阅读说明：本技术 一种一步法制备致密六铝酸钙耐火熟料的工艺方法 (Technological method for preparing compact calcium hexaluminate refractory clinker by one-step method ) 是由 尹雪亮 韩廷全 丁洪海 王全洲 尹雪冬 司伟 张博 于 2021-01-12 设计创作，主要内容包括：一种一步法制备致密六铝酸钙耐火熟料的工艺方法,其成分按重量百分比含Al-2O-387.96～89.79%,CaO 8.04～8.21%,重量比为1:1的La-2O-3与TiO-2混合微粉2.00～4.00%；相对密度为91.30～94.60%,显气孔率为2.80～4.50%；制备方法为：(1)将铝矾土、石灰石和重量比为1:1的La-2O-3与TiO-2混合微粉分别磨细后混合；(2)将混合物料压制成生球,然后进行煅烧制成熟料。本发明采用重量比为1:1的La-2O-3与TiO-2混合微粉作为促烧结剂,在煅烧过程重量比为1:1的La-2O-3与TiO-2混合微粉固溶到六铝酸钙相中形成固溶体,从而提高了六铝酸钙相的烧结活性,促进六铝酸钙相的长大,从而可在较低的煅烧温度和较短的保温时间条件下获得致密六铝酸钙耐火熟料,有效降低了生产能耗,提高了生产效率,促进了节能减排。(A one-step process for preparing compact calcium hexaluminate refractory clinker contains Al 2 O 3 87.96-89.79 percent of La, CaO 8.04-8.21 percent of La with the weight ratio of 1:1 2 O 3 With TiO 2 2.00-4.00% of mixed micro powder; the relative density is 91.30-94.60%, and the apparent porosity is 2.80-4.50%; the preparation method comprises the following steps: (1) mixing bauxite, limestone and La with the weight ratio of 1:1 2 O 3 With TiO 2 Respectively grinding the mixed micro powder and mixing; (2) pressing the mixed material into green pellets, and calcining to obtain clinker. The invention adopts La with the weight ratio of 1:1 2 O 3 With TiO 2 The mixed micro powder is used as a sintering promoting agent, and the weight ratio of La to La is 1:1 in the calcining process 2 O 3 With TiO 2 Dissolving the mixed micro powder into six degrees of solutionSolid solution is formed in the calcium aluminate phase, so that the sintering activity of the calcium hexaluminate phase is improved, the growth of the calcium hexaluminate phase is promoted, and compact calcium hexaluminate refractory clinker can be obtained under the conditions of lower calcination temperature and shorter heat preservation time, thereby effectively reducing the production energy consumption, improving the production efficiency and promoting energy conservation and emission reduction.)

1. A one-step process for preparing compact calcium hexaluminate refractory clinker is characterized in that the components contain Al according to weight percentage₂O₃ 87.96-89.79 percent of La, CaO 8.04-8.21 percent of La with the weight ratio of 1:1₂O₃With TiO₂2.00-4.00% of mixed micro powder; the relative density is 91.30-94.60%, the apparent porosity is 2.80-4.50%, and the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material; wherein the bauxite accounts for 83.61-87.37% of the total weight of the mixed material, the limestone accounts for 11.15-13.12% of the total weight of the mixed material, and the La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 1.5-3.3% of the total weight of the mixed material;

(2) pressing the mixed material into green balls by a ball press machine under the pressure of 120-150 MPa;

(3) and (3) keeping the temperature of the green pellets at 1600-1650 ℃ for 2-2.5 hours, and calcining to obtain the compact calcium hexaluminate refractory clinker.

2. The dense calcium hexaluminate refractory clinker of claim 1, La₂O₃、TiO₂The purity of the micro powder is more than or equal to 98.00 percent and the granularity is less than or equal to 10 mu m.

3. The dense calcium hexaluminate refractory clinker of claim 1, wherein Al is in bauxite₂O₃The weight content of the limestone is more than or equal to 76.20 percent, and the weight content of CaO in the limestone is more than or equal to 50.20 percent.

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a process method for preparing compact calcium hexaluminate refractory clinker by a one-step method.

