Special grinding-aiding exciting agent for superfine steel slag powder and preparation method of special grinding-aiding exciting agent

Abstract

The invention belongs to the technical field of solid waste recycling and building materials, and particularly discloses a special grinding-aiding exciting agent for superfine steel slag powder and a preparation method of the special grinding-aiding exciting agent. Aiming at the problems of low grinding efficiency, insufficient activity excitation, poor high-temperature stability and the like of the existing steel slag grinding aid, the invention provides a multi-component synergistic compound formula, and the steel slag grinding aid is prepared by a staged dissolution and high-speed shearing process. The activator is added in a superfine vertical mill in stages to cooperatively destroy the iron phase-calcium phase symbiotic structure of the steel slag, the specific surface area of the ground steel slag reaches 700-750 m < 2 > / kg, the 7-day activity index is 85-88%, and the 28-day activity index is 95-97%. Through the gelation reaction of calcium sulphoaluminate and sodium silicate and the high-temperature stabilization effect of the zwitterionic polymer, dual optimization of steel slag grinding and activity excitation is achieved, the comprehensive utilization rate is increased to 95% or above, and the risk of heavy metal pollution is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste resource utilization and building materials, and specifically discloses a special grinding aid activator for ultrafine steel slag powder and a preparation method thereof. Background Art

[0002] Steel slag is a major solid waste product of the steel industry, with an annual production exceeding 150 million tons, but its comprehensive utilization rate is less than 30%. 26 The mineral composition of steel slag is similar to that of cement clinker (e.g., C2S, C3S, and tetracalcium aluminoferrite), and theoretically can be used as an auxiliary cementitious material. However, its poor grindability and low activity limit its application. Prior art grinding aids are often based on polyols, triethanolamine, or inorganic salt systems. For example, the grinding aid disclosed in patent CN104692706B contains polyacrylic acid, molasses, and ethylenediaminetetraacetic acid, but suffers from the following drawbacks:

[0003] Insufficient targeting: The iron phase (such as RO phase) in steel slag is densely coexisting with calcium phase minerals. Traditional grinding aids have weak bonding ability with the iron phase and cannot effectively destroy its crystal structure, resulting in high grinding energy consumption and limited fineness improvement;

[0004] Limitations of activity stimulation: Although existing stimulants (such as citrate and sodium silicate) can promote the dissolution of the calcium phase, they have insufficient complexation with the iron phase and do not cooperate with the ultrafine grinding process to optimize the activity release path, resulting in the activity index being difficult to exceed 80%610;

[0005] Poor component stability: Polymers such as polyacrylic acid have insufficient thermal stability and are prone to decomposition and failure during high-temperature grinding, affecting the grinding aid effect;

[0006] Single adaptability: Most grinding aids are suitable for ordinary steel slag powder (specific surface area ≤ 500m 2 / kg), lack of ultrafine powder (specific surface area ≥700m 2 / kg) of the dispersion and activity of the synergistic regulation mechanism. Summary of the Invention

[0007] In order to solve the above-mentioned problems in the prior art, the present invention discloses a special grinding aid activator for ultrafine steel slag powder and its preparation method. Through the synergistic effect of multiple components, efficient grinding aid and activity activation are simultaneously achieved in the ultrafine vertical mill process, so that the specific surface area of ​​the steel slag powder reaches 700-750m 2 / kg, the activity index increased to 85-88%.

[0008] To achieve the above objectives, the present invention includes the following technical solutions.

[0009] A special grinding aid activator for ultrafine steel slag powder, comprising the following components in parts by weight:

[0010]

[0011]

[0012] Furthermore, in the above-mentioned special grinding aid activator for ultrafine steel slag powder, the isothiocyanate compound containing phenylthiocyanate is selected from at least one of benzyl thiocyanate, p-toluene isothiocyanate or 4-methoxyphenyl isothiocyanate.

[0013] Furthermore, in the above-mentioned special grinding aid activator for ultrafine steel slag powder, the benzene-containing hydroxycarboxylic acid compound is selected from at least one of 2,4-dihydroxybenzoic acid, 3,5-dihydroxyphenylacetic acid or 4-hydroxyphthalic acid.

[0014] Furthermore, the specific surface area of ​​the calcium sulfoaluminate in the above-mentioned special grinding aid activator for ultrafine steel slag powder is ≥600m 2 / kg, and Al2O3 content ≥28%.

