Hydrothermal formation of the calcium silicate hydrates, tobermorite

The calcium silicate hydrate (C–S–H) minerals, tobermorite (Ca 5 Si 6 O 16 (OH) 2 ·4H 2 O) and xonotlite (Ca 6 Si 6 O 17 (OH) 2), are rare minerals formed in hyper-alkaline, hydrothermal environments. They usually occur where hydrothermal fluids react with basic igneous rocks, e.g., Okayama, Japan (Henmi and Kusachi, 1992) and Skye, …

The Synthesis of Hydroxyapatite by Hydrothermal Process …

General reaction during the hydrothermal synthesis of hydroxyapatite from calcium lactate pentahydrate and orthophosphoric acid is presented below (reaction …

Hydrothermal preparation of lightweight calcium silicate …

When the hydrothermal temperature is 160 °C, the reaction duration is 2.0 h, the liquid-solid ratio is 10, and the caustic alkali concentration is 60 g·L −1, the residual content of Na 2 O in the calcium silicate powder is below 0.42%, and the main silicate phases are Ca 5 Si 6 O 16 (OH) 2 ·4H 2 O and Ca 3 Al 2 SiO 8 ·4H 2 O.

Hydrothermal synthesis of Mn2+- and Cu2+-doped calcium …

The hydrothermal technique offers additional advantages, such as being more environmentally friendly and cost-effective. Recently, In et al. reported hydrothermal synthesis to obtain both plate and nanorod-shaped HA crystals by using sebacic acid as an additive and altering the pH of the reaction solution [26].

Hydrothermal reactions of γ-dicalcium silicate

The action of water on γ-Ca2SiO4, either alone or in the presence of calcium hydroxide, quartz, or amorphous silica, has been studied mainly at 150–600° and 5–350 bars. A new compound, of probable composition Ca8Si5O18, is formed over a wide range of conditions; its appears to have a regularly interstratified structure composed of alternate layers of γ …

Hydrothermal processes in industry | ChemTexts

Hydrothermal Preparation of Calcium Hydroxyapatite …

Calcium hydroxyapatite powders were prepared by hydrothermal reactions of calcium pyrophosphate and calcium oxide. Primary particles of the hydroxyapatite obtained were spherical with diameters less than 0.2 μm, and small prismatic crystals were rarely observed in some fields. The effects of temperature, pressure, and soaking time …

Phase relations in the CaO–SiO2–H2O system to 200

Hydrothermal reactions. 1. Introduction. Hydration of Portland cement at or near ambient temperature produces more than 50% of a calcium silicate hydrate, …

HYDROTHERMAL REACTIONS OF CALCIUM …

HYDROTHERMAL REACTIONS OF CALCIUM HYDROXIDE—QUARTZ AT 120-220° ... Calcium Silicate Materials: Substitution of Hydrated Lime by Ground Granulated Blast Furnace Slag in Autoclaving Conditions. ... study of the use of a quartz poor sand and a pure quartz sand for lime silica bricks and the kinetics of the hydrothermal hardening …

Hydrothermal formation and conversion of calcium

The hydrothermal reaction of calcium oxide and sodium aluminate solution was carried out in the stirred laboratory autoclave (miniclave drive, Switzerland) with a high-temperature sampling system. The other hydrothermal experiments were carried out in the self-designed high-pressure autoclave heated by the mixed molten salts of sodium …

Hydrothermal Growth of Calcium Titanate Nanowires from Titania

Calcium titanate crystallization has been observed following the hydrothermal reaction of titanium dioxide (TiO2) and calcium in alkaline solution at 250 °C, using time-resolved in situ energy ...

Influence of Hydrothermal Synthesis Conditions on the

Both the mechanochemical and the hydrothermal methods are referred to as pozzolanic reaction systems, which produce C-S-H by the chemical reaction between calcium hydroxide and silicon dioxide in ...

