Cement raw material grinding aid and preparation method thereof

Abstract

The invention discloses a cement raw material grinding aid and a preparation method thereof. The cement raw material grinding aid is obtained by reacting saponification waste alkali liquor generated in the process of producing cyclohexanone through cyclohexane air oxidation with tartaric acid and / or molasses. In the invention, the grinding aid reduces the healing trend of microcracks on calcium carbonate coarse particles, so that the calcium carbonate coarse particles are easier to crush and refine, the overall grinding efficiency is improved, the grinding power consumption is reduced, and the grinding aid contains organic carbon, can be combusted at high temperature, has a certain heat value, and can reduce the coal consumption in the incineration process of cement raw materials.

Description

Technical Field

[0001] This invention relates to a cement raw material grinding aid and its preparation method, belonging to the field of cement processing technology. Background Technology

[0002] With fossil energy becoming increasingly scarce and environmental protection requirements constantly rising, energy conservation, emission reduction, improving coal thermal efficiency, and reducing the emission of harmful substances have become key directions for new product development and research.

[0003] Existing cement coal-saving and energy-reducing additives contain NaCl, an industrial salt that corrodes metals and pollutes the atmosphere. While industrial salt has excellent coal-saving and combustion-aiding effects, it severely corrodes the furnace and kiln metal, leading to high maintenance costs. Furthermore, the Cl⁻ produced after the combustion of industrial salt contributes to acid rain, damaging the environment. Some coal-saving and energy-reducing additives, considering oxygen supply, shorten the coal's combustion time, resulting in rapid burning. This prevents the coal from being completely burned and thoroughly, failing to meet the coal-saving process requirements of industrial kilns.

[0004] New dry-process cement production technology boasts a series of advantages, including large production capacity, high automation, high product quality, low energy consumption, low emissions of harmful substances, and large-scale utilization of industrial waste, making it a major technology in the global cement industry. However, in my country's current production line construction process, investors have repeatedly cut back on investment, resulting in low operational efficiency, frequent malfunctions, and, more importantly, high heat consumption. To address the current high heat consumption of new dry-process cement kilns in my country, in addition to strengthening meticulous management, adding cement raw material additives is a simple and effective method to reduce heat consumption.

[0005] The fineness and particle size distribution of cement raw meal directly affect the calcination quality of cement clinker and the performance of the final cement product. The development of specialized cement raw meal additives aims to regulate and optimize the crushing, dispersion, and grading processes of raw meal in vertical grinding to achieve ideal raw meal fineness and particle size distribution. With increasingly stringent national environmental protection requirements, the cement industry faces enormous pressure to conserve energy and reduce emissions. The research and application of specialized cement raw meal additives can improve grinding efficiency while reducing energy consumption and dust emissions, contributing to the green and sustainable development of the cement industry.

[0006] Developing cement raw meal additives can improve the flowability, dispersibility, and grindability of materials, reduce grinding energy consumption, and increase the processing capacity and fineness compliance rate of raw meal per unit time, thereby improving overall grinding efficiency. They can also help adjust the particle size distribution of raw meal, making the clinker mineral composition more uniform, which is conducive to the full reaction of minerals such as C3S and C2S during subsequent firing, thus improving the strength and durability of cement products. Furthermore, cement raw meal additives can reduce coal consumption, reduce coal combustion pollution, and protect the environment. Developing cement raw meal additives also helps improve the quality of enterprise products and their market competitiveness.

[0007] Some domestic companies have already made some attempts in the synthesis technology of cement raw material grinding aids.

[0008] CN201110063590.9 discloses a method for preparing a cement grinding aid. The main process involves adding diethanolamine, polyvinyl alcohol, sodium hexametaphosphate, graphite powder, deionized water, and sodium dodecylbenzenesulfonate to a reaction vessel in a specific ratio, heating and stirring to mix, and then circulating the mixture in a colloid mill for ultrafine grinding. CN201711180480.4 discloses a cement raw meal additive, its application, and a cement production process. This cement raw meal additive contains industrial waste liquid and an alkalinity improver. CN2011910503199.2 discloses a cement raw meal additive, its application, and a cement production process. This cement raw meal additive contains BDO waste liquid from the acetylene aldehyde process and an optional alkalinity improver. CN201810639345.x discloses a cement raw meal grinding aid. The cement raw material grinding aid comprises 13-20% by weight of calcium lignosulfonate, 18-27% by weight of polyacrylamide, 20-25% by weight of polyoxyethylene amide, 17-28% by weight of sodium hexametaphosphate, and 20-30% by weight of water.

