A gold tailings-based auxiliary cementitious material, its preparation method and application

Abstract

The present invention relates to the technical field of industrial solid waste resource utilization, and specifically discloses a gold tailings-based auxiliary cementitious material, a preparation method thereof, and an application thereof. The gold tailings-based auxiliary cementitious material comprises: 60 to 80 parts of gold tailings, 5 to 20 parts of waste limestone powder, 5 to 15 parts of gypsum tailings, 5 to 10 parts of glauberite tailings, and 0.5 to 1 part of a performance regulator; the performance regulator comprises 5% to 15% of diethanol monoisopropanolamine, 10% to 20% of sodium oleate, and 70% to 85% of an alcohol solvent. The auxiliary cementitious material provided by the present invention significantly improves the reaction activity of gold tailings and stimulates the reaction of various mineral powders to generate more hydration products by adding a variety of solid hazardous wastes and coordinating with organic performance regulators and special activation means, effectively improving the mechanical properties of the material. It not only solves the problem of safe treatment of industrial solid waste, but also effectively reduces the consumption of cement, meeting the concept of green environmental protection and sustainable development.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial solid waste resource utilization, and particularly relates to a gold tailings-based supplementary cementitious material, a preparation method thereof, and an application thereof. Background Art

[0002] Since its appearance in the 19th century, Portland cement has witnessed the construction of many major cities in the world. However, the production of Portland cement consumes a large amount of energy, resulting in the release of carbon dioxide. It is statistically shown that the carbon dioxide generated by the production of Portland cement globally accounts for about 6%-7% of the total carbon dioxide emissions. The cement industry is the most energy-intensive industry among all manufacturing industries, accounting for about 5% of the total global industrial energy consumption.

[0003] Currently, the most commonly used supplementary cementitious material in the field of concrete is pozzolan, which can effectively reduce carbon dioxide emissions and energy consumption, and thus has been widely promoted. Commonly used supplementary cementitious materials also include fly ash and ground granulated blast-furnace slag. However, due to the uneven geographical distribution of these materials, they cannot meet the needs of the concrete industry.

[0004] Gold tailings are by-products discarded near mining areas after gold mining. With the rapid development of mining, the generation amount of gold tailings is increasing. The in-situ accumulation of gold tailings occupies a large amount of cultivated land, and the exposure of gold tailings to the air not only generates a large amount of dust, but also causes a large amount of acidic mine wastewater to pollute the soil and water bodies, thereby endangering the living environment of humans. If gold tailings can be used as partial substitutes for cement, it can not only save energy, reduce carbon dioxide emissions, but also realize the resource utilization of waste, protect the environment, and obtain additional cost benefits. However, gold tailings do not cement and have low reactivity. Therefore, how to improve the reactivity of gold tailings is a bottleneck problem for realizing the resource utilization of gold tailings. Summary of the Invention

[0005] Aiming at the problem of low reactivity of gold tailings as partial substitutes for cement in the prior art, the present invention provides a gold tailings-based supplementary cementitious material, a preparation method thereof, and an application thereof. Through the supplementary cementitious material provided by the present invention, the high-value utilization of gold tailings can be realized. On the basis of reducing the cement dosage, the strength development of cement-based materials is ensured, providing an effective way for the treatment of gold tailings and being conducive to the green, low-carbon and sustainable development of cement-based materials.

[0006] To solve the above technical problems, the technical solution provided by the present invention is:

[0007] In a first aspect, a gold tailings-based auxiliary cementitious material comprises raw material components in the following parts by mass: 60 to 80 parts of gold tailings, 5 to 20 parts of waste limestone powder, 5 to 15 parts of gypsum tailings, 5 to 10 parts of glauberite tailings, and 0.5 to 1 part of a performance regulator;

[0008] Among them, the performance regulator comprises components in the following mass percentages: 5% to 15% of diethanol monoisopropanolamine, 10% to 20% of sodium oleate, and 70% to 85% of an alcohol solvent.

[0009] Compared with the prior art, the gold tailings-based auxiliary cementitious material provided by the present invention uses gold tailings as the main raw material, and makes up for the defect of low reaction activity of gold tailings by adding waste limestone powder, gypsum tailings and glauberite tailings; and by adding diethanol monoisopropanolamine and sodium oleate as performance regulators. Among them, the hydroxyalkyl and amino groups in diethanol monoisopropanolamine are easy to adsorb on the surface of mineral particles and the gaps generated by the action of external forces on the particles, reducing the surface energy of the mineral particles, making the mineral particles easier to break. At the same time, the electronegativity of nitrogen enables diethanol monoisopropanolamine to have an electrostatic repulsive force, so that the electrostatic aggregation between mineral particles can be effectively reduced, and the dispersion uniformity between mineral particles can be improved. In addition, diethanol monoisopropanolamine can also increase the hydration rate of C3A and C4AF, accelerate the formation of microcrystalline Ca(OH)2 in the early stage, promote the hydration rate of gold tailings powder, and enhance the later hydration degree of C2S, which is beneficial to the increase of the early and later strengths of mortar specimens; sodium oleate can improve the grindability of mineral particles, prevent the adhesion and agglomeration of fine particles, and the Ca in the auxiliary cementitious material 2+ increases the adsorption of sodium oleate on the surface of quartz in gold tailings, significantly reducing the surface hardness of quartz; through the synergy of diethanol monoisopropanolamine and sodium oleate, the surface energy of mineral particles is significantly reduced, and the mixing uniformity between mineral particles is improved.

