Superfine Unclassified Tailings Filling Paste Water Reducing Agent and Its Preparation Method and Application

Abstract

The present invention discloses a superfine full-tailings filling paste water reducer and its preparation method and application. The water reducer comprises the following raw material components by weight: 60 parts to 120 parts of mother liquor, 0.08 parts to 0.12 parts of hydroxypropyl methylcellulose with a viscosity of 60,000 MPa·s to 80,000 MPa·s, and the mother liquor is prepared using ethylene glycol mono vinyl polyethylene glycol ether as the large monomer. The superfine full-tailings filling paste water reducer of the present invention has the advantages of short synthesis time, low reaction temperature, good economic benefits, good applicability, good operability, and can significantly improve the compressive strength and stability of the filling body. It is a new water reducer with excellent performance, can be widely used in superfine tailings filling, can effectively fill superfine tailings under the action of the water reducer, has high use value and good application prospects, and is of great significance for realizing cost reduction and efficiency increase, as well as for green sustainable economic development.

Description

Technical Field

[0001] The present invention belongs to the field of mine tailings filling, and relates to a superfine full-tailings filling paste water reducer, a preparation method thereof and an application thereof. Background Art

[0002] Underground mining is widely used in the excavation and extraction of valuable mineral resources. However, this inevitably generates a large amount of waste tailings. At the same time, these waste minerals are usually stacked at the surface to build dams to intercept the valley mouths by low-cost methods, which not only easily brings huge safety hazards (such as tailing dam landslides, earthquakes, etc.), but also has an adverse impact on the environment (such as heavy metal leaching and groundwater pollution, etc.). In this regard, the technology of filling goafs with full tailings can effectively solve the above problems. While alleviating the problem of tailings discharge and storage, it can also fully realize the comprehensive utilization of waste ore resources, and is one of the important supporting technologies for green mine construction.

[0003] According to the classification of filling tailings in "Cemented Filling Theory and Engineering of Metal Mines", it is generally considered that tailings with a particle size fraction of -74μm greater than 80%, a particle size fraction of -19μm greater than 50% and an average particle size less than 19μm belong to superfine tailings. However, when using the technology of filling goafs with full tailings to treat superfine tailings, the filling effect is usually poor. This is not only because it is difficult to thicken and dehydrate superfine tailing slurries, but also because due to the relatively large specific surface area, the filling materials made of superfine tailings often have high viscosity, poor water retention and low strength of the hardened filling body, which seriously restricts the popularization and application of this technology. For this reason, domestic and foreign scholars often pre-classify or deslime superfine tailings, fill the obtained coarse-grained tailings into the underground goafs, and return the fine-grained tailings to the tailing pond for storage through pipelines. This not only significantly reduces the utilization rate of tailings, but also seriously hinders the construction of green tailing-free mines. In particular, in recent years, with the reduction of high-quality mineral resources, in order to ensure sufficient metal recovery rate, superfine grinding technology has been widely used to process low-grade complex ores, resulting in the generation of a large amount of superfine tailings. Therefore, how to effectively treat superfine tailings is an urgent problem to be overcome at present.

[0004] Water reducing agents are essential admixtures in construction concrete, which can significantly improve the fluidity of concrete, control the setting or hardening time, enhance the strength of concrete and improve the workability, etc. It is also considered an effective method to increase the concentration, workability and filling body strength of ultra-fine tailings filling slurry. Currently, common water reducing agents include naphthalene-based water reducing agents, melamine water reducing agents, lignosulfonate water reducing agents, polycarboxylate water reducing agents, etc. Among them, polycarboxylate water reducing agents have the advantages of low dosage, high water reduction rate, small slump loss and good cement applicability, and are currently the most widely used water reducing agents. However, the commonly used polycarboxylate water reducing agents on the market are usually synthesized from macromonomers such as methyl allyl poly(ethylene glycol) ether (HPEG) and isopentenyl poly(ethylene glycol) ether (TPEG). These raw materials have low synthesis efficiency and high reaction temperature, resulting in relatively high synthesis costs, which not only increases the tailings filling cost, but also is not conducive to the green, sustainable and economic development of mines. However, among the existing water reducing agents for tailings filling, there is no application research suitable for various types of ultra-fine whole tailings and no low-cost water reducing agent synthesis method. According to the previous research of the inventors of this application, the use of existing polycarboxylate water reducing agents synthesized from HPEG macromonomers and TPEG macromonomers is often accompanied by problems such as high dosage and early strength loss of the filling body. In particular, due to the relatively high content of ultra-fine particle size in ultra-fine tailings, it is difficult for existing polycarboxylate water reducing agents to effectively reduce the cement dosage in the whole tailings filling paste, seriously affecting the tailings treatment efficiency and being not conducive to reducing the material cost and tailings treatment cost. The existence of the above defects indicates that the existing polycarboxylate water reducing agents may not be suitable for treating ultra-fine whole tailings. Therefore, developing a new type of water reducing agent with short synthesis time, low reaction temperature, good economic benefits, good particle size applicability, good operability, and capable of significantly improving the compressive strength and stability of the filling body is of great significance for effectively improving the filling effect of ultra-fine tailings, achieving cost reduction and efficiency increase, and improving the applicability to mine tailings, cementitious materials and ratios. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a water reducing agent for ultra-fine whole tailings filling paste, its preparation method and application, which have short synthesis time, low reaction temperature, good economic benefits, good applicability, good operability, and can significantly improve the compressive strength and stability of the filling body.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A water reducing agent for ultra-fine whole tailings filling paste includes the following raw material components by weight:

