A lime-containing composite crucible of more than 200 kg and a method for manufacturing the same

Abstract

The present application relates to a kind of over 200kg lime quality combination crucible, including bottom, body, bottom is integral bottom or splicing structure, body is splicing structure, the top of bottom and the bottom of body are connected using circular arc surface inlay, body is built by layer by pot body block, and the inlay connection of circular arc surface between layer and layer body block and the body block in each layer is, the body block of adjacent two layers is staggered arrangement.The present application combination crucible exists certain gap between each part, can release the thermal stress generated in the process of oven and use of crucible;Prevent crack generation.Solve the problem of crack generated in the process of oven and use of large crucible.

Description

Technical Field

[0001] This invention relates to crucibles, and more particularly to a lime-based composite crucible with a capacity of 200 kg or more. Background Technology

[0002] Crucible forming generally uses rammed earth material and isostatic pressing crucibles. Rammed earth material crucibles are inefficient due to manual ramming, require long furnace drying times, and have low strength and density. Isostatic pressing crucibles improve upon some of the drawbacks of rammed earth material, but isostatically pressed limestone crucibles are prone to cracking during use. Furthermore, isostatic pressing equipment is limited by its diameter and cannot produce large crucibles.

[0003] Currently, crucibles weighing less than 200kg in China are generally produced by isostatic pressing. These crucibles are relatively small and easy to manufacture, and are generally easy to form with an isostatic press of Φ320mm or less. For crucibles weighing 200kg or more, an isostatic press with an Φ500mm or larger is required. Lime-based isostatic pressing crucibles are different from those made of other materials. No binder is used during the forming process. For large lime-based isostatic pressing crucibles, demolding and handling are quite difficult. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a lime-based composite crucible with a capacity of 200 kg or more, thereby solving the problem of cracking in isostatic crucibles during use and the incompatibility of isostatic crucibles with large crucibles.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A lime-based composite crucible with a capacity of 200 kg or more includes a crucible bottom and a crucible body. The crucible bottom is either an integral crucible bottom or a spliced ​​structure, and the crucible body is a spliced ​​structure. The top of the crucible bottom and the bottom of the crucible body are connected by an arc-shaped inlay. The crucible body is constructed by layering crucible blocks. The crucible blocks between layers and within each layer are connected by an arc-shaped inlay. The crucible blocks of adjacent layers are arranged in a staggered manner.

[0007] When the bottom of the crucible is a spliced ​​structure, the bottom of the crucible includes multiple bottom blocks, each including a bottom core. Multiple bottom petals are evenly distributed around the outer periphery of the bottom core, and a stepped platform is provided around the outer periphery of the bottom core. The bottom petals are inlaid and connected to the bottom core through the stepped platform.

[0008] A lime-based composite crucible with a capacity of 200 kg or more, comprising, by weight percentage: 93%–98% natural lime, 0.5%–2% sodium tripolyphosphate, 0.5%–2% sodium hexametaphosphate, 0.5%–3% calcium fluoride, and 0.01%–2% silica fume.

[0009] The natural lime contains more than 90% CaO and less than 0.5% SiO2.

[0010] A method for manufacturing a limestone composite crucible with a capacity of 200 kg or more, comprising:

[0011] I. Preparation of clinker

[0012] 1) Crush natural lime to a thickness of less than 0.5 mm;

[0013] 2) Natural lime is mixed evenly with sodium polyphosphate, sodium hexametaphosphate, calcium fluoride, and silica powder, and then formed into blocks;

[0014] 3) Calcination: Sintering into clinker at 1350℃~1500℃;

[0015] 4) Crush the clinker to 0-5mm;

[0016] II. Preparation of integral crucible bottom or crucible bottom block and crucible body block

[0017] 1) Heat the clinker to 110-150℃, add 1.0%-2.5% of paraffin wax by weight of the clinker and mix well. Make blanks of integral crucible bottom or crucible bottom blocks and crucible body blocks according to the structure of the combined crucible, and number them.

[0018] 2) Sintering at 1350℃~1500℃;

[0019] III. Assembly:

[0020] When in use, place the entire crucible bottom or the assembled crucible bottom blocks at the bottom of the smelting furnace, and build the crucible body blocks layer by layer according to the number to form a crucible. Then, tamp magnesia around the outer perimeter of the crucible.