[0015] Furthermore, in the above-mentioned special grinding aid activator for ultrafine steel slag powder, the sodium silicate is anhydrous sodium silicate with a modulus of 1.0-1.5.

[0016] The present invention also discloses a method for preparing the above-mentioned special grinding aid activator for ultrafine steel slag powder, which comprises the following steps:

[0017] (1) Heat water to 40-50°C, add zwitterionic polyacrylamide and polyoxyethylene polyoxypropylene block copolymer, and stir at 200-300 r / min until completely dissolved;

[0018] (2) Add potassium thiocyanate, sodium silicate and calcium sulfoaluminate and continue stirring for 15-25 minutes;

[0019] (3) Under high-speed stirring at 300-400 r / min, slowly add the phenylthiocyanate isothiocyanate compound and the phenylhydroxycarboxylic acid compound in sequence, and stir for 30-40 minutes to obtain a homogeneous liquid exciter.

[0020] Furthermore, in the above preparation method, in step (3), the interval between adding the phenylthiocyanate-containing isothiocyanate compound and the phenylhydroxycarboxylic acid-containing compound is 5-10 minutes.

[0021] The present invention also discloses the use of the grinding aid activator in preparing ultrafine steel slag powder, comprising the steps of mixing the steel slag raw material with the grinding aid activator in a mass ratio of 100:0.5-1.2, grinding the mixture in an ultrafine vertical mill to a specific surface area of ​​700-750 m 2 / kg, the grinding temperature is controlled at 80-120℃.

[0022] Furthermore, in the above application, the grinding aid activator is added in stages during the grinding process, with the initial addition amount being 60%-70% of the total mass, and the remaining amount being added in two additions in the later stage of grinding.

[0023] Furthermore, in the above application, the 7-day activity index of the obtained ultrafine steel slag powder is ≥85%, and the 28-day activity index is ≥95%.

[0024] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0025] The present invention discloses a special grinding aid activator for ultrafine steel slag powder and its preparation method. The present invention significantly improves the grinding efficiency and gelling activity of steel slag through the synergistic effect of multiple components. Compared with traditional grinding aids, the phenylthiocyanate isothiocyanate compound and the benzene hydroxycarboxylic acid compound synergistically destroy the dense iron-calcium phase structure of steel slag, reducing the grinding energy consumption by 30%-40% and the specific surface area reaching 700-750m 2 / kg; calcium sulfoaluminate and sodium silicate activate mineral activity through a dual pathway of gelation reaction and iron phase transformation, increasing the activity index to 95%-97% in 28 days. The zwitterionic polyacrylamide and block copolymer composite system endows the activator with excellent high-temperature stability (no decomposition at 120°C), and is compatible with the ultra-fine vertical mill's phased addition process to avoid component failure. The formula is free of heavy metals and toxic substances, and the overall cost is over 30% lower than traditional technologies. It is also suitable for multi-solid waste systems (steel slag / mineral slag / fly ash mixture), providing an efficient and environmentally friendly solution for the large-scale replacement of cement clinker with steel slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Comparison of grinding time (min) of each group in Test Example 1;

[0027] Figure 2 The specific surface area of ​​each group in Test Example 1 (m 2 / kg)) comparison;

[0028] Figure 3 Comparison of grinding energy consumption (kWh / t) of each group in Test Example 1. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] The following is a table of raw materials and instruments used in the examples.

[0031] Table 1 Source of raw materials

[0032]

[0033]

[0034] illustrate:

[0035] 1. Special requirements for calcium sulphoaluminate:

[0036] High-alumina bauxite and gypsum must be synthesized at high temperature (calcined at 1350°C) to ensure that the Al2O3 content is ≥28% to provide sufficient active aluminum source;

[0037] Specific surface area ≥600m 2 / kg, which needs to be achieved through air flow crushing process to avoid lattice distortion caused by mechanical crushing.

[0038] 2. Process adaptability of ultrafine vertical mill:

[0039] Equipped with air separation and classification system (cutting particle size D97≤10μm) to ensure that the powder fineness meets the standard;

[0040] The grinding temperature needs to be controlled at 80-120℃ through a circulating water cooling system to prevent thermal decomposition of the activator.

[0041] 3. Molecular weight control of zwitterionic polyacrylamide:

[0042] The molecular weight range of 400,000-600,000 can be achieved by adjusting the monomer addition ratio of the polymerization reaction (acrylamide: methacryloyloxyethyl trimethyl ammonium chloride = 3:1);

[0043] A molecular weight that is too high (>800,000) will result in excessive solution viscosity, affecting grinding permeability.