[0008] Mother liquor: 60 parts to 120 parts,

[0009] Hydroxypropyl methylcellulose: 0.08 parts to 0.12 parts;

[0010] The mother liquor is prepared using ethylene glycol mono vinyl polyethylene glycol ether as the large monomer; the viscosity of the hydroxypropyl methylcellulose is 60,000 MPa·s to 80,000 MPa·s.

[0011] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the raw material components of the superfine whole-tailings filling paste water reducer are composed of a mother liquor and hydroxypropyl methylcellulose.

[0012] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the mother liquor is prepared using ethylene glycol mono vinyl polyethylene glycol ether, acrylic acid, a chain transfer agent, an oxidizing agent, and a reducing agent as raw materials.

[0013] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the acid-ether ratio of the acrylic acid to the ethylene glycol mono vinyl polyethylene glycol ether is 5.5 to 8.5∶0.8 to 1.2.

[0014] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the dosage of the chain transfer agent is 0.6% to 1% of the mass of the ethylene glycol mono vinyl polyethylene glycol ether.

[0015] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the dosage of the oxidizing agent is 1.2% to 1.8% of the mass of the ethylene glycol mono vinyl polyethylene glycol ether.

[0016] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the dosage of the reducing agent is 0.12% to 0.28% of the mass of the ethylene glycol mono vinyl polyethylene glycol ether.

[0017] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the chain transfer agent is at least one of mercaptoacetic acid, isopropanol, and mercaptoethanol.

[0018] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the oxidizing agent is at least one of ammonium persulfate, hydrogen peroxide, and potassium peroxide.

[0019] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the reducing agent is at least one of L-ascorbic acid, sodium sulfite, ferrous sulfate, and sodium bisulfite.

[0020] For the above-mentioned superfine whole-tailings filling paste water reducer, further improved, the preparation method of the mother liquor includes the following steps:

[0021] (1) Prepare solution A from acrylic acid; prepare solution B from the chain transfer agent and the reducing agent;

[0022] (2) Mix ethylene glycol mono vinyl polyethylene glycol ether and the oxidizing agent and stir, while dropping solution A and solution B simultaneously to obtain the mother liquor.

[0023] For the above-mentioned superfine all-tailings filling paste water reducer, for further improvement, in step (1), the liquid A is prepared by mixing acrylic acid and water; the liquid B is prepared by the following method: mixing a chain transfer agent, a reducing agent and water, and ultrasonicating for 5 min to 10 min to obtain the liquid B.

[0024] For the above-mentioned superfine all-tailings filling paste water reducer, for further improvement, in step (2), the stirring is carried out under the condition that the temperature is 20°C to 40°C; the stirring time is 1 min to 3 min; the dropping time of the liquid A and the liquid B is controlled within 0.5 h to 3 h.

[0025] As a general technical concept, the present invention also provides a preparation method of the above-mentioned superfine all-tailings filling paste water reducer, including the following steps: mixing a mother liquor and hydroxypropyl methylcellulose to obtain the superfine all-tailings filling paste water reducer.

[0026] As a general technical concept, the present invention also provides an application of the above-mentioned superfine all-tailings filling paste water reducer or the superfine all-tailings filling paste water reducer prepared by the above-mentioned preparation method in treating superfine all-tailings filling paste.

[0027] For the above-mentioned application, for further improvement, the application includes the following steps: mixing the superfine all-tailings filling paste water reducer and the superfine all-tailings filling paste to complete the treatment of the superfine all-tailings filling paste; the dosage of the superfine all-tailings filling paste water reducer is 0.06% to 0.08% of the total mass of the superfine all-tailings filling paste.

