THE SUDANESE MINERAL LAW REGIME AND POTENTIAL …

By creating a system that applies to the entire mining lifecycle, mining cadastres provide a tool through which governments may enforce mining laws as well …

Calcium sulfate, dihydrate CAS N°: 1

Calcium sulfate, dihydrate is produced in two companies as a waste-solid in the phosphatic fertilizer industry in Korea and this chemical is used as a primary material in gypsum industry, in which residues of calcium sulfate, dihydrate are recycled. Calcium sulfate, dihydrate is used in portland-cement retarders, tiles, polishing powders,

Hydration characteristics and mechanism analysis of β-calcium sulfate

1. Introduction. Gypsum plaster, prepared with water and calcium sulfate hemihydrate (CaSO 4 ∙1/2H 2 O), has excellent properties and performance, such as lightweight, high-temperature resistance, and recyclability [1, 2].Calcium sulfate hemihydrate is classified into α-calcium sulfate hemihydrate (α-HH) and β-calcium …

Calcium sulfates in planetary surface environments

Currently, there are at least eight known (ambient pressure) modifications of calcium sulfate with varying degrees of hydration (Ritterbach, 2021; Christensen et al., 2008).Of these, four have been shown to exist on the Earth's surface, as well as on Mars – gypsum, bassanite, anhydrite and γ-CaSO 4 (Table 1) (Voigt et al., 2020; Shi et al., 2022).

An Integrated Process Including Rb Leaching from Rubidium …

In the traditional chlorination roasting-water leaching-solvent extraction process for the extraction of rubidium-bearing ore, Rb leaching from the ore and calcium removing from the leachate are conducted separately, and this results in the complicated process and high energy consumption. In order to integrate the Rb leaching and …

Calcium transfer process of cement paste for ettringite …

It can be seen from Table 5 that after 28 days of corrosion, the interlayer calcium of C-S-H gel is not affected by the pH value and the sulfate ions concentration, and the interlayer calcium remains stable within the range of 2.3–2.4, which is basically consistent with the interlayer calcium before sulfate attack. The slight changes in the ...

(PDF) Sulfate Removal from Water

Average sulfate concentrations in the effluent using different concentrations of bentonite (400, 500, 600, 700, 800, and 900 mg/L) (N = 3). …

Dynamic characteristics and evolution laws of underground …

During the mining process, the overall calcium ion concentration of the underground brine in the study area shows a decreasing trend, which is the opposite trend of normal groundwater evolution ...

Calcium Sulfate

Calcium sulfate has been used for bone substitutes for long time. Peltier et al. (1957) mixed a plaster of paris (POP), calcium sulfate hemihydrates, and water allowing to set in the mold to make column- and tablet-form calcium sulfate dihydrate. The set plaster was used to fill defects in dog bone.

The influence of calcium sulphoaluminate cement on the …

Sulphoaluminate cement is considered green cement, which has the characteristics of rapid setting and high early strength.The partial substitution of sulphoaluminate cement (CSA) for ordered portland cement (OPC) was investigated in the system mixed with alkali free liquid accelerator. The hydration process and products …

Calcium Mining In The United States

Calcium Mining In The United States Overview 134K Total Mines; Table 51 Total Mines; Browse 134,153 mining USGS records in the united states. Most records highlight mining opportunities and activity in Alabama, Alaska, and Arizona. Quick Facts. 134,153 records of mining in the united states.

Sulfate Removal Technologies: A Review

In Situ Sulfate Mine Water Treatment – Practical Engineering in the Field. INAP Sulfate Workshop, Salt Lake City, February 27 th. Golder Associates, 2014. Established and Innovative Sulfate Removal Treatment Processes. INAP Sulfate Workshop, Salt Lake City, February 27 th. ITRC, 2013. Biochemical Reactors for Mining …

Calcium Sulfate Dihydrate

Calcium sulfate. J L RICCI, ... H ALEXANDER, in Bioceramics and their Clinical Applications, 2008. 14.2.1 Gypsum and its derivatives. CS cements begin as gypsum, or calcium sulfate dihydrate (CaSO 4 · