Conventional ettringite syntheses are time‐, energy‐, and water‐consuming and produce large quantities of chemical waste. 21 Furthermore, the preparation of ettringite precursors is accompanied by release of significant quantities of CO 2.This owes to the burning of CaCO 3 as the source of calcium. Ettringite production would, …

The technology can be scaled easily to any capacity within the existing cement production system. The grinding and blending can be done in existing ball mills or other grinding facilities. Thus, the technology is widely known to producers of equipment for cement plants and can be adapted to any scale required. 5.1. Raw materials

In addition to ettringite and C–S–H, the hydration products of SSCs also contains the low fractions of OH-hydrotalcite (Mg 4 Al 2 (OH) 14 ·3H 2 O) and monosulfoaluminate ... During cement production, most of the equipment, such as fans, motors, and mills, is driven by electricity.

Ettringite is a primary constituent of hydration of Portland cement concrete. Its formation plays an important role in the control of setting. Minor amounts of secondary ettringite …

first five hours. In addition, soluble sulfates significantly affect the formation of ettringite. Feng et al. [23] found that ettringite precipitated in the C3A-Na2SO4 system was less than that in the C3A-gypsum system in the first hour, and the morphology of ettringite slightly changed.

The process of ettringite production can be divided into three stages. • The first stage of ettringite production is kinetically controlled in LC3 cement. • The …

An environmentally friendly mechanochemical synthesis of ettringite was developed which combines the advantages of a high …

1. Introduction. Global cement production was approximately 4.1 billion tons in 2018 [1].The average global warming potential (GWP) of 1 t of cement is 0.981 t CO 2 eq [2].Cement is primarily used for concrete production, and this process generates a large amount of CO 2 (approximately 4–8% of the world's CO 2), alongside consuming several …

Carbonation process of CH can also be detected by Raman spectroscopy by comparing the relative intensity change of peaks related to CH and CaCO 3.In the research of Black et al. [15], the Raman spectral for the fresh sample and samples after 1 h and 40 h air exposure were shown in Fig. 1.Reduction in the intensity of the peaks at …

The feasibility of removal of sulfate ions from the sodium alkali FGD wastewater using the ettringite precipitation method was evaluated. Factors affecting the removal of sulfate ions, such as NaAlO 2 dosage, Ca(OH) 2 …

The first stage of ettringite production, which has a high rate of formation, is kinetically controlled by the increasing of CC/CC + L ratio, especially for the mixtures with 30 %, and 45 % cement replacement during the sulfate attack. The limitation of monosulfate production due to the hydration process controls the rate of ettringite ...

An environmentally friendly mechanochemical synthesis of ettringite was developed which combines the advantages of a high conversion/short reaction time (94 % in 2 h) with no CO 2 release or waste water production and the need for product separation compared to conventional wet-chemical industrial synthesis. Insights into the reaction …

Ettringite has wide technical application in the ceramic and paper industry. However, its typical wet-chemical synthesis is cumbersome and produces waste water …

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4 Citations. Metrics. Abstract. The search for new materials to replace Portland cement (PC) has increased due to the high release of carbon dioxide (CO 2) …

Chemical, physical and biological technologies for removal of sulphate from mine tailings pond water (8 g SO 4 2− /L) were investigated. Sulphate concentrations of approximately 1,400, 700, 350 and 20 mg/L were obtained using gypsum precipitation, and ettringite precipitation, biological sulphate reduction or reverse osmosis (RO) after …

Operating costs for near-complete sulfate removal using the process, which has been demonstrated successfully for many industrial waters, are estimated at $3 to $6 per 1000 gallons treated. Hydrometrics, Inc., 2727 Airport Road, Helena, MT 59601. Tel: 406-443-4150; Fax: 406-443-0760. Many industrial wastewaters, particularly those associated ...

During the production of cement, the operation of equipment requires a large amount of electricity, mainly including clinker production and cement grinding (Teo et al., 2010). The generation of electricity by using fossil fuels emits a lot of CO 2, which is regarded as indirect CO 2 emissions.

CSA cements are a good binder for S/S of heavy metals (Peysson et al., 2005).In fact, heavy metal cations can substitutes calcium in the flexible structure of ettringite (Berger et al., 2011).The crystal structure of ettringite consists of columns and channels running parallel to c-axis with SO 4 2− groups and H 2 O molecules lying in the channels (Cau-dit …

The treatment of sulfate-bearing soil with calcium-based stabilizers such as cement or lime often results in ettringite formation, consequently leading to swelling and strength deterioration. Ettringite …

The cement industry is an energy-intensive industry, and improving the energy efficiency of cement has become necessary to reduce its carbon footprint and to compete in the global market. Clinker production consumes more than 90% of the total energy used in the cement industry. Therefore, a reduction in the burning temperature of the cement clinker …

Smaller-size ettringite was noted, and its amount rose with the sulfate content. ... The topic is critical considering its implications for production, quality control and performance of the binder. ... To minimize noise signals and strayed X-rays, the equipment was fixed with a divergence slit of 1/2°. The scanning was conducted through an X ...

One of the main challenges in industrial wastewater treatment and recovery is the removal of sulfate, which usually coexists with Ca 2+ and Mg 2+.The effect of Mg 2+ on sulfate removal by ettringite precipitation was investigated, and the process was optimized in the absence and presence of Mg 2+.In the absence of Mg 2+, the optimum conditions …

The influence of different amounts of gypsum on the hydration of a belite-rich and a ye'elimite-rich belite-calcium sulfoaluminate clinker (BCSA) was investigated. The hydration kinetics, phase assemblages and compressive strength development of cements prepared using ye'elimite/ calcium sulfate molar ratios of 1, 1.5 and 2 were studied. …

Ettringite (Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O) is a naturally occurring compound in calcium-rich, alkaline environments, which is found as a secondary mineral in both igneous and sedimentary rocks [1–3].The compound can be easily synthesized in an aqueous solution through a pH-controlled reaction (with a pH above 10) from compounds …

In contrast, two types of ettringite morphology were observed in C-CSA: (1) thick crystals of ettringite grouped in balls about 20 lm in diameter, and (2) constrained or massive ettringite on the ...

Ettringite crystals in air voids and cracks are typically 2 to 4 micrometers in cross-section and 20 to 30 micrometers long. ... Cements are optimized prior to …

Ettringite binders develop early high strength and mainly consist of ladle slag, another side stream of the industry. Here, the ettringite-based binder is assessed …

Ettringite crystals in air voids and cracks are typically 2 to 4 micrometers in cross-section and 20 to 30 micrometers long. ... Cements are optimized prior to production by testing at various sulfate levels to achieve maximum strengths in mortar cubes (and/or minimum shrinkage of mortar prisms). ASTM C 150

External sulfate attack (ESA) is the process of concrete degradation involving expansive reactions between sulfate ions coming from an external source and the phases in the hardened matrices [1, 2].Degradation mechanisms vary depending on several factors, such as the type of binder used, the formulation of the concrete and the type and …