In situsynthesis and thermal shock resistance of mullite used for thermal storage ceramics in solar thermal power generation

Abstract

Mullite ceramic, as one of high performance thermal storage ceramics for solar thermal power generation systems, was in situ fabricated via semidry pressing and pressureless sintering in the air. Andalusite (57–68 wt-%) and calcined bauxite (24–29 wt-%) were used as the raw materials, with kaolin and a tiny of boric acid being added to promote the densification and improve the mechanical properties. The best physical properties and thermal shock resistance were obtained on an optimum A3 sample sintered at 1600°C for 3 h, i.e. a bending strength of 120·44 MPa and 30 cycles thermal shock cycling without cracking (wind cooling from 1000°C to room temperature) with a loss of bending strength of 8·7%.

Preparation and properties of endothermic functional ceramics with iron tailings as raw materials

“…The thermal conductivity of the Sample A 1 is shown in table 3. Compared with common cordierite-based ceramics and shale-based ceramics [18,20], the thermal conductivity is slightly higher which could be attributed to the high melting temperature of iron oxide in Sample A 1 . The liquid phase such as the low-temperature eutectic mixture in iron ore and tailings, the feldspar and the silicon dioxide permeate into the pore fully, promotes the densification of the samples thereby improving the thermal conductivity.…”

Preparation of MgAl2O4 solar thermal storage ceramics from different magnesium sources

“…To sum up, A1, A2, and A6 are the prominent formulations, in the samples with same kind of magnesium raw materials respectively. The bulk density of the samples is 3.31 g/cm 3 , 3.21 g/cm 3 and 3.21 g/cm 3 , respectively. Sample A1 with fused magnesia shows outstanding in thermal shock resistance.…”

“…The diffusion speed of ions is decelerated, the delivery process and rearrangement of particles were trapped because of solid mass transfer processing of sample A1. Szczerba 21 prepared magnesia-alumina spinel refractory with fused magnesia sintered at 1700 • C. The bulk density and bending strength were 3.05 g/cm 3 and 80.36 MPa, respectively. In this work, there was better performance compared with above research.…”

“…Therefore, thermal storage ceramics have become the research hotspot on thermal storage materials in the field of solar thermal power generation. Nowadays, there are plenty of researchers have prepared thermal storage ceramics with different crystalline phases, such as mullite, 3 cordierite, 4 anorthite, 5 silicon carbide 6 . With reference to these ideas, this work intends to prepare MgAl 2 O 4 thermal storage ceramics with different magnesium sources, on which there are few researches before.…”

“…The bulk density of stoichiometric magnesia-alumina spinel is 3.58 g/cm 3 , and melting point is 2250 • C. Magnesia-alumina spinel is widely used in refractory, such as ladle and cement rotary kiln. 7 Magnesia-alumina spinel has many advantages such as high hardness, high temperature resistance, and low emissivity.…”