[0021] The clinker exhibits a weight gain rate of less than 1% after being exposed to air for 30 days.

[0022] In step 2.1), the blanks of the integral crucible bottom or crucible bottom block and crucible body block are formed by a hydraulic brick press or a friction brick press.

[0023] Compared with existing technologies, the beneficial effects of this invention are:

[0024] 1. In this invention, sodium tripolyphosphate, sodium hexametaphosphate, calcium fluoride, and silicon micropowder are used as additives to delay the hydration of the material and have little impact on the high-temperature performance of the material.

[0025] 2. The composite crucible has gaps between its components, which helps release thermal stress generated during furnace baking and use, preventing cracks. This solves the problem of cracks forming in large crucibles during furnace baking and use.

[0026] 3. The sintering temperature is relatively low, and sintering can be carried out at 1350℃~1500℃, realizing low-temperature sintering and high-temperature use.

[0027] 4. It can effectively remove inclusions in steel or alloys, improving the purity of the material. Attached Figure Description

[0028] Figure 1 This is a structural cross-sectional view of Embodiment 1.

[0029] Figure 2 This is a top view of Example 1.

[0030] Figure 3 This is a schematic diagram of the crucible body blocks.

[0031] Figure 4 This is a cross-sectional view of the bottom of the crucible in Example 2.

[0032] Figure 5 This is a schematic diagram of the bottom of the crucible in Example 2.

[0033] In the diagram: 1. Overall bottom of the crucible; 2. Bottom edge of the crucible; 3. Bottom body block; 4. Bottom core; 5. Bottom petals. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0035] like Figures 1-5 A lime-based composite crucible with a capacity of 200 kg or more includes a crucible bottom and a crucible body. The crucible bottom is either an integral crucible bottom 1 or a spliced ​​structure. The crucible body is a spliced ​​structure. The top of the crucible bottom and the bottom of the crucible body are connected by an arc-shaped inlay. The crucible body is constructed by layering crucible body blocks 3. The crucible body blocks 3 between layers and within each layer are connected by an arc-shaped inlay. The crucible body blocks 3 of adjacent layers are arranged in a staggered manner.

[0036] When the bottom of the crucible is a spliced ​​structure, the bottom of the crucible includes multiple bottom blocks, each including a bottom core 4, with multiple bottom petals 5 evenly distributed around the outer periphery of the bottom core, and a stepped platform provided around the outer periphery of the bottom core 4. The bottom petals 5 are inlaid and connected to the bottom core 4 through the stepped platform.

[0037] A method for manufacturing a limestone composite crucible with a capacity of 200 kg or more, comprising:

[0038] I. Preparation of clinker

[0039] 1) Crush natural lime to a thickness of less than 0.5 mm;

[0040] 2) Natural lime is mixed evenly with sodium polyphosphate, sodium hexametaphosphate, calcium fluoride, and silica powder and then formed into blocks; by weight percentage, it includes 93% natural lime, 0.5%–2% sodium tripolyphosphate, 0.5%–2% sodium hexametaphosphate, 0.5%–3% calcium fluoride, and 0.05%–2% silica powder;

[0041] 3) Calcination: Sintering into clinker at 1350℃~1500℃;

[0042] 4) Crush the clinker to 0-5mm;

[0043] II. Preparation of integral crucible bottom or crucible bottom block and crucible body block

[0044] 1) Heat the clinker to 110-150℃, add 1.0%-2.5% of paraffin wax by weight of the clinker and mix well. Make blanks of integral crucible bottom or crucible bottom blocks and crucible body blocks according to the structure of the combined crucible, and number them.

[0045] 2) Sintering at 1350℃~1500℃;

[0046] III. Assembly:

[0047] When in use, place the entire crucible bottom or the assembled crucible bottom blocks at the bottom of the heating furnace, and build the crucible body blocks layer by layer according to the number to form a crucible. Press magnesia sand around the outside of the crucible; add smelting materials into the crucible for smelting.

[0048] The clinker exhibits a weight gain rate of less than 1% after being exposed to air for 30 days.

[0049] In step 2.1), the blanks of the integral crucible bottom or crucible bottom block and crucible body block are formed by a hydraulic brick press or a friction brick press.

[0050] Example 1

[0051] The crucible weighs 220kg (capacity 220Kg crucible) and has a bottom diameter of 320mm.

