- Mon - Sat 8:00 - 18:00
- [email protected]
- 0086-21-58386256
These findings imply that non-hydrostatic stress has a significant influence on hydration rates and subsequent ... (water) have failed to produce hydration products or show relatively slow hydration rates (e.g., Ramsdell and Patridge, 1929; Leininger et al., 1957; Hardie, 1967). ... 140 surface of anhydrite, which increases the specific surface ...
When hemihydrate or anhydrite is mixed with water calcium sulfale dihydrate is formed again due to re-hydralion. During re-hydration of hemihydrate, the fol - lowing exothermic reaction occurs: CaSO 4 1/2H 2 O + 3/2H 2 O => CaSO 4 2H
Peaks at 20.7° 2θ, 31.2° 2θ, and 11.62° 2θ, indicate the presence of secondary gypsum, which may be due to the reaction between water and anhydrite present in the mix. As hydration progresses, more gypsum and anhydrite are consumed and the peaks for gypsum become weaker.
The inhibition effect of organic salt solution OS500A (containing 75% potassium formate)and OS500B(containing 75% ammonium formate), potassium chloride solution and clean water on the hydration ...
Anhydrite is typically composed of calcium sulfate with one molecule of water, but can also contain other mineral impurities, such as iron and magnesium. Anhydrite can affect drilling fluids in several ways. Anhydrite can contribute to the weight of the drilling fluid, increasing its density and allowing it to cut more abrasive formations.
The effect of K 2 SO 4 activator on the hydration of chemical anhydrite obtained from burned FGD-gypsum has been studied by different experimental techniques. Results obtained show that the degree of hydration increases when the K 2 SO 4 concentrations increase from 0.5 to 3.3 wt%. Their heat evolution rate and maximum value also increase …
However, a significantly higher rate of increase in skin hydration was observed in the groups of water immersion with sodium hydrogen carbonate as compared with the plain water immersion.
The hydration properties of hemihydrate gypsum and anhydrite affect the quality of MPPG-based materials. Anhydrite has a much slower hydration rate and strength development than hemihydrate gypsum, and is commonly blended with cement, strong alkali or alkali sulfate to increase its hydration activity [15–17].
Anhydrite is an important constituent of white, usually marginal, zones of amygdules residing within the slag sample LdS15 (Figure 13.2.7C and D).However, it is also found in the blue, …
The effects of varying Li 2 CO 3 additions on the hydration kinetics of a ternary CSA-OPC-anhydrite system were investigated. The presence of Li led to increased ye'elimite and C 3 S dissolution as well as accelerated ettringite precipitation. Excessive additions however resulted in heavily decreased ye'elimite dissolution and hydration kinetics after the initial …
salt beds, and the heats required to raise the temperature of each to 1,500°C and to 2>000°C were calculated. For a half and half mixture of salt and anhydrite, 1,300 cal/gm were required to raise the tempera ture to 2,000°C. For an evaporite containing 60 percent salt and about equal amounts of anhydrite, calcite, and quartz, 1,100 cal/gm
Anhydrite also occurs as a vein-filling mineral in hydrothermal deposits. It is deposited from solution, often along with calcite and halite, as gangue in sulfide mineral deposits. Anhydrite is also found in the cap rock of salt domes.. …
We draw auxiliary horizontal lines AB and BC. During hydration of FLA, water binds and hydration products with a lower true density are formed, as a result, the volume fraction of the solid phase increases, so the diagram contains auxiliary lines K s2 = const for anhydrite stone at the age of 3, 7, 14, 28 days.
Regarding the effect of TEA at the dosage of 0.1 wt%, the presence of TEA can accelerate the dissolution of gypsum formed through the hydration of hemihydrate and anhydrite under 30 % RH, which in turn alleviates the retardation effect of aging on cement hydration. Along with increased curing age and curing RH, more sulfate carriers could be ...
The rate constant almost doubles for gypsum, but it increases by a factor of 9 for anhydrite, as the salt concentration rises from 0 to 10 g/L. Apparently, this effect needs to be considered when interpreting karst development in deep-seated …
140 surface of anhydrite, which increases the specific surface area, and the formation of gypsum. Sievert et al. (2005) proposed a five step mechanism of hydration via solution …
An increase of the hydration rate of orthorhombic anhydrite has been obtained by mechanical activation (grinding) of the solid: that allows a direct calorimetric investigation on the reaction kinetics. ... So the grinding of anhydrite greatly increases the hydration rate, what allows to use calorimetry to make comparative kinetical ...
Consequently, the use of chemical activators such as metallic sulfates, aluns, calcium or sodium hydroxydes or portland cement has been suggested by many investigators to increase the hydration rate of 633 634 Vol. 17, No. 4 M. Murat, et al. the anhydrous solid (1-8). Mechanical activation of anhydrite by grinding has also been tested (9).
Anhydrite transforms into gypsum upon contact with water, while unstable f-CaO readily converts to calcium hydroxide (CH) during hydration, contributing to the formation of ettringite [5]. As a result, a high content of f-CaO can lead to volumetric expansion and even cracking, which negatively affects the long-term durability of the material.
The ASLF linear rate change was correlated with the hydration process of anhydrite. In the early stage, the anhydrite hydration was delayed owing to the chelation of the anionic group of WRA with Ca 2+. At this time, the shrinkage caused by water volatilization is the main reason for the overall shrinkage of the hardened body.
In the case of anhydrite an acceleration was also observed (Fig. 5 d), which, however, seemed to depend on the anhydrite concentration and was faster in pastes with 20 wt% anhydrite (i.e., bassanite hydration was 3.2 times faster than in pastes prepared with pure bassanite) as compared to samples containing only 1–10 wt% anhydrite (i.e ...
The binding rate of SAC mortar containing GGBS increased with the increase of the dosage, in which SAC mortar containing 40% GGBS had the strongest resistance to internal Cl − erosion, which was ...
【Solved】Click here to get an answer to your question : Anhydrite is a "dry" (water-free) variety of _____. Group of answer choices: - Rock salt. - Quartz sand.
The hydration of slag forms water rigid minerals such as ettringite and hydrated calcium silicate, and the strength and water-resistance of the anhydrite binder material are accordingly increased ...
The presence of up to 10% of salt accelerated the hydration process and increased the hydration of C3S and C3A, while the 20% of the salt causes a delayed hydration and decreased the hydration of ...
Crush the salt : By this action the rate increases because the surface area of solute (salt) increased by the crushing. So, the salt will be dissolved easily in water. Heat the water : By this action the rate increases because when we are heating the water the temperature of the water increases. As the temperature increases, some empty voids ...
the hormone _____ stimulates the bone marrow to produce red blood cells; this hormone is secreted by the _____
It is interesting to note the concentration of ettringite seems to increase for hydration periods of 24 hours through 14 days, then the concentration of ettringite seems to decrease from 14 days ...
The hydration of slag forms water rigid minerals such as ettringite and hydrated calcium silicate, and the strength and water-resistance of the anhydrite binder material are accordingly increased ...
Agitation and stirring will increase the rate at which salt dissolves in water. I I. Increased movement of water molecules allow sodium ions and chloride ions to be pulled apart as shells of hydration are formed. Statement I is true, Statement I I is true and is a correct explanation of the phenomena described in I; Statement I is true ...