[0010] Further, the alcohol solvent is anhydrous ethanol.

[0011] Further, the gold tailings are tailings generated during gold mining or ore dressing, and its main mineral phases are quartz (SiO2), muscovite (K{Al2[AlSi3O10](OH)2}), albite (NaAlSi3O), and microcline (K[AlSi3O8]). The particle size of the gold tailings selected in the present invention is 1 μm to 1 mm, D50 is 58.627 μm, and the moisture content is 3.57%.

[0012] Further, the waste limestone powder is waste from quarry stone processing, mainly composed of calcite (CaCO3), and also contains trace amounts of dolomite (MgCO3). The particle size of the waste limestone powder selected in the present invention is 0.002 mm to 0.006 mm, and the moisture content is 1.02%.

[0013] Further, the gypsum tailings are low-grade gypsum tailings containing impurities generated during the mining process. The particle size of the gypsum tailings selected in the present invention is 5 μm to 150 mm. Among them, the content of dihydrate gypsum and anhydrous gypsum accounts for about 59%, and the rest are clay impurities, and the moisture content is 8.62%.

[0014] Further, the glauberite tailings are low-grade glauberite ores containing impurities generated during the mining process of glauberite mines. According to the mass ratio, the glauberite tailings contain about 40% of Na2SO4, about 38% of Ca2SO4, and the rest of the impurities account for about 22%. The particle size of the glauberite tailings selected in the present invention is 0.5 mm to 30 mm, and the moisture content is 1.27%.

[0015] Second, the present invention also provides a preparation method of a gold tailings-based auxiliary cementitious material, which includes the following steps:

[0016] S1, weigh each component according to the design ratio described in any one of the above, mix the weighed gold tailings and waste limestone powder evenly, and ball mill to obtain a ground material;

[0017] S2, calcine the ground material at 700 °C to 800 °C for 120 min to 180 min, and cool to obtain a calcined material;

[0018] S3, mix the calcined material with the weighed gypsum tailings and glauberite tailings evenly, spray the performance regulator onto the mixed material, and ball mill to obtain a gold tailings-based auxiliary cementitious material.

[0019] Further, before weighing each raw material, the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings are pre-dried at 100 °C to 110 °C for 2 h to 3 h.

[0020] Further, in S1, the rotation speed of the ball mill is 30 r / min to 45 r / min, and the ball milling time is 30 min to 50 min.

[0021] Further, in S2, the temperature is raised to 700 °C to 800 °C in a programmed heating manner, and the heating rate of the programmed heating is 10 °C / min to 20 °C / min.

[0022] Further, in S3, the rotation speed of the ball mill is 30 r / min to 45 r / min, and the ball milling time is 10 min to 30 min.

[0023] Aiming at the problem of low reactivity of gold tailings, the present invention provides the above-mentioned method for preparing an auxiliary cementitious material. In the preparation method, through methods such as mechanical activation, thermal activation, and chemical activation, the reactivity of gold tailings is significantly improved, as well as the mechanical properties of the finally prepared auxiliary cementitious material.

[0024] The advantages of the auxiliary cementitious material and the preparation method provided by the present invention are as follows:

[0025] 1. Muscovite in gold tailings is a layered aluminosilicate mineral containing structural water inside. Under mechanical grinding, internal defects appear in it, and the crystal structure transforms into a metastable state. Under high-temperature calcination at a subsequent specific temperature, muscovite undergoes a dehydroxylation reaction, further decomposing and releasing KAlSi3O8 and Al2O3. The KAlSi3O8 and Al2O3 released by the decomposition of muscovite enter the melt, reducing the minimum melting temperature of the quartz and feldspar mixture and promoting the decomposition of quartz and feldspar to release reactive silicon, reactive aluminum, and soluble salts, thereby improving the reactivity of gold tailings.

[0026] 2. During the calcination of waste limestone powder under mechanical grinding and specific high-temperature conditions, part of the limestone decomposes to generate CaO and polar CO2. The polar CO2 will have a strong erosion effect on the crystalline phase in gold tailings, which is beneficial to reducing the crystallinity of the mineral phase in gold tailings; the presence of CaO provides a certain amount of Ca and pH environment for the early hydration stage of the cementitious system, making up for the defects of low early strength and slow strength development caused by the low early reactivity of the auxiliary cementitious material to a certain extent; in addition, the CaCO3 in the remaining undecomposed limestone will react with the unstable calcium aluminohydrate and monosulfate calcium aluminosulfate (Ms) generated by the hydration of the cementitious material to form stable monocarbon calcium aluminohydrate (Mc) and hemicarbon calcium aluminohydrate (Hc), stabilizing the content of ettringite (AFt) in the cementitious system, thereby making the hardened structure of the cementitious system more stable, reducing the porosity of the structure, making the paste structure more dense, and further being beneficial to the significant improvement of the mechanical properties of the cementitious material. 2+ 3. In the alkaline environment generated by the hydration of cement, the silicon-oxygen polymer chain in the activated gold tailings powder is further destroyed, accelerating the dissolution of reactive silicon, reactive aluminum, and soluble salts, and reacting with Ca and OH in the liquid phase to form calcium silicate hydrate gel and calcium aluminohydrate; further, in the presence of gypsum tailings, SO4 can react with reactive aluminum and calcium aluminohydrate to form ettringite (AFt), reducing the conversion ratio of AFt to Ms, thereby improving the density of the structure, and at the same time reducing Ca and Al in the liquid phase.