[0028] For the above-mentioned application, for further improvement, the superfine all-tailings filling paste is composed of superfine all-tailings, cement and water; the content of the -19μm particle size fraction in the superfine all-tailings > 50%, the content of the -74μm particle size fraction > 80%, D 50 <19μm.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] (1) Aiming at the defects of existing polycarboxylate water reducers, such as long synthesis time, high reaction temperature, poor economic efficiency, poor applicability, poor operability, and difficulty in effectively improving the compressive strength and stability of filling bodies, the present invention provides a superfine full-tailings filling paste water reducer. Using ethylene glycol mono-vinyl polyethylene glycol ether as the macromonomer, which has an unsaturated C═C bond and forms a p-π conjugate bond with the O atom, causing a large shift in the double-bond electron cloud, resulting in high polymerization activity. Therefore, using ethylene glycol mono-vinyl polyethylene glycol ether (EPEG) as the raw material, the water reducer of the present invention has the advantages of short synthesis time, low reaction temperature, and good economic efficiency. At the same time, the mother liquor prepared with ethylene glycol mono-vinyl polyethylene glycol ether (EPEG) as the macromonomer can improve the fluidity of the filling paste, reduce the water consumption, and reduce the cement dosage, thereby reducing the cost. On this basis, by adding hydroxypropyl methylcellulose and optimizing the dosage of hydroxypropyl methylcellulose, the bridging effect between hydroxypropyl methylcellulose and the matrix can be utilized to prevent the formation of internal voids and cracks in the filling body or change their propagation direction. At the same time, hydroxypropyl methylcellulose also promotes the hydration of the cementitious material and increases the bonding strength. On the one hand, it can effectively improve the uniaxial compressive strength and stability of the filling paste, which is beneficial to improving the compressive strength of the filling paste. On the other hand, according to the particle size distribution characteristics of superfine full-tailings, by optimizing the viscosity of hydroxypropyl methylcellulose to be 60,000 MPa·s to 80,000 MPa·s, the cementing performance of the water reducer can be effectively improved, enabling the water reducer to effectively bond superfine full-tailings with different particle sizes together. Especially when the content of superfine particle size in the superfine tailings is relatively high, it can also ensure that the filling paste has sufficient cementing performance, and at the same time, it can effectively avoid the adverse impact on the strength of the hardened paste due to too high viscosity of hydroxypropyl methylcellulose. In addition, when the dosage of hydroxypropyl methylcellulose is too high, it will significantly increase the viscosity of the paste and reduce its fluidity, increasing the construction difficulty; while when the dosage of hydroxypropyl methylcellulose is too low, the small amount of hydroxypropyl methylcellulose is not enough to prevent the formation of internal voids in the filling body, thus affecting the uniaxial compressive strength of the filling body. Compared with conventional polycarboxylate water reducers, the superfine full-tailings filling paste water reducer of the present invention has the following advantages: (a) It requires a short synthesis time, low reaction temperature, and has good economic efficiency. (b) The synthesis steps are simple, it is easily soluble in water, non-toxic and harmless, and is friendly to the environment and construction workers. (c) It can adapt to different types of superfine full-tailings, with strong versatility. (d) It can significantly increase the concentration of the superfine full-tailings filling paste, reduce the ash-sand ratio, improve the fluidity and strength, and improve the operability under the condition of greatly reducing the water consumption. (e) It can reduce the cement dosage in the superfine full-tailings filling paste, increase the consumption of tailings, and maintain or improve the slurry performance, which helps to save material costs and tailings treatment costs.The superfine full-tailings filling paste water reducer of the present invention has the advantages of short synthesis time, low reaction temperature, good economic benefits, good applicability, good operability, and can significantly improve the compressive strength and stability of the filling body. It is a new water reducer with excellent performance, can be widely used in superfine tailings filling, can effectively fill superfine tailings, has high use value and good application prospects, and is of great significance for realizing cost reduction and efficiency increase, as well as for green sustainable economic development.

[0031] (2) The present invention also provides an application of the superfine full-tailings filling paste water reducer in treating the superfine full-tailings filling paste. Specifically: mixing the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste, under the action of the water reducer, it can effectively improve the spread and compressive strength of the filling body under the conditions of high solid concentration and low ash-sand ratio, which is of great significance for realizing the effective treatment of superfine full-tailings.

[0032] (3) In the present invention, by optimizing the dosage of the superfine full-tailings filling paste water reducer to be 0.06% - 0.08% of the total mass of the superfine full-tailings filling paste, it is beneficial to improve the fluidity of the filling paste, and can avoid problems such as increased bubbles, increased viscosity, decreased strength, and extended setting time caused by too high dosage, as well as problems such as insufficient fluidity, construction difficulties, and poor strength caused by too low dosage, and can reduce material costs, achieving double optimization of performance and economic benefits. Description of the Drawings

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0034] Figure 1 It is the particle size distribution diagram of the superfine full-tailings in Embodiment 1 of the present invention.

[0035] Figure 2 It is the state diagram of the superfine full-tailings filling paste without adding water reducer in Embodiment 1 of the present invention.

[0036] Figure 3 It is the state diagram of the superfine full-tailings filling paste after adding water reducer in Embodiment 1 of the present invention. Detailed Embodiments

[0037] The present invention will be further described below in conjunction with the drawings in the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0038] Embodiment 1

[0039] A superfine full-tailings filling paste water reducer includes the following raw material components by weight:

[0040] 60 parts of mother liquor,

[0041] 0.1 part of hydroxypropyl methylcellulose.

[0042] In this embodiment, the raw material components of the superfine full-tailings filling paste water reducer are composed of mother liquor and hydroxypropyl methylcellulose.

[0043] In this embodiment, the mother liquor used is prepared with ethylene glycol mono vinyl polyethylene glycol ether as the large monomer. Specifically: it is prepared with ethylene glycol mono vinyl polyethylene glycol ether (EPEG), acrylic acid (AA), chain transfer agent, oxidant and reductant as raw materials, wherein the chain transfer agent is thioglycolic acid (TGA), the oxidant is ammonium persulfate (APS), and the reductant is L-ascorbic acid (Vc).

