A review on the utilization of fly ash

Alkali-activated materials

The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

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Hallmarks of mechanochemistry: From nanoparticles to technology

Geopolymer concrete: A review of some recent developments

A review of the multi-component utilisation of coal fly ash

Synthesis of cordierite from fly ash and its refractory properties

The invention relates to a novel purified isozyme of an autoclavable superoxide dismutase extracted from the plant Potentilla atrosanguinea Lodd. Var. orgyrophylla, said isozyme having the following characteristics, O2 − scavenging activity remains same before and after autoclaving; scavenges O2 − from sub-zero temperature of −20° C. to high temperature of +80° C.; O2 − scavenging activity at 25° C. for 30 days without adding any stabilizing agent such as polyols or sugars; O2 − scavenging activity in the presence of saline (0.9% sodium chloride) to 61.8% of the control (without 0.9% sodium chloride), stable at 4° C. for at least 8 months; contamination free and infection free from any living micro- and/or macro-organism after autoclaving; possesses temperature optima at 0° C.; possesses a molecular weight of 33 kD under non-denaturating conditions; possesses a molecular weight of 36 kD under denaturating conditions; has clear peaks in UV range at 268 and 275 nm; has an enzyme turnover number of 19.53×104% per nmol per min at 0° C.; and requires Cu/Zn as a co-factor, method for the preparation of the purified isozyme of autoclavable superoxide dismutase and formulations containing the said autoclavable superoxide dismutase.

Isozyme of autoclavable superoxide dismutase (SOD), a process for the identification and extraction of the SOD in cosmetic, food and pharmaceutical compositions

Reaction kinetics, microstructure and strength behavior of alkali activated silico-manganese (SiMn) slag – Fly ash blends

This paper assesses the effect of alkali concentration on the reaction kinetics and mechanism of fly ash geopolymerization. The kinetic parameters of fly ash with different alkali (6–10 M NaOH) solution have been determined by using heat of reaction data measured at isothermal conduction calorimeter at different reaction temperatures, 34–60 °C. With increasing alkali concentration the peak gets intensify and position shifts towards higher time and total heat of reaction enhances. At higher alkali concentration amount of Al and Si dissolute increases, thus, higher energy is required to initiate and forward the reaction. However, the kinetic parameters are varying with alkali, but no alternation is determined in the involved reaction mechanism, nucleation and growth. The apparent activation energy has been evaluated by rate method, suggests three main steps such as dissolution, gel formation and restructuring process of geopolymer reaction. Fly ash geopolymerization is kinetically favored in between 39 and 45 °C temperature with all alkali concentration in experimented condition.

Role of alkali concentration on reaction kinetics of fly ash geopolymerization

This work focuses on gainful utilization of low reactive fly ash at ambient temperature into alkali-activated binder with the addition of another industrial waste silico-manganese (SiMn) slag. Granulated SiMn slag (GSS) percentage was gradually increased into fly ash-based reference batch. The influence of slag on reactivity of the blends was monitored by isothermal conduction calorimetry. Reactivity was improved with increasing slag content. The structural reorganizations of the resultant binder were detected by peak shifting in Fourier transform infrared spectroscopy study. The positional change of the hump in X-ray diffraction analysis was due to structural rearrangement of the binder. The calcium-rich hydrated product formation was increased with slag inclusion. The fly ash-derived geopolymer gel (N–A–S–H) was coexisted with slag activated gel (C–S–H/C–A–S–H), (where N = Na2O, A = Al2O3, C = CaO, S = SiO2, and H = H2O) in the blend matrix. EDX analysis confirmed the variation in Si/Al, Ca/Si, and Na/Al ratios of the binder with the alteration of reaction products. The development of better compressive strength in slag-rich binder attributed with the formation of Ca-rich gel phases.

Sanjay Kumar

Papers

Synthesis of cordierite from fly ash and its refractory properties

Isozyme of autoclavable superoxide dismutase (SOD), a process for the identification and extraction of the SOD in cosmetic, food and pharmaceutical compositions

Reaction kinetics, microstructure and strength behavior of alkali activated silico-manganese (SiMn) slag – Fly ash blends

Role of alkali concentration on reaction kinetics of fly ash geopolymerization

Influence of Granulated Silico-Manganese Slag on Compressive Strength and Microstructure of Ambient Cured Alkali-Activated Fly Ash Binder