Background

Calcium hexaluminate (CA)₆) The material has the advantages of high melting point (1870 ℃), good fire resistance, low solubility in iron-containing slag, high stability in reducing atmosphere (CO), good chemical stability in alkaline environment and low wettability to molten metal and slag (steel and nonferrous metal), so the material is a novel refractory material which has good high temperature resistance, erosion resistance and molten slag infiltration resistance, has high-temperature heat insulation performance, and can be directly used for metallurgical furnace linings and metallurgical ladle lining hot surfaces, and the contact of molten metal and molten salt. Meanwhile, the calcium hexaluminate has good chemical compatibility and similar thermal expansion property with alumina, and can be matched with the alumina in any proportion, and the characteristics ensure that the calcium hexaluminate has very wide application prospect in high-temperature industries such as metallurgy, glass, cement, ceramics, petrochemical industry and the like.

In the process of preparing the compact calcium hexaluminate refractory clinker by solid phase synthesis, the volume expansion effect accompanied by the reaction among the components of each raw material inhibits the sintering and densification processes, meanwhile, the sintering activity of the calcium hexaluminate phase is low, the compact clinker is difficult to obtain even through high-temperature calcination, and in addition, the sintering densification of the calcium hexaluminate refractory material is further influenced because the calcium hexaluminate crystal phases are easy to form a network porous structure by dendritic bridging and interconnection in the reaction process. The invention discloses a preparation method of compact calcium hexaluminate refractory clinker disclosed in patent CN105585314B and patent CN110171980A, the technological process is a production mode of adopting a two-step method, namely, one-step presintering to eliminate volume expansion effect, and two-step sintering to densify, and the technological process is complex, the energy consumption is large, and the production cost is high.

Disclosure of Invention

Aiming at the problems in the existing preparation technology of the calcium hexaluminate refractory clinker, the invention provides a one-step process for preparing compact calcium hexaluminate refractory clinker, which is based on the principle that La with the weight ratio of 1:1 of a burning promoter is added in the mixing process₂O₃With TiO₂Mixing with micro powder additive, calcining with La at weight ratio of 1:1₂O₃With TiO₂The mixed micro powder is dissolved in the calcium hexaluminate crystal phase to form a solid solution, so that the sintering activity of the calcium hexaluminate phase is enhanced powerfully, the growth of the calcium hexaluminate phase is promoted effectively, the good sintering of the calcium hexaluminate refractory clinker can be realized under the conditions of lower calcination temperature and shorter heat preservation time by a one-step method, the compact calcium hexaluminate refractory clinker is obtained, the production efficiency is improved, and the energy conservation and emission reduction are promoted.

The compact calcium hexaluminate refractory clinker comprises Al in percentage by weight₂O₃87.96-89.79 percent of La, CaO 8.04-8.21 percent of La with the weight ratio of 1:1₂O₃With TiO₂2.00-4.00% of mixed micro powder; the relative density is 91.30-94.60%, and the apparent porosity is 2.80-4.50%.

The preparation method of the compact calcium hexaluminate refractory clinker comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material; wherein bauxite accounts for 83.61-87.37 percent of the total weight of the mixture, limestone accounts for 11.15-13.12 percent of the total weight of the mixture, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 1.5 to 3.3 percent of the total weight of the mixed material;

(2) pressing the mixed material into green balls by a ball press machine under the pressure of 120-150 MPa;

(3) and (3) keeping the temperature of the green pellets at 1600-1650 ℃ for 2-2.5 hours, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Al in the above-mentioned bauxite₂O₃The weight content of the limestone is more than or equal to 76.20 percent, and the weight content of CaO in the limestone is more than or equal to 50.20 percent.

La as described above₂O₃、TiO₂The purity of the micro powder is more than or equal to 98.00 percent, and the granularity is less than or equal to 10 mu m.