[0044] For example, the synthesis method of "zwitterionic polyacrylamide" is as follows:

[0045] 1. Raw materials and equipment

[0046] monomer:

[0047] Acrylamide (AM, purity ≥99%);

[0048] Anionic monomer: acrylic acid (AA) or sodium acrylate (MAS);

[0049] Cationic monomer: methacryloyloxyethyltrimethylammonium chloride (DMC) or acryloyloxyethyltrimethylammonium chloride (DAC).

[0050] Initiator: Redox initiation system consisting of ammonium persulfate (APS) and sodium bisulfite (SHS), or azobisisobutylamidine hydrochloride (AIBA).

[0051] Solvent: deionized water.

[0052] Equipment: reactor (with stirring, temperature control and nitrogen protection), pH meter, viscometer.

[0053] 2. Synthesis steps

[0054] (Taking the molar ratio of anionic / cationic monomers as an example)

[0055] Monomer premix:

[0056] Acrylamide (AM), acrylic acid (AA) and methacryloyloxyethyltrimethylammonium chloride (DMC) were mixed in a molar ratio of 6:1:1 and dissolved in deionized water to prepare a solution with a total monomer concentration of 15% to 20%;

[0057] The pH of the solution was adjusted to 6.0-7.0 with NaOH.

[0058] Polymerization reaction:

[0059] The mixed solution was added to the reactor and deoxygenated with nitrogen for 30 minutes;

[0060] Raise the temperature to 35-40°C and add initiator (APS 0.05%-0.1%, SHS 0.02%-0.05%);

[0061] Control the reaction temperature at 45-55°C and continue stirring for 4-6 hours until the viscosity of the system increases significantly (molecular weight reaches 400,000-600,000).

[0062] Post-processing:

[0063] After the reaction, the polymer was precipitated with ethanol, washed, and dried to obtain a white solid;

[0064] The product was crushed and sieved (80-100 mesh), and the molecular weight (GB / T 13940-2020) and ionicity (potentiometric titration method) were tested.

[0065] 3. Key parameter control

[0066] Molecular weight control: through the amount of initiator (reducing the initiator can increase the molecular weight) and the reaction temperature (low temperature is conducive to chain growth);

[0067] Ion ratio adjustment: adjust the molar ratio of AA to DMC (1:1 to 1:2) to achieve a balanced distribution of anionic / cationic groups;

[0068] Avoid cross-linking: control the monomer concentration to ≤20%, and add a chain transfer agent (such as isopropyl alcohol) to inhibit side reactions.

[0069] 4. Technical basis

[0070] The synthesis method refers to GB / T 13940-2020 "Polyacrylamide" and patent CN108084241B "Preparation method of zwitterionic polyacrylamide";

[0071] The product meets the technical requirements of "molecular weight of 400,000-600,000, anionic / cationic monomer molar ratio of 1:1" in the examples.

[0072] Table 2 Instruments and equipment

[0073]

[0074] Example 1

[0075] 1. Grinding aid activator formula

[0076] 5 parts of zwitterionic polyacrylamide (molecular weight 500,000)

[0077] 15 parts of benzyl thiocyanate (containing phenylthiocyanate isothiocyanate compound)

[0078] 20 parts of 3,5-dihydroxyphenylacetic acid (containing benzene hydroxycarboxylic acid compound)

[0079] Calcium sulphoaluminate (specific surface area 650m 2 / kg, Al2O3 content 30%) 8 parts

[0080] 12 parts of anhydrous sodium silicate with a modulus of 1.2

[0081] 7 parts potassium thiocyanate

[0082] 2 parts of polyoxyethylene polyoxypropylene block copolymer (HLB=14)

[0083] Add water to 100 parts

[0084] 2. Preparation method

[0085] Heat 30 parts of water to 45°C, add zwitterionic polyacrylamide and block copolymer, and stir at 250 r / min until dissolved;

[0086] Add potassium thiocyanate, sodium silicate and calcium sulfoaluminate and stir for 20 minutes;

[0087] At 350 r / min, benzyl thiocyanate was added first, and then 3,5-dihydroxyphenylacetic acid was added after an interval of 8 minutes. The mixture was stirred for 35 minutes to obtain a homogeneous liquid.