[0044] In this embodiment, the preparation method of the mother liquor used includes the following steps:

[0045] (1) Prepare solution A from acrylic acid. Specifically: mix acrylic acid with appropriate amount of deionized water to prepare solution A. Prepare solution B from the chain transfer agent and the reductant. Specifically: mix thioglycolic acid, L-ascorbic acid with appropriate amount of deionized water, and ultrasonicate for 10 min to obtain solution B.

[0046] (2) Place ethylene glycol mono vinyl polyethylene glycol ether and ammonium persulfate in a beaker, stir in a constant temperature magnetic stirrer, control the temperature at 20 °C during the stirring process. After stirring for 1 min, simultaneously drip solution A and solution B using a constant flow pump, and control the dripping time within 1.5 h to obtain a yellow and thick mother liquor.

[0047] In this embodiment, during the preparation of the mother liquor, the acid-ether ratio of acrylic acid (AA) to ethylene glycol mono vinyl polyethylene glycol ether (EPEG) is 5.5∶1; the dosage of thioglycolic acid (TGA) is 0.6% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of ammonium persulfate (APS) is 1.5% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of L-ascorbic acid (Vc) is 0.2% of the mass of ethylene glycol mono vinyl polyethylene glycol ether.

[0048] In this embodiment, the viscosity of hydroxypropyl methylcellulose is 70000 MPa·s.

[0049] A preparation method of the above-mentioned superfine full-tailings filling paste water reducer includes the following steps: mix the mother liquor with hydroxypropyl methylcellulose to obtain the superfine full-tailings filling paste water reducer.

[0050] In this embodiment, the copolymerization synthesis formula of the superfine full-tailings filling paste water reducer is as follows:

[0051]

[0052] In the above formula, a and b respectively represent the molar ratios of two different monomers, and n represents the number of repeating units in the copolymer formed.

[0053] An application of the above-mentioned superfine full-tailings filling paste water reducer in treating superfine full-tailings filling paste is as follows: Mix the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste to complete the treatment of the superfine full-tailings filling paste, where the dosage of the superfine full-tailings filling paste water reducer is 0.08% of the total mass of the superfine full-tailings filling paste.

[0054] In this embodiment, the superfine full-tailings filling paste is composed of superfine full-tailings, cement and water. In Example 1, the content of the -19μm particle size fraction in the superfine full-tailings is 65%, the content of the -74μm particle size fraction is 84%, and D 50 is 10μm, as Figure 1 shown.

[0055] The filling paste after adding the water reducer in Example 1 was tested, and the results are shown in Table 1.

[0056] Figure 2 This is the state diagram of the superfine full-tailings filling paste (blank sample) without adding the water reducer in Example 1 of the present invention.

[0057] Figure 3 This is the state diagram of the superfine full-tailings filling paste after adding the water reducer in Example 1 of the present invention.

[0058] Comparative Example 1

[0059] A water reducer, which is basically the same as Example 1, except that: hydroxypropyl methylcellulose is not added in Comparative Example 1.

[0060] Comparative Example 2

[0061] A water reducer, which is basically the same as Example 1, except that: in Comparative Example 2, methyl allyl polyethylene glycol ether (HPEG) is used instead of ethylene glycol mono vinyl polyethylene glycol ether (EPEG).

[0062] Comparative Example 3

[0063] A water reducer, which is basically the same as Example 1, except that: in Comparative Example 3, isopentenyl polyethylene glycol ether (TPEG) is used instead of ethylene glycol mono vinyl polyethylene glycol ether (EPEG).

[0064] Comparative Example 4

[0065] A preparation method of a polycarboxylate water reducer. By mass, 380 parts of ethylene glycol mono vinyl polyethylene glycol ether macromonomer and 8 parts of methacrylamide are put into a reactor, and water is added and stirred. The reaction is controlled at 25 °C until the monomers are completely dissolved. Then 2.4 parts of ammonium persulfate are added, and after stirring for 10 min, solution I and solution II are simultaneously added dropwise. The dropping time is 2 h, and it is kept warm at 25 °C for 2 h. An alkali solution is added to neutralize to pH 6 - 7 to obtain the polycarboxylate water reducer. Among them, solution I is prepared by uniformly stirring 12 parts of vinyl acetate and 23 parts of acrylic acid with water, and solution II is prepared by uniformly stirring 1.4 parts of sodium sulfite and 1.0 part of mercaptoacetic acid with water.

[0066] Comparative Example 5

[0067] A water reducer is basically the same as that in Example 1, except that: in Comparative Example 5, the viscosity of hydroxypropyl methylcellulose is 40000 MPa·s.

[0068] Comparative Example 6

[0069] A water reducer is basically the same as that in Example 1, except that: in Comparative Example 6, the viscosity of hydroxypropyl methylcellulose is 90000 MPa·s.

[0070] The water reducers prepared in Comparative Examples 1 - 6 are used to treat ultra-fine full tailings filling paste. Except for the different water reducers, other conditions are the same as those in Example 1.