[0009] CN202011556250.5 discloses a raw cement additive and its application method. The additive comprises the following substances in parts by weight: 8-15 parts diethanolamine, 15-25 parts sodium tripolyphosphate, 3-7 parts molasses, 8-15 parts propylene glycol, 1-6 parts nitrophenol, 10-15 parts calcium chloride, 1-3 parts potassium nitrate, 1-5 parts sodium nitrate, 2-8 parts sodium silicate, 1-6 parts sodium carbonate, 2-5 parts sodium bicarbonate, and 8-15 parts modified sodium humate. CN202011621301.8 discloses a cement raw meal admixture with both grinding aid and decomposition promoting effects, comprising 10-40% grinding aid component, 10-40% organic acid, 10-40% mineralizing component, and the remainder being water. CN202111199716.5 discloses a cement raw meal additive and its application and cement production process, wherein the cement raw meal additive contains waste liquid from the rearrangement method for producing caprolactam. CN202111645842.9 discloses a cement raw meal grinding aid and its preparation method, the specific method being as follows: first, prepare a mixed solution A, then prepare a mixed solution B, then add dodecylbenzene, mixed solution A, and mixed solution B to beaker C, then add ethylene glycol, sugar ether, triethanolamine, and triisopropanolamine to beaker C, and after stirring, obtain the cement raw meal grinding aid.

[0010] CN202210431272.1 discloses a cement raw material grinding aid, which comprises the following raw materials in parts by weight:

[0011] The preparation method comprises 10-30 parts triisopropanolamine, 2-4 parts polyolamine, 3-9 parts sugar, 1-5 parts sodium hexametaphosphate, 3-9 parts nonylphenol polyoxyethylene ether, 5-15 parts polycarboxylic acid-olamine type composite, and 20-40 parts water. The method involves mixing triisopropanolamine, polyolamine, nonylphenol polyoxyethylene ether, and water, heating, and mixing thoroughly to obtain a mixture; adding the polycarboxylic acid-olamine type composite and sodium hexametaphosphate to the mixture, mixing thoroughly, adding the sugar, mixing thoroughly, and cooling to obtain a cement grinding aid. CN202210590576.2 discloses a cement raw material additive containing a hydrolysate obtained by hydrolyzing acrylate heavy component waste liquid. CN202210765037.8 discloses a cement grinding aid and its preparation method, wherein the cement grinding aid includes a polymer. CN202211056075.2 discloses a cement raw material grinding aid and its preparation method, which is prepared from sodium carbonate, lignin sulfonate, polycarboxylate, hydroxyalkylaminosulfonate, polyhydroxyalkyl tertiary amine, polyether polyol and water.

[0012] While the grinding aids disclosed in the aforementioned patents do have some grinding-aiding effect, their production costs are relatively high, their production processes are complex, and their grinding-aiding effect is generally limited. Therefore, it is of great significance to develop a low-cost, high-efficiency, halogen-free grinding aid for cement raw materials. Summary of the Invention

[0013] In view of the technical problems existing in the prior art, such as high production cost, complex production process and ordinary grinding aid effect, the first objective of the present invention is to provide a method for preparing a cement raw material grinding aid. The method uses the saponified waste alkali generated in the process of producing cyclohexane ketone by air oxidation of cyclohexane as the main raw material, and reacts it with tartaric acid and / or molasses to obtain a cement raw material grinding aid. The method has the advantages of simple process, easy operation, obvious grinding aid effect and no halogen.