[0088] 3. Application effect

[0089] The steel slag and activator are mixed at a ratio of 100:0.8 and added in three stages in the ultrafine vertical mill (60% for the first time and the remaining amount in two stages of 20% each);

[0090] Grinding temperature 100℃, final specific surface area 730m 2 / kg;

[0091] Activity index: 87% in 7 days, 96% in 28 days.

[0092] Example 2

[0093] 1. Grinding aid activator formula

[0094] 3 parts of zwitterionic polyacrylamide (molecular weight 400,000)

[0095] 10 parts of p-toluene isothiocyanate

[0096] 25 parts of 4-hydroxyphthalic acid

[0097] Calcium sulphoaluminate (specific surface area 600m 2 / kg, Al2O3 content 28%) 12 parts

[0098] Modulus 1.5 sodium silicate 8 parts

[0099] 10 parts potassium thiocyanate

[0100] 3 parts of block copolymer (HLB=16)

[0101] Add water to 100 parts

[0102] 2. Preparation method

[0103] Heat water to 50°C, add the polymer components, and dissolve at 300 r / min;

[0104] Add the inorganic salt component and stir for 15 minutes;

[0105] With high-speed stirring (400 r / min), add p-toluene isothiocyanate first, then add 4-hydroxyphthalic acid after an interval of 5 minutes, and stir for 40 minutes.

[0106] 3. Application effect

[0107] Mix steel slag and activator at a ratio of 100:1.2 and add once;

[0108] Grinding temperature 120℃, specific surface area 750m 2 / kg;

[0109] Activity index: 88% in 7 days, 97% in 28 days.

[0110] Example 3

[0111] 1. Grinding aid activator formula

[0112] 8 parts of zwitterionic polyacrylamide (molecular weight 600,000)

[0113] 18 parts of 4-methoxyphenyl isothiocyanate

[0114] 15 parts of 2,4-dihydroxybenzoic acid

[0115] Calcium sulphoaluminate (specific surface area 700m 2 / kg, Al2O3 content 32%) 5 parts

[0116] Modulus 1.0 sodium silicate 15 parts

[0117] 5 parts potassium thiocyanate

[0118] 1 part of block copolymer (HLB=12)

[0119] Add water to 100 parts

[0120] 2. Preparation method

[0121] Heat water to 40°C, add polymer, and dissolve at 200 r / min;

[0122] Add inorganic salt and stir for 25 minutes;

[0123] Isothiocyanate and carboxylic acid compound were added in sequence (10 minute intervals) at 300 r / min and stirred for 30 minutes.

[0124] 3. Application effect

[0125] The slag and activator were mixed at a ratio of 100:0.5 and added in two stages (70% for the first time and the remaining 30%);

[0126] Grinding temperature 80℃, specific surface area 700m 2 / kg;

[0127] Activity index: 85% in 7 days, 95% in 28 days.

[0128] Example 4

[0129] 1. Grinding aid activator formula

[0130] 6 parts of zwitterionic polyacrylamide (molecular weight 550,000)

[0131] 12 parts of p-toluene isothiocyanate (including phenylthiocyanate isothiocyanate compound)

[0132] 18 parts of 4-hydroxyphthalic acid (including benzene hydroxycarboxylic acid compound)

[0133] Calcium sulphoaluminate (specific surface area 620m 2 / kg, Al2O3 content 29%) 9 parts

[0134] 10 parts of anhydrous sodium silicate with a modulus of 1.3

[0135] 8 parts potassium thiocyanate

[0136] 2.5 parts of polyoxyethylene-polyoxypropylene block copolymer (HLB=15)

[0137] Add water to 100 parts

[0138] 2. Preparation method

[0139] Heat 35 parts of water to 48°C, add zwitterionic polyacrylamide and block copolymer, and stir at 280 r / min until dissolved;

[0140] Add potassium thiocyanate, sodium silicate and calcium sulfoaluminate and stir for 22 minutes;

[0141] At 380 r / min, p-toluene isothiocyanate was added first, and 4-hydroxyphthalic acid was added after an interval of 7 minutes. The mixture was stirred for 38 minutes to obtain a homogeneous liquid.

[0142] 3. Application effect

[0143] The slag and activator were mixed at a ratio of 100:1.0 and added in four stages (50% for the first time and 17% for the remaining three times);

[0144] Grinding temperature 110℃, final specific surface area 740m 2 / kg;

[0145] Activity index: 86% in 7 days, 96% in 28 days.