[0071] The filling paste added with the water reducer in Comparative Examples 1 - 6 is tested, and the results are shown in Table 1.

[0072] Table 1 Test results of the filling paste in Example 1 and Comparative Examples 1 - 5

[0073]

[0074] From Table 1 and Figure 2 、 Figure 3 it can be seen that compared with the blank sample, when the solid concentration is increased by 2% and the ash-sand ratio is reduced by about 14%, the spread of the paste obtained after adding the water reducer in Example 1 is increased by 79 mm (as Figure 2 and Figure 3 ), the 7-day compressive strength is increased by 0.76 MPa·s, and the 28-day compressive strength is increased by 1.04 MPa·s.

[0075] As can be seen from Table 1, compared with Comparative Example 1, Comparative Example 2, and Comparative Example 3, when the solid concentration and the ash-sand ratio are close, after adding the water reducer in Example 1, the slump of the obtained filling paste increased by 17 mm, 24 mm, and 31 mm respectively, the 7-day compressive strength increased by 1.11 MPa·s, 0.30 MPa·s, and 0.18 MPa·s respectively, and the 28-day compressive strength increased by 1.23 MPa·s, 0.34 MPa·s, and 0.28 MPa·s respectively.

[0076] As can be seen from Table 1, compared with Comparative Example 4, when the solid concentration and the ash-sand ratio are close, after adding the water reducer in Example 1, the slump of the obtained filling paste increased by 19 mm, the 7-day compressive strength increased by 0.85 MPa·s, and the 28-day compressive strength increased by 0.54 MPa·s. In addition, for the water reducer prepared in Example 1, the types of synthetic raw materials required are few, the steps are simple, and the synthesis time is greatly shortened.

[0077] As can be seen from Table 1, compared with Comparative Example 5 and 6, when the solid concentration and the ash-sand ratio are close, after adding the water reducer in Example 1, the slump of the obtained filling paste increased by 15 mm and 25 mm respectively, the 7-day compressive strength increased by 0.29 MPa·s and 0.17 MPa·s respectively, and the 28-day compressive strength increased by 0.42 MPa·s and 0.31 MPa·s respectively.

[0078] Example 2

[0079] A superfine full-tailings filling paste water reducer, comprising the following raw material components by weight:

[0080] Mother liquor: 60 parts,

[0081] Hydroxypropyl methylcellulose: 0.08 part.

[0082] In this example, the mother liquor used was prepared with ethylene glycol mono vinyl polyethylene glycol ether as the large monomer. Specifically, it was prepared with ethylene glycol mono vinyl polyethylene glycol ether (EPEG), acrylic acid (AA), a chain transfer agent, an oxidant, and a reducing agent as raw materials. Among them, the chain transfer agent was thioglycolic acid (TGA), the oxidant was ammonium persulfate (APS), and the reducing agent was L-ascorbic acid (Vc).

[0083] In this example, the preparation method of the mother liquor used included the following steps:

[0084] (1) Prepare solution A with acrylic acid. Specifically, mix acrylic acid with an appropriate amount of deionized water to prepare solution A. Prepare solution B with the chain transfer agent and the reducing agent. Specifically, mix thioglycolic acid, L-ascorbic acid with an appropriate amount of deionized water, and ultrasonicate for 10 min to obtain solution B.

[0085] (2) Place ethylene glycol mono vinyl polyethylene glycol ether and ammonium persulfate in a beaker, stir in a constant temperature magnetic stirrer, control the temperature at 30 °C during stirring. After stirring for 1 min, simultaneously drip solution A and solution B using a peristaltic pump, and control the dripping time within 1 h to obtain a yellow and thick mother liquor.

[0086] In this example, during the preparation of the mother liquor, the acid-ether ratio of acrylic acid (AA) to ethylene glycol mono vinyl polyethylene glycol ether (EPEG) is 5.5:1; the dosage of thioglycolic acid (TGA) is 0.9% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of ammonium persulfate (APS) is 1.4% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of L-ascorbic acid (Vc) is 0.2% of the mass of ethylene glycol mono vinyl polyethylene glycol ether.

[0087] In this example, the viscosity of hydroxypropyl methyl cellulose is 60000 MPa·s.

[0088] A preparation method of the superfine full-tailings filling paste water reducer as described above includes the following steps: Mix the mother liquor with hydroxypropyl methyl cellulose to obtain the superfine full-tailings filling paste water reducer.

[0089] An application of the superfine full-tailings filling paste water reducer as described above in treating the superfine full-tailings filling paste is specifically: Mix the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste to complete the treatment of the superfine full-tailings filling paste, where the dosage of the superfine full-tailings filling paste water reducer is 0.08% of the total mass of the superfine full-tailings filling paste.

[0090] In this example, the superfine full-tailings filling paste is composed of superfine full-tailings, cement and water, where the content of the -19 μm particle size fraction in the superfine full-tailings is 70%, the content of the -74 μm particle size fraction is 87%, and D 50 is 9 μm.

[0091] Test the filling paste with the water reducer added in Example 2, and the results are shown in Table 2.

