阅读说明：本技术 一种超高温冶炼用莫来石质耐火浇注料 (Mullite refractory castable for ultrahigh-temperature smelting ) 是由 冯海霞 柳军 于 2020-07-10 设计创作，主要内容包括：本发明属于耐火材料技术领域,具体涉及一种超高温冶炼用莫来石质耐火浇注料。涉及的一种超高温冶炼用莫来石质耐火浇注料的的原料以莫来石颗粒熔融石英颗粒以及红柱石族颗粒为骨料,以莫来石细粉、单斜氧化锆细粉、а-Al<Sub>2</Sub>O<Sub>3</Sub>微粉和水合氧化铝基质：外加有减水剂和水。本发明以高纯莫来石为主原料,采用一定的颗粒级配,同时选择合适的结合剂和分散剂,可获得具备高耐火性、良好抗热震性能、抗熔液/熔渣侵蚀性能的耐火材料,取代现有高温下易氧化的碳素制品,满足1700℃以上的超高温冶炼工况条件。(The invention belongs to the technical field of refractory materials, and particularly relates to a mullite refractory castable for ultrahigh-temperature smelting. Relating to a raw material of mullite refractory castable for ultrahigh temperature smelting, which takes mullite fused quartz particles and andalusite group particles as aggregates, and takes mullite fine powder, monoclinic zirconia fine powder and a-Al fine powder 2 O 3 Micro powder and hydrated alumina matrix: a water reducing agent and water are added. The invention uses high-purity mullite as a main raw material, adopts a certain grain composition, and simultaneously selects a proper bonding agent and a proper dispersing agent, so that a refractory material with high fire resistance, good thermal shock resistance and molten slag/slag corrosion resistance can be obtained, the existing carbon product which is easy to oxidize at high temperature is replaced, and the ultrahigh-temperature smelting working condition of more than 1700 ℃ is met.)

1. The mullite refractory castable for ultrahigh-temperature smelting is characterized by comprising the following components in parts by weight: the castable comprises the following raw materials in percentage by mass:

aggregate:

the grain diameter of the mullite grains is more than or equal to 5mm and is more than 3mm and 10 to 20 percent;

the 3mm or more of mullite grains has a grain diameter of more than 1mm and 25 to 30 percent;

the grain diameter of the mullite grains is more than or equal to 1mm and is more than 0.074mm, and 10 to 15 percent;

the fused quartz particles with the particle size of more than 0.074mm and 0-5 percent of more than or equal to 1 mm;

1mm or more of andalusite group particles have the particle size of more than 0.074mm and 0-5 percent;

matrix:

the grain diameter of the mullite fine powder is more than or equal to 74 mu m and is more than 44 mu m, 10 to 25 percent;

the particle size of the monoclinic zirconia fine powder is more than or equal to 44 mu m and is more than 10 mu m and 3 to 8 percent;

а-Al₂O₃5-0.1 μm of 8% -15% of micro powder;

2% -5% of hydrated alumina;

the total mass of the raw materials is 100 percent;

the water reducing agent is added, and the adding amount of the water reducing agent is 0.1-0.3% of the weight of the raw materials;

water is added externally, and the adding amount of the water is 5.5-6.5% of the weight of the raw materials.

2. The mullite refractory castable for ultrahigh-temperature smelting according to claim 1, wherein: the mullite grains or fine powder are any one of high-purity electrofused mullite or high-purity sintered mullite.

3. The mullite refractory castable for ultrahigh-temperature smelting according to claim 1, wherein: the fused quartz particles are high-purity fused quartz raw materials, wherein SiO₂≥99.5%。

4. The mullite refractory castable for ultrahigh-temperature smelting according to claim 1, wherein: the andalusite group includes any one of kyanite, andalusite or sillimanite.

5. The mullite refractory castable for ultrahigh-temperature smelting according to claim 1, wherein: the fine powder of monoclinic zirconia is any one of high-purity monoclinic zirconia or baddeleyite, wherein ZrO is₂≥95%。

6. The mullite refractory castable for ultrahigh-temperature smelting according to claim 1, wherein: the water reducing agent is one of a polycarboxylic acid water reducing agent or a polyethylene glycol type condensation polymer.

