A kind of mgo-cao series lightweight refractory material and its preparation method

A kind of refractory material, lightweight technology, applied in the field of refractory material production, can solve the problems of easy reaction with water, product cracking, etc., to achieve low bulk density, high compressive strength, good resistance to medium erosion and hydration resistance. Effect

Active Publication Date: 2018-05-18
西安华清科教产业(集团)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the free CaO contained in the MgO-CaO refractory material is easy to react with water, resulting in cracking of the product
In order to improve its hydration resistance, it is usually necessary to use sintering aids or increase the firing temperature to increase the density of MgO-CaO refractory materials. For this reason, there is currently no lightweight material with a high internal closed porosity available.

Method used

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  • A kind of mgo-cao series lightweight refractory material and its preparation method
  • A kind of mgo-cao series lightweight refractory material and its preparation method
  • A kind of mgo-cao series lightweight refractory material and its preparation method

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preparation example Construction

[0021] This example gives the preparation method of MgO—CaO light-weight refractory material, and the specific preparation process includes the following steps:

[0022] Step 1: Select magnesia and carbon as the reaction raw materials, grind the raw materials to 180 mesh or below, mix them evenly according to the molar ratio of MgO and C at 1:1, and use them as pore-forming and reaction components in the fine powder in the refractory ingredients.

[0023] Step 2, batching the refractory raw materials according to a certain particle size distribution. The aggregate part uses MgO-CaO dense granular materials with different CaO contents (often called magnesia-calcium sand). Generally, the ratio of the aggregate part to the fine powder part is controlled between 60-70:30-40, wherein the fine powder part contains MgO and C powder mixed in step 1, and the rest of the fine powder is magnesia-calcium sand fine powder. According to product requirements, the mixed powder of MgO and C p...

Embodiment 1

[0033]Mix 180 mesh fused magnesia and 180 mesh graphite evenly according to the molar ratio of MgO and C at 1:1. The 1-3mm and 0.1-1mm magnesia-calcium sand particles with a CaO content of 56% are used as coarse particles and medium particles, respectively. Magnesia fine powder, graphite fine powder and 22% CaO content magnesia-calcium sand fine powder are used as the matrix part, and the ratio of coarse particles: medium particles: fine powder is 40:20:40. Among them, the ratio of the fine powder part of the magnesia-calcium sand fine powder to the mixed powder of magnesium oxide and graphite is 2:1. Paraffin wax is used as a binder, and the addition amount is 8% of the total weight of the ingredients. The ingredients are fully mixed in a hot state, and the mixture is placed in an airtight container or plastic bag for 2 hours, and then molded on a hydraulic press. The molding pressure is 150MPa. The sample is naturally cooled for half a day to 1 day, and then dried in the dr...

Embodiment 2

[0037] Mix 180 mesh sintered magnesia and 180 mesh graphite evenly according to the molar ratio of MgO and C at 1:1. The 1-3mm and 0.1-1mm magnesia-calcium sand particles with a CaO content of 22% are used as coarse particles and medium particles, respectively. Magnesia fine powder, graphite fine powder and 22% CaO content magnesia-calcium sand fine powder are used as the matrix part, and the ratio of coarse particles: medium particles: fine powder is 40:20:40. Among them, the ratio of the fine powder part of the magnesia-calcium sand fine powder to the mixed powder of magnesium oxide and graphite is 2:1. Paraffin wax is used as a binder, and the addition amount is 8% of the total weight of the ingredients. The ingredients are fully mixed in a hot state. After mixing, they are placed in an airtight container or a plastic bag to trap the materials for 3 hours, and then molded on a hydraulic press. The molding pressure is 150MPa. Raise the temperature to 240°C in order to remov...

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Abstract

The invention discloses an MgO-CaO series light-weight refractory material and a method for preparing the same. The prepared MgO-CaO series light-weight refractory material has good medium impregnation resistance and hydration resistance on the premise that low thermal conductivity is maintained, because an outer layer of a prepared test sample is compact and an internal portion is porous. The method for preparing the same comprises the steps of selecting magnesia and carbon as reaction raw materials, magnesia-calcia as a main raw material and paraffin as a bonding agent; quickly heating a pressed sample to 240 DEG C to remove paraffin, then performing vacuum pumping to a controllable atmosphere furnace, filling Ar for protection, heating a furnace body to certain temperature, feeding O2, and performing carbon thermal reduction reaction to magnesia and carbon to produce Mg steam which is diffused and reacts with the fed O2 to produce magnesium oxide which enables particles and matrixes to be bonded. The MgO-CaO series light-weight refractory material and the method for preparing the same have the characteristics of lower sintering temperature, adjustable sample porosity and volume density, and higher compression strength and refractoriness under load.

Description

technical field [0001] The invention relates to the technical field of refractory production, in particular to a MgO—CaO-based lightweight refractory and a preparation method thereof. Background technique [0002] MgO-CaO series refractories have the following excellent physical and chemical properties: ① high refractoriness; ② stable thermodynamic properties at high temperature; ③ good thermal shock stability; ④ good slag resistance; The reserves are abundant, and the products are pollution-free. It can be used in the field of iron and steel smelting, such as high temperature equipment such as ladles, tundishes and out-of-furnace refining. Especially with the development of clean steel, the call for MgO—CaO refractory materials is getting higher and higher. At the same time, it is an ideal material to replace magnesia-chrome materials when it is applied to the firing zone of cement rotary kiln. For furnaces where the working lining is in direct contact with molten metal ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B38/02C04B35/66C04B35/622C04B35/65
CPCC04B35/043C04B35/622C04B35/65C04B38/02C04B2235/3208C04B2235/96
Inventor 尹洪峰袁蝴蝶高魁辛亚楼
Owner 西安华清科教产业(集团)有限公司
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