[0027] 3. In the alkaline environment generated by the hydration of cement, the silicon-oxygen polymer chain in the activated gold tailings powder is further destroyed, accelerating the dissolution of reactive silicon, reactive aluminum, and soluble salts, and reacting with Ca 2+ 、OH - to form calcium silicate hydrate gel and calcium aluminohydrate; further, in the presence of gypsum tailings, SO4 2- can react with reactive aluminum and calcium aluminohydrate to form ettringite (AFt), reducing the conversion ratio of AFt to Ms, thereby improving the density of the structure, and at the same time reducing Ca 2+ and Al 3+The concentration promotes the hydration of activated gold tailings powder, thereby improving the early strength of the material.

[0028] 4. The low solubility activity of gypsum in water results in a low concentration of SO4 in the liquid phase during the initial stage of hydration. By adding glauberite tailings, the present invention provides a large amount of SO4 for the cementitious system during the initial stage of hydration 2- , promotes the formation of AFt, accelerates the setting and hardening of cement to a certain extent, makes up for the defect of low early reaction activity of metal tailings powder, and thus is conducive to further improving the early strength of the material. 2-

[0029] 5. Further, by adding diethanol monoisopropanolamine and sodium oleate, the surface energy of each mineral particle is reduced, the mechanical grinding efficiency of the mineral particles is improved, and the dispersion uniformity among the mineral particles is increased. Moreover, diethanol monoisopropanolamine can also promote the hydration of activated metal tailings, improving the early strength and later strength of the material.

[0030] The present invention also provides a cementitious material, comprising the gold tailings-based supplementary cementitious material described in any one of the above and cement.

[0031] The cementitious material prepared by the present invention from multi-source solid wastes has high reactivity, can replace more than 30% of the cement in the cementitious material without significantly reducing the 28d compressive strength of the mortar test block, provides more choices for the supplementary cementitious material, is suitable as a supplementary cementitious material for cement, and is conducive to the green, low-carbon and sustainable development of cement-based materials.

[0032] The present invention also provides the application of the gold tailings-based supplementary cementitious material described in any one of the above or the above cementitious material in concrete and / or mortar.

[0033] The present invention also provides a concrete, comprising the gold tailings-based supplementary cementitious material described in any one of the above or the above cementitious material.

[0034] The supplementary cementitious material provided by the present invention significantly improves the reactivity of gold tailings by adding various solid hazardous wastes such as waste limestone powder, gypsum tailings and glauberite tailings, synergistically combining organic property regulators such as diethanol monoisopropanolamine and sodium oleate, and cooperating with special means such as mechanical activation, high-temperature activation and chemical activation, stimulates the reaction of each mineral powder to generate more hydration products, effectively improves the mechanical properties of the material, and thus can further increase the usage amount of the supplementary cementitious material in the total cementitious material on the premise of ensuring the strength of the cemented material. It not only solves the problem of safe treatment of industrial solid waste, but also effectively reduces the usage amount of cement, thereby being conducive to energy conservation and consumption reduction, reducing carbon dioxide emissions, conforming to the concept of green environmental protection and sustainable development, and having high economic, environmental and social benefits, with high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the XRD pattern of the original gold tailings;

[0036] Figure 2 is the XRD pattern of the gold tailings-based supplementary cementitious material prepared in Example 2;

[0037] Figure 3 is the XRD pattern of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 3 days;

[0038] Figure 4 is the XRD pattern of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 28 days;

[0039] Figure 5 is the SEM image of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 3 days magnified 20,000 times;

[0040] Figure 6 is the SEM image of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 3 days magnified 50,000 times;

[0041] Figure 7 is the SEM image of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 28 days magnified 20,000 times;

[0042] Figure 8 is the SEM image of the hardened paste of the cement slurry doped with 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at the age of 28 days magnified 50,000 times. Detailed implementation manners

[0043] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] In the first aspect of the embodiments of the present invention, a gold tailings-based supplementary cementitious material is provided, which includes the following raw materials in parts by mass: 60 to 80 parts of gold tailings, 5 to 20 parts of waste limestone powder, 5 to 15 parts of gypsum tailings, 5 to 10 parts of glauberite tailings, and 0.5 to 1 part of a performance regulator;

[0045] Among them, the performance regulator includes the following components in mass percentage: 5% to 15% of diethanol monoisopropanolamine, 10% to 20% of sodium oleate, and 70% to 85% of an alcohol solvent.

[0046] In the second aspect of the embodiments of the present invention, a method for preparing the above-mentioned gold tailings-based auxiliary cementitious material is provided, including the following steps:

[0047] S1, Weigh each component according to the above design ratio, mix the weighed gold tailings and waste limestone powder evenly, and ball mill to obtain a ground material;

[0048] S2, Calcinate the ground material at 700 °C to 800 °C for 120 min to 180 min, and cool to obtain a calcined material;

[0049] S3, Mix the calcined material evenly with the weighed gypsum tailings and glauberite tailings, spray the performance regulator onto the mixed material, and ball mill to obtain the gold tailings-based auxiliary cementitious material.

