A grinding aid modifier for oil shale semi-coke

Abstract

The application discloses a grinding aid modifier for oil shale semi-coke, which is prepared by sequentially adding 20-40% of silica, 5-15% of crosslinked polyacrylic acid salt, 5-10% of lignin sulfonate, 20-40% of polymeric polyol, 10-15% of anhydrous sodium sulfate and 0-15% of vinyl acetate into a mixing container in percentage by weight, and fully stirring and uniformly mixing the obtained mixture. The product has excellent grinding aid property for oil shale semi-coke, and can greatly improve the defects of high water absorption, high adsorption, poor fluidity, easy water bleeding and the like of the oil shale semi-coke. Meanwhile, the raw materials are easy to obtain, the formula is reasonable, the product is environment-friendly, energy-saving, pollution-free, low in cost, easy to realize industrialized production, simple in preparation process, does not need special processing equipment, and has good economic benefit, social benefit and environmental benefit.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste utilization technology, specifically a grinding aid modifier for oil shale semi-coke. Background Technology

[0002] Oil shale produces a large amount of by-product waste during the dry distillation and refining process, namely oil shale semi-coke. This is a low-quality fuel with high ash content and low calorific value, containing toxic pollutants such as water-soluble phenols, sulfides, and polycyclic aromatic hydrocarbons. If not properly handled, it will cause serious harm to the environment.

[0003] Currently, both domestically and internationally, shale semi-coke is mostly disposed of through stockpiling, which not only occupies a large amount of usable arable land but also pollutes water resources, deteriorates water quality, and wastes resources. As a byproduct of oil shale, oil shale semi-coke is often ground and used as an admixture in concrete for highways, railways, building installation projects, tunnel engineering, and mortar masonry. However, grinding one ton of oil shale semi-coke consumes approximately 20 kWh of electricity, resulting in high energy consumption, with most of the energy being converted into heat. This not only wastes limited energy resources but also increases the electrostatic effect within the mill, causing the oil shale semi-coke powder to clump and become sticky. Furthermore, even with increased water-cement ratios and water-reducing agents, concrete containing oil shale semi-coke powder still suffers from poor fluidity and low early strength, significantly limiting the resource utilization of oil shale semi-coke in concrete. Summary of the Invention

[0004] The purpose of this invention is to provide a grinding aid modifier for oil shale semi-coke, which reduces the power consumption during grinding while ensuring the fineness of the oil shale semi-coke powder, improves the problems of poor concrete fluidity and low early strength, promotes its application in concrete, and thus effectively promotes the high-value utilization of industrial solid waste oil shale semi-coke.

[0005] To achieve its purpose, the present invention adopts the following technical solution: A grinding aid modifier for oil shale semi-coke is obtained by adding 20-40% silica fume, 5-15% crosslinked polyacrylate, 5-10% lignin sulfonate, 20-40% polymeric polyol, 10-15% sodium sulfate, and 0-15% vinyl acetate sequentially to a mixing container and stirring thoroughly until homogeneous. As a further preferred embodiment of the technical solution of the present invention, the silica fume refers to off-grade ash with a SiO2 content of ≤80%.

[0006] Furthermore, the cross-linked polyacrylate refers to one or a mixture of several of cross-linked sodium polyacrylate, cross-linked potassium polyacrylate, or cross-linked calcium polyacrylate.

[0007] Furthermore, the lignin sulfonate refers to either sodium lignin sulfonate or calcium lignin sulfonate.

[0008] Furthermore, the polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 10-50%:20-70%:5-40%.

[0009] Furthermore, the polymeric polyol, sodium sulfate, and vinyl acetate are all industrial grade.

[0010] Furthermore, during the grinding of oil shale semi-coke, the grinding aid modifier is incorporated into the oil shale semi-coke in the mill at an amount of 0.2-1 wt%, preferably 0.6-0.9 wt%.

[0011] Compared with the prior art, the present invention has the following advantages: 1. This invention incorporates a grinding aid modifier during the grinding of industrial solid waste oil shale semi-coke. On the one hand, it acts as a dispersant and grinding aid, reducing power consumption during grinding while ensuring the fineness of the oil shale semi-coke powder. On the other hand, it improves the defects of oil shale semi-coke's strong water absorption and high adsorption of water-reducing agents, which can improve the problems of poor concrete fluidity and low early strength, thereby realizing the large-scale resource utilization of oil shale semi-coke in concrete.

