阅读说明：本技术 一种水泥窑用喷煤管预制件及其制备方法 (Coal injection pipe prefabricated part for cement kiln and preparation method thereof ) 是由 王立旺 朱国平 李新明 王琪 彭晶晶 方利华 于 2021-10-12 设计创作，主要内容包括：本发明属于水泥生产配件技术领域,具体公开了一种水泥窑用喷煤管预制件及其制备方法,所述预制件包括预制主体以及涂覆在所述预制主体上的涂层,所述预制主体至少由以下重量份的原料制成：钛刚玉43～59份,黑刚玉15～25份,煅烧叶腊石8～12份,硅线石粉6～10份,氧化铝粉8～12份,结合剂4～6份,耐热钢纤维1～2份,聚合氯化铝0.15～0.2份；所述预制主体呈弧形管壳状,用于拼接成套设在喷煤管头部的圆管,其内弧面沿轴向方向贯穿开设有呈倒T型的凹槽；外弧面涂覆有所述的涂层。本发明预制件抗热震性好,强度高,不易开裂剥落,施工简单,使用寿命长。(The invention belongs to the technical field of cement production accessories, and particularly discloses a coal injection pipe prefabricated part for a cement kiln and a preparation method thereof, wherein the prefabricated part comprises a prefabricated main body and a coating coated on the prefabricated main body, and the prefabricated main body is at least prepared from the following raw materials in parts by weight: 43-59 parts of titanium corundum, 15-25 parts of black corundum, 8-12 parts of calcined pyrophyllite, 6-10 parts of sillimanite powder, 8-12 parts of alumina powder, 4-6 parts of a binding agent, 1-2 parts of heat-resistant steel fiber and 0.15-0.2 part of polyaluminium chloride; the prefabricated main body is in an arc tube shell shape and is used for splicing into a round tube sleeved on the head of the coal injection tube, and an inverted T-shaped groove is formed in the inner arc surface of the prefabricated main body in a penetrating manner along the axial direction; the extrados surface is coated with said coating. The prefabricated member has the advantages of good thermal shock resistance, high strength, difficult cracking and stripping, simple construction and long service life.)

1. The utility model provides a coal injection pipe prefab for cement kiln which characterized in that: the coating comprises a prefabricated main body (1) and a coating layer (2) coated on the prefabricated main body (1), wherein the prefabricated main body (1) is at least prepared from the following raw materials in parts by weight: 43-59 parts of titanium corundum, 15-25 parts of black corundum, 8-12 parts of calcined pyrophyllite, 6-10 parts of sillimanite powder, 8-12 parts of alumina powder, 4-6 parts of a binding agent, 1-2 parts of heat-resistant steel fiber and 0.15-0.2 part of polyaluminium chloride.

2. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the titanium corundum comprises the following components: 18-24 parts of titanium corundum with the particle size of 5-8 mm, 15-20 parts of titanium corundum with the particle size of 3-5 mm and 10-15 parts of titanium corundum with the particle size of 1-3 mm.

3. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: in the titanium corundum, Al₂O₃85-90% of TiO₂The mass percentage of the component (A) is 5-8%.

4. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the black corundum comprises the following components: 10-15 parts of black corundum with the particle size of 0.075-1 mm, and 5-10 parts of black corundum with the particle size of less than 0.075 mm.

5. The coal injection pipe prefabricated member for cement kiln as claimed in claim 1, wherein the coal injection pipe prefabricated member is characterized in that: in the black corundum, Al₂O₃65-74% by mass of Fe₂O₃The mass percentage of the component (A) is 8-12%.

6. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the binding agent is SioxX-Zero powder.

7. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the particle size of the calcined pyrophyllite is 0-1 mm, and the particle size of the sillimanite powder is not more than 200 meshes.

8. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the coating (2) is a glaze layer, and the glaze layer comprises the following raw materials in percentage by mass: SiO 2₂ 35~40%，B₂O₃ 3~8%，Na₂O 2~5%。

9. The coal injection pipe prefabricated member for the cement kiln as claimed in claim 1, wherein: the prefabricated main body (1) is in an arc tube shell shape and comprises an inner arc surface (11), an outer arc surface (12) and two joint end surfaces (13) connecting the inner arc surface (11) and the outer arc surface (12); an inverted T-shaped groove (14) penetrates through the inner arc surface (11) of the prefabricated main body (1) along the axial direction; the coating (2) is coated on the outer arc surface (12).

