Preparation and characterization of microporous magnesia‐based refractory

Abstract

In recent years, there was a huge demand for basic lightweight insulation materials in the metallurgical industry, especially magnesia‐based refractories with low thermal conductivity. Therefore, the preparation of microporous magnesia‐based refractory products through the synthesis of lightweight aggregate and the different grain compositions to meet the supply of light basic refractories is discussed in this paper. The microstructure, pore size distribution, phase composition, coefficient of thermal expansion, thermal conductivity and sintering properties of the microporous magnesia‐based refractory products sintered at 1600°C were characterized. The results indicated that the original salt pseudomorph produced by the thermal decomposition of magnesite fine powder (porogenic agent) provides a uniform microporous structure for the synthesis of lightweight aggregates. The microporous morphology of the periclase phase was controlled by adjusting the content of the porogenic agent. The average pore size of microporous magnesia‐based refractory ranged from 1.5 to 4.2 μm, and the apparent porosity increased from 29.88% to 32.46%. In the same time, the thermal conductivity increased from 0.037 to 0.217 W/(m K), indicating that the introduction of homologous porogenic agents could produce lightweight alkaline refractories with high porosity and low thermal conductivity.

Effect of hollow spheres on the properties of lightweight periclase‐magnesium aluminate spinel refractories

“…10 It is widely known that the heat insulation performance of refractory linings is an important factor affecting the energy efficiency and energy consumption of high-temperature furnaces. 11 Therefore, fabricating periclase-magnesium aluminate spinel refractories with low thermal conductivity would be highly significant for improving energy efficiency. 12,13 The potential of using lightweight refractories as the energy-saving working linings of high-temperature furnaces had been widely recognized, and this strategy has attracted significant commercial interest.…”

“…Various energy‐saving measures have been proposed for enabling cement production enterprises to meet energy efficiency requirements 10 . It is widely known that the heat insulation performance of refractory linings is an important factor affecting the energy efficiency and energy consumption of high‐temperature furnaces 11 . Therefore, fabricating periclase‐magnesium aluminate spinel refractories with low thermal conductivity would be highly significant for improving energy efficiency 12,13 …”

Leaching kinetics of magnesium extraction from boron mud in ammonium bisulphate solutions

“…[6][7][8][9][10] Magnesium and its compounds are widely used in several applications, including automotive, aerospace, fertilizer, food, and medicine. [11][12][13][14][15][16][17][18][19][20] Thus, the utilization of BM for magnesium extraction has environmental and economic value.…”

Characterization of Sintered Niobium–Alumina Refractory Composite Granules Synthesized by Castable Technology

“…The synthesized composite showed porosity of %35%, which is at the lower end of the ones for porous refractory aggregates developed for heating insulation with good thermal shock resistance. [16][17][18] The aim of this work is 1) to develop a procedure for aggregate characterization by means of morphology, roughness, porosity, and chemistry on the example of our crushed castable-based granules [15] and 2) investigate reliability of the production process by comparing three synthesized aggregate batches with DOI: 10.1002/adem.202200407 Aggregates of niobium-alumina refractory composites are characterized, which are produced by a castable technology followed by a crushing process. Phase separation between niobium and corundum is found for the obtained aggregate classes and the impurity phases NbO and β-Nb 2 C are present according to X-ray diffraction measurements.…”

“…The synthesized composite showed porosity of ≈35%, which is at the lower end of the ones for porous refractory aggregates developed for heating insulation with good thermal shock resistance. [ 16–18 ]…”