at least as follows: The method for rapidly assessing the compatibility of steel slag-blast furnace slag-gypsum-based cementitious materials provided by this invention has significant advantages such as high identification efficiency, strong judgment accuracy, and excellent practical guidance. This method shortens the identification cycle to 1-3 hours, enabling rapid screening of the activity of solid waste cementitious materials. Simultaneously, this invention, through a comprehensive determination using two indicators—ternary alkalinity and hydrated ion concentration—essentially reveals the causes of varying cementitious material activity. The judgment results of this invention can directly guide the optimization and adjustment of steel slag content, are highly practical, can be implemented using conventional testing equipment, and have low testing costs and are easy to promote. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 A technical roadmap for a method to rapidly assess the compatibility of steel slag-blast furnace slag-gypsum-based cementitious materials provided in embodiments of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0033] Unless otherwise specified, the techniques or conditions described in the embodiments of this invention shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Devices, instruments, reagents, etc., without specified manufacturers, are all conventional products that can be purchased through legitimate channels. All experimental reagents and raw materials involved are commercially available products, and all reagents are analytical grade products.

[0034] In this embodiment of the invention, the mass fractions of CaO, SiO2, and Al2O3 in steel slag and blast furnace slag raw materials are determined according to the fused plate method specified in GB / T175. When preparing the samples, they are first dried to constant weight at 100±5℃, and then ground to pass through a 200-mesh (75μm) sieve.

[0035] In this embodiment of the invention, solid waste cementitious material and water are added to a stirring device at a mass ratio, and stirred at 300 r / min for 2 min until the system is homogeneous. Then, the system is placed in a constant temperature water bath environment of 20±1℃ for hydration reaction.

[0036] In this embodiment of the invention, four types of steel slag and mineral slag raw materials, as well as one type of desulfurized gypsum, were selected. The mass fractions of CaO, SiO2, and Al2O3 in the three raw materials were determined by X-ray fluorescence spectrometry (XRF). The detection results are shown in the table below: Table 1. Chemical composition of raw materials (mass percentage)

[0037] In this embodiment of the invention, the water used meets the Class II water standard in GB / T6682.

[0038] In this embodiment of the invention, before determining the ion concentration, a 15mm sample of the middle liquid phase is taken using a pipette, filtered through medium-speed filter paper, and then the Si content in the filtrate is quantitatively determined using inductively coupled plasma optical emission spectrometry (ICP-OES). 4+ The sample used to test the concentration of hydrated ions weighs 50g, and the corresponding mixing water weighs 150g.

[0039] Example 1 After selecting steel slag 1 and ore 1 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.01. Then, all raw materials are ground until the specific surface area is 400±20m². 2 / kg, mixed with steel slag 1: ore 1: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 0.706 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 28.9 MPa.

[0040] Example 2 After selecting steel slag 1 and slag 2 in a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.05. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 1: slag 2: desulfurized gypsum in a ratio of 40:45:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 0.665 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40 mm × 40 mm × 160 mm triple mold. The compressive strength after 28 days of curing was 26.4 MPa.

[0041] Example 3 After selecting steel slag 1 and ore 3 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.11. Then, all raw materials are ground until the specific surface area is 400±20m². 2 / kg, after being mixed with steel slag 1: slag 3: desulfurized gypsum in a ratio of 40:45:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 0.722 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 20.1 MPa.

[0042] Example 4 After selecting steel slag 1 and ore 4 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.08. Then, all raw materials are ground until the specific surface area is 400±20m². 2 / kg, mixed with steel slag 1: ore slag 4: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 0.891 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 22.8 MPa.

[0043] Example 5 After selecting steel slag 2 and slag 1 at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.01. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 2: slag 1: desulfurized gypsum in a ratio of 40:45:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 1.267 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 32.0 MPa.

[0044] Example 6 After selecting steel slag 2 and blast furnace slag 2 at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.04. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, mixed with steel slag 2: ore slag 2: desulfurized gypsum in a ratio of 40:45:15, and then mixed with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 1.278 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 33.2 MPa.

[0045] Example 7 After selecting steel slag 2 and ore 3 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.11. Then, all raw materials are ground until the specific surface area is 400±20m². 2 / kg, after being mixed with steel slag 2: ore slag 3: desulfurized gypsum in a ratio of 40:45:15, and then mixed with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 1.256 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 32.2 MPa.

[0046] Example 8 After selecting steel slag 2 and ore 4 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.07. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 2: ore slag 4: desulfurized gypsum in a ratio of 40:45:15, and then mixed with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+The concentration was 1.536 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 43.2 MPa.