[0146] Example 5

[0147] 1. Grinding aid activator formula

[0148] 4 parts of zwitterionic polyacrylamide (molecular weight 450,000)

[0149] 14 parts of benzyl thiocyanate

[0150] 22 parts of 3,4-dihydroxybenzoic acid (including benzene hydroxycarboxylic acid compound)

[0151] Calcium sulphoaluminate (specific surface area 680m 2 / kg, Al2O3 content 31%) 7 parts

[0152] Modulus 1.4 Sodium silicate 11 parts

[0153] 6 parts potassium thiocyanate

[0154] 1.5 parts of block copolymer (HLB=13)

[0155] Add water to 100 parts

[0156] 2. Preparation method

[0157] Heat water to 42°C, add polymer, and dissolve at 220 r / min;

[0158] Add the inorganic salt component and stir for 18 minutes;

[0159] With high-speed stirring (320 r / min), benzyl thiocyanate was added first, and 3,4-dihydroxybenzoic acid was added after an interval of 6 minutes, and the mixture was stirred for 33 minutes.

[0160] 3. Application effect

[0161] The slag and activator were mixed at a ratio of 100:0.7 and added in two stages (65% for the first time and the remaining 35%);

[0162] Grinding temperature 90℃, specific surface area 720m 2 / kg;

[0163] Activity index: 85% in 7 days, 95% in 28 days.

[0164] Example 6

[0165] 1. Grinding aid activator formula

[0166] 7 parts of zwitterionic polyacrylamide (molecular weight 580,000)

[0167] 17 parts of 4-methoxyphenyl isothiocyanate

[0168] 19 parts of 2,5-dihydroxyphenylacetic acid (containing benzene hydroxycarboxylic acid compound)

[0169] Calcium sulphoaluminate (specific surface area 640m 2 / kg, Al2O3 content 28.5%) 10 parts

[0170] Modulus 1.1 Sodium silicate 14 parts

[0171] 9 parts of potassium thiocyanate

[0172] 2.2 parts of block copolymer (HLB=15)

[0173] Add water to 100 parts

[0174] 2. Preparation method

[0175] Heat water to 47°C, add polymer, and dissolve at 260 r / min;

[0176] Add inorganic salt and stir for 19 minutes;

[0177] Isothiocyanate and carboxylic acid compound were added in sequence (at intervals of 9 minutes) at 340 r / min and stirred for 36 minutes.

[0178] 3. Application effect

[0179] The slag and activator were mixed at a ratio of 100:1.1 and added in three stages (55% for the first time and 22.5% for the remaining two times);

[0180] Grinding temperature 105℃, specific surface area 735m 2 / kg;

[0181] Activity index: 87% in 7 days, 96% in 28 days.

[0182] Comparative Example 1

[0183] Based on the existing technology CN102503220B

[0184] Formula: 20 parts of triethanolamine, 15 parts of calcium lignin sulfonate, 10 parts of polycarboxylate water reducer, 25 parts of sodium sulfate, 30 parts of water;

[0185] Application effect: The specific surface area of ​​steel slag powder is 480m 2 / kg, activity index was 72% on 7 days and 80% on 28 days.

[0186] Comparative Example 2

[0187] Removal of isothiocyanate compounds containing phenylthiocyanate based on Example 1

[0188] formula:

[0189] 5 parts of zwitterionic polyacrylamide (molecular weight 500,000)

[0190] (Removal of benzyl thiocyanate)

[0191] 20 parts of 3,5-dihydroxyphenylacetic acid

[0192] 8 parts calcium sulfoaluminate

[0193] 12 parts of sodium silicate

[0194] 7 parts potassium thiocyanate

[0195] 2 parts of block copolymer

[0196] Add water to 100 parts

[0197] Application effect: specific surface area 620m 2 / kg, activity index was 78% at 7 days and 85% at 28 days.

[0198] Comparative Example 3

[0199] Removal of calcium sulfoaluminate based on Example 1

[0200] formula:

[0201] 5 parts of zwitterionic polyacrylamide

[0202] 15 parts of benzyl thiocyanate

[0203] 20 parts of 3,5-dihydroxyphenylacetic acid

[0204] (Removal of calcium sulfoaluminate)

[0205] 12 parts of sodium silicate

[0206] 7 parts potassium thiocyanate

[0207] 2 parts of block copolymer

[0208] Add water to 100 parts

[0209] Application effect: specific surface area 700m 2 / kg, the activity index was 82% after 7 days and 88% after 28 days, but the iron phase conversion rate was only 68%.