[0014] The second objective of this invention is to provide a cement raw meal grinding aid that can significantly improve the fineness of raw meal grinding, effectively reduce the clinker firing temperature, and reduce the standard coal consumption for clinker firing.

[0015] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing a cement raw material grinding aid, which is obtained by reacting the saponification waste alkali solution generated during the air oxidation of cyclohexane to produce cyclohexanone with tartaric acid and / or crude protein in molasses; the saponification waste alkali solution includes the following active components: sodium organic acid, organic alcohol, butyl hexanoate, ethyl furan, pentylcyclopropane, octene, C5-C6 ketones, sodium carbonate and sodium hydroxide.

[0016] This invention fully utilizes the saponified waste alkaline liquid micro-raw material generated during the air oxidation of cyclohexane to produce cyclohexanone. This material contains sodium organic acid salts, which can activate the calcium carbonate lattice in limestone raw materials in solid solution form, thus aiding in the grinding of cement raw materials. To further enhance the grinding effect, tartaric acid and / or molasses are added to react with the sodium carbonate and sodium hydroxide in the saponified waste alkaline liquid, further generating sodium tartrate salts. This reduces the tendency for microcracks to heal on coarse calcium carbonate particles, making them easier to break down and refine, thereby improving the grinding effect. Simultaneously, the saponified waste alkaline liquid also contains organic compounds such as cyclohexanediol, butyl hexanoate, and hexanediol. These organic compounds can synergistically work with the sodium organic acid salts to further improve the flowability of cement raw materials and enhance the grinding effect. Furthermore, these organic compounds can adjust the viscosity and dispersibility of the grinding aid, making it more adaptable to different cement raw materials. In addition, since the grinding aid also contains alkaline substances such as sodium carbonate and sodium hydroxide, it can react with sulfur dioxide and sulfur trioxide in the cement kiln exhaust gas, reducing the sulfur content in the exhaust gas to a certain extent.

[0017] The inventors discovered that high concentrations of sodium hydroxide and sodium carbonate are key raw materials for the reaction. They react with tartaric acid to form sodium tartrate, and also regulate the pH of the reaction system, ensuring the smooth progress of the reaction. The guaranteed sodium hydroxide content ensures the sufficiency of the reaction and the amount of organic acid sodium salts formed in the grinding aid.

[0018] As a preferred embodiment, the sodium organic acid is at least one selected from sodium propionate, sodium butyrate, sodium valerate, sodium hexanoate, sodium malonate, sodium succinate, sodium glutarate, sodium adipic acid, and sodium hydroxyhexanoate; the organic alcohol is at least one selected from cyclohexanediol, hexanediol, and 4-methylcyclopentanol; and the C5-C6 ketone is cyclopentanone and / or pentanone.

[0019] As a preferred embodiment, the saponification waste alkali liquid comprises the following active components by mass percentage: sodium propionate 0.2–3.0%, sodium butyrate 0.5–6.0%, sodium valerate 1.0–5.0%, sodium hexanoate 1.0–5.0%, sodium malonate 0.1–5.0%, sodium succinate 0.5–8.0%, sodium glutarate 0.2–4.0%, sodium adipic acid 1.0–15.0%, and sodium hydroxyhexanoate 0.1–1% The components are: 0.0% cyclohexanediol, 0.1-5.0% butyl hexanoate, 0.1-2.0% hexanediol, 0.05-1.0% ethyl furan, 0.2-4.0% 4-methylcyclopentanol, 0.05-1.0% pentylcyclopropane, 0.01-1.0% octene, 0.1-1.0% cyclopentanone, 0.2-3.0% pentanone, 0.01-3% sodium carbonate, and 3.5-5% sodium hydroxide. The specific content of each component in this invention is related to the load of the cyclohexanone oxidation process and the quality of process operation.

[0020] As a preferred embodiment, the total mass of tartaric acid and molasses added is 0.3-4 wt% of the mass of the saponification waste alkali solution. More preferably, the mass ratio of tartaric acid to molasses is (1-2):1.

