A massive gypsum scale in a discharge pipe of a desalination plant occurred despite the presence of an antiscalant (PermaTreat, PC-191). The scaling occurred following a sharp drop in the reject-brine pH when an acidic effluent (pH < 2) was introduced.Batch experiments revealed that the antiscalant is effective in postponing …
The solubility of the PG sample in distilled water (2.7 g/L) is nearly close to that of pure gypsum (2.25 g/L (Sfar Felfoul et al., 2002) and is higher in sodium chloride solution (10 g/L) than in sea water (3.9 g/L and 2.4 g/L respectively) (see Fig. 3).To determine the optimal sodium chloride amount allowing the increase of PG's solubility, …
Unlike calcium in lime, the solubility of calcium in gypsum is not affected by pH (see figure below) so gypsum provides a soluble source of calcium if sodium needs to be displaced in neutral to alkaline soils. Soils that have more than 5–6 per cent of the cation exchange capacity occupied by sodium are called sodic.
Gypsum is a naturally occurring mineral that has been used by humans for various purposes for thousands of years. It is a versatile mineral with a wide range of applications in construction, agriculture, …
According to the findings, at 0.5 mol/dm 3 HCl concentration, increasing the concentration of metal chlorides to a certain level improves gypsum solubility, and then …
The dissolution of gypsum increases at pH 12-13 [47] explaining why, no gypsum crystal is observed at later stages (14 and 28 days cured samples). The degree of hydration (DOH) is calculated by ...
While it is unclear why gypsum did not behave similarly to alum and Epsom salt, the differences in their solubilities may have played a role; the solubility of gypsum is much lower than that of alum and Epsom salt, particularly under subzero temperatures (Marion & Farren, 1997) that existed in the field from late fall to early spring.
Under the condition of saline–alkaline-coupled excitation, the ratio of slag, steel slag, and desulfurization gypsum was 53:40:7, and the late mechanical properties of the cementitious material decreased the least (only 5.67%, and the 28 d compressive strength was 40.44 MPa).
An experimental apparatus is presented for the measurement of thermodynamic equilibria in aqueous suspensions. The solubility of calcite and gypsum, measured at 298.15 K in aqueous solutions with calcium chloride and organic acids as formic, acetic and adipic acid, is compared to data calculated using Pitzer's electrolyte …
This chapter gives theoretical and practical information for proper gypsum management in salt-affected soils. Although gypsum is well known as amendment an to …
soil properties. Gypsum is somewhat soluble in water, but more than 100 times more soluble than limestone in neutral pH soils. When applied to soil, its solubility depends on several factors, including particle size, soil moisture, and soil properties. Gypsum dissolves in water to release Ca2+ and SO 4 2-, with no significant direct impact on ...
The likely progression for calcium sulfate mineralogy was original gypsum precipitation that was altered to anhydrite under burial diagenesis, with subsequent exhumation and shallower depth of burial resulting in alteration back to gypsum. The higher solubility of gypsum facilitates extensive development of karst topography on the …
Solubility of gypsum in water at 25 °C, (4) calculated and (1–3) measured under certain experimental condi-tions. Dissolution of dispersed gypsum: (1) under the con-ditions of dependence on particle size, = (r), and (2) under the conditions when such an effect is absent, ≠ (r); (3) dissolution of a flat gypsum surface simi-
Salalah International Gypsum Co. L.L.C., or SIG in short, is the leading natural gypsum producer & exporter from Sultanate of Oman. We are located at Salalah in the Dhofar governorate, which is the southernmost part of Oman. Our gypsum mines are located at Thumrait, around 80 km from Salalah city. SIG's gate way to the world is the Port of ...
The FFNN-BR outperforms the other models to determine gypsum solubility at 295 and 313 K. The results obtained from Pitzer and CMIS models are satisfactory. The CSA-LSSVM provides the least accurate predictions under these conditions. The Pitzer model is the most accurate to determine the gypsum solubility in …
While our study showed non-significant changes in soil pH under all amendments after six weeks incubation, there was a modest decrease in soil pH under gypsum and biochar (Table 1). There was a non-significant increase of soil pH under CaCO 3 treatment, which may be due to a higher insolubility of carbonate in saline …
Gypsum has been used for centuries to reclaim sodium affected soils (alkali soils). It is effective since it has good solubility regardless of soil pH. In fact, its solubility is enhanced in sodic soils. Some data would suggest that the solubility of gypsum in alkali soils is four times greater. Once the gypsum dissociates intoGypsum has been used for …
Gypsum solubility (at 25 °C) and logarithm of rate coefficients for gypsum growth at a range of temperatures (25 °C, 50 °C, 70 °C, and 90 °C) in stoichiometric solutions as a function of ...