[0210] Comparative Example 4

[0211] Based on Example 1, zwitterionic polyacrylamide was replaced with ordinary polyacrylamide

[0212] formula:

[0213] 5 parts of ordinary polyacrylamide (non-zwitterionic, molecular weight 500,000)

[0214] 15 parts of benzyl thiocyanate

[0215] 20 parts of 3,5-dihydroxyphenylacetic acid

[0216] 8 parts calcium sulfoaluminate

[0217] 12 parts of sodium silicate

[0218] 7 parts potassium thiocyanate

[0219] 2 parts of block copolymer

[0220] Add water to 100 parts

[0221] Application effect: specific surface area 710m 2 / kg, the component decomposition rate is 12% when the grinding temperature is 100℃, the activity index is 83% after 7 days and 90% after 28 days.

[0222] Test Example 1

[0223] Grinding efficiency and fineness verification

[0224] Test Method

[0225] Grinding process:

[0226] Equipment: Ultrafine vertical mill (model LM-3800, power 315kW);

[0227] Steel slag raw material: converter steel slag (CaO content 45%, FeO content 25%, particle size ≤ 10mm);

[0228] The amount of activator added: weigh 0.5-1.2% of the mass of the steel slag;

[0229] Grinding conditions: temperature 80-120°C, adding activator in stages (controlled according to claims 8-9).

[0230] Specific surface area determination:

[0231] Instrument: Fully automatic specific surface area analyzer (model Blaine-2020);

[0232] Standard: GB / T 8074-2008 "Determination of specific surface area of ​​cement (Blaine method)"

[0233] Sampling point: Take powder samples every 30 minutes, repeat 3 times and take the average value.

[0234] Calculation of grinding energy consumption:

[0235] Formula: Energy consumption (kWh / t) = total power consumption (kWh) / slag processing volume (t);

[0236] Data collection: Real-time recording of power consumption through the vertical mill electronic control system.

[0237] The results are shown in Table 3 and Figure 1-3 .

[0238] Table 3 Grinding efficiency and fineness verification

[0239]

[0240] The following conclusions can be drawn from Table 3:

[0241] The core role of benzyl thiocyanate: its isothiocyanate group (-NCS) reacts with the iron phase Fe 2+ Forming stable coordination bonds and reducing the mineral interface binding energy through the "chemical wedging" effect (reduction of up to 35%);

[0242] The synergistic mechanism of calcium sulfoaluminate: its high specific surface area (≥600m 2 / kg) provides nucleation sites, promotes powder dispersion, and reduces ineffective mechanical energy loss.

[0243] Test Example 2

[0244] Activity activation and iron phase conversion rate

[0245] Test Method

[0246] Activity index test:

[0247] Standard: GB / T 18046-2017 "Steel slag powder for use in cement";

[0248] Specimen preparation: Steel slag powder and standard cement were mixed at a ratio of 3:7, with a water-binder ratio of 0.5, and molded into 40×40×160mm specimens;

[0249] Curing conditions: 20℃±1℃, humidity ≥95%, test compressive strength ratio after 7 days and 28 days.

[0250] Iron phase conversion rate determination:

[0251] Instrument: X-ray diffractometer (XRD, model D8 Advance) combined with chemical titration;

[0252] step:

[0253] (1) The powder is selectively dissolved in 1 mol / L hydrochloric acid to dissolve the calcium phase minerals, and the remaining residue is the iron phase;

[0254] (2) The conversion rate was calculated by quantifying the peak area change of the RO phase (FeO-MgO-MnO solid solution) by XRD.

[0255] The results are shown in Table 4

[0256] Table 4 Activity excitation and iron phase conversion rate

[0257]

[0258]

[0259] The following conclusions can be drawn from the data in Table 4: The core contribution of calcium sulfoaluminate: when its Al2O3 content is ≥28%, it reacts with sodium silicate to form nano-scale CASH gel, which fills the pores and densifies the structure (porosity is reduced by 22%);

[0260] Iron phase transformation path: Fe 2+ Under the action of carboxylic acid complexation, it migrates to the silica-alumina network to form gelled almandine, which contributes 35% of the 28-day strength increase.

[0261] Test Example 3

[0262] High temperature stability and component decomposition

[0263] Test Method

[0264] Thermal stability test:

[0265] Instrument: Thermogravimetric analyzer (TGA, model STA-449F3);

[0266] Conditions: nitrogen atmosphere, heating rate 10°C / min, temperature range 25-200°C;

[0267] Calculation of decomposition rate: mass loss rate at 200°C.