[0021] As a preferred embodiment, the saponification waste alkali solution has a pH of 13-14, a solid content of 35-50 wt%, and a density of 1.200-1.300 g / ml at 60°C. This invention controls the physicochemical properties of the saponification waste alkali solution, ensuring the stable performance and significant grinding effect of the resulting cement raw material grinding aid, while also guaranteeing the quality of the raw materials and the efficiency and controllability of the reaction. A high pH value indicates that the waste alkali solution is highly alkaline. In the preparation of the grinding aid, high alkalinity promotes the reaction between tartaric acid and alkaline components, generating more sodium tartrate salts and synergistic sodium organic acid salts, which effectively improves the fluidity of cement raw materials and reduces energy consumption during the grinding process. Density is an important indicator for measuring the concentration and quality of the waste alkali solution. At 60°C, a density exceeding 1.200 g / ml indicates a high concentration of waste alkali solution, containing more organic and inorganic salt components that can be converted into grinding aids, ensuring reaction efficiency and the quality of the grinding aid.

[0022] As a preferred embodiment, the molasses comprises the following components: 36-60 wt% sugars, 2-7 wt% crude protein, 3-4 wt% soluble colloids, and the balance being water. In this invention, the sugars include sucrose, glucose, and fructose.

[0023] This invention also provides a cement raw meal grinding aid, obtained by the above preparation method. This grinding aid can significantly improve the fineness of raw meal grinding, effectively reduce the clinker firing temperature, and reduce the standard coal consumption for clinker firing.

[0024] As a preferred embodiment, the cement raw meal grinding aid is added before the cement raw meal enters the mill; the amount of the cement raw meal grinding aid added is 0.01-0.5 wt%. Cement raw meal mainly contains limestone raw materials (including limestone, chalk, calcareous tuff, etc.) and clay raw materials. Compared with the grinding aids in the prior art, the grinding aid of the present invention has a good grinding effect with low dosage.

[0025] Compared with existing technologies, the innovativeness and beneficial technical effects of the present invention are as follows:

[0026] 1) This invention utilizes the saponification waste alkaline liquid generated during the air oxidation of cyclohexane to produce cyclohexanone, which reacts with tartaric acid and / or molasses to generate a grinding aid. The sodium organic acid salt contained in this aid can form a solid solution with the calcium carbonate lattice in cement raw materials, activating the calcium carbonate lattice activity. This mechanism makes the raw material particles easier to break during grinding, thus significantly improving grinding efficiency and fineness. Furthermore, other organic compounds in the grinding aid, such as cyclohexanediol and butyl hexanoate, synergistically work with the sodium organic acid salt to further improve the flowability of the raw material, reduce energy consumption during grinding, and ensure high efficiency and improved fineness in raw material grinding.

[0027] 2) The grinding aid of this invention indirectly reduces energy consumption during clinker calcination by improving the fineness of the raw meal. Increased fineness allows for more complete chemical reactions during calcination, thereby reducing the required calcination temperature and time. Simultaneously, the grinding aid contains a certain amount of organic carbon, which is combustible at high temperatures and has a certain calorific value, further reducing coal consumption during cement raw meal incineration.

[0028] 3) The grinding aid of this invention contains various sodium salts of organic acids and organic compounds, such as sodium propionate, sodium butyrate, and cyclohexanediol. These components interact with the inorganic components in the raw meal, significantly enhancing its dispersibility. Improved dispersibility allows the raw meal to be distributed more evenly during grinding, reducing the formation of large particles and increasing grinding efficiency. Furthermore, improved raw meal dispersibility also means that under the same process conditions, the amount of raw meal that can be processed can be increased, thereby increasing production capacity by 2-5%, bringing significant economic benefits to cement production enterprises.

[0029] 4) The grinding aid of this invention does not contain halogens or other harmful substances, which avoids the introduction of harmful substances during the production process and reduces the emission levels of harmful gases such as sulfur dioxide. The generation and use of sodium organic acid salts not only optimizes the grinding process of raw materials, but also indirectly promotes the reduction of harmful substances during the clinker calcination process. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to specific embodiments. It should be noted that the described embodiments are only some embodiments of the present invention, and not all embodiments; these embodiments are only for better understanding of the present invention, and not for limiting the scope of protection of the present invention.