10. The method for preparing the coal injection pipe prefabricated member for the cement kiln as claimed in any one of claims 1 to 9, comprising the steps of:

s1, mixing the raw materials of the prefabricated main body (1) with water, and uniformly stirring; then vibrating, pouring and forming in a mould, demoulding after 6-8 hours of forming, and curing at normal temperature for 70-75 hours;

s2, coating a coating (2) with the thickness of 0.3-0.5 mm on the surface of the prefabricated main body (1) to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 100-110 ℃ at a heating rate of 7.5-8.5 ℃/h, and preserving heat for 3.5-4.5 hours; then heating to 270-290 ℃ at a heating rate of 9.5-10.5 ℃/h, and preserving heat for 5.5-6.5 hours; heating to 390-410 ℃ at a heating rate of 14.5-15.5 ℃/h, and keeping the temperature for 7.5-8.5 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

Technical Field

The invention belongs to the technical field of cement production accessories, and particularly relates to a coal injection pipe prefabricated part for a cement kiln and a preparation method thereof.

Background

The cement is required to be calcined at high temperature in the production process, and the high-temperature fuel is required to be conveyed into the cement kiln through the coal injection pipe, along with the development of the novel dry-process cement kiln towards the large-scale direction and the continuous application of an external decomposition technology, the performance requirement of the coal injection pipe of the cement kiln is also increasingly improved, and the requirement is that the heat supply in the cement calcination process must be ensured. In order to improve the service performance of the coal injection pipe, a layer of refractory material is generally poured at the port of the coal injection pipe to serve as a protective sleeve, and the coal injection pipe is in a high-temperature environment for a long time, and is subjected to severe environments such as cement clinker scouring, abrasion, rapid cooling and rapid heating, so that the performance requirement on the protective sleeve is very high.

The refractory castable for forming the protective sleeve generally has high aluminum content and high strength, but has poor thermal shock resistance, is easy to crack and strip, and has limited service life. Although the thermal shock resistance of the castable containing silicon carbide is improved to a certain extent, the service performance is also obviously reduced along with the oxidation of the silicon carbide under the service condition. In addition, when the port of the coal injection pipe is poured with refractory materials, the requirements on construction conditions and construction environments are high: the formwork support is needed during pouring, the mixed material needs to be put into a mold within 30 minutes, otherwise, the mixed material becomes hard, the mixed material needs to be vibrated during the mold putting, and the construction time is long; a maintenance period of about 3d is needed after construction, and the maintenance time is long; the construction difficulty is high by adopting the castable in winter, and necessary heat preservation measures are needed during construction due to low air temperature, so that the construction difficulty is increased, and the construction speed is influenced; even if the construction technical requirements are strictly executed, the local burst phenomenon always occurs after the operation is carried out for a period of time, and the maintenance cost is higher; under the condition of unscheduled maintenance, the kiln is opened for ignition usually for several hours or half a day during actual maintenance, so that the service life of the castable is greatly shortened. Therefore, besides the defects of the material, the construction quality directly influences the use effect of the protective sleeve, the construction difficulty of the conventional protective sleeve is high, the construction quality is difficult to ensure, cracking and peeling are easy to generate in the use process, and the use period is short (the use period of the conventional protective sleeve for the port of the coal injection pipe is only 6-8 months).

Disclosure of Invention

In order to solve the problems, the invention provides the coal injection pipe prefabricated part for the cement kiln, which has the advantages of good thermal shock resistance, high strength, difficult cracking and stripping, simple construction and long service life.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

the coal injection pipe prefabricated part for the cement kiln comprises a prefabricated main body and a coating coated on the prefabricated main body, wherein the prefabricated main body is at least prepared from the following raw materials in parts by weight: 43-59 parts of titanium corundum, 15-25 parts of black corundum, 8-12 parts of calcined pyrophyllite, 6-10 parts of sillimanite powder, 8-12 parts of alumina powder, 4-6 parts of a binding agent, 1-2 parts of heat-resistant steel fiber and 0.15-0.2 part of polyaluminium chloride.

The invention provides a prefabricated member for splicing round pipes (namely a protective sleeve), wherein in the formula of a prefabricated main body of the prefabricated member, titanium corundum and black corundum which have better thermal shock resistance and toughness and high strength are compounded to be used as main raw materials of a coal injection pipe prefabricated member, so that the prefabricated member has higher basic strength and thermal shock resistance, and in addition, alpha-Al is used in the titanium corundum₂O₃And aluminum titanate as main mineral phase, and can prevent Fe in black corundum²⁺To Fe³⁺The transformation of the black corundum ensures the stability of the hercynite phase in the black corundum and the thermal shock resistance of the prefabricated member is not reduced; the calcined pyrophyllite plays a transition role, so that the adhesion performance of the coating on the surface of the prefabricated main body can be improved, and the coating is prevented from being peeled off due to the difference of the thermal expansion coefficients of the pyrophyllite and the coating; the heat-resistant steel fiber plays a role in strengthening and toughening in the prefabricated part; the polyaluminium chloride can adjust the hardening time of the prefabricated member and improve the working efficiency. Therefore, the prefabricated part is provided by the invention through material optimizationHas good strength, thermal shock resistance and toughness, thereby prolonging the service cycle of the prefabricated member.

Preferably, the composition of the titanium corundum is as follows: 18-24 parts of titanium corundum with the particle size of 5-8 mm, 15-20 parts of titanium corundum with the particle size of 3-5 mm and 10-15 parts of titanium corundum with the particle size of 1-3 mm.

Preferably, in the titanium corundum, Al₂O₃85-90% of TiO₂The mass percentage of the component (A) is 5-8%.

Preferably, the composition of the black corundum is as follows: 10-15 parts of black corundum with the particle size of 0.075-1 mm, and 5-10 parts of black corundum with the particle size of less than 0.075 mm.

Preferably, in the black corundum, Al₂O₃65-74% by mass of Fe₂O₃The mass percentage of the component (A) is 8-12%.

Preferably, the binding agent is SioxX-Zero powder. SioxX-Zero powder is used as modified composite silicon micro powder, so that on one hand, the SioxX-Zero powder can play a role in dispersing, reduce the water adding amount and improve the fluidity during casting forming; on the other hand, the bonding effect is realized, and higher strength can be generated at low temperature.

Preferably, the particle size of the calcined pyrophyllite is 0-1 mm, and the particle size of the sillimanite powder is not more than 200 meshes.

Preferably, the coating is a glaze layer, and the glaze layer comprises the following raw materials in percentage by mass: SiO 2₂ 35~40%，B₂O₃ 3~8%，Na₂And (3) O2-5%. The coating has immune protection function on the coal injection pipe prefabricated part, and the coating of the formula can effectively improve the K resistance of the prefabricated part₂O、Na₂And (4) the corrosion capability of alkaline gases such as O and the like.

Preferably, the prefabricated main body is in an arc tube shell shape and comprises an inner arc surface, an outer arc surface and two joint end surfaces for connecting the inner arc surface and the outer arc surface; an inverted T-shaped groove penetrates through the inner arc surface of the prefabricated main body along the axial direction; the coating is coated on the outer cambered surface. The groove is used for mounting an anchoring piece with the top end fixed on the core body of the coal injection pipe, and the anchoring piece penetrates into the groove in the axial direction; and the grooves can release stress, so that the possibility of cracking of the prefabricated part is effectively reduced. Besides materials, the fireproof material is made into the modularized prefabricated member, the traditional pouring construction mode is changed, installation can be completed only by splicing and sleeving during construction, adverse effects of pouring construction factors on products are avoided, construction quality is guaranteed, and the service life is further prolonged.

The invention also provides a preparation method of the coal injection pipe prefabricated part for the cement kiln, which comprises the following steps:

s1, mixing the raw materials of the prefabricated main body with water, and uniformly stirring; then vibrating, pouring and forming in a mould, demoulding after 6-8 hours of forming, and curing at normal temperature for 70-75 hours;

s2, coating a coating with the thickness of 0.3-0.5 mm on the surface of the prefabricated main body to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 100-110 ℃ at a heating rate of 7.5-8.5 ℃/h, and preserving heat for 3.5-4.5 hours; then heating to 270-290 ℃ at a heating rate of 9.5-10.5 ℃/h, and preserving heat for 5.5-6.5 hours; heating to 390-410 ℃ at a heating rate of 14.5-15.5 ℃/h, and keeping the temperature for 7.5-8.5 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

Preferably, in step S3, the semi-finished product is placed in a heating device, heated to 105 ℃ at a heating rate of 8 ℃/h, and kept for 4 hours; then heating to 280 ℃ at a heating rate of 10 ℃/h, and preserving heat for 6 hours; then the temperature is raised to 400 ℃ at the temperature raising speed of 15 ℃/h, and the temperature is preserved for 8 hours.