[0092] Table 2 Test results of the filling paste in Example 2

[0093] Parameter Unit Blank Test Measurement Value Solid Concentration ％ 61 63 Sand-to-Lime Ratio - 1:6 1:7 Water-Reducing Agent Concentration ％ 0 0.08 Slump Flow mm 232 314 7-day Compressive Strength MPa.s 2.55 3.7 28-day Compressive Strength MPa.s 3.27 4.92

[0094] Example 3

[0095] A superfine full-tailings filling paste water reducer includes the following raw material components by weight:

[0096] Mother liquor 80 parts,

[0097] Hydroxypropyl methyl cellulose 0.1 part.

[0098] In this embodiment, the mother liquor used is prepared with ethylene glycol mono vinyl polyethylene glycol ether as the large monomer. Specifically, it is prepared from ethylene glycol mono vinyl polyethylene glycol ether (EPEG), acrylic acid (AA), a chain transfer agent, an oxidizing agent, and a reducing agent. The chain transfer agent is thioglycolic acid (TGA), the oxidizing agent is ammonium persulfate (APS), and the reducing agent is L-ascorbic acid (Vc).

[0099] In this embodiment, the preparation method of the mother liquor used includes the following steps:

[0100] (1) Prepare solution A from acrylic acid. Specifically, mix acrylic acid with an appropriate amount of deionized water to prepare solution A. Prepare solution B from the chain transfer agent and the reducing agent. Specifically, mix thioglycolic acid, L-ascorbic acid with an appropriate amount of deionized water and ultrasonicate for 10 min to obtain solution B.

[0101] (2) Place ethylene glycol mono vinyl polyethylene glycol ether and ammonium persulfate in a beaker and stir in a constant temperature magnetic stirrer. During stirring, control the temperature at 25°C. After stirring for 1 min, simultaneously drip solution A and solution B using a constant flow pump, and control the dripping time within 2 h to obtain a yellow and thick mother liquor.

[0102] In this embodiment, during the preparation of the mother liquor, the acid-ether ratio of acrylic acid (AA) to ethylene glycol mono vinyl polyethylene glycol ether (EPEG) is 8:1; the dosage of thioglycolic acid (TGA) is 0.8% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of ammonium persulfate (APS) is 1.7% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of L-ascorbic acid (Vc) is 0.25% of the mass of ethylene glycol mono vinyl polyethylene glycol ether.

[0103] In this embodiment, the viscosity of hydroxypropyl methylcellulose is 75000 MPa·s.

[0104] A preparation method of the superfine full-tailings filling paste water reducer as described above includes the following steps: Mix the mother liquor with hydroxypropyl methylcellulose to obtain the superfine full-tailings filling paste water reducer.

[0105] An application of the superfine full-tailings filling paste water reducer as described above in treating the superfine full-tailings filling paste. Specifically, mix the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste to complete the treatment of the superfine full-tailings filling paste, where the dosage of the superfine full-tailings filling paste water reducer is 0.06% of the total mass of the superfine full-tailings filling paste.

[0106] In this embodiment, the superfine full-tailings filling paste is composed of superfine full-tailings, cement, and water. Among them, the content of the -19 μm particle size fraction in the superfine full-tailings is 63%, the content of the -74 μm particle size fraction is 81%, and D 50 is 12 μm.

[0107] The filled paste after adding the water reducer in Example 3 was tested, and the results are shown in Table 3.

[0108] Table 3 Test Results of the Filled Paste in Example 3

[0109] Parameter Unit Blank Test Measurement Value Solid Concentration ％ 63 65 Sand-to-Lime Ratio - 1:6 1:7 Water-Reducing Agent Concentration ％ 0 0.06 Slump Flow mm 256 337 7-day Compressive Strength MPa.s 3.63 4.47 28-day Compressive Strength MPa.s 4.88 5.51

[0110] Example 4

[0111] An ultra-fine full-tailings filled paste water reducer, comprising the following raw material components by weight:

[0112] Mother liquor 110 parts,

[0113] Hydroxypropyl methylcellulose 0.08 part.

[0114] In this example, the mother liquor used was prepared with ethylene glycol mono vinyl polyethylene glycol ether as the large monomer. Specifically: it was prepared with ethylene glycol mono vinyl polyethylene glycol ether (EPEG), acrylic acid (AA), a chain transfer agent, an oxidizing agent, and a reducing agent as raw materials. Among them, the chain transfer agent was thioglycolic acid (TGA), the oxidizing agent was ammonium persulfate (APS), and the reducing agent was L-ascorbic acid (Vc).

[0115] In this example, the preparation method of the mother liquor used included the following steps:

[0116] (1) Prepare solution A from acrylic acid. Specifically: mix acrylic acid with an appropriate amount of deionized water to prepare solution A. Prepare solution B from the chain transfer agent and the reducing agent. Specifically: mix thioglycolic acid, L-ascorbic acid with an appropriate amount of deionized water, and ultrasonicate for 10 min to obtain solution B.

[0117] (2) Place ethylene glycol mono vinyl polyethylene glycol ether and ammonium persulfate in a beaker, stir in a constant temperature magnetic stirrer, control the temperature at 30 °C during stirring. After stirring for 1 min, use a constant flow pump to simultaneously drip solution A and solution B, and control the dripping time within 2 h to obtain a yellow, thick mother liquor.