Compared with the prior art, the invention has the characteristics and beneficial effects that:

the compact calcium hexaluminate refractory clinker of the invention adopts La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder is used as a sintering promoting agent, and the weight ratio of La to La is 1:1 in the calcining process₂O₃With TiO₂The mixed micro powder is solid-dissolved in the calcium hexaluminate phase, so that the calcium hexaluminate phase generates lattice distortion, the activity is greatly improved, and the sintering and densification behaviors are promoted, thereby obtaining the compact calcium hexaluminate refractory clinker by a one-step method under the conditions of lower calcination temperature and shorter heat preservation time, greatly improving the production efficiency, and reducing the production energy consumption and the production cost.

Drawings

FIG. 1 is a process flow for preparing compact calcium hexaluminate refractory clinker by a one-step method;

figure 2 is a product XRD analysis.

Detailed Description

The equipment adopted for mixing the materials in the embodiment of the invention is an S1110 type sand mixer.

The equipment used for pressing the balls in the embodiment of the invention is a GY650-180 type ball press machine.

The equipment adopted for calcination in the embodiment of the invention is a high-temperature shaft kiln.

Bauxite, limestone and La used in examples of the present invention₂O₃、TiO₂The micro powder is a commercial product.

Example 1

Al in the raw bauxite employed in this example₂O₃76.20 percent by weight, and 54.60 percent by weight of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃89.79 percent of La, 8.21 percent of CaO and the weight ratio of 1:1₂O₃With TiO₂2.00 percent of mixed micro powder; the relative density is 91.30%, and the apparent porosity is 4.50%; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 87.37% of the total weight of the mixed material, limestone accounts for 11.15% of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 1.48 percent of the total weight of the mixed materials;

(2) and pressing the mixed materials into green balls by a ball press machine under the pressure of 150MPa, preserving the heat of the green balls for 2.5 hours at 1650 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Without adding La in a weight ratio of 1:1₂O₃With TiO₂Under the condition of mixing the micro powder, carrying out a comparison experiment according to the mode to obtain sintered clinker of the comparison experiment; XRD (X-ray diffraction) and SEM (scanning Electron microscope) analysis are respectively carried out on the obtained compact calcium hexaluminate refractory clinker and the sintered clinker in a comparison experiment, and the result shows that the internal structure of a sintered sample is loose and has more pores under the condition of no additive, and compared with the La with the additive weight ratio of 1:1₂O₃With TiO₂The addition of the mixed micro powder obviously reduces the air holes of the sample, has obviously compact microstructure, and can clearly observe the main crystal phase CA of the sample₆Further indicates the presence of La in a 1:1 additive weight ratio from the microstructure₂O₃With TiO₂The mixed micro powder plays an effective promoting role in sintering the calcium hexaluminate refractory material; EDS separation is carried out on the obtained compact calcium hexaluminate refractory clinkerAs a result, it was found that La was added in a weight ratio of 1:1₂O₃With TiO₂The mixed micro powder mainly exists in a calcium hexaluminate crystal phase in a system to form a solid solution, which can promote the crystal phase of the calcium hexaluminate to generate lattice distortion and improve the activity, and the weight ratio of La to the additive is 1:1₂O₃With TiO₂The addition of the mixed micro powder effectively promotes the sintering and densification behaviors of the calcium hexaluminate.

Example 2

Al in the raw bauxite employed in this example₂O₃77.50 wt%, and 53.70 wt% of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃89.60 percent of CaO, 8.20 percent of CaO and La with the weight ratio of 1:1₂O₃With TiO₂2.20 percent of mixed micro powder; the relative density is 91.90%, and the apparent porosity is 4.30%; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 86.88% of the total weight of the mixed material, limestone accounts for 11.47% of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 1.65 percent of the total weight of the mixed materials;

(2) and pressing the mixed material into green balls by a ball press machine under the pressure of 140MPa, preserving the heat of the green balls for 2.5 hours at 1650 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 3

Al in the raw bauxite employed in this example₂O₃78.80 wt%, and 53.10 wt% of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃89.33 percent, CaO 8.17 percent and La with the weight ratio of 1:1₂O₃With TiO₂2.50 percent of mixed micro powder; the relative density is 92.50 percent, and the apparent porosity is 3.90 percent; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the fine powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 86.37 percent of the total weight of the mixed material, limestone accounts for 11.72 percent of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 1.9 percent of the total weight of the mixed materials;