The invention has the following beneficial effects:

1. the prefabricated part has good and stable thermal shock resistance and impact toughness by the matching use of the titanium corundum and the black corundum, and can adapt to the deformation of the coal injection pipe in the using and hoisting processes; and good volume stability, wear resistance and high-temperature mechanical property are obtained through the optimization of the whole raw materials, the strength of the prefabricated part produced by low-temperature baking is greatly improved compared with that of the conventional castable, and the service cycle of the prefabricated part is effectively prolonged.

2. The invention is formed by arranging SiO_2、B₂O_3、Na₂And the coating made of O improves the capability of the prefabricated part for resisting the corrosion of alkaline gas.

3. According to the invention, calcined pyrophyllite is adopted in the raw materials of the prefabricated main body, so that a transition effect is achieved, the adhesion performance of the coating on the surface of the prefabricated main body is improved, and the coating is prevented from being peeled off due to the difference of the thermal expansion coefficients of the calcined pyrophyllite and the coating.

4. According to the invention, the refractory material is made into the modularized prefabricated member, the traditional pouring construction mode is changed, the adverse effects of strength reduction, easy cracking and the like caused by factors such as water adding amount, construction temperature, baking system and the like in the field construction process are avoided, the field assembly enables the construction to be simpler and easier, the steps of field stirring, pouring, ramming, maintenance and the like are directly omitted, the construction time is saved, the construction is not influenced by environment and seasons, the construction quality is ensured, the service life of the coal injection pipe is further prolonged on the basis of material optimization, and the service life of the prefabricated member assembled into a circular pipe sleeved at the end port of the coal injection pipe can reach 1-1.5 years.

5. When the round pipe assembled by the prefabricated parts is sleeved at the end opening of the coal injection pipe and is partially destroyed in the using process, the whole part of the round pipe does not need to be replaced like the existing protective sleeve molded by casting, and only the prefabricated parts corresponding to the damaged parts need to be replaced, so that the waste of materials is reduced, and the disassembly and the assembly are more convenient.

Drawings

FIG. 1: the invention discloses a structural schematic diagram of a coal injection pipe prefabricated part for a cement kiln.

FIG. 2: the invention discloses an application and installation schematic diagram of a coal injection pipe prefabricated part for a cement kiln.

FIG. 3: fig. 2 is a schematic structural view of a coal injection core body.

In the figure: 1-prefabricating a main body, 2-coating, 3-anchoring piece, 4-coal injection pipe core body and 5-round pipe; 11-intrados, 12-extrados, 13-junction end face, 14-groove.

Detailed Description

The invention is further described below with reference to the accompanying drawings and specific embodiments.

Example 1

A coal injection pipe prefabricated part for a cement kiln is shown in figure 1 and comprises a prefabricated main body 1 and a coating layer 2; the prefabricated main body 1 is in a semicircular tube shell shape and comprises an inner arc surface 11, an outer arc surface 12 and two joint end surfaces 13 connecting the inner arc surface 11 and the outer arc surface 12; an inverted T-shaped groove 14 penetrates through the inner arc surface 11 of the prefabricated main body 1 along the axial direction; the coating 2 is applied to the extrados face 12.

The prefabricated main body 1 is prepared from the following raw materials in parts by weight: 18 parts of titanium corundum with the particle size of 5-8 mm, 20 parts of titanium corundum with the particle size of 3-5 mm, 10 parts of titanium corundum with the particle size of 1-3 mm, 15 parts of black corundum with the particle size of 0.075-1 mm, 12 parts of calcined pyrophyllite with the particle size of 0-1 mm, 6 parts of sillimanite powder with the particle size not larger than 200 meshes, 12 parts of alumina powder, 10 parts of black corundum with the particle size smaller than 0.075mm, 6 parts of SioxX-Zero powder, 2 parts of heat-resistant steel fiber and 0.15 part of polyaluminium chloride; in the titanium corundum, Al₂O₃Is 88 percent by mass, TiO₂The mass percentage content of (A) is 6%; in the black corundum, Al₂O₃70 percent by mass of Fe₂O₃The mass percentage of (B) is 10%. The coating 2 is a glaze layer and is specifically prepared from the following raw materials (by mass percent): SiO 2₂ 38%，B₂O₃ 5%，Na₂O 4%。