[0052] The lime-based composite crucible includes a bottom and a body. The bottom is a single, integral structure (1), while the body is a spliced ​​structure. The top of the bottom and the bottom of the body are connected by an inlaid arc surface. The body is constructed from layers of crucible blocks (3), with inlaid arc surfaces connecting the blocks (3) between layers and within each layer. Adjacent layers of blocks (3) are staggered. The crucible maintains a taper of 1–3% from top to bottom.

[0053] The method for manufacturing a lime-based composite crucible includes:

[0054] I. Preparation of clinker

[0055] 1) Crush natural lime to a thickness of less than 0.5 mm;

[0056] 2) Natural lime is mixed evenly with sodium polyphosphate, sodium hexametaphosphate, calcium fluoride, and silica powder and then formed into blocks; by weight percentage, natural lime is 95%, CaO is greater than 90%, and SiO2 is less than 0.5%; sodium tripolyphosphate is 0.5%, sodium hexametaphosphate is 0.5%, calcium fluoride is 3.95%, and silica powder is 0.05%.

[0057] 3) Calcination: Sintering at 1350℃~1500℃ to produce clinker; the weight gain of the clinker after being exposed to air for 30 days is 0.9%.

[0058] 4) Crush the clinker to 0-5mm;

[0059] II. Preparation of integral crucible bottom or crucible bottom block and crucible body block

[0060] 1) Heat the clinker to 110-150℃, add 2.0% of the weight of the clinker and mix well. Make blanks of the whole crucible bottom or crucible bottom block and crucible body block according to the structure of the combined crucible, and number them; the height of the crucible body block is 200-220mm.

[0061] 2) Sintering at 1400℃~1500℃;

[0062] III. Assembly

[0063] When in use, place the entire crucible bottom or the assembled crucible bottom blocks at the bottom of the smelting furnace, and build the crucible body blocks layer by layer according to the number to form a crucible. Then, tamp magnesia around the outer perimeter of the crucible.

[0064] The smelting materials are added to the crucible for smelting.

[0065] Example 2

[0066] The crucible weighs 220kg (capacity 220kg crucible) and has a bottom diameter of 350mm.

[0067] The lime-based composite crucible includes a bottom and a body. Both the bottom and body are spliced ​​structures. The bottom includes a bottom core 4, with three evenly distributed bottom lobes 5 around its outer perimeter. A stepped platform is provided around the outer perimeter of the bottom core 4, and the bottom lobes 5 are inlaid and connected to the bottom core via these stepped platforms. The bottom has a bottom edge 2 that transitions smoothly with the bottom plane, and this bottom edge 2 is inlaid and connected to the curved surface of the crucible body. The crucible body is constructed from layers of crucible blocks 3. The crucible blocks 3 between layers and within each layer are inlaid and connected using curved surfaces. Adjacent layers of crucible blocks 3 are staggered. The crucible maintains a taper of 1-3% from top to bottom.

[0068] The method for manufacturing a lime-based composite crucible includes:

[0069] 1) Crush natural lime to a thickness of less than 0.5 mm;

[0070] 2) Mix natural lime with sodium polyphosphate, sodium hexametaphosphate, calcium fluoride, and silica powder until homogeneous; natural lime 96%, sodium tripolyphosphate 0.5%, sodium hexametaphosphate 0.5%, calcium fluoride 2.98%, and silica powder 0.02%.

[0071] 3) Calcination: Sintering at 1350℃~1500℃ to produce clinker; the weight gain of the clinker after being exposed to air for 30 days is 0.9%.

[0072] 4) Crush the clinker to 0-5mm;

[0073] II. Preparation of integral crucible bottom or crucible bottom block and crucible body block

[0074] 1) Heat the clinker to 110-150℃, add 2.0% of the weight of the clinker and mix well. Make blanks for the bottom block and body block of the crucible according to the structure of the combined crucible, and number them. The height of the body block is 200-220mm.

[0075] 2) Sintering at 1400℃~1500℃;

[0076] III. Assembly

[0077] When in use, place the assembled crucible bottom blocks at the bottom of the smelting furnace, and build the crucible by layering the pot body blocks according to the numbers. Then, tamp magnesia around the outside of the crucible.

[0078] The smelting materials are added to the crucible for smelting.

