scholarly journals Utilization of By-Product of Alumina Extraction from Fly Ash as Silicate Fertilizer

2021 ◽  
Author(s):  
Yang Luo ◽  
Yinghong Wu
Keyword(s):  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Coal Fly Ash ◽  
Wheat Seedling ◽  
Silica Content ◽  
Liquid Volume ◽  
Wheat Seedlings ◽  
Sodium Calcium ◽  
Hydrochemical Process

Calcium silicate hydrate is proposed as a potential silicate fertilizer. It is the main phase of the by-product of a mild hydrochemical process used to extract alumina from coal fly ash. Its preparation by decomposing sodium calcium silicate hydrate, the residue after extracting alumina from coal fly ash, was investigated. The results revealed that the intermediate of the sodium calcium silicate hydrate was easily decomposed into calcium silicate hydrate in a dilute alkaline solution and an available silica content of 28.57% was obtained under the decomposition conditions of a 30 g/L Na2O solution, a liquid-volume to solid-mass ratio of 25, a reaction temperature of 150 °C and a reaction time of 4 h, with a stirring speed of 600 rpm. Subsequently, Si uptake experiments were conducted on wheat seedlings by hydroponics to test Si’s effects on their growth. The results proved that the Si concentration in the wheat seedling shoots was greatly enhanced from 1.213 mg/g to 3.983 mg/g when 0.02 g of calcium silicate hydrate was distributed in the pot in which 3.87 g of seeds were cultivated.

scholarly journals Utilization of By-Product of Alumina Extraction from Fly Ash as Silicate Fertilizer

2021 ◽  
Author(s):  
Yang Luo ◽  
Yinghong Wu
Keyword(s):  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Coal Fly Ash ◽  
Wheat Seedling ◽  
Silica Content ◽  
Liquid Volume ◽  
Wheat Seedlings ◽  
Sodium Calcium ◽  
Hydrochemical Process

Calcium silicate hydrate is proposed as a potential silicate fertilizer. It is the main phase of the by-product of a mild hydrochemical process used to extract alumina from coal fly ash. Its preparation by decomposing sodium calcium silicate hydrate, the residue after extracting alumina from coal fly ash, was investigated. The results revealed that the intermediate of the sodium calcium silicate hydrate was easily decomposed into calcium silicate hydrate in a dilute alkaline solution and an available silica content of 28.57% was obtained under the decomposition conditions of a 30 g/L Na2O solution, a liquid-volume to solid-mass ratio of 25, a reaction temperature of 150 °C and a reaction time of 4 h, with a stirring speed of 600 rpm. Subsequently, Si uptake experiments were conducted on wheat seedlings by hydroponics to test Si’s effects on their growth. The results proved that the Si concentration in the wheat seedling shoots was greatly enhanced from 1.213 mg/g to 3.983 mg/g when 0.02 g of calcium silicate hydrate was distributed in the pot in which 3.87 g of seeds were cultivated.

Hydration Activity of Ceramic Polishing Powder at Autoclaved Condition

2012 ◽  
Vol 568 ◽  
pp. 392-395
Author(s):  
Ming Feng Zhong ◽  
Da Gen Su ◽  
Yi Xiang Zhao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Civil Engineering

Hydration activity of waste ceramic polishing powder at autocalved condition were studied by IR, XRD, SEM and EDS in civil engineering. The results shown that autoclaved condition is beneficial to inspire hydration ability of polishing powder, the more active silicon and aluminium were dissolved, and they were converted into low Ca/Si ratio calcium silicate hydrate, whose ratio of Ca/Si was 1.58, and the compressive strength of autoclaved silicate product made by the ceramic polishing powder was higher than that of fly ash.