[0118] In this example, during the preparation of the mother liquor, the acid-ether ratio of acrylic acid (AA) to ethylene glycol mono vinyl polyethylene glycol ether (EPEG) was 5.5:1; the dosage of thioglycolic acid (TGA) was 0.8% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of ammonium persulfate (APS) was 1.5% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of L-ascorbic acid (Vc) was 0.28% of the mass of ethylene glycol mono vinyl polyethylene glycol ether.

[0119] In this example, the viscosity of hydroxypropyl methylcellulose was 70000 MPa·s.

[0120] A preparation method of the above-mentioned superfine full-tailings filling paste water reducer, comprising the following steps: mixing the mother liquor with hydroxypropyl methylcellulose to obtain the superfine full-tailings filling paste water reducer.

[0121] An application of the above-mentioned superfine full-tailings filling paste water reducer in treating superfine full-tailings filling paste, specifically: mixing the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste to complete the treatment of the superfine full-tailings filling paste, wherein the dosage of the superfine full-tailings filling paste water reducer is 0.08% of the total mass of the superfine full-tailings filling paste.

[0122] In this embodiment, the superfine full-tailings filling paste is composed of superfine full-tailings, cement and water, wherein the content of the -19μm particle size fraction in the superfine full-tailings is 65%, the content of the -74μm particle size fraction is 84%, and D 50 is 10μm.

[0123] The filling paste after adding the water reducer in Example 4 was tested, and the results are shown in Table 4.

[0124] Table 4 Test results of the filling paste in Example 4

[0125] Parameter Unit Blank Test Measurement Value Solid Concentration ％ 63 65 Sand-to-Lime Ratio - 1:6 1:7 Water-Reducing Agent Concentration ％ 0 0.08 Slump Flow mm 248 315 7-day Compressive Strength MPa.s 3.36 3.95 28-day Compressive Strength MPa.s 4.17 4.94

[0126] Example 5

[0127] A superfine full-tailings filling paste water reducer, comprising the following raw material components by weight:

[0128] Mother liquor 80 parts,

[0129] Hydroxypropyl methylcellulose 0.12 parts.

[0130] In this embodiment, the mother liquor used is prepared with ethylene glycol mono vinyl polyethylene glycol ether as the large monomer, specifically: prepared from ethylene glycol mono vinyl polyethylene glycol ether (EPEG), acrylic acid (AA), chain transfer agent, oxidant and reducing agent, wherein the chain transfer agent is thioglycolic acid (TGA), the oxidant is ammonium persulfate (APS), and the reducing agent is L-ascorbic acid (Vc).

[0131] In this embodiment, the preparation method of the mother liquor used includes the following steps:

[0132] (1) Prepare liquid A from acrylic acid, specifically: mix acrylic acid with an appropriate amount of deionized water to prepare liquid A. Prepare liquid B from the chain transfer agent and the reducing agent, specifically: mix thioglycolic acid, L-ascorbic acid with an appropriate amount of deionized water and ultrasonicate for 10 min to obtain liquid B.

[0133] (2) Place ethylene glycol mono vinyl polyethylene glycol ether and ammonium persulfate in a beaker, stir in a constant temperature magnetic stirrer, control the temperature at 35 °C during stirring. After stirring for 1 min, simultaneously drip Solution A and Solution B using a constant flow pump, and control the dripping time within 1 h to obtain a yellow and thick mother liquor.

[0134] In this example, during the preparation of the mother liquor, the acid-ether ratio of acrylic acid (AA) to ethylene glycol mono vinyl polyethylene glycol ether (EPEG) is 6:1; the dosage of thioglycolic acid (TGA) is 1% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of ammonium persulfate (APS) is 1.7% of the mass of ethylene glycol mono vinyl polyethylene glycol ether; the dosage of L-ascorbic acid (Vc) is 0.16% of the mass of ethylene glycol mono vinyl polyethylene glycol ether.

[0135] In this example, the viscosity of hydroxypropyl methylcellulose is 80000 MPa·s.

[0136] A preparation method of the superfine full-tailings filling paste water reducer as described above includes the following steps: Mix the mother liquor with hydroxypropyl methylcellulose to obtain the superfine full-tailings filling paste water reducer.

[0137] An application of the superfine full-tailings filling paste water reducer as described above in treating the superfine full-tailings filling paste is specifically: Mix the superfine full-tailings filling paste water reducer with the superfine full-tailings filling paste to complete the treatment of the superfine full-tailings filling paste, where the dosage of the superfine full-tailings filling paste water reducer is 0.08% of the total mass of the superfine full-tailings filling paste.

[0138] In this example, the superfine full-tailings filling paste is composed of superfine full-tailings, cement and water, where the content of the -19 μm particle size in the superfine full-tailings is 65%, the content of the -74 μm particle size is 84%, and D 50 is 10 μm.

[0139] Test the filling paste after adding the water reducer in Example 5, and the results are shown in Table 5.