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a mullite refractory castable for ultrahigh-temperature smelting, which is suitable for a refractory castable or a casting process prefabricated part for a die casting metal or alloy smelting process under the working condition of ultrahigh temperature (1700 ℃).

Background

The smelting process of metals can be classified into two main types: the first process is a relatively complex process route of smelting furnace, external refining and continuous casting process, and is mainly used for manufacturing conventional products or high-grade finished products; secondly, smelting furnace and die casting process, which is mainly used for manufacturing products with special specification requirements; taking a silicon metal die casting process as an example, after silica and carbon undergo a high-temperature reduction reaction at a temperature of 1800 ℃ or higher in an intermediate frequency furnace or an induction furnace to form molten silicon, the initial molten silicon is generally put into an intermediate container and then further purified and refined to form a silicon simple substance or a silicon-based alloy with higher purity for subsequent use. As the requirements of high temperature and heat performance such as high temperature fire resistance, good thermal shock resistance, slag corrosion resistance and the like are required, most of the traditional 'middle containers' adopt carbon products. However, when the die casting process is used for smelting, the carbon product is at a high temperature of over 1700 ℃ and in air or an oxidizing atmosphere, so that the carbon material is very easy to oxidize, and the using effect of the product is seriously reduced; meanwhile, with the requirements of energy conservation, environmental protection and cost reduction, the carbon product can be replaced by the castable with a simpler production process; at present, after the castable is used, large-area cracking occurs quickly, even large longitudinal cracking occurs locally to form a 'bag penetrating' accident, so that great economic loss is caused, and the personal safety of surrounding operators is even endangered.

According to the introduction of the situation, a new refractory material is urgently needed to be developed, and the refractory material can adapt to the working condition of high-temperature smelting at the temperature of more than 1700 ℃; the material needs to have excellent characteristics of high refractoriness, good thermal shock resistance (eliminating the appearance of large cracks and reducing the formation of micro cracks), resistance to corrosion and penetration of high-temperature molten liquid or molten slag and the like.

Disclosure of Invention

In order to solve the problems, the invention provides a mullite refractory castable for ultrahigh temperature smelting.

The invention adopts the following technical scheme for achieving the purpose:

the mullite refractory castable for ultrahigh-temperature smelting comprises the following raw materials in percentage by mass:

aggregate:

the grain diameter of the mullite grains is more than or equal to 5mm and is more than 3mm and 10 to 20 percent;

the 3mm or more of mullite grains has a grain diameter of more than 1mm and 25 to 30 percent;

the grain diameter of the mullite grains is more than or equal to 1mm and is more than 0.074mm, and 10 to 15 percent;

the fused quartz particles with the particle size of more than 0.074mm and 0-5 percent of more than or equal to 1 mm;

1mm or more of andalusite group particles have the particle size of more than 0.074mm and 0-5 percent;

matrix:

the grain diameter of the mullite fine powder is more than or equal to 74 mu m and is more than 44 mu m, 10 to 25 percent;

the particle size of the monoclinic zirconia fine powder is more than or equal to 44 mu m and is more than 10 mu m and 3 to 8 percent;

а-Al₂O₃5-0.1 μm of 8% -15% of micro powder;

2% -5% of hydrated alumina;

the total mass of the raw materials is 100 percent;

the water reducing agent is added, and the adding amount of the water reducing agent is 0.1-0.3% of the weight of the raw materials;

water is added externally, and the adding amount of the water is 5.5-6.5% of the weight of the raw materials.

The mullite grains and the mullite fine powder are any one of high-purity electrofused mullite or high-purity sintered mullite.

The fused quartz particles are high-purity fused quartz raw materials, wherein SiO₂≥99.5%。

The andalusite group is any one of kyanite, andalusite or sillimanite.

The fine powder of monoclinic zirconia is any one of high-purity monoclinic zirconia or baddeleyite, wherein ZrO is₂≥95%。。

The water reducing agent is one of a polycarboxylic acid water reducing agent or a polyethylene glycol type condensation polymer.