[0031] Unless otherwise specified, all reagents and raw materials used in this invention are commercially available products or products that can be prepared by known methods.

[0032] Cyclohexanone saponification waste alkaline liquid is an alkaline process wastewater generated during the production of cyclohexanone by cyclohexane oxidation. The remainder is water, with a sodium carbonate content of 0.01 wt% and a sodium hydroxide content of 4 wt%. Due to its COD content being as high as 300,000 mg / L or more, it is now treated by incineration. Its main organic composition is shown in Table 1.

[0033] Table 1 Organic composition of cyclohexanone saponification waste alkaline solution

[0034]

[0035]

[0036] The molasses used in the embodiments and comparative examples of this invention consists of the following components: 60 wt% sugars, 7 wt% crude protein, 3 wt% soluble colloids, and the balance being water. The sugars are sucrose, glucose, and fructose.

[0037] Example 1

[0038] 30,000 kg of polycaprolactone from cyclohexanone saponification waste alkaline solution was mixed with 90 kg of tartaric acid and reacted for 2 hours. Sampling and analysis showed a pH of 13.63, a solids content of 45.1 wt%, and a density of 1.200 g / ml at 60℃. The grinding aid and coal-saving effects were evaluated on a small mill (φ2.2×11 m) according to GB / T1345-2005. The residue on a 0.08 mm sieve was 16.2%, on a 0.02 mm sieve was 1.5%, and the raw material specific surface area was 360 m². 2 / kg.

[0039] Example 2

[0040] 30,000 kg of polycaprolactone from cyclohexanone saponification waste liquid was mixed with 90 kg of tartaric acid and 90 kg of molasses and reacted for 2 hours. Sampling and analysis showed a pH of 13.51, a solids content of 45.4 wt%, and a density of 1.300 g / ml at 60℃. The grinding aid and coal-saving effects were evaluated on a small mill. The residue on a 0.08 mm sieve was 15.3%, on a 0.02 mm sieve was 1.45%, and the raw material specific surface area was 364 m². 2 / kg.

[0041] Example 3

[0042] 30,000 kg of polycaprolactone from cyclohexanone saponification waste liquid was mixed with 600 kg of tartaric acid and 600 kg of molasses and reacted for 2 hours. Sampling and analysis showed a pH of 13.28, a solids content of 49.4 wt%, and a density of 1.200 g / ml at 60℃. The grinding aid and coal-saving effects were evaluated on a small mill. The residue on a 0.08 mm sieve was 14.5%, on a 0.02 mm sieve was 1.40%, and the raw material specific surface area was 385 m². 2 / kg.

[0043] Example 4

[0044] 30,000 kg of polycaprolactone from cyclohexanone saponification waste alkaline solution was mixed with 600 kg of tartaric acid and reacted for 2 hours. Sampling and analysis showed a pH of 13.71, a solids content of 47.4 wt%, and a density of 1.200 g / ml at 60℃. The grinding aid and coal-saving effects were evaluated on a small mill. The residue on a 0.08 mm sieve was 14.9%, on a 0.02 mm sieve was 1.45%, and the raw material specific surface area was 370 m². 2 / kg.

[0045] Example 5

[0046] 30,000 kg of polycaprolactone from cyclohexanone saponification waste liquid was mixed with 600 kg of molasses and reacted for 3 hours. Sampling and analysis showed a pH of 13.32, a solids content of 47.2 wt%, and a density of 1.200 g / ml at 60℃. The grinding aid and coal-saving effects were evaluated on a small mill. The residue on a 0.08 mm sieve was 17.4%, on a 0.02 mm sieve was 1.55%, and the raw material specific surface area was 358 m². 2 / kg.

[0047] Comparative Example 1

[0048] Without adding raw material grinding aids, the grinding aid and coal-saving effects were evaluated on a small mill in the same manner as in Example 1. The residue on the 0.08mm sieve was 19.0%, the residue on the 0.02mm sieve was 2.10%, and the specific surface area of ​​the raw material was 325m². 2 / kg.