[0140] Table 5 Test results of the filling paste in Example 5

[0141] Parameter Unit Blank Test Measurement Value Solid Concentration ％ 63 65 Sand-to-Lime Ratio - 1:6 1:7 Water-Reducing Agent Concentration ％ 0 0.08 Slump Flow mm 248 308 7-day Compressive Strength MPa.s 3.36 4.04 28-day Compressive Strength MPa.s 4.17 5.13

[0142] As can be seen from the above results, compared with conventional polycarboxylate water reducers, the superfine full-tailings filling paste water reducer of the present invention has the following advantages: (a) It requires a short synthesis time, a low reaction temperature, and has good economic benefits. (b) The synthesis steps are simple, it is easily soluble in water, non-toxic and harmless, and is friendly to the environment and construction personnel. (c) It can adapt to different types of superfine full-tailings, and has strong versatility. (d) It can significantly increase the concentration of the superfine full-tailings filling paste, reduce the ash-sand ratio, improve the fluidity and strength, and improve the workability while greatly reducing the water consumption. (e) It can reduce the cement consumption in the superfine full-tailings filling paste, increase the tailings consumption, and at the same time maintain or improve the slurry performance, which helps to save material costs and tailings treatment costs. It can be seen that the superfine full-tailings filling paste water reducer of the present invention has the advantages of short synthesis time, low reaction temperature, good economic benefits, good applicability, good workability, and can significantly improve the compressive strength and stability of the filling body. It is a new type of water reducer with excellent performance, can be widely used in superfine tailings filling, can effectively fill superfine tailings, has high use value and good application prospects, and is of great significance for realizing cost reduction and efficiency increase, as well as for green sustainable economic development.

[0143] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An ultra-fine full tailings filling paste water reducing agent, characterized in that: The following raw material components are included by weight: 60 to 120 parts of mother liquor, Hydroxypropyl methylcellulose 0.08 to 0.12 parts; The mother liquor is prepared from ethylene glycol monovinyl polyethylene glycol ether, acrylic acid, a chain transfer agent, an oxidant and a reducing agent as raw materials; the acid-ether ratio of the acrylic acid to the ethylene glycol monovinyl polyethylene glycol ether is 5.5-8.5:0.8-1.2; the amount of the chain transfer agent is 0.6%-1% of the mass of the ethylene glycol monovinyl polyethylene glycol ether; the amount of the oxidant is 1.2%-1.8% of the mass of the ethylene glycol monovinyl polyethylene glycol ether; the amount of the reducing agent is 0.12%-0.28% of the mass of the ethylene glycol monovinyl polyethylene glycol ether; the viscosity of the hydroxypropyl methylcellulose is 60000 MPa·s-80000 MPa·s; the content of the particle size less than 19μm in the ultrafine whole tailings is greater than 50%, the content of the particle size less than 74μm is greater than 80%, and the content of D 50 <19μm.

2. The ultra-fine full tailings filling paste water reducer according to claim 1, characterized in that: The chain transfer agent is at least one of thioglycolic acid, isopropanol, and mercaptoethanol; The oxidant is at least one of ammonium persulfate, hydrogen peroxide, and potassium peroxide; The reducing agent is at least one of L-ascorbic acid, sodium sulfite, ferrous sulfate and sodium bisulfite.

3. The ultra-fine full tailings filling paste water reducer according to claim 1 or 2, characterized in that: The preparation method of the mother solution comprises the following steps: (1) Prepare liquid A with acrylic acid; prepare liquid B with chain transfer agent and reducing agent; (2) Ethylene glycol monovinyl polyglycol ether and an oxidant are mixed and stirred, and liquid A and liquid B are added dropwise to obtain a mother liquid.

4. The ultra-fine full tailings filling paste water reducing agent according to claim 3, characterized in that: In step (1), the liquid A is prepared by mixing acrylic acid with water; the liquid B is prepared by the following method: a chain transfer agent, a reducing agent and water are mixed, and ultrasonicated for 5 minutes to 10 minutes to obtain liquid B; In step (2), the stirring is carried out at a temperature of 20°C to 40°C; the stirring time is 1 min to 3 min; and the dropwise addition time of the liquid A and the liquid B is controlled at 0.5 h to 3 h.

5. A method for preparing the ultrafine full tailings filling paste water reducer as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: The mother liquor is mixed with hydroxypropyl methylcellulose to obtain an ultrafine full tailings filling paste water reducing agent.

6. Use of the ultrafine full tailings filling paste water reducer as described in any one of claims 1 to 4 or the ultrafine full tailings filling paste water reducer prepared by the preparation method according to claim 5 in treating ultrafine full tailings filling paste.

7. The use according to claim 6, characterized in that: The application includes the following steps: mixing the ultrafine full tailings filling paste water reducer with the ultrafine full tailings filling paste to complete the treatment of the ultrafine full tailings filling paste; the dosage of the ultrafine full tailings filling paste water reducer is 0.06% to 0.08% of the total mass of the ultrafine full tailings filling paste.

8. The use according to claim 7, characterized in that: The ultra-fine full tailings filling paste consists of ultra-fine full tailings, cement and water.

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