Kinetics and Mechanisms of the Hydrothermal Crystallization of Calcium

Calcium titanate crystallization has been observed following the hydrothermal reaction of titanium dioxide (TiO 2) and calcium in alkaline solution at 250 °C, using time-resolved in situ energy-dispersive diffraction.The nature of the calcium source used was found to influence the type of calcium titanate formed; CaTiO 3 was …

Hydrothermal processes in industry | ChemTexts

The composition of the starting materials and the chosen reaction conditions of the hydrothermal synthesis facilitate the formation of calcium hydrosilicates, which contain silanol groups, e.g., α-Ca 2 [HSiO 4]OH. The calcium hydrosilicates are hydraulically inactive, since the silanol groups are stabilized by hydrogen bonds.

Hydrothermal Method

After the hydrothermal reaction, the products were washed with ultrapure water under ultrasonication, dried overnight, and thermally treated at 350 °C for 2 h in air. Fig. 9 depicts the process of forming nanosheet and nanowire-structured Co 3 O 4 on Ni , including the chemical reactions occurring during the hydrothermal synthesis.

Low hydrothermal temperature synthesis of porous calcium …

This study presents a novel approach for the synthesis of porous calcium silicate hydrate (CSH) at a low hydrothermal temperature of 110 °C based on enhanced reactivity SiO 2 (i.e. silica/polyethylene glycol (PEG 2000) composites) as the source silica material.The as-prepared CSH materials exhibited a porous microstructure with a large …

Hydrothermal reactions of γ-dicalcium silicate

The action of water on γ-Ca 2 SiO 4, either alone or in the presence of calcium hydroxide, quartz, or amorphous silica, has been studied mainly at 150–600° and 5–350 bars.A new compound, of probable composition Ca 8 Si 5 O 18, is formed over a wide range of conditions; its appears to have a regularly interstratified structure composed of alternate …

Low-temperature hydrothermal carbonization of activated …

Low-temperature (200 °C) hydrothermal process produced activated carbon materials with prolonged reaction time. • A high- surface area of activated carbon spheres up to 2296 m 2 /g was achieved by KOH activation.. KOH activated carbon exhibited high CO 2 uptake, 7.07 mmol/g at 25 °C for 300 min contact time.. The textural properties …

Optimizing food waste hydrothermal parameters to reduce Maillard

In the hydrothermal reaction, water mainly plays two roles: one is to provide solution environment for chemical reaction of various substances; the other is to accelerate the speed of mass transfer and heat transfer. Ren et al. (2006) found when the moisture content is more than 85%, the heat transfer rate does not increase significantly. If ...

Study of K-Feldspar and Lime Hydrothermal Reaction: …

To elucidate the physicochemical properties of the artificial silicate composite material, K-feldspar and lime were reacted in mild hydrothermal conditions (different reaction temperatures and various K-feldspar/lime ratios). Formed phases were investigated using various techniques, such as X-ray powder diffraction, the Rietveld …

Synthesis method of hydroxyapatite: A review

The use of this modifier in the hydrothermal treatment had been proven to help control the shape of the HAp particle. Hoai et al. [33] added the CTAB to diammonium hydrogen phosphate and calcium during the hydrothermal reaction. The results show that the nano-rod shaped HAp was synthesised and the mean length of the nano-rod …

Hydrothermal preparation of diatomaceous earth combined with calcium

A novel composite for the removal of color in waste water was prepared by subjecting slurries consisting diatomaceous earth and slaked lime to a hydrothermal reaction at 180 °C.Subsequently, calcium silicate hydrate gels covered the surface of diatomaceous earth due to the reaction between the amorphous silica of …

Nucleation and growth of hydroxyapatite nanocrystals by hydrothermal …

Hydroxyapatite (HA) was synthesized by using a hydrothermal method with Ca(NO 3) 2 ·4H 2 O and H 3 PO 4.We use x-ray diffraction and field-emission scanning electron microscopy to investigate how pH, reaction temperature, hydrothermal-reaction time, and calcium-ion concentration affects the microstructure and the growth of HA …