(2) and pressing the mixed material into green balls by a ball press machine under the pressure of 130MPa, preserving the temperature of the green balls for 2 hours at 1650 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 4

Al in the raw bauxite employed in this example₂O₃79.40 wt%, and the weight percentage of CaO in the limestone is 52.70 wt%.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃89.05 percent of CaO, 8.15 percent of CaO and 1:1 of La by weight ratio₂O₃With TiO₂2.80 percent of mixed micro powder; the relative density is 93.20%, and the apparent porosity is 3.60%; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 86.00% of the total weight of the mixed material, limestone accounts for 11.85% of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 2.15 percent of the total weight of the mixed materials;

(2) and pressing the mixed materials into green balls by a ball press machine under the pressure of 120MPa, preserving the heat of the green balls for 2 hours at 1650 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 5

Al in the raw bauxite employed in this example₂O₃80.30 percent by weight, and 52.10 percent by weight of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃88.87 percent, CaO 8.13 percent and La with the weight ratio of 1:1₂O₃With TiO₂3.00 percent of mixed micro powder; the relative density is 93.70 percent, and the apparent porosity is 3.40 percent; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the fine powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 85.61 percent of the total weight of the mixed material, limestone accounts for 12.07 percent of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 2.32 percent of the total weight of the mixed materials;

(2) pressing the mixed materials into green balls by a ball press machine under the pressure of 150MPa, preserving the temperature of the green balls for 2.5 hours at the temperature of 1600 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 6

Al in the raw bauxite employed in this example₂O₃82.20 wt%, and 51.80 wt% of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃88.69 percent, CaO 8.11 percent and La with the weight ratio of 1:1₂O₃With TiO₂3.20 percent of mixed micro powder; the relative density is 94.10%, and the apparent porosity is 3.20%; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 85.12 percent of the total weight of the mixed material, limestone accounts for 12.35 percent of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 2.52 percent of the total weight of the mixed materials;

(2) and pressing the mixed materials into green balls by a ball press machine under the pressure of 140MPa, preserving the temperature of the green balls for 2.5 hours at 1600 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 7

Al in the raw bauxite employed in this example₂O₃84.30 percent by weight, and 51.30 percent by weight of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃88.41 percent, CaO 8.09 percent and La with the weight ratio of 1:1₂O₃With TiO₂3.50 percent of mixed micro powder; the relative density is 94.40%, and the apparent porosity is 3.00%; the preparation method comprises the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 84.48% of the total weight of the mixed material, limestone accounts for 12.70% of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 2.82 percent of the total weight of the mixed materials;

(2) pressing the mixed materials into green balls by a ball press machine under the pressure of 130MPa, preserving the temperature of the green balls for 2 hours at 1600 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.

Example 8

Al in the raw bauxite employed in this example₂O₃86.10% by weight, and 50.20% by weight of CaO in the limestone.

The prepared compact calcium hexaluminate refractory clinker component contains Al according to weight percentage₂O₃87.96 percent, CaO 8.04 percent and La with the weight ratio of 1:1₂O₃With TiO₂4.00 percent of mixed micro powder; the relative density is 94.60 percent, and the apparent porosity is 2.80 percent; the preparation method comprises the following stepsCarrying out the following steps:

(1) respectively crushing and grinding bauxite and limestone until the granularity is less than or equal to 88 meshes, and adding La with the weight ratio of 1:1₂O₃With TiO₂Mixing the micro powder in a sand mixer to prepare a mixed material, wherein bauxite accounts for 83.61% of the total weight of the mixed material, limestone accounts for 13.12% of the total weight of the mixed material, and La with the weight ratio of 1:1₂O₃With TiO₂The mixed micro powder accounts for 3.27 percent of the total weight of the mixed materials;

(2) pressing the mixed materials into green balls by a ball press machine under the pressure of 120MPa, preserving the temperature of the green balls for 2 hours at 1600 ℃, and calcining to obtain the compact calcium hexaluminate refractory clinker.