A preparation method of mullite refractory material adapting to ultra-high temperature smelting working condition comprises the steps of taking high-purity mullite as a main raw material, adding active alumina micropowder, adding substances such as fused quartz, andalusite group, monoclinic zirconia and the like, and adopting a vibration forming process or on-site pouring construction or preprocessing to form a prefabricated member; the mullite is 3Al₂O₃·SiO₂Refractory material with crystal phase as main component and high refractoriness, melting point 1870 deg.C, and relatively small thermal expansion coefficient only 5.3 × 10 compared with most refractory materials of corundum or spinel^-6℃^-1Therefore, the mullite body material has smaller thermal stress generated inside the mullite body material under the high-temperature thermal condition and better thermal shock resistance, the added monoclinic zirconia forms microcracks through phase change toughening, the thermal shock resistance of the material is greatly improved, the viscosity of a molten phase can be improved and increased by permeating the components into high-temperature molten metal or slag, so that the thermal shock resistance of the material is improved, and the fused quartz (0.49-0.59 × 10) is added^-6℃^-1) The thermal expansion coefficient of the material can be further reduced, and the thermal shock resistance of the material is improved; therefore, the refractory material mainly comprising the high-purity mullite can meet the common requirements on the high fire resistance, the thermal shock resistance, the slag corrosion resistance and other properties of the material under the condition of the working condition of the smelting at the ultrahigh temperature of 1700 ℃.

The added andalusite group refractory raw material is mainly used for adjusting the high-temperature over-sintering of the material and preventing the material from generating large shrinkage in the using process; the family substance can generate mullite reaction in the high-temperature use process, the reaction is a one-time permanent expansion process, and the refractoriness under load and compressive strength of the system can be improved, and high-temperature sintering shrinkage can be eliminated.

The bonding agent is hydrated alumina, and reacts with water at normal temperature to generate polycondensate, so that the material is endowed with certain bonding strength; the corundum phase with high melting point is converted at medium and high temperature, and the high-temperature use performance of the material is improved.

alpha-Al added in the invention₂O₃The micro powder is high-activity ultra-fine powder, and mainly aims at filling pores, reducing water addition and improving forming performance; meanwhile, the micro-powder alumina can promote the high-temperature sintering of the material, improve the high-temperature bonding strength of the material and resist the erosion of molten liquid/molten slag.

The water reducing agent is a polycarboxylate water reducing agent 225P or a polyethylene glycol type polycondensate FS-10, and mainly has the effects of reducing the water adding amount of the casting material and improving the fluidity; meanwhile, the water reducing agent is required not to introduce a new low-melting-point impurity phase so as to avoid reducing the high-temperature service performance of the material.

The mullite refractory castable for ultrahigh-temperature smelting has the following beneficial effects by adopting the technical scheme:

1) the invention adopts casting molding, can be directly implemented on site, can also be made into prefabricated parts, has simple process and low cost, can replace the traditional high-cost carbon product, and is suitable for the working condition of high-temperature smelting at the temperature of more than 1700 ℃.

2) The invention adopts high-purity mullite as a main raw material, and the material has better high-temperature service performance and good thermal shock resistance and molten liquid/slag corrosion resistance.

3) In the invention, a proper amount of fused quartz and monoclinic zirconia are added, and the low thermal conductivity and the phase change toughening of the raw materials are respectively utilized to reduce or slow down the thermal stress generated when the system is subjected to temperature change, thereby being beneficial to improving the thermal shock resistance of the material.

4) The bonding agent, the micro powder or the water reducing agent introduced in the invention can not generate any new low-melting-point impurity phase in the using process, thereby influencing the high-temperature service performance of the material.

In conclusion, the high-purity mullite is used as a main raw material, a certain grain composition is adopted, and meanwhile, a proper bonding agent and a proper dispersing agent are selected, so that the refractory material with high fire resistance, good thermal shock resistance and molten liquid/slag corrosion resistance can be obtained, the existing carbon product which is easy to oxidize at high temperature is replaced, and the ultrahigh-temperature smelting working condition of more than 1700 ℃ is met.

Detailed Description

Examples of the present invention are given, but not to be construed as limiting the invention in any way. According to the scheme of the following 3 embodiments, a base material (containing a water reducing agent and other additives) and aggregate are firstly dry-mixed in a stirrer for 3-4 minutes, then water is added, and after wet mixing for 4-5 minutes, the mixture is poured in a triple die for vibration forming. Finally, the physicochemical index at 1600 ℃ (see table 1) is measured, and if not indicated, the ambient temperature is about 25 ℃.