[0268] Activity retention rate test:

[0269] Simulated high temperature grinding: pre-treat the activator in an oven at 120°C for 2 hours, and then test the activity index according to the standard method.

[0270] The results are shown in Table 5

[0271] Table 5 High temperature stability and component decomposition

[0272]

[0273] The following conclusions can be drawn from Table 5:

[0274] Advantages of zwitterionic polymers: their molecular chains carry cations (-NH3 + ) and anionic (-COO-) groups, forming a three-dimensional network structure through electrostatic cross-linking, and the thermal decomposition temperature is increased to 220 ° C

[0275] (Ordinary type only 160℃);

[0276] Synergistic effect of block copolymers: PEO-PPO copolymers with an HLB value of 12-16 are adsorbed on the powder surface, reducing interfacial friction heat (temperature difference reduced by 15-20°C).

[0277] Test Example 4

[0278] Comparison between economic efficiency and environmental protection

[0279] Test Method

[0280] Cost accounting:

[0281] Raw material purchase price: based on the average market price of chemical products in East China in 2023;

[0282] Comprehensive cost = unit price (yuan / kg) × amount used (kg / ton of steel slag).

[0283] Environmental testing:

[0284] Heavy metal content: ICP-OES method (GB 30760-2014) to detect Pb, Cd, Cr, and Hg;

[0285] Toxicity test: Refer to GB 5085.3-2007 "Identification Standard for Hazardous Wastes".

[0286] The results are shown in Table 6

[0287] Table 6 Comparison of economic efficiency and environmental protection

[0288]

[0289] From Table 6 we can draw the following conclusions

[0290] Cost optimization path: Reduce activator waste by adding in stages (Example 5), and reduce the amount by 12.5%;

[0291] Environmental advantages: The chlorine-free and heavy metal-free formula of the present invention has passed the Class A certification of GB 6566-2010 "Limits of Radioactive Nuclides in Building Materials".

[0292] In summary, it can be seen from the above embodiments that the present invention has the following specific advantages:

[0293] 1) High-efficiency grinding aid and fineness breakthrough

[0294] Traditional steel slag grinding has high energy consumption (≥65kWh / t) and limited fineness (≤500m due to the dense structure of iron phase (RO phase). 2 / kg). In the present invention, the isothiocyanate compound containing phenylthiocyanate (such as benzyl thiocyanate) reacts with Fe via the isothiocyanate group (-NCS). 2+ Forming coordination bonds, combined with the "wedge effect" to destroy the mineral interface, while containing benzene hydroxycarboxylic acid compounds (such as 3,5-dihydroxyphenylacetic acid) to complex Ca 2 + Reduce surface energy, the two work together to reduce grinding energy consumption to 42-50kWh / t, and increase specific surface area by more than 40% (700-750m 2 The data of Examples 1-6 show that the grinding time is shortened by 25%-30%, and the iron phase dissociation rate is ≥90%, which is significantly better than that of Comparative Example 1 (CN102503220B, energy consumption 68kWh / t).

[0295] 2) Dual-pathway activity stimulation mechanism

[0296] Traditional activators rely on the dissolution of a single calcium phase (such as citrate) and are ineffective in releasing the activity of the iron phase. In the present invention, calcium sulfoaluminate (Al2O3 ≥ 28%) and sodium silicate form a nanoscale hydrated calcium aluminosilicate (CASH) gel on the powder surface, filling the pores and improving the density; at the same time, the benzene-hydroxycarboxylic acid compound promotes the iron phase Fe through complexation. 2+ Migrates to the silica-alumina network to form gelled almandine (Fe3Al2(SiO4)3). Examples 1-3 show an activity index of 85-88% after 7 days, 95-97% after 28 days, and an iron phase conversion rate of 89-92%, a 25%-30% improvement over Comparative Example 3 (calcium sulfoaluminate deficiency).

[0297] 3) High temperature stability and process adaptability

[0298] Existing grinding aids (such as polyacrylic acid) tend to decompose and become ineffective at grinding temperatures above 100°C (comparative Example 4 shows a decomposition rate of 12%). The present invention utilizes a composite system of zwitterionic polyacrylamide (molecular weight 400,000-600,000) and a block copolymer (HLB 12-16), forming a thermally stable network through hydrogen bonding and electrostatic crosslinking. This results in a decomposition rate of less than 1% at 120°C and an activity retention rate of ≥97%. Furthermore, a phased addition process (Claim 9) optimizes the activator's permeation path, avoids local overload, and keeps grinding temperature fluctuations within ±5°C (data from Example 1).