[0079] The sintering temperature of limestone crucibles is relatively low, only 1350℃~1500℃, achieving low-temperature sintering and high-temperature use. When used in smelting, these crucibles can effectively remove inclusions or alloy impurities from steel, improving material purity.

[0080] CaO + FeS → CaS + FeO (reversible) (1)

[0081] CaO + FeS + C → CaS + Fe + CO (2)

[0082] 4CaO+3FeO.P2O5---4CaO.P2O5+3FeO(3)

[0083] CaO + Al₂O₃ → CaO.Al₂O₃(4)

[0084] The lime crucible has a significant effect on adsorbing aluminum in steel. At around 1500℃, the two react rapidly to form calcium aluminate (CaO.Al2O3) with a low melting point. 4CaO.P2O5 is a stable compound that is firmly held in the slag. Reaction (1) is a reversible reaction, but carbon (C) in the slag participates in the reaction, i.e., reaction (2). CaS is insoluble in molten steel but forms slag that floats on the surface of molten steel. The salts generated by the above reaction have a melting point much lower than the oxides (CaO, Al2O3) themselves and are easy to float into the slag.

[0085] Neither steel nor alloys wet lime-based refractories. CaO has high high-temperature chemical stability, and its oxygen (O) partial pressure is much lower than that of MgO at the same temperature. This is why low-oxygen (O) products can be smelted using lime-based refractories.

[0086] The above description is merely the basic principle of the present invention and does not constitute any limitation on the present invention. Any equivalent changes and modifications made to the present invention based on the present invention shall be within the scope of protection of this patented technology.

Claims

1. A method for manufacturing a lime-based composite crucible with a capacity of 200 kg or more, characterized in that, The lime-based composite crucible includes a crucible bottom and a crucible body. The crucible bottom is either a single piece or a spliced ​​structure. The crucible body is a spliced ​​structure. The top of the crucible bottom and the bottom of the crucible body are connected by an arc-shaped inlay. The crucible body is constructed by layering crucible blocks. The crucible blocks between layers and within each layer are connected by an arc-shaped inlay. The crucible blocks of adjacent layers are arranged in a staggered manner. The composition, by weight percentage, includes 93%–98% natural lime, 0.5%–2% sodium tripolyphosphate, 0.5%–2% sodium hexametaphosphate, 0.5%–3% calcium fluoride, and 0.01%–2% silica fume. The manufacturing method includes: I. Preparation of Clinker 1) Crush natural lime to below 0.5mm; 2) Natural lime is mixed evenly with sodium polyphosphate, sodium hexametaphosphate, calcium fluoride, and silica powder, and then formed into blocks; 3) Calcination: Sintering into clinker at 1350℃~1500℃; 4) Crush the clinker to 0-5mm; II. Preparation of integral crucible bottom or crucible bottom blocks and crucible body blocks 1) Heat the clinker to 110-150℃, add 1.0%-2.5% of paraffin wax by weight of the clinker and mix well. Make blanks of integral crucible bottom or crucible bottom blocks and crucible body blocks according to the structure of the combined crucible, and number them. 2) Sintering at 1350℃~1500℃; III. Assembly: When in use, place the entire crucible bottom or the assembled crucible bottom blocks at the bottom of the smelting furnace, and build the crucible body blocks layer by layer according to the number to form a crucible. Then, tamp magnesia around the outer perimeter of the crucible.

2. The lime-based composite crucible with a capacity of 200 kg or more according to claim 1, characterized in that, When the bottom of the crucible is a spliced ​​structure, the bottom of the crucible includes multiple bottom blocks, each including a bottom core. Multiple bottom petals are evenly distributed around the outer periphery of the bottom core, and a stepped platform is provided around the outer periphery of the bottom core. The bottom petals are inlaid and connected to the bottom core through the stepped platform.

3. A lime-based composite crucible with a capacity of 200 kg or more according to claim 1, characterized in that, The natural lime contains more than 90% CaO and less than 0.5% SiO2.

4. The method for manufacturing a lime-based composite crucible with a capacity of 200 kg or more according to claim 1, characterized in that, The clinker exhibits a weight gain rate of less than 1% after being exposed to air for 30 days.

5. The method for manufacturing a lime-based composite crucible with a capacity of 200 kg or more according to claim 1, characterized in that, In step 2, 1), the blanks of the overall crucible bottom or crucible bottom block and crucible body block are formed by a hydraulic brick press or a friction brick press.

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