Formula and production method of special refractory brick for sodium sulfide production

Abstract

The invention discloses a formula and a production method for producing a special refractory brick from sodium sulfide, the formula comprises high-alumina bauxite, magnesia, silicon carbide, silica powder, a binding agent and sodium polysulfide residues (the PH value is 6-8), during production, the high-alumina bauxite, the magnesia, the silicon carbide and the sodium polysulfide residues are crushed and screened to a specific particle size; according to the first embodiment, the refractory brick is prepared through the steps of mixing according to a specific proportion, stirring, forming, drying, sintering and the like, process parameters of all links are clear, according to the second embodiment, the proportion and the process parameters of part of raw materials are adjusted, and performance tests show that the refractory brick is excellent in volume density, apparent porosity, normal-temperature compressive strength, refractoriness under load, thermal shock resistance and the like, and has good application prospects. And traditional refractory bricks are far better. The method can meet the production requirement of sodium sulfide, can be used for more than 12 months for a long period, can effectively improve the production efficiency and quality, reduces the production cost, is simple and convenient in production technology, and is easy to realize industrial large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field related to refractory bricks, and specifically relates to a formula and a production method of special refractory bricks used for producing sodium sulfide. Background Art

[0002] Refractory bricks are a kind of high temperature resistant inorganic non-metallic material, commonly used for lining of high temperature industrial equipment, such as metallurgical furnaces, glass kilns, chemical reactors, etc.

[0003] Traditional refractory bricks often have many shortcomings when dealing with the complex working conditions of sodium sulfide production.

[0004] Traditional refractory bricks are usually not optimized in terms of raw material selection and formula ratio, resulting in low volume density and high apparent porosity, which affects the strength and high temperature resistance of refractory bricks. In terms of production technology, insufficient molding pressure and inaccurate parameter control during drying and sintering make the structure of refractory bricks less dense and prone to damage and deformation in high temperature and chemical corrosion environments.

[0005] In addition, traditional refractory bricks have poor corrosion resistance and thermal shock resistance, which not only shortens their service life and increases the cost of replacement and maintenance, but may also affect the production efficiency and quality of sodium sulfide due to frequent equipment maintenance.

[0006] In order to improve the efficiency and quality of sodium sulfide production, reduce production costs, and meet increasingly stringent industrial production requirements, it is imperative to develop a new type of special refractory brick for sodium sulfide production and its production method. Summary of the invention

[0007] The object of the present invention is to provide a formula and a production method for special refractory bricks for sodium sulfide production, so as to solve the problem of poor corrosion resistance and thermal shock resistance of traditional refractory bricks mentioned in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A special refractory brick formula for producing sodium sulfide, the formula comprising high-alumina bauxite, magnesia, silicon carbide, silicon micropowder, a binder and sodium polysulfide residue;

[0010] Among them, high-alumina bauxite, magnesia, silicon carbide and sodium polysulfide residues are crushed and screened.

[0011] Preferably, the production method is as follows:

[0012] Step 1: Mix the ingredients:

[0013] The ingredients are prepared in precise proportions of 30-55% high-alumina bauxite, 15-20% magnesia, 7-10% silicon carbide, 3-5% silicon micropowder, 4-5% binder and 3-5% sodium polysulfide residue. The raw materials and additives are carefully placed in a large-scale high-efficiency mixer for thorough mixing. The mixing time is as long as 45 minutes. Continuous mixing ensures that the various ingredients are evenly distributed, laying a solid foundation for subsequent processes.

[0014] Step 2: Molding:

[0015] The carefully mixed raw materials are accurately loaded into a special mold and molded using an advanced pressure molding machine. The molding pressure is strictly controlled at 150MPa and the pressure holding time is accurately set to 45 seconds to ensure that the size of the molded refractory bricks is accurate and reaches the standard 230mm×114mm×65mm;

[0016] Step 3: Drying:

[0017] The formed refractory bricks are placed in a drying kiln for drying. During the drying process, the temperature must be stably controlled at 150°C and the drying time lasts for 24 hours to fully remove the moisture in the refractory bricks and improve their initial strength;

[0018] Step 4: Sintering:

[0019] The dried refractory bricks are placed in a high-temperature sintering furnace in an orderly manner for the key sintering step. The sintering temperature is precisely set to 1600°C and the sintering time is as long as 10 hours. During this high-temperature process, the raw materials undergo physical and chemical reactions, allowing the refractory bricks to form a dense structure, thus possessing excellent high-temperature resistance and chemical stability.