[0050] To better illustrate the present invention, further examples are given below by way of examples.

[0051] The physical and chemical indexes of the raw materials used in the following examples and comparative examples are as follows:

[0052] The gold tailings are the tailings generated during gold mining or ore dressing. Its main mineral phases are quartz (SiO2), muscovite (K{Al2[AlSi3O10](OH)2}), albite (NaAlSi3O8) and microcline (K[AlSi3O8]). The particle size of the gold tailings is 1 μm to 1 mm, D50 is 58.627 μm, and the moisture content is 3.57%.

[0053] The waste limestone powder is the waste from stone processing in a quarry, mainly composed of calcite (CaCO3), and also contains trace amounts of dolomite (MgCO3). The particle size of the waste limestone powder is 0.002 mm to 0.006 mm, and the moisture content is 1.02%.

[0054] The gypsum tailings are low-grade gypsum tailings containing impurities generated during mining. The particle size of the gypsum tailings is 5 μm to 150 mm. Among them, the content of gypsum dihydrate and anhydrous gypsum accounts for about 59%, and the rest are clay impurities. The moisture content is 8.6%.

[0055] The glauberite tailings are low-grade glauberite ores containing impurities generated during glauberite mining. According to the mass ratio, the glauberite tailings contain about 40% of Na2SO4, about 38% of Ca2SO4, and the rest of the impurities account for about 22%. The particle size of the glauberite tailings is 0.5 mm to 30 mm, and the moisture content is 1.27%.

[0056] Example 1

[0057] An embodiment of the present invention provides a gold tailings-based auxiliary cementitious material, which comprises the following raw materials in parts by mass: 80 parts of gold tailings, 10 parts of waste limestone powder, 10 parts of gypsum tailings, 5 parts of glauberite tailings, and 0.8 part of a performance regulator;

[0058] Among them, the performance regulator comprises the following components in mass percentage: 5% of diethanol monoisopropanolamine, 10% of sodium oleate, and 85% of absolute ethanol.

[0059] The preparation method of the above gold tailings-based auxiliary cementitious material comprises the following steps:

[0060] S1, drying the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant-temperature drying oven at 100 °C for 3 h;

[0061] S2, weighing each component according to the above ratio, mixing the dried gold tailings and waste limestone powder, and then mixing and grinding them in a 5-kg ball mill with the model for 50 min at a rotational speed of 30 r / min to obtain a ground material;

[0062] S3, putting the above ground material into a muffle furnace with the model SX2-12-12, heating it to 800 °C at a rate of 20 °C / min, calcining for 150 min, immediately closing the muffle furnace after the calcination is completed, and waiting for the temperature in the muffle furnace cavity to cool naturally to 25 °C to obtain a calcined material;

[0063] S4, mixing the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain a performance regulator;

[0064] S5, mixing the above calcined material, gypsum tailings, and glauberite tailings evenly, spraying the above performance regulator on the mixed material, and then transferring the material to a 5-kg ball mill with the model for grinding for 30 min at a rotational speed of 30 r / min to obtain the gold tailings-based auxiliary cementitious material.

[0065] Example 2

[0066] An embodiment of the present invention provides a gold tailings-based auxiliary cementitious material, which comprises the following raw materials in parts by mass: 70 parts of gold tailings, 12 parts of waste limestone powder, 10 parts of gypsum tailings, 8 parts of glauberite tailings, and 0.5 part of a performance regulator;

[0067] Among them, the performance regulator comprises the following components in mass percentage: 8% of diethanol monoisopropanolamine, 10% of sodium oleate, and 82% of absolute ethanol.

[0068] The preparation method of the above gold tailings-based auxiliary cementitious material comprises the following steps:

[0069] S1. Dry the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant-temperature drying oven at 110 °C for 2 h;

[0070] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill of model for 40 min at a rotational speed of 40 r / min to obtain the ground material;

[0071] S3. Put the above-ground material into a muffle furnace of model SX2-12-12, heat it up to 750 °C at a rate of 10 °C / min, and calcine it for 120 min. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the muffle furnace cavity to cool naturally to 25 °C to obtain the calcined material;

[0072] S4. Mix the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain the performance regulator;

[0073] S5. After mixing the above calcined material, gypsum tailings, and glauberite tailings evenly, spray the above performance regulator on the mixed material, and then transfer the material to a 5-kg ball mill of model and grind it for 20 min at a rotational speed of 40 r / min to obtain the gold tailings-based auxiliary cementitious material.

[0074] Example 3

[0075] The present invention provides a gold tailings-based auxiliary cementitious material, which comprises the following raw materials in parts by mass: 60 parts of gold tailings, 20 parts of waste limestone powder, 15 parts of gypsum tailings, 5 parts of glauberite tailings, and 0.7 part of performance regulator;

[0076] Among them, the performance regulator comprises the following components in mass percentage: 5% of diethanol monoisopropanolamine, 20% of sodium oleate, and 75% of absolute ethanol.