[0012] 2. The raw materials of this invention are readily available, the design formula is reasonable, it is easy to process, and the cost is low, making it convenient for industrial production.

[0013] 3. The grinding aid modifier of this invention contains cross-linked polyacrylate and lignin sulfonate, which have certain water-reducing and air-entraining properties. It can modify the defects of oil shale semi-coke such as adsorption and water absorption and poor fluidity, improve the compactness of concrete filling, and the resulting concrete sets quickly, has high early compressive strength, and good impermeability and corrosion resistance.

[0014] 4. The sodium sulfate added to the grinding aid modifier of this invention can effectively activate the activity of oil shale semi-coke, thereby improving the early strength of concrete.

[0015] 5. The grinding aid modifier of this invention introduces silica fume from industrial solid waste, which not only achieves the rational utilization of industrial solid waste, but also gives full play to its characteristic of containing a large amount of active calcium oxide. It can react with active silica in oil shale semi-coke powder to form CSH gel. At the same time, the nano-sized silica fume particles have the functions of filling and improving pore structure.

[0016] 6. The grinding modifier of this invention contains vinyl acetate, which can effectively prevent concrete segregation, bleeding, and water seepage, while also improving the cohesiveness of concrete and increasing its early strength. Detailed Implementation

[0017] The composition, usage, and effects of the oil shale semi-coke grinding aid modifier of the present invention will be described in detail below with reference to specific embodiments.

[0018] In the following embodiments of the present invention, the polymeric polyol, sodium sulfate, and vinyl acetate are all industrial grade. The silica fume refers to off-grade silica fume with a SiO2 content of 80%.

[0019] Example 1 The grinding aid modifier for oil shale semi-coke provided in this embodiment is obtained by adding 20% ​​silica fume, 10% crosslinked polyacrylate, 10% lignin sulfonate, 30% polymeric polyol, 15% sodium sulfate, and 15% vinyl acetate sequentially into a mixing container and stirring thoroughly until homogeneous.

[0020] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 20%:70%:10%.

[0021] The cross-linked polyacrylate refers to a mixture of cross-linked sodium polyacrylate, cross-linked potassium polyacrylate, and cross-linked calcium polyacrylate in a weight ratio of 1:1:2.

[0022] The lignin sulfonate refers to calcium lignin sulfonate.

[0023] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke inside the mill at a dosage of 0.6 wt%.

[0024] Example 2 This embodiment provides a grinding aid modifier for oil shale semi-coke, which is obtained by adding 30% silica fume, 15% crosslinked polyacrylate, 5% lignin sulfonate, 40% polymeric polyol, and 10% sodium sulfate sequentially to a mixing container and stirring thoroughly.

[0025] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 10%:50%:40%.

[0026] The cross-linked polyacrylate refers to a mixture of cross-linked sodium polyacrylate and cross-linked potassium polyacrylate in a weight ratio of 1:1.

[0027] The lignin sulfonate refers to sodium lignin sulfonate.

[0028] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke inside the mill at a dosage of 0.2 wt%.

[0029] Example 3 This embodiment provides a grinding aid modifier for oil shale semi-coke, which is obtained by adding 40% silica fume, 5% crosslinked polyacrylate, 10% lignin sulfonate, 20% polymeric polyol, 15% sodium sulfate, and 10% vinyl acetate sequentially to a mixing container and stirring thoroughly.

[0030] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 50%:45%:5%.

[0031] The cross-linked polyacrylate refers to a mixture of cross-linked potassium polyacrylate and cross-linked calcium polyacrylate in a weight ratio of 1:2.

[0032] The lignin sulfonate refers to calcium lignin sulfonate.

[0033] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke in the mill at a dosage of 0.9 wt%.

[0034] Example 4 The grinding aid modifier for oil shale semi-coke provided in this embodiment is obtained by adding 20% ​​silica fume, 10% crosslinked polyacrylate, 10% lignin sulfonate, 40% polymeric polyol, 15% sodium sulfate, and 5% vinyl acetate sequentially to a mixing container and stirring thoroughly until homogeneous.