[0020] Compared with the prior art, the present invention provides a formula and production method for producing special refractory bricks for sodium sulfide, which has the following beneficial effects:

[0021] The performance of the prepared refractory bricks is significantly improved: Compared with traditional refractory bricks, the refractory bricks of the present invention perform well in key performance indicators such as bulk density, room temperature compressive strength, load softening temperature and thermal shock resistance. The bulk density is higher, the apparent porosity is lower, the room temperature compressive strength is higher, the load softening temperature is higher, and the thermal shock resistance is better;

[0022] Meet the production needs of sodium sulfide: It can effectively cope with complex working conditions such as high temperature and corrosion in the production of sodium sulfide, ensure long-term use of more than 12 months, and improve production efficiency and quality;

[0023] Reduce production costs: Due to its good performance and long-term use, the replacement frequency and maintenance cost of refractory bricks are reduced;

[0024] Production technology advantages: The production technology is simple and feasible, easy to realize industrial large-scale production, and conducive to wide promotion and application;

[0025] Material optimization: The overall performance of refractory bricks is improved by selecting high-purity raw materials, strictly controlling their particle size, and accurately formulating the proportions;

[0026] Process improvement: Advanced process parameters are used in the forming, drying and sintering links, such as higher forming pressure, more suitable drying temperature and time, higher sintering temperature and longer sintering time, so that the refractory bricks form a denser structure and further enhance their performance. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a technical solution:

[0029] Embodiment 1

[0030] A special refractory brick formula for sodium sulfide production includes high-alumina bauxite (Al2O3 content ≥ 70%), magnesia (MgO content ≥ 90%), silicon carbide (SiC content ≥ 95%), silicon micropowder (SiO2 content ≥ 90%), binder (high temperature resistant inorganic binder) and sodium polysulfide residue (PH value 6-8). High-alumina bauxite, magnesia, silicon carbide and sodium polysulfide residue are crushed and sieved to make their particle sizes 3-5mm, 2-3mm, 1-2mm and 1.5-2mm respectively. The particle size of silicon micropowder is 0.1-0.5μm.

[0031] The production method is as follows:

[0032] Step 1: Mix the ingredients:

[0033] The ingredients are prepared in precise proportions of 30-55% high-alumina bauxite, 15-20% magnesia, 7-10% silicon carbide, 3-5% silicon micropowder, 4-5% binder and 3-5% sodium polysulfide residue. The raw materials and additives are carefully placed in a large-scale high-efficiency mixer for thorough mixing. The mixing time is as long as 45 minutes. Continuous mixing ensures that the various ingredients are evenly distributed, laying a solid foundation for subsequent processes.

[0034] Step 2: Molding:

[0035] The carefully mixed raw materials are accurately loaded into a special mold and molded using an advanced pressure molding machine. The molding pressure is strictly controlled at 150MPa and the pressure holding time is accurately set to 45 seconds to ensure that the size of the molded refractory bricks is accurate and reaches the standard 230mm×114mm×65mm;

[0036] Step 3: Drying:

[0037] The formed refractory bricks are placed in a drying kiln for drying. During the drying process, the temperature must be stably controlled at 150°C and the drying time lasts for 24 hours to fully remove the moisture in the refractory bricks and improve their initial strength;

[0038] Step 4: Sintering:

[0039] The dried refractory bricks are placed in a high-temperature sintering furnace in an orderly manner for the key sintering step. The sintering temperature is precisely set to 1600°C and the sintering time is as long as 10 hours. During this high-temperature process, the raw materials undergo physical and chemical reactions, allowing the refractory bricks to form a dense structure, thus possessing excellent high-temperature resistance and chemical stability.

[0040] Embodiment 2

[0041] A special refractory brick formula for sodium sulfide production includes high-alumina bauxite (Al2O3 content ≥ 75%), magnesia (MgO content ≥ 92%), silicon carbide (SiC content ≥ 97%), silicon micropowder (SiO2 content ≥ 92%), binder (high temperature resistant inorganic binder) and sodium polysulfide residue (PH value 6-8). High-alumina bauxite, magnesia, silicon carbide and sodium polysulfide residue are crushed and sieved to make their particle sizes respectively 3-5mm, 2-3mm, 0.5-1mm and 1-1.5mm. The particle size of silicon micropowder is 0.05-0.3μm.