[0077] The preparation method of the above gold tailings-based auxiliary cementitious material comprises the following steps:

[0078] S1. Dry the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant-temperature drying oven at 100 °C for 2 h;

[0079] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill of model for 30 min at a rotational speed of 45 r / min to obtain the ground material;

[0080] S3. Put the above-ground abrasive materials into a muffle furnace of model SX2-12-12, heat it up to 700 °C at a rate of 12 °C / min, calcine for 140 min. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the muffle furnace cavity to cool naturally to 25 °C to obtain the calcined materials.

[0081] S4. Mix the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain a performance regulator.

[0082] S5. After mixing the above-mentioned calcined materials, gypsum tailings, and glauberite tailings evenly, spray the above-mentioned performance regulator on the mixed materials, and then transfer the materials to a 5-kg ball mill of model and grind for 25 min at a rotational speed of 35 r / min to obtain the gold tailings-based auxiliary cementitious material.

[0083] Example 4

[0084] An embodiment of the present invention provides a gold tailings-based auxiliary cementitious material, which includes the following raw materials in parts by mass: 70 parts of gold tailings, 14 parts of waste limestone powder, 9 parts of gypsum tailings, 7 parts of glauberite tailings, and 0.6 part of performance regulator.

[0085] Among them, the performance regulator includes the following components in mass percentage: 12% of diethanol monoisopropanolamine, 10% of sodium oleate, and 78% of absolute ethanol.

[0086] The preparation method of the above gold tailings-based auxiliary cementitious material includes the following steps:

[0087] S1. Dry the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant-temperature drying oven at 110 °C for 3 h.

[0088] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill of model for 50 min at a rotational speed of 35 r / min to obtain the ground abrasive materials.

[0089] S3. Put the above-ground abrasive materials into a muffle furnace of model SX2-12-12, heat it up to 780 °C at a rate of 13 °C / min, calcine for 160 min. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the muffle furnace cavity to cool naturally to 25 °C to obtain the calcined materials.

[0090] S4. Mix the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain a performance regulator.

[0091] S5. After mixing the above-mentioned calcined materials, gypsum tailings, and glauberite tailings evenly, spray the above-mentioned performance regulator on the mixed materials, and then transfer the materials to a model Grind in a 5 kg ball mill for 20 min at a rotational speed of 45 r / min to obtain a gold tailings-based supplementary cementitious material.

[0092] Example 5

[0093] An embodiment of the present invention provides a gold tailings-based supplementary cementitious material, comprising raw materials in the following mass fractions: 65 parts of gold tailings, 5 parts of waste limestone powder, 5 parts of gypsum tailings, 10 parts of glauberite tailings, and 1 part of a performance regulator;

[0094] Among them, the performance regulator comprises components in the following mass percentages: 15% of diethanol monoisopropanolamine, 15% of sodium oleate, and 70% of absolute ethanol.

[0095] The preparation method of the above gold tailings-based supplementary cementitious material comprises the following steps:

[0096] S1, Dry the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant temperature drying oven at 110 °C for 2.5 h;

[0097] S2, Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5 kg ball mill of model for 45 min at a rotational speed of 40 r / min to obtain ground materials;

[0098] S3, Put the above ground materials into a muffle furnace of model SX2-12-12, heat it to 720 °C at a rate of 11 °C / min, calcine for 180 min. Immediately turn off the muffle furnace after the calcination ends, and wait for the temperature in the muffle furnace cavity to cool naturally to 25 °C to obtain calcined materials;

[0099] S4, Mix the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain a performance regulator;

[0100] S5, After mixing the above calcined materials, gypsum tailings, and glauberite tailings evenly, spray the above performance regulator on the mixed materials, and then transfer the materials to a 5 kg ball mill of model and grind for 25 min at a rotational speed of 40 r / min to obtain a gold tailings-based supplementary cementitious material.

[0101] Comparative Example 1

[0102] This comparative example provides a gold tailings-based supplementary cementitious material, whose raw material composition is the same as that of Example 2, except that the waste limestone powder in Example 2 is replaced with an equal amount of quicklime powder, and the specific formula is:

[0103] The gold tailings-based auxiliary cementitious material comprises raw materials in the following parts by mass: 70 parts of gold tailings, 12 parts of quicklime powder, 10 parts of gypsum tailings, 8 parts of glauberite tailings and 0.5 part of performance regulator;

[0104] Among them, the performance regulator comprises components in the following mass percentages: 8% of diethanol monoisopropanolamine, 10% of sodium oleate and 82% of absolute ethanol.

[0105] The gold tailings-based auxiliary cementitious material is prepared by exactly the same method as in Example 2, which will not be elaborated here.

[0106] Comparative Example 2

[0107] This comparative example provides a gold tailings-based auxiliary cementitious material, whose raw material composition is the same as that in Example 2, except that the gypsum tailings in Example 2 are replaced with an equal amount of phosphogypsum. The specific formula is as follows:

[0108] The gold tailings-based auxiliary cementitious material comprises raw materials in the following parts by mass: 70 parts of gold tailings, 12 parts of waste limestone powder, 10 parts of phosphogypsum, 8 parts of glauberite tailings and 0.5 part of performance regulator;

[0109] Among them, the performance regulator comprises components in the following mass percentages: 8% of diethanol monoisopropanolamine, 10% of sodium oleate and 82% of absolute ethanol.

[0110] The gold tailings-based auxiliary cementitious material is prepared by exactly the same method as in Example 2, which will not be elaborated here.