The preparation method of the coal injection pipe prefabricated part for the cement kiln comprises the following steps:

s1, mixing the raw materials of the prefabricated main body 1 in proportion, adding 4 parts of water, and uniformly stirring; then vibrating and pouring the mixture in a mould for forming, demoulding after 8 hours, and curing at normal temperature for 72 hours;

s2, coating the coating 2 with the thickness of 0.3mm on the surface of the prefabricated main body 1 to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 105 ℃ at the heating rate of 8 ℃/h, and preserving heat for 4 hours; then heating to 280 ℃ at a heating rate of 10 ℃/h, and preserving heat for 6 hours; then the temperature is raised to 400 ℃ at the temperature raising speed of 15 ℃/h, and the temperature is kept for 8 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

The embodiment further provides an application and installation example of the coal injection pipe prefabricated member for the cement kiln, as shown in fig. 2, the coal injection pipe head structure comprises a coal injection pipe core body 4, a circular pipe 5 sleeved on the coal injection pipe core body 4, and an anchoring part 3 connecting the coal injection pipe core body 4 and the circular pipe 5; the circular tube 5 is formed by splicing two coal injection tube prefabricated parts for the cement kiln, and the adjacent prefabricated parts are spliced by bonding the joint end surfaces 13; the anchoring piece 3 is a Y-shaped anchoring piece and is clamped in the groove 14, and the top end of the anchoring piece is welded with the coal injection pipe core body 4; each prefabricated member is correspondingly provided with a group of anchoring members 3, and the group of anchoring members 3 are distributed at intervals along the axial direction on the outer wall of the coal injection pipe core body 4 (as shown in figure 3).

Example 2

The coal injection pipe prefabricated part for the cement kiln has the same structure as that of the prefabricated part in the embodiment 1, and is different in raw material composition and specifically comprises the following components:

the prefabricated main body 1 is prepared from the following raw materials in parts by weight: 24 parts of titanium corundum with the particle size of 5-8 mm, 15 parts of titanium corundum with the particle size of 3-5 mm, 15 parts of titanium corundum with the particle size of 1-3 mm, 10 parts of black corundum with the particle size of 0.075-1 mm, 8 parts of calcined pyrophyllite with the particle size of 0-1 mm, 10 parts of sillimanite powder with the particle size not greater than 200 meshes, 8 parts of alumina powder, 5 parts of black corundum with the particle size of less than 0.075mm, 4 parts of SioxX-Zero powder, 1 part of heat-resistant steel fiber and 0.2 part of polyaluminium chloride; in the titanium corundum, Al₂O₃Is 85 percent by mass and TiO₂The mass percentage content of the compound is 5 percent; in the black corundum, Al₂O₃65% by mass of Fe₂O₃The mass percentage of (B) is 8%. The coating 2 is a glaze layer and is specifically prepared from the following raw materials (by mass percent): SiO 2₂ 35%，B₂O₃ 3%，Na₂O 2%。

The preparation method of the coal injection pipe prefabricated part for the cement kiln comprises the following steps:

s1, mixing the raw materials of the prefabricated main body 1 in proportion, adding 6 parts of water, and uniformly stirring; then vibrating and pouring the mixture in a mould for forming, demoulding after 6 hours, and curing at normal temperature for 72 hours;

s2, coating the coating 2 with the thickness of 0.5mm on the surface of the prefabricated main body 1 to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 105 ℃ at the heating rate of 8 ℃/h, and preserving heat for 4 hours; then heating to 280 ℃ at a heating rate of 10 ℃/h, and preserving heat for 6 hours; then the temperature is raised to 400 ℃ at the temperature raising speed of 15 ℃/h, and the temperature is kept for 8 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