Tobermorite Synthesis Under Hydrothermal Conditions

Tobermorite is a mineral, which, thanks to its composition and properties, is an important phase in aerated concrete and it can be also used as an ion exchanger. Tobermorite crystallizes together with other calcium silicate hydrates from the system CaO–SiO 2 –H 2 O during hydrothermal reactions. Paper deals with the key role of …

Phase relations in the CaO–SiO2–H2O system to 200

Hydrothermal reactions in the system CaO–SiO 2 –H 2 O and the steam curing of cement–silica products. Proc. 4th Intl. Symp. Chem of Cement, ... Hydrothermal reactions between calcium hydroxide and amorphous silica; the reactions between 180 and 220 °C. J. Phys. Chem., 61 (1957), pp. 473-479. Google Scholar [12]

Hydrothermal Reactions between Calcium Hydroxide and …

Hydrothermal Reactions between Calcium Hydroxide and Amorphous Silica in Atmospheres of Unsaturated Steam Gunnar O. Assarsson Cite this: J. Phys. Chem. 1956, 60, 11, 1559–1564

Synergistic effects of Mg-substitution and particle size of …

HA crystals have been widely obtained in hydrothermal reactions due to lower solubility than other calcium phosphates in the aqueous condition [22]. In addition, temperature, microstructure and Mg substitution have been reported to influence the hydrothermal reactions of calcium carbonate skeletons [20, 23, 24]. For example, the …

HYDROTHERMAL REACTIONS OF CALCIUM …

HYDROTHERMAL REACTIONS OF CALCIUM HYDROXIDE—QUARTZ AT 120-220°. Gunnar O. Assarsson. Cite this: J. Phys. Chem. 1960, 64, 3, 328–331. Publication Date: March 1, 1960. https://doi/10.1021/j100832a010. © American Chemical Society. …

Hydrochloric Acid Catalyzed Hydrothermal Treatment to …

Resource utilization of sludge is critical because traditional sludge treatment methods cause a large amount of nutrient loss. This study investigated the impact of hydrochloric acid quantity, reaction temperature, and time on phosphorus release and migration from municipal sludge during hydrothermal treatment and designed a sludge …

Hydrothermal Reactions between Calcium Hydroxide and …

The Reactions between 120 and 160 | Semantic Scholar. DOI: 10.1021/J150560A019. Corpus ID: 104474719. Hydrothermal Reactions between Calcium Hydroxide and …

REACTION BETWEEN SILICA AND CALCIUM HYDROXIDE …

REACTION BETWEEN SILICA AND CALCIUM HYDROXIDE SOLUTIONS. I. ... The precipitation and hydrothermal crystallisation of alkaline‐earth. Metal aluminosilicate hydrates from aqueous solution: Crystalline phases and …

Hydrothermal Preparation of Calcium Hydroxyapatite Powders

Hydrothermal Preparation of Calcium Hydroxyapatite Powders. T. Hattori, Yasuhiko Lwadate. Published 1 June 1990. Materials Science. Journal of the American …

Influence of Hydrothermal Synthesis Conditions on the

Influence of Hydrothermal Synthesis Conditions on the Formation of Calcium Silicate Hydrates: from Amorphous to Crystalline Phases. October 2018. Journal of …

Elucidating the Maillard Reaction Mechanism in the Hydrothermal …

Hydrothermal liquefaction (HTL) transforms wet biomass and biowaste feedstock into water-insoluble biocrude and valuable water-soluble organic products. HTL takes advantage of the exceptional properties of water near the critical point to break bio-macromolecule linkages, and as a reaction medium, subcritical water ions allow the …

Coprecipitation of Crystalline Calcium Silicates and …

Calcium silicates are abundant but sparingly soluble feedstocks of interest for making low-carbon alternative cements. Under hydrothermal and alkaline conditions, they can form crystalline calcium silicate hydrate (CCSH) products, which are abundant in Roman concrete, or they can form carbonates when CO2 is present. To understand …