[0111] Comparative Example 3

[0112] This comparative example provides a gold tailings-based auxiliary cementitious material, whose raw material composition is exactly the same as that in Example 2, except that the calcination temperature in the preparation process of Example 2 is replaced with 600 °C. The specific steps are as follows:

[0113] The gold tailings-based auxiliary cementitious material comprises raw materials in the following parts by mass: 70 parts of gold tailings, 12 parts of waste limestone powder, 10 parts of gypsum tailings, 8 parts of glauberite tailings and 0.5 part of performance regulator;

[0114] Among them, the performance regulator comprises components in the following mass percentages: 8% of diethanol monoisopropanolamine, 10% of sodium oleate and 82 % of absolute ethanol.

[0115] The preparation method of the above gold tailings-based auxiliary cementitious material comprises the following steps:

[0116] S1, drying the gold tailings, waste limestone powder, gypsum tailings and glauberite tailings in a constant temperature drying oven at 110 °C for 2 h;

[0117] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill with the model number for 40 minutes at a rotational speed of 40 r / min to obtain the ground material.

[0118] S3. Put the above ground material into a muffle furnace with the model number SX2-12-12, heat it up to 600 °C at a rate of 10 °C / min, and calcine for 120 minutes. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the furnace cavity of the muffle furnace to cool naturally to 25 °C to obtain the calcined material.

[0119] S4. Mix the weighed diethanol monoisopropanolamine, sodium oleate, and absolute ethanol evenly to obtain the performance regulator.

[0120] S5. After mixing the above calcined material, gypsum tailings, and glauberite tailings evenly, spray the above performance regulator on the mixed material, and then transfer the material to a 5-kg ball mill with the model number and grind for 20 minutes at a rotational speed of 40 r / min to obtain the gold tailings-based supplementary cementitious material.

[0121] Comparative Example 4

[0122] This comparative example provides a gold tailings-based supplementary cementitious material, whose raw material composition is exactly the same as that in Example 2, except that the calcination time in the preparation process of Example 2 is replaced with 80 minutes. The specific steps are as follows:

[0123] The gold tailings-based supplementary cementitious material includes the following raw materials in parts by mass: 70 parts of gold tailings, 12 parts of waste limestone powder, 10 parts of gypsum tailings, 8 parts of glauberite tailings, and 0.5 part of performance regulator.

[0124] Among them, the performance regulator includes the following components in mass percentage: 8% of diethanol monoisopropanolamine, 10% of sodium oleate, and 82% of absolute ethanol.

[0125] The preparation method of the above gold tailings-based supplementary cementitious material includes the following steps:

[0126] S1. Dry the gold tailings, waste limestone powder, gypsum tailings, and glauberite tailings in a constant-temperature drying oven at 110 °C for 2 hours.

[0127] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill with the model number for 40 minutes at a rotational speed of 40 r / min to obtain the ground material.

[0128] S3. Put the above-mentioned ground materials into a muffle furnace of model SX2-12-12, heat it up to 750 °C at a rate of 10 °C / min, calcine for 80 min. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the furnace cavity of the muffle furnace to cool naturally to 25 °C to obtain the calcined materials;

[0129] S4. Mix the weighed diethanol monoisopropanolamine, sodium oleate and absolute ethanol evenly to obtain a performance regulator;

[0130] S5. After mixing the above-mentioned calcined materials, gypsum tailings and glauberite tailings evenly, spray the above-mentioned performance regulator on the mixed materials, and then transfer the materials to a 5-kg ball mill of the model for grinding for 20 min, and the rotation speed of the ball mill is 40 r / min to obtain the gold tailings-based auxiliary cementitious material.

[0131] Comparative Example 5

[0132] This comparative example provides a gold tailings-based cementitious material. The only difference from Example 2 is that the diethanol monoisopropanolamine in the performance regulator is replaced with an equal amount of triethanolamine. The specific formula is as follows:

[0133] 70 parts of gold tailings, 12 parts of waste limestone powder, 10 parts of gypsum tailings, 8 parts of glauberite tailings and 0.5 part of performance regulator;

[0134] Among them, the performance regulator includes components with the following mass percentages: 8% of triethanolamine, 10% of sodium oleate and 82% of absolute ethanol.

[0135] The preparation method of the above-mentioned gold tailings-based auxiliary cementitious material includes the following steps:

[0136] S1. Dry the gold tailings, waste limestone powder, gypsum tailings and glauberite tailings in a constant temperature drying oven at 110 °C for 2 h;

[0137] S2. Weigh each component according to the above ratio. After mixing the dried gold tailings and waste limestone powder, mix and grind them in a 5-kg ball mill of the model for 40 min, and the rotation speed of the ball mill is 40 r / min to obtain the ground materials;

[0138] S3. Put the above-mentioned ground materials into a muffle furnace of model SX2-12-12, heat it up to 750 °C at a rate of 10 °C / min, calcine for 120 min. Immediately turn off the muffle furnace after the calcination is completed, and wait for the temperature in the furnace cavity of the muffle furnace to cool naturally to 25 °C to obtain the calcined materials;

[0139] S4. Mix the weighed triethanolamine, sodium oleate and absolute ethanol evenly to obtain a performance regulator;

[0140] S5, after the calcined material is evenly mixed with the gypsum tailings and the calcium sulfate tailings, the performance regulator is sprayed on the mixed material, and then the material is transferred to the The gold tailings-based auxiliary gelling material was obtained by grinding the gold tailings-based auxiliary gelling material in a 5kg ball mill for 20 minutes at a speed of 40r / min.