[0042] The production method is as follows:

[0043] Step 1: Mix the ingredients:

[0044] The ingredients are prepared in precise proportions of 30-55% high-alumina bauxite, 18-25% magnesia, 10-12% silicon carbide, 3-4% silicon powder, 3-4% binder and 3-5% sodium polysulfide residue. The raw materials and additives are carefully placed in a large-scale high-efficiency mixer for thorough mixing. The mixing time is as long as 45 minutes. Continuous mixing ensures that the various ingredients are evenly distributed, laying a solid foundation for subsequent processes.

[0045] Step 2: Molding:

[0046] The carefully mixed raw materials are accurately loaded into a special mold and molded using an advanced pressure molding machine. The molding pressure is strictly controlled at 180MPa and the pressure holding time is accurately set to 45 seconds to ensure that the size of the molded refractory bricks is accurate and reaches the standard 230mm×114mm×65mm;

[0047] Step 3: Drying:

[0048] The formed refractory bricks are placed in a drying kiln for drying. During the drying process, the temperature must be stably controlled at 180°C and the drying time lasts for 36 hours to fully remove the moisture in the refractory bricks and improve their initial strength;

[0049] Step 4: Sintering:

[0050] The dried refractory bricks are placed in a high-temperature sintering furnace in an orderly manner for the key sintering step. The sintering temperature is precisely set to 1700°C and the sintering time is as long as 12 hours. During this high-temperature process, the raw materials undergo physical and chemical reactions, allowing the refractory bricks to form a dense structure, thus possessing excellent high-temperature resistance and chemical stability.

[0051] Comparative Example:

[0052] The conventional refractory bricks are used for the sodium sulfide production comparison test. The main components of the conventional refractory bricks are high-alumina bauxite and binder, and the production process is similar to the present invention, but they are different in raw material selection, formula, sintering temperature, process control, etc.

[0053] Performance Test:

[0054] The performance tests were conducted on the refractory bricks prepared in Example 1 and Example 2 and the conventional refractory bricks of the comparative example. The test results are shown in the following table:

[0055]

[0056] It can be seen from the test results that the refractory bricks prepared by the present invention are significantly superior to traditional refractory bricks in terms of bulk density, room temperature compressive strength, load softening temperature and thermal shock resistance, can meet the requirements of sodium sulfide production, and can be used for a long period of more than 12 months after trial in industrial equipment.

[0057] The refractory brick has high strength, good corrosion resistance, excellent thermal shock resistance and good thermal insulation performance, can effectively improve the efficiency and quality of sodium sulfide production, and reduce production costs. The production technology of the invention is simple and feasible, and is easy to realize industrial production.

[0058] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A formula for producing special refractory bricks for sodium sulfide, characterized in that: The formula includes high-alumina bauxite, magnesia, silicon carbide, silicon micropowder, binder and sodium polysulfide residue; Among them, high-alumina bauxite, magnesia, silicon carbide and sodium polysulfide residues are crushed and screened.

2. The method for producing a special refractory brick formula for sodium sulfide according to claim 1, characterized in that: The production method is as follows: Step 1: Mix the ingredients: The ingredients are prepared in precise proportions of 30-55% high-alumina bauxite, 15-20% magnesia, 7-10% silicon carbide, 3-5% silicon micropowder, 4-5% binder and 3-5% sodium polysulfide residue. The raw materials and additives are carefully placed in a large-scale high-efficiency mixer for thorough mixing. The mixing time is as long as 45 minutes. Continuous mixing ensures that the various ingredients are evenly distributed, laying a solid foundation for subsequent processes. Step 2: Molding: The carefully mixed raw materials are accurately loaded into a special mold and molded using an advanced pressure molding machine. The molding pressure is strictly controlled at 150MPa and the pressure holding time is accurately set to 45 seconds to ensure that the size of the molded refractory bricks is accurate and reaches the standard 230mm×114mm×65mm; Step 3: Drying: The formed refractory bricks are placed in a drying kiln for drying. During the drying process, the temperature must be stably controlled at 150°C and the drying time lasts for 24 hours to fully remove the moisture in the refractory bricks and improve their initial strength; Step 4: Sintering: The dried refractory bricks are placed in a high-temperature sintering furnace in an orderly manner for the key sintering step. The sintering temperature is precisely set to 1600°C and the sintering time is as long as 10 hours. During this high-temperature process, the raw materials undergo physical and chemical reactions, allowing the refractory bricks to form a dense structure, thus possessing excellent high-temperature resistance and chemical stability.

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