Preparation of ultra-light xonotlite thermal insulation material using carbide slag

Liu, Fei; Zeng, Lingke; Cao, Jian; Li, Jing

doi:10.1007/s11595-010-2295-x

Cited by 14 publications

(5 citation statements)

References 5 publications

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“…For this reason, it is worthwhile to further investigate insulating heat-resistant materials based on calcium silicate hydrates [ 37 ]. The properties of the products made from them are regulated by the Standard EN 16977:2020 [ 38 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

et al. 2022

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The main measure to reduce energy losses is the usage of insulating materials. When the temperature exceeds 500 °C, silicate and ceramic products are most commonly used. In this work, high-crystallinity 1.13 nm tobermorite and xonotlite were hydrothermally synthesized from lime and Ca–Si sedimentary rock, opoka. By XRD, DSC, TG and dilatometry methods, it has been shown that 1.13 nm tobermorite becomes the predominant compound in stirred suspensions at 200 °C after 4 h of synthesis in the mixture with a molar ratio CaO/SiO2 = 0.83. It is suitable for the production of insulating products with good physical–mechanical properties (average density < 200 kg·m−1, compressive strength ~0.9 MPa) but has a limited operating temperature (up to 700 °C). Sufficiently pure xonotlite should be used to obtain materials with a higher operating temperature. Even small amounts of semi-amorphous C–S–H(I) significantly increase its linear shrinkage during firing. It has also been observed that an increase in the strength values of the samples correlated well with the increase in the size of xonotlite crystallites. The optimal technological parameters are as follows: molar ratio of mixture CaO/SiO2 = 1.2; water/solid ratio W/S = 20.0; duration of hydrothermal synthesis at 220 °C—8 h, duration of autoclaving at 220 °C—4 h. The average density of the samples was ~180 kg·m−1, the operating temperature was at least 1000 °C, and the compressive strengths exceeded 1.5 MPa.

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Section: Introductionmentioning

confidence: 99%

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

et al. 2022

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“…One of the most efficient types of insulating products with an operating temperature of 1050 °C are materials based on calcium silicates and/or calcium silicate hydrates: aerogel–xonotlite composite [ 14 ]; ultra-light xonotlite [ 15 ]; xonotlite-type calcium silicate [ 16 ], and needle-like xonotlite–tobermorite mixture [ 17 ], the properties of which are regulated by Standard EN 16977: 2020 [ 18 ]. Calcium silicate hydrates can be produced by using widespread materials: limestone, quartz sand, silica fume [ 19 ]; as well as fibers, biomass ashes [ 20 ] and other unconventional materials [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Porosity of Calcium Silicate Hydrates Synthesized from Natural Rocks

2021

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In this work, the suitability of natural raw materials with various modifications of SiO2—granite sawing waste (quartz) and opoka (a mixture of cristobalite, tridymite, quartz, and an amorphous part)—for the 1.13 nm tobermorite and xonotlite synthesis is examined, and their specific surface area, pore diameter and volume, and the predominant pores are determined. Hydrothermal syntheses were carried out at 200 °C for 12 and 72 h from mixtures with a molar ratio of CaO/SiO2 = 1.0. X-ray diffraction analysis, simultaneous thermal analysis, and scanning electronic microscopy were used, which showed that in the lime–calcined opoka mixture the formation of crystalline calcium silicate hydrates takes place much faster than in the lime–granite sawing waste mixture. The high reactivity of amorphous SiO2 results in the rapid formation of 1.13 nm tobermorite and xonotlite (12 h). According to Brunauer, Emmet and Taller (BET) analysis data, this product features a specific surface area of ~68 m2/g, a total pore volume of 245·10−3 cm3/g, and has dominating 1–2.5 nm and 5–20 nm diameter pores. This porosity of the material should provide good thermal insulation properties of the products made from it as no air convection occurs in the fine pores.

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“…Nowadays, calcium silicate hydrate(Xonotlite) has been attracting attention because of its high thermal stability, environment friendliness, fireproofing and bioactivity [1][2][3][4][5]. It is usually prepared in the CaO-SiO 2 -H 2 O system from suspension of silica and calcium hydroxide by hydrothermal processing (with CaO/SiO 2 ≈1:1) [6][7][8][9]. Xonotlite has double chains running parallel to the b-axis which form layers in the ab plane [10], and these could, in certain conditions of hydrothermal synthesis and different material systems, form orbicular particles or whiskers.…”

Section: Introductionmentioning

confidence: 99%

“…Xonotlite has double chains running parallel to the b-axis which form layers in the ab plane [10], and these could, in certain conditions of hydrothermal synthesis and different material systems, form orbicular particles or whiskers. Some work has been conducted on preparing larger scale xonotlite whiskers, however, the hydrothermal synthesis of xonotlite whiskers was much more difficult than that of orbicular particles which could be prepared at 215 °°°°C for 8h [6], mainly due to the composition and raw materials. So far, synthesis of xonotlite whiskers at high temperature(250-350 °°°°C), long time(72-300 h) and using special equipment has been carried out [1,3,11,12], whereas, little effort have been made to take material systems into account, therefore, it is necessary to study the factor of material systems on synthesized xonotlite whiskers.…”

Section: Introductionmentioning

confidence: 99%

Influence of Material Systems on Synthesized Xonotlite Whiskers

Liu

Wang

Cao

2011

AMR

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The material systems were taken into account to prepare xonotlite whiskers without any surfactant, special instruments and synthesis conditions. Effect of material systems on the crystal phase and morphology of synthesized xonotlite whiskers was studied by using XRD and SEM techniques. The results indicated that the different material systems had great impact on the crystal phase and morphology of synthesized product. The xonotlite crystal could be formed both in C-S-H and C-S-K-H systems, while the formation of xonotlite whiskers was promoted and the large scale whiskers were prepared at 225 °C for 15 h only in C-S-K-H system. In the C-S-N-H system, the synthesized product was pectolite but xonotlite.

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Preparation of ultra-light xonotlite thermal insulation material using carbide slag

Cited by 14 publications

References 5 publications

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

Porosity of Calcium Silicate Hydrates Synthesized from Natural Rocks

Influence of Material Systems on Synthesized Xonotlite Whiskers

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