[0035] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 40%:20%:40%.

[0036] The cross-linked polyacrylate refers to cross-linked calcium polyacrylate.

[0037] The lignin sulfonate refers to calcium lignin sulfonate.

[0038] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke inside the mill at a dosage of 0.5 wt%.

[0039] Example 5 This embodiment provides a grinding aid modifier for oil shale semi-coke, which is obtained by adding 25% silica fume, 13% crosslinked polyacrylate, 7% lignin sulfonate, 35% polymeric polyol, 14% sodium sulfate, and 6% vinyl acetate sequentially to a mixing container and stirring thoroughly.

[0040] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 30%:50%:20%.

[0041] The cross-linked polyacrylate refers to cross-linked sodium polyacrylate.

[0042] The lignin sulfonate refers to sodium lignin sulfonate.

[0043] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke inside the mill at a dosage of 0.8 wt%.

[0044] Example 6 This embodiment provides a grinding aid modifier for oil shale semi-coke, which is obtained by adding 30% silica fume, 12% crosslinked polyacrylate, 8% lignin sulfonate, 25% polymeric polyol, 13% sodium sulfate, and 12% vinyl acetate sequentially to a mixing container and stirring thoroughly.

[0045] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 20%:50%:30%.

[0046] The cross-linked polyacrylate refers to a mixture of cross-linked sodium polyacrylate, cross-linked potassium polyacrylate, and cross-linked calcium polyacrylate in a weight ratio of 1:1:1.

[0047] The lignin sulfonate refers to calcium lignin sulfonate.

[0048] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke inside the mill at a dosage of 0.7 wt%.

[0049] Example 7 This embodiment provides a grinding aid modifier for oil shale semi-coke, which is obtained by adding 22% silica fume, 10% crosslinked polyacrylate, 10% lignin sulfonate, 33% polymeric polyol, 15% sodium sulfate, and 10% vinyl acetate sequentially to a mixing container and stirring thoroughly.

[0050] The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol (30000), and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 35%:30%:35%.

[0051] The cross-linked polyacrylate refers to a mixture of cross-linked sodium polyacrylate and cross-linked potassium polyacrylate in a weight ratio of 1:1.

[0052] The lignin sulfonate refers to sodium lignin sulfonate.

[0053] In use, during the grinding of oil shale semi-coke, the grinding aid and absorption inhibitor are incorporated into the oil shale semi-coke in the mill at a dosage of 0.4 wt%.

[0054] Examples 1-7: Experimental Raw Materials and Equipment The experimental oil shale semi-coke came from Yaojie Coal and Power Group.

[0055] Main experimental equipment: SYM∮500*500mm cement testing mill, FSY-150 cement fineness negative pressure sieve analyzer The test protocols for Examples 1-7 are as follows: Oil shale semi-coke was crushed to a particle size of less than 7 mm using a jaw crusher. 5 kg samples were taken each time. The test method for the grinding aid effect of the grinding modifier was based on Appendix A of GB / T26748-2011 "Cement Grinding Aids" standard. The grinding time was 20 min, and the specific surface area was 350 m². 2 / kg±10 m 2 / kg. The grinding aid modifier is added directly to a ∮500*500mm cement test mill at a certain dosage for grinding.

[0056] The grinding effect analysis of the grinding modifier was based on the reduction value of residue on a 5µm sieve. Other cementitious properties were analyzed according to the corresponding standards under the same conditions after replacing 30% of cement in equal amounts.

[0057] The grinding aid effects of Examples 1-7 are shown in Table 1, and the modification effect on the properties of oil shale semi-coke is shown in Table 2.

[0058] Table 1. Analysis of the grinding-aiding effect of grinding modifiers

[0059] As can be clearly seen from Table 1, after adding the grinding aid modifiers from Examples 1-7 during the grinding of oil shale semi-coke, the fineness of the oil shale semi-coke was superior to that of the blank oil shale semi-coke without the grinding aid modifier. The reduction rate of sieve residue on the 45µm sieve was approximately 18.9-29.9%, showing a significant reduction in sieve residue. At the same time, the specific surface area increased by 22-69 m². 2 / kg, all of which were higher than those without grinding aid modifier. In summary, the addition of the grinding aid modifier demonstrated certain grinding-aiding properties, played a good dispersing role in grinding, improved the fineness of oil shale semi-coke, increased the specific surface area, and showed significant grinding-aiding effects. Examples 1 and 5 showed better performance in terms of grinding aid and dispersion.