[0047] Example 9 After selecting steel slag 3 and ore 1 at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 0.96. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 3: slag 1: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3, and after hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 4.421 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 29.1 MPa.

[0048] Example 10 After selecting steel slag 3 and ore 2 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.00. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 3: ore slag 2: desulfurized gypsum in a ratio of 40:45:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 4.844 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The 28-day compressive strength after curing was 36.9 MPa.

[0049] Example 11 After selecting steel slag 3 and blast furnace slag 3 at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.06. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, mixed with steel slag 3: ore slag 3: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 4.116 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 34.8 MPa.

[0050] Example 12 After selecting steel slag 3 and ore 4 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.02. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 3: ore slag 4: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 4.885 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 41.2 MPa.

[0051] Comparative Example 1 After selecting steel slag 1 and slag 2 and mixing them at a mass ratio of 30:55, the ternary basicity TA of the mixed powder is 0.95. Then, all raw materials are ground until the specific surface area is 400±20m². 2 / kg, after being mixed with steel slag 1: slag 2: desulfurized gypsum in a ratio of 30:55:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+ The concentration was 0.801 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 28.8 MPa.

[0052] Comparative Example 2 After selecting steel slag 2 and slag 1 at a mass ratio of 30:55, the ternary basicity TA of the mixed powder is 0.91. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, mixed with steel slag 2: slag 1: desulfurized gypsum in a ratio of 30:55:15, and then with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 1.374 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 33.9 MPa.

[0053] Comparative Example 3 After selecting steel slag 3 and ore 2 and mixing them at a mass ratio of 30:55, the ternary basicity TA of the mixed powder is 0.92. Then, all raw materials are ground to a specific surface area of ​​400±20m². 2 / kg, after being mixed with steel slag 3: ore slag 2: desulfurized gypsum in a ratio of 30:55:15, and then with water at a mass ratio of 1:3, and hydrated for 1 hour, the Si content in the solution was measured. 4+The concentration was 4.531 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 30.9 MPa.

[0054] Comparative Example 4 After selecting steel slag 4 and blast furnace slag 4 and mixing them at a mass ratio of 40:45, the ternary basicity TA of the mixed powder is 1.06. Then, the blast furnace slag and gypsum are ground to a specific surface area of ​​400±20m². 2 / kg, steel slag ground to a specific surface area of ​​300±20m² 2 / kg, mixed with steel slag 4: ore slag 4: desulfurized gypsum = 40: 45: 15, and then mixed with water at a mass ratio of 1:3. After hydration for 1 hour, the Si content in the solution was measured. 4+ The concentration was 1.298 mg / L. This group of cementitious materials was mixed with standard sand (ISO) at a mass ratio of 1:3 under a water-cement ratio of 0.5 and poured into a 40mm×40mm×160mm triple mold. The compressive strength after 28 days of curing was 25.5 MPa.

[0055] All embodiments are summarized below: Table 2 Summary of Results of Examples

[0056] The results from the examples show that when the specific surface area of ​​the mixed powder is controlled at 400±20m², 2 When the mass ratio of steel slag to ore slag is 40:45, and the Si content in the solution after 1 hour of hydration of the solid waste-based adhesive is / kg 4+ When the concentration is <1.2 mg / L (as in Examples 1-4) or the TA parameter is less than 1.0 (as in Example 7), the 28-day compressive strength of the mortar test blocks is less than 30 MPa. In contrast, the other examples that simultaneously meet the requirements for ion concentration and ternary basicity all achieve a 28-day compressive strength of over 30 MPa. Furthermore, comparing the results of Examples 2, 5, and 10 with those of Comparative Examples 1, 2, and 3 shows that when the mass ratio of steel slag to slag in the solid waste-based cementitious material is adjusted from 40:45 to 30:55, the 28-day compressive strength of the mortar test blocks corresponding to the three groups of cementitious materials significantly increases. This indicates that as the amount of steel slag added to the solid waste-based cementitious material increases, its overall mechanical properties tend to decrease. Therefore, controlling the mass ratio of steel slag to slag at 40:45 provides a more reliable evaluation of the raw material compatibility. Simultaneously, when the specific surface area of ​​steel slag is 300±20 m²... 2At a concentration of / kg (as in Comparative Example 4), even if the adhesive material simultaneously meets the requirements for ternary basicity and silicon ion concentration, the compressive strength of its 28-day mortar specimen still cannot reach 30MPa. Therefore, controlling the specific surface area index of the powder is equally important for ensuring the validity of the evaluation results. Based on the results of the above examples and comparative examples, the method of the present invention has excellent identification effects.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the compatibility of steel slag-blast furnace slag-gypsum-based cementitious materials, characterized in that, include: 1) Mix the steel slag powder to be tested with slag powder at a mass ratio of 40:45, and calculate the ternary basicity of the mixed powder; 2) Steel slag powder, blast furnace slag powder, and gypsum powder to be identified were mixed at a mass ratio of 40:45:15 to obtain a solid waste cementitious material. The solid waste cementitious material was then mixed with water at a mass ratio of 1:

3. The Si content during the early hydration process of the resulting mixture was measured. 4+ ion concentration; 3) Based on ternary alkalinity and Si 4+ Ion concentration is used to assess the compatibility of raw materials.

2. The method of claim 1, wherein, The specific surface area of the steel slag powder, the slag powder and the gypsum powder in Step 2) is 350~450 m 2 / kg.

3. The method according to claim 1 or 2, characterized in that, In step 2), the time of early hydration is controlled at 1-3h; the Si ion concentration of the middle liquid phase of the mixing system is determined 4+ ion concentration.

4. The method according to any one of claims 1 to 3, characterized in that, Step 1) further includes drying and grinding the steel slag and ore slag to be identified to a specified fineness, and then using X-ray fluorescence spectroscopy to determine the mass fractions of CaO, SiO2, and Al2O3 in the steel slag powder and ore slag powder. The ternary basicity is calculated based on the ratio of the mass fraction of CaO to the sum of the mass fractions of SiO2 and Al2O3.

5. The method according to any one of claims 1 to 4, characterized in that, The selected steel slag is either converter steel slag discharged from the converter smelting process or steel slag sludge discharged after wet grinding and magnetic separation. It is determined that there are no problems with poor stability according to the test method specified in GB / T 20491. And / or, the selected slag is granulated blast furnace slag with TiO2 < 2% and glass content greater than 95% after water quenching and rapid cooling. And / or, the selected gypsum is desulfurized gypsum, phosphogypsum, titanium gypsum or fluorogypsum, preferably desulfurized gypsum with a CaSO4·2H2O content greater than 92% produced by the wet flue gas desulfurization process.

6. The method of claim 5, wherein, The selected steel slag and slag raw materials were all from the same batch of furnace products. A multi-point mixed sampling method was used, with no fewer than 8 sampling points and a minimum sample size of 500g at each point. All samples were then mixed evenly and reduced to 500g using the quartering method, awaiting subsequent testing. Before reduction, the steel slag and slag particles needed to be crushed to below 4.75mm. Preferably, the mass fractions of CaO, SiO2, and Al2O3 in the steel slag and slag raw materials should be determined according to the fused plate method specified in GB / T 175. When preparing steel slag powder, slag powder, and gypsum powder samples, the steel slag, slag, and gypsum raw materials were first dried to constant weight at 100±5℃, and then ground to pass through a 200-mesh sieve.

7. The method according to any one of claims 1-6, characterized in that, In step 2), the solid waste cementitious material is mixed with water and stirred at a speed of 250~350 r / min for 1~3 min, and then subjected to a hydration reaction at a temperature of 18~22℃.

8. The method according to any one of claims 1-7, characterized in that, In step 2), the middle liquid phase of the mixing system is filtered, and the Si content in the filtrate is quantitatively determined by inductively coupled plasma atomic emission spectrometry. 4+ The ion concentration.

9. The method according to any one of claims 1-8, characterized in that, In step 3), when the ternary basicity is ≥1.0, and Si 4+ When the ion concentration is ≥1.2 mg / L, the raw material compatibility of the steel slag-blast furnace slag-gypsum-based cementitious material is considered good; when the ternary basicity is <1.0, and / or Si 4+ When the ion concentration is <1.2mg / L, the raw material compatibility of the steel slag-blast furnace slag-gypsum-based cementitious material is judged to be poor.

10. The method according to claim 9, characterized in that, For steel slag-slag-gypsum solid waste-based cementitious materials that are determined to have good raw material compatibility, the steel slag content in the solid waste cementitious materials can be arbitrarily selected between 20% and 40% during use; for steel slag-slag-gypsum-based cementitious materials that are determined to have poor raw material compatibility, their usability should be assessed in conjunction with the mechanical properties of the mortar, and the steel slag content in the solid waste cementitious materials should not exceed 30% during use.

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