Micromechanical Properties of Calcium Silicate Hydrate

2013 ◽  
Vol 539 ◽  
pp. 75-79
Author(s):  
Wu Yao ◽  
Li He
Keyword(s):  
Fly Ash ◽  
Reaction Zone ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Cement Hydration ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Indentation Modulus ◽  
Micromechanical Properties ◽  
Secondary Hydration

The indentation modulus of several cementitious materials is discussed with the assumption that the C-S-H gel is an aggregation of precipitated, colloidal-sized particles. At least two kinds of structurally distinct but compositional similar phases are found existent during the hydration process. In addition, the C-S-H originated from the pozzolanic reaction of fly ash is found to be the same to that of cement hydration in micromechanical properties; however, the C-S-H gel formed from the secondary hydration is inclined to develop into high density packing configuration, due to the limitation of reaction zone available.

Preparation of Xonotlite Nano-Fibres Using the Silica Source from Coal Fly Ash and Ca(OH)2

2014 ◽  
Vol 633 ◽  
pp. 7-10 ◽  
Author(s):  
Jing Yang ◽  
Xin Zhang ◽  
Hong Wen Ma ◽  
Ming Wei Wang ◽  
Han Wu
Keyword(s):  
Fly Ash ◽  
Calcium Silicate ◽  
Coal Fly Ash ◽  
High Alumina ◽  
Thermal Synthesis ◽  
Hydrated Calcium Silicate ◽  
Hydrothermal Temperature ◽  
Silica Source ◽  
Naoh Solution ◽  
Hydrated Calcium

Extracting aluminum oxide from high-alumina coal fly ash are significant to make up for the inadequacy of bauxite resource in China. How to comprehensively utilize silica components in coal fly ash is a key technical question in industrialization for extracting of alumina from coal fly ash. Desilication of coal fly ash (CFA) and preparation of xonotlite were studied using the silica-rich solution from the CFA as silica source and calcium oxide as calcium source respectively. The CFA is from a power plant at Shizuishan city in Ningxia, China. Xonotlite was successfully prepared by a series processes including predesilication, hydro-thermal synthesis. The experimental results indicated that SiO2in the coal fly ash changed into NaSiO3after the coal fly ash was treated by desilication using NaOH solution. Hydrated calcium silicate was obtained from the reaction of the solutions produced by desilication and Ca (OH)2at the condition of Ca/Si (mol)=1, T=160°Cand t=1h. Xonotlite was synthesized by the hydrated calcium silicate using the hydrothermal temperature of 260°C for 2 hours. Keywords: Coal Fly Ash, Pre-desilication, alkali Hydrothermally-treated, Xonotlite nanofibres

Preparation and evaluation of a mesoporous calcium-silicate material (MCSM) from coal fly ash for removal of Co(II) from wastewater

2015 ◽  
Vol 279 ◽  
pp. 777-787 ◽  
Author(s):  
Guangxia Qi ◽  
Xuefei Lei ◽  
Lei Li ◽  
Chao Yuan ◽  
Yinglong Sun ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Silicate ◽  
Coal Fly Ash ◽  
Silicate Material ◽  
Preparation And Evaluation

scholarly journals Study of the Effects of the Addition of Fly Ash from Carwash Sludge in Lime and Cement Pastes

2020 ◽  
Vol 12 (16) ◽  
pp. 6451
Author(s):  
María C. Rodríguez-Fernández ◽  
Juan D. Alonso ◽  
Carolina Montero ◽  
Juan F. Saldarriaga
Keyword(s):  
Compressive Strength ◽  
Wastewater Treatment ◽  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Wastewater Treatment Plants ◽  
Strength Properties ◽  
Cement Pastes ◽  
Cement Mortars ◽  
Sludge Waste

Sludge from carwash wastewater treatment plants has been evaluated as substitute for lime paste, as well as its behavior in cement mortars. Dry sludge waste was used with (CSlud) and without (USlud) pretreatment and have been characterized. The pastes were prepared with weight replacement of 5, 10, 15, and 20% of sludge. The formation of calcium silicate hydrate was determined by TGA, both in lime and cement pastes. The compressive strength properties were evaluated in mortars. It was found the mixtures which present the best results were those of 5 and 10% for USlud, and 10 and 20% for CSlud.

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