[0060] Table 2. Effects of grinding aid modifiers on the properties of oil shale semi-coke

[0061] As can be clearly seen from Table 2, if the standard consistency of cement is 26.8%, when 30% of cement is replaced by an equal amount of oil shale semi-coke powder, the standard consistency water consumption is 38.8%, indicating that oil shale semi-coke has extremely strong water absorption. However, when the oil shale semi-coke is modified by adding the grinding aid modifiers from Examples 1-7 during the grinding process, and then the modified oil shale semi-coke powder from Examples 1-7 is used to replace an equal amount of cement, the standard consistency water consumption fluctuates between 25.4% and 28.6%, with the water consumption decreasing by about 30%. Ultimately, the standard consistency water consumption is basically the same as that of pure cement. Among them, the standard consistency water consumption of Examples 3 and 5 is lower than that of pure cement. This indicates that each grinding aid modifier exhibits good water absorption resistance, and the fluidity fluctuates between 131-139 mm, which is basically the same as the fluidity of pure cement. Compared with the fluidity without the addition of grinding aid modifiers, it is 3-11 mm higher, indicating that each grinding aid modifier also improves the morphology of the oil shale semi-coke after grinding. Secondly, when the grinding aid modifiers used in Examples 1-7 for oil shale semi-coke were added during the grinding process, the setting time, both the initial and final setting times, was longer than that without the grinding aid modifier, and was basically the same as that of pure cement. Simultaneously, the mortar strength at 3 days and 28 days showed an increase, mostly reaching the strength of pure cement, with Examples 1, 3, and 5 showing particularly significant improvements.

[0062] In summary, this invention improves the grindability of oil shale semi-coke by incorporating grinding aid modifiers during the grinding process, thereby enhancing its activity and promoting the development of early and late strength. It also solves problems such as strong water absorption and poor flowability of oil shale semi-coke, thus facilitating its high-value resource utilization.

[0063] The content of this invention is not limited to the embodiments listed. Any equivalent changes made by those skilled in the art to the technical solutions of this invention are within the scope of protection of this invention.

Claims

1. A grinding aid modifier for oil shale semi-coke, characterized in that, The grinding aid modifier is obtained by adding 20-40% silica fume, 5-15% crosslinked polyacrylate, 5-10% lignin sulfonate, 20-40% polymeric polyol, 10-15% sodium sulfate, and 0-15% vinyl acetate sequentially to a mixing container and stirring thoroughly until homogeneous.

2. The grinding aid modifier for oil shale semi-coke as described in claim 1, characterized in that, The silica fume refers to silica fume with a SiO2 content of ≤80%.

3. The grinding aid modifier for oil shale semi-coke as described in claim 1, characterized in that, The cross-linked polyacrylate refers to one or a mixture of cross-linked sodium polyacrylate, cross-linked potassium polyacrylate, and cross-linked calcium polyacrylate.

4. The grinding aid modifier for oil shale semi-coke as described in claim 1, characterized in that, The lignin sulfonate refers to either sodium lignin sulfonate or calcium lignin sulfonate.

5. A grinding aid modifier for oil shale semi-coke as described in claim 1, characterized in that, The polymeric polyol is a mixture of triethanolamine dodecyl sulfate, tripropylene glycol, and polycarboxylic acid high-efficiency plasticizer in a mass percentage ratio of 10-50%: 20-70%: 5-40%.

6. A grinding aid modifier for oil shale semi-coke as described in any one of claims 1-5, characterized in that, The polymeric polyol, sodium sulfate, and vinyl acetate are all industrial grade.

7. A grinding aid modifier for oil shale semi-coke as described in claim 1, characterized in that, During the grinding of oil shale semi-coke, the grinding aid modifier is added to the oil shale semi-coke in the mill at a dosage of 0.2-1 wt%.

8. A grinding aid modifier for oil shale semi-coke as described in claim 7, characterized in that, The amount of grinding aid modifier added is 0.6-0.9 wt%.

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