Note that the pH value of slag based gypsum was 8.5. Under high pH, cation exchange sites displaced into the solution, leading to an increase in soil pH. Fig. 9 (b) showed that increasing the content of industrial by-product gypsum reduced the pH value of acidic soil. This improvement was achieved by the neutralization reaction of alkaline ...
This study measured gypsum solubility under its stable phase conditions up to 1400 bar; it also confirmed the anhydrite solubility reported in the literature.
The solubility of gypsum in different salt solutions containing Ca, Mg, Na, Cl, and SO4 was determined experimentally at 298 …
The solubilities and dissolution rates of three gypsum sources (analytical grade (AG), phosphogypsum (PG) and mined gypsum (MG)) with six MG size fractions ((mm) > 2.0, 1.0-2.0, 0.5-1.0, 0.25-0.5, 0.125-0.25, and PG > MG) due to reactivity and surface area differences, with 1:20 gypsum:solution suspensions reaching saturation …
TITLE Example 2.--Temperature dependence of solubility of gypsum and anhydrite SOLUTION 1 Pure water pH 7.0 temp 25.0 EQUILIBRIUM_PHASES 1 Gypsum 0.0 1.0 Anhydrite 0.0 1.0 REACTION_TEMPERATURE 1 25.0 75.0 in 51 steps SELECTED_OUTPUT -file ex2.pun -si anhydrite gypsum END
The solubility and precipitation kinetic of siderite were measured under 90, 120, and 150 °C, with 1m of NaCl under unchanged pH (pH=6). The solubility data were in agreement with SSP prediction...
The heat released during the reaction dries the soil while the increased calcium ion concentration raises pH, ... This is probably because of the relatively high solubility of gypsum in water. Unlike fine-grained material, where cation exchange is the main mechanism for improved behavior of the treated soil, the stabilizing effect of …
This was primarily attributed to the precipitation of soluble alkali compounds (e.g. NaOH, Na2CO3, NaHCO3, NaAl(OH)4, KOH, K2CO3)[34] to more stable calcite, tri-calcium aluminate, hydrocalumite, and other calcium aluminate minerals during the treatment with gypsum [33,35–38], which exhibit lower solubility and therefore give …
Experiments were carried out by mixing equimolar solutions of Na 2 SO 4 and CaCl 2, and encompassing the entire experimentally accessible concentration range (0.04 M – 0.2 M; this range is limited in the low concentration end by the solubility of gypsum, and by the too fast and experimentally not approachable precipitation rate observed at ...
Measuring the solubility of gypsum under all different operational conditions is not cost effective and is time consuming, owing to the wide number of components and temperatures involved. Moreover, obtained data will not cover all the operating conditions and ionic compositions frequently encountered in process …
Gypsum solubility (at 25 °C) and logarithm of rate coefficients for gypsum growth at a range of temperatures (25 °C, 50 °C, 70 °C, and 90 °C) in stoichiometric solutions as a function of ...
Effect of pH on the Solubility of CaSO4·2H2O in Aqueous NaCl Solutions and Physicochemical Solution Properties at 35 °C. Journal of Chemical & Engineering Data 2008, 53 ... Experimental investigation and modelling of the solubility of calcite and gypsum in aqueous systems at higher ionic strength. Fluid Phase Equilibria 2004, 219 …
In the field of experimental measurements of gypsum solubility, extensive investigations have been conducted by academic researchers over many years, the most important of which are briefly mentioned below. Barba et al. [20] evaluated the gypsum solubility in salty water solutions including Na 2 SO 4 and MgCl 2 with. Overview of the …
The amendment of salt-affected soils with elemental sulfur (S 0) has been recognized for its potential to effectively reduce soil salinity and pH, thereby enhancing soil physicochemical properties, promoting crop growth, and improving yields.Despite these known benefits, the widespread adoption of S 0 for managing saline soils, particularly in …
Calcium sulfate exists in three forms, namely dihydrate or gypsum (CaSO4·2H2O), anhydrite (CaSO4), and hemihydrate or bassanite (CaSO4·0.5H2O) depending on temperature, pressure, pH, and formation conditions. The formation of calcium sulfates occurs widely in nature and in many engineering settings. Herein, a …
The alkaline pH levels observed in slag-based gypsum and flue gas desulfurization gypsum are attributed to CaCO 3 impurities originating from the steel and …
Established in 2010, GLOBAL GYPSUM BOARD CO LLC is the first to operate gypsum board and value added plaster plants in the Sultanate of Oman, with production capacities of 15 Million sqm for 12.5mm thicknesss plasterboards, 60,000 MT/year of value added plaster and 150,000 MT/year stucco production capacity.
The analysis of published data and our experimental results showed that the existing estimates of gypsum solubility in water (Cm↑) at 25°C range from 0.0147 to 0.0182 M.
The obtained enthalpy and entropy changes at 298.15 K for the solubility reactions are in good agreement with literature values yielding solubility products of 2.40 × 10–05, 3.22 × 10–05 ...