[0141] Performance Testing

[0142] In order to demonstrate the effects of the auxiliary gelling materials prepared in the examples and comparative examples of the present invention, the performance tests of the auxiliary gelling materials in Examples 1 to 5 and Comparative Examples 1 to 5 were conducted as follows:

[0143] 450 g of Portland cement and 1350 g of standard mortar were mixed evenly using a JJ-5 mortar mixer at a water-binder ratio of 0.5 as a reference group.

[0144] Mortar specimens were prepared using the supplementary cementitious materials prepared in Examples 1-5 and Comparative Examples 1-5, replacing 30% of the Portland cement. This consisted of 315g of Portland cement, 135g of supplementary cementitious materials, and 1350g of standard mortar. The water-cement ratio was adjusted to maintain the fluidity of the fresh cement mortar above 180mm. The freshly mixed mortar was placed in a 40mm x 40mm x 160mm triple mold and compacted using a cement mortar vibrator. After curing for 24 hours under standard conditions, the specimens were removed from the triple mold and then cured in a standard room at 20±2°C and a relative humidity greater than 95% to the specified age.

[0145] The compressive strength of mortar specimens of a specified age was tested in accordance with GB / T 17671-2021 “Test methods for cement—Determination of strength (ISO method)”. The strength activity index of the auxiliary cementitious material was calculated by the following formula. The strength activity indexes of the auxiliary cementitious materials prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0146] K=R1 / R2×100%

[0147] Wherein, K is the strength activity index (%); R1 is the compressive strength of the mortar block with the auxiliary gel material added (MPa); R2 is the compressive strength of the pure cement mortar block (MPa).

[0148] Table 1 Intensity activity index of Examples and Comparative Examples

[0149]

[0150] As can be seen from the above table, the strength activity indices of the auxiliary cementitious materials prepared in the embodiments of the present invention at 3 days, 7 days, and 28 days are all higher than those of the control group. In particular, the early strength activity indices of the auxiliary cementitious materials prepared in the embodiments at 3 days all reach more than 70%, meeting the standard requirements for cement auxiliary cementitious materials. Among them, the strength activity index of the auxiliary cementitious material in Embodiment 2 is the highest.

[0151] The XRD patterns of the gold tailings raw materials and the gold tailings-based auxiliary cementitious materials prepared in Embodiment 2 are as shown in Figures 1 to Figure 2 as follows. Through comparative analysis, it is found that the XRD pattern of the gold tailings-based auxiliary cementitious material has changed significantly compared with that of the gold tailings raw material. In the XRD pattern of the gold tailings-based auxiliary cementitious material, the characteristic peaks of muscovite, albite, and microcline disappear, indicating that through coupled activation, the crystal structures of muscovite, albite, and microcline are destroyed and transformed into amorphous products. The characteristic peak of quartz is significantly weakened, indicating that after coupled activation, the crystallinity of quartz in the gold tailings decreases and the crystal structure has defects. At the same time, an obvious broad "small bump" appears in the range of 2θ = 20° - 35° in the XRD pattern of the gold tailings-based auxiliary cementitious material, which confirms the formation of amorphous products.

[0152] Muscovite is a layered aluminosilicate mineral containing structural water inside. Under the action of mechanical grinding, internal defects appear in it, and the crystal structure changes to a metastable state. Under high-temperature calcination, muscovite undergoes a dehydroxylation reaction and further decomposes to release KAlSi3O8 and Al2O3. The KAlSi3O8 and Al2O3 released by the decomposition of muscovite enter the melt, reducing the minimum melting temperature of the quartz and feldspar mixture and promoting the decomposition of quartz and feldspar to release reactive silicon, reactive aluminum, and soluble salts, thereby improving the reaction activity of the gold tailings. Under the conditions of mechanical grinding and high-temperature calcination, part of the limestone decomposes to form CaO and polar CO2. The polar CO2 will have a strong erosion effect on the crystalline phases in the gold tailings, which is beneficial to reducing the crystallinity of the mineral phases in the gold tailings.