[0299] 4) Environmental protection and economic advantages

[0300] While traditional formulations contain pollutants such as sodium sulfate and triethanolamine (Comparative Example 1 contains less than 5 ppm of lead), the present invention's components are free of heavy metals and chloride ions, and have passed GB 6566-2010 Class A certification. Furthermore, the low-cost combination of calcium sulfoaluminate and sodium silicate (accounting for 35%-40% of the total formulation cost) reduces overall costs by 30%-40% compared to traditional technologies. Example 5 shows that even with an activator dosage of 0.7 kg / ton of slag, the 28-day activity index still reaches 95%, and the processing cost per ton of slag is only 61 yuan, a 34.4% reduction compared to Comparative Example 1 (93 yuan).

[0301] 5) Wide applicability

[0302] The grinding aid of this invention is suitable for multi-solid waste systems (steel slag: slag: fly ash = 4:4:2 to 5:3:2) and is highly adaptable to fluctuating slag composition (CaO 40-50%, FeO 20-30%). Test Example 4 shows that when blending slag and fly ash in varying proportions, the 28-day activity index remains at 94-96%, significantly higher than that of Comparative Examples 2-3 (78-83%). This provides technical support for the large-scale replacement of cement clinker (≥30%) with steel slag.

[0303] The above are only a few preferred embodiments of the present invention, and their description is relatively specific and detailed, but it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and such modifications and improvements are within the scope of protection of the present invention.

Claims

1. A special grinding aid activator for ultrafine steel slag powder, characterized in that: The following components are included in parts by weight: 1-3 parts of a polyoxyethylene-polyoxypropylene block copolymer having an HLB value of 12-16; Add water to make up to 100 parts.

2. The grinding aid activator according to claim 1, characterized in that: The isothiocyanate compound containing phenylthiocyanate is at least one selected from benzyl thiocyanate, p-toluene isothiocyanate or 4-methoxyphenyl isothiocyanate.

3. The grinding aid activator according to claim 1, characterized in that: The benzene-containing hydroxycarboxylic acid compound is selected from at least one of 2,4-dihydroxybenzoic acid, 3,5-dihydroxyphenylacetic acid or 4-hydroxyphthalic acid.

4. The grinding aid activator according to claim 1, characterized in that: The specific surface area of ​​the calcium sulfoaluminate is ≥600m 2 / kg, and Al2O3 content ≥28%.

5. The grinding aid activator according to claim 1, characterized in that: The sodium silicate is anhydrous sodium silicate with a modulus of 1.0-1.

5.

6. A method for preparing the special grinding aid activator for ultrafine steel slag powder according to any one of claims 1 to 5, comprising the following steps: (1) Heat water to 40-50°C, add zwitterionic polyacrylamide and polyoxyethylene polyoxypropylene block copolymer, and stir at 200-300 r / min until completely dissolved; (2) Add potassium thiocyanate, sodium silicate and calcium sulfoaluminate and continue stirring for 15-25 minutes; (3) Under high-speed stirring at 300-400 r / min, slowly add the phenylthiocyanate isothiocyanate compound and the phenylhydroxycarboxylic acid compound in sequence, and stir for 30-40 minutes to obtain a homogeneous liquid exciter.

7. The preparation method according to claim 6, characterized in that: In step (3), the interval between adding the phenylthiocyanate-containing isothiocyanate compound and the phenylhydroxycarboxylic acid-containing compound is 5-10 minutes.

8. Use of the grinding aid activator according to any one of claims 1 to 5 in the preparation of ultrafine steel slag powder, characterized in that: The steel slag raw material and the grinding aid activator are mixed in a mass ratio of 100:0.5-1.2, and ground in an ultra-fine vertical mill to a specific surface area of ​​700-750m 2 / kg, the grinding temperature is controlled at 80-120℃.

9. The use according to claim 8, characterized in that: The grinding aid activator is added in stages during the grinding process. The initial addition amount is 60%-70% of the total mass, and the remaining amount is added twice in the later stage of grinding.

10. The use according to claim 8, characterized in that: The 7-day activity index of the obtained ultrafine steel slag powder is ≥85%, and the 28-day activity index is ≥95%.

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