[0049] Application Example 1

[0050] The cement raw meal grinding aid formulated in Example 2 was applied at Guangxi YF Cement Plant at a dosage of 0.1 wt% of the raw meal. The application results showed that after adding the grinding aid, the raw meal mill reduced power consumption by 1.28 kWh / t and saved 3.79 kg / t.cl of standard coal per ton of clinker.

[0051] Comparative Application Example 1

[0052] Cyclohexanone saponification waste alkaline solution without grinding aid was applied at Guangxi YF Cement Plant at an addition rate of 0.1 wt% of raw meal. The application results showed that after adding the grinding aid, the raw meal mill reduced power consumption by 0.5 kWh / t and saved 1.23 kg / t.cl of standard coal per ton of clinker.

[0053] The above embodiments are only for better explaining the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention, and are not intended to limit the patent scope of the present invention. All equivalent modifications made using the content of the present invention are within the patent protection scope of the present invention.

Claims

1. A method for preparing a cement raw meal grinding aid, characterized in that: The saponification waste alkali solution generated during the air oxidation of cyclohexane to produce cyclohexanone is obtained by reacting tartaric acid and / or molasses with tartaric acid. The saponification waste alkaline solution includes the following active components: sodium organic acid, organic alcohol, butyl hexanoate, ethyl furan, pentylcyclopropane, octene, C5-C6 ketones, sodium carbonate, and sodium hydroxide.

2. The method for preparing a cement raw meal grinding aid according to claim 1, characterized in that: The organic acid sodium is at least one selected from sodium propionate, sodium butyrate, sodium valerate, sodium hexanoate, sodium malonate, sodium succinate, sodium glutarate, sodium adipic acid, and sodium hydroxyhexanoate. The organic alcohol is at least one of cyclohexanediol, hexanediol and 4-methylcyclopentanol; The C5-C6 ketones are cyclopentanone and / or pentanone.

3. The method for preparing a cement raw meal grinding aid according to claim 2, characterized in that: The saponification waste alkaline solution mainly comprises the following active components by mass percentage: sodium propionate 0.2–3.0%, sodium butyrate 0.5–6.0%, sodium valerate 1.0–5.0%, sodium hexanoate 1.0–5.0%, sodium malonate 0.1–5.0%, sodium succinate 0.5–8.0%, sodium glutarate 0.2–4.0%, sodium adipic acid 1.0–15.0%, and sodium hydroxyhexanoate 0.1–10.0%. Cyclohexanediol 0.1–5.0%, Butyl hexanoate 0.1–5.0%, Hexanediol 0.1–2.0%, Ethyl furan 0.05–1.0%, 4-Methylcyclopentanol 0.2–4.0%, Pentylcyclopropane 0.05–1.0%, Octene 0.01–1.0%, Cyclopentanone 0.1–1.0%, Pentyl ketone 0.2–3.0%, Sodium carbonate 0.01–3%, Sodium hydroxide 3.5–5%.

4. The method for preparing a cement raw meal grinding aid according to claim 1, characterized in that: The total mass of tartaric acid and molasses added is 0.3 to 4 wt% of the mass of the saponification waste alkali solution.

5. A method for preparing a cement raw meal grinding aid according to claim 1 or 2, characterized in that: The saponification waste alkali solution has a pH of 13-14, a solid content of 35-50 wt%, and a density of 1.200-1.300 g / ml at 60°C.

6. The method for preparing a cement raw meal grinding aid according to claim 5, characterized in that: The molasses consists of the following components: 36-60 wt% sugars, 2-7 wt% crude protein, 3-4 wt% soluble colloids, and the balance being water.

7. A cement raw meal grinding aid, characterized in that: It is obtained by the preparation method according to any one of claims 1 to 6.

8. A cement raw meal grinding aid according to claim 7, characterized in that: The cement raw meal grinding aid is added before the cement raw meal enters the mill; the amount of the cement raw meal grinding aid added is 0.01 to 0.5 wt%.

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