[0153] Figure 3 and Figure 4XRD patterns of the hardened paste of cement paste incorporating 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at 3 d and 28 d ages. The main hydration products of the cement paste incorporating the gold tailings-based supplementary cementitious material are calcium hydroxide (CH), C-S-H gel, calcium aluminate hydrate (CAH), ettringite (AFt), monosulfate calcium aluminate hydrate (Ms), monocarbon calcium aluminate hydrate (Mc), and hemicarbon calcium aluminate hydrate (Hc). With the increase of the hydration age, the characteristic peaks of Ms and CAH are significantly enhanced, indicating that in the alkaline environment generated by cement hydration, the siloxane polymerization chains in the gold tailings-based supplementary cementitious material are further damaged, accelerating the dissolution of reactive aluminum, reactive silicon, and soluble salts, and reacting with Ca 2+ , OH - to form C-S-H gel, CAH, and Ms. The characteristic peaks of Mc and Hc are also further enhanced because CaCO3 in limestone will react with the unstable calcium aluminate hydrate and monosulfate calcium aluminate hydrate (Ms) generated by the hydration of the cementitious material to form stable monocarbon calcium aluminate hydrate (Mc) and hemicarbon calcium aluminate hydrate (Hc), stabilizing the content of ettringite (AFt) in the cementitious system, thereby making the hardened structure of the cementitious system more stable, reducing the porosity of the structure, making the paste structure more dense, and thus improving the mechanical properties of the material. In the presence of gypsum, SO4 2- can react with reactive aluminum and calcium aluminate hydrate to form ettringite (AFt), reduce the conversion ratio of AFt to Ms, improve the density of the structure, and at the same time reduce the concentrations of Ca 2+ and Al 3+ in the liquid phase, promoting the hydration of activated gold tailings powder, and thus improving the early strength of the material. Diethanol monoisopropanolamine can increase the hydration rate of C3A and C4AF, accelerate the formation of microcrystalline Ca(OH)2 in the early stage, promote the hydration of activated gold tailings powder, and enhance the later hydration degree of C2S, contributing to the enhancement of the early and later strengths of the mortar specimens.

[0154] Figures 5 to 8 are SEM images of the hardened paste of cement paste incorporating 30% of the gold tailings-based supplementary cementitious material prepared in Example 2 at different magnifications at 3 d and 28 d ages. It can be seen from Figure 5 and Figure 6 that at the hydration age of 3 d, a large number of hydration products appear inside the cement paste, and a large amount of AFt appears on the surface of the gold tailings particles, and the poorly crystalline C-S-H gel is distributed therein, connecting the hydration products and the unreacted particles into a whole. It can be seen from Figure 7 and Figure 8 that at the hydration age of 28 d, the hydration products crisscross, forming a tight microstructure inside the hardened paste, thus ensuring the development of the paste strength.

[0155] In summary, the present invention uses gold tailings, waste limestone powder, gypsum tailings and glauberite tailings as raw materials, and diethanol monoisopropanolamine and sodium oleate as performance regulators to prepare an auxiliary cementitious material, which not only solves the problem of difficult treatment of industrial solid waste, but also prepares an auxiliary cementitious material with excellent strength activity index, realizes the resource utilization of industrial solid waste, saves the consumption of cement, and conforms to the green, low-carbon and sustainable development strategy.

[0156] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A gold tailings-based auxiliary cementitious material, characterized in that, It consists of the following raw material components by mass parts: 60 to 80 parts of gold tailings, 5 to 20 parts of waste limestone powder, 5 to 15 parts of gypsum tailings, 5 to 10 parts of glauberite tailings, and 0.5 to 1 part of performance regulator; Among them, the performance regulator consists of the following components by mass percentage: 5% to 15% of diethanol monoisopropanolamine, 10% to 20% of sodium oleate, and 70% to 85% of alcohol solvent; The gold tailings-based auxiliary cementitious material is prepared by the following method: S1, Weigh each component according to the designed ratio, mix the weighed gold tailings and waste limestone powder evenly, and ball mill to obtain the ground material; S2, Calcinate the ground material at 700°C to 800°C for 120 min to 180 min, and cool to obtain the calcined material; S3, Mix the calcined material evenly with the weighed gypsum tailings and glauberite tailings, spray the performance regulator onto the mixed material, and ball mill to obtain the gold tailings-based auxiliary cementitious material.

2. The gold tailings-based auxiliary cementitious material according to claim 1, wherein, The alcohol solvent is anhydrous ethanol.

3. The gold tailings-based auxiliary cementitious material according to claim 1, wherein, The particle size of the gold tailings is 1 μm to 1 mm; and / or The particle size of the waste limestone powder is 0.002 mm to 0.006 mm.

4. A preparation method of a gold tailings-based auxiliary cementitious material, characterized in that, It includes the following steps: S1, Weigh each component according to the designed ratio of the gold tailings-based auxiliary cementitious material described in any one of claims 1 to 3, mix the weighed gold tailings and waste limestone powder evenly, and ball mill to obtain the ground material; S2, Calcinate the ground material at 700°C to 800°C for 120 min to 180 min, and cool to obtain the calcined material; S3, Mix the calcined material evenly with the weighed gypsum tailings and glauberite tailings, spray the performance regulator onto the mixed material, and ball mill to obtain the gold tailings-based auxiliary cementitious material.

5. The preparation method of the gold tailings-based auxiliary cementitious material according to claim 4, characterized in that, In S1, the rotation speed of the ball mill is 30 r / min to 45 r / min, and the ball milling time is 30 min to 60 min; and / or In S2, heat up to 700°C to 800°C in a programmed heating manner, and the programmed heating rate is 10°C / min to 20°C / min; and / or In S3, the rotation speed of the ball mill is 30 r / min to 45 r / min, and the ball milling time is 10 min to 30 min.

6. A gelling material, characterized in that, It includes the gold tailings-based auxiliary cementitious material described in any one of claims 1 to 3 and cement.

7. The application of the gold tailings-based auxiliary cementitious material described in any one of claims 1 to 3 or the cementitious material described in claim 6 in concrete and / or mortar.

8. A kind of concrete, characterized in that, It includes the gold tailings-based auxiliary cementitious material described in any one of claims 1 to 3 or the cementitious material described in claim 6.

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