Example 3

The coal injection pipe prefabricated part for the cement kiln has the same structure as that of the prefabricated part in the embodiment 1, and is different in raw material composition and specifically comprises the following components:

the prefabricated main body 1 is prepared from the following raw materials in parts by weight: 22 parts of titanium corundum with the particle size of 5-8 mm, 18 parts of titanium corundum with the particle size of 3-5 mm, 12 parts of titanium corundum with the particle size of 1-3 mm, 13 parts of black corundum with the particle size of 0.075-1 mm, 10 parts of calcined pyrophyllite with the particle size of 0-1 mm, 8 parts of sillimanite powder with the particle size not larger than 200 meshes, 10 parts of alumina powder, 8 parts of black corundum with the particle size smaller than 0.075mm, 5 parts of SioxX-Zero powder, 1.5 parts of heat-resistant steel fiber and 0.18 part of polyaluminium chloride; in the titanium corundum, Al₂O₃90 percent by mass of TiO₂The mass percentage content of (A) is 8%; in the black corundum, Al₂O₃74 percent by mass of Fe₂O₃The mass percentage of (B) is 12%. The coating 2 is a glaze layer and is specifically prepared from the following raw materials (by mass percent): SiO 2₂ 40%，B₂O₃ 8%，Na₂O 5%。

The preparation method of the coal injection pipe prefabricated part for the cement kiln comprises the following steps:

s1, mixing the raw materials of the prefabricated main body 1 in proportion, adding 5 parts of water, and uniformly stirring; then vibrating and pouring the mixture in a mould for forming, demoulding the mixture after forming for 7 hours, and curing the mixture for 72 hours at normal temperature;

s2, coating the coating 2 with the thickness of 0.5mm on the surface of the prefabricated main body 1 to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 105 ℃ at the heating rate of 8 ℃/h, and preserving heat for 4 hours; then heating to 280 ℃ at a heating rate of 10 ℃/h, and preserving heat for 6 hours; then the temperature is raised to 400 ℃ at the temperature raising speed of 15 ℃/h, and the temperature is kept for 8 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

Example 4

The coal injection pipe prefabricated part for the cement kiln has the same structure as that of the prefabricated part in the embodiment 1, and is different in raw material composition and specifically comprises the following components:

the prefabricated main body 1 is prepared from the following raw materials in parts by weight: 23 parts of titanium corundum with the particle size of 5-8 mm, 17 parts of titanium corundum with the particle size of 3-5 mm, 14 parts of titanium corundum with the particle size of 1-3 mm, 11 parts of black corundum with the particle size of 0.075-1 mm, 11 parts of calcined pyrophyllite with the particle size of 0-1 mm, 9 parts of sillimanite powder with the particle size of not more than 200 meshes, 11 parts of alumina powder, 6 parts of black corundum with the particle size of less than 0.075mm, 4 parts of SioxX-Zero powder, 1.5 parts of heat-resistant steel fiber and 0.16 part of polyaluminium chloride; in the titanium corundum, Al₂O₃Is 85 percent by mass and TiO₂The mass percentage content of (A) is 8%; in the black corundum, Al₂O₃70 percent by mass of Fe₂O₃The mass percentage of (B) is 8%. The coating 2 is a glaze layer and is specifically prepared from the following raw materials (by mass percent): SiO 2₂ 35%，B₂O₃ 8%，Na₂O 4.5%。

The preparation method of the coal injection pipe prefabricated part for the cement kiln comprises the following steps:

s1, mixing the raw materials of the prefabricated main body 1 in proportion, adding 6 parts of water, and uniformly stirring; then vibrating and pouring the mixture in a mould for forming, demoulding after 8 hours, and curing at normal temperature for 72 hours;

s2, coating the coating 2 with the thickness of 0.3mm on the surface of the prefabricated main body 1 to obtain a semi-finished product;

s3, placing the semi-finished product in heating equipment, heating to 105 ℃ at the heating rate of 8 ℃/h, and preserving heat for 4 hours; then heating to 280 ℃ at a heating rate of 10 ℃/h, and preserving heat for 6 hours; then the temperature is raised to 400 ℃ at the temperature raising speed of 15 ℃/h, and the temperature is kept for 8 hours; and finally, naturally cooling to obtain the coal injection pipe prefabricated part for the cement kiln.

The performance tests of the coal lance preforms for cement kilns prepared in examples 1 to 4 were carried out, and the test items, test methods and test results are shown in the following table:

as can be seen from the table above, the prefabricated member of the invention has excellent thermal shock resistance, strength, wear resistance, alkali resistance, high temperature resistance and volume stability, is not easy to deform and strip, and can effectively prolong the service life.

This detailed description is to be construed as illustrative only and is not to be taken as limiting the invention, as any changes that may be made by a person skilled in the art after reading the present specification will be protected by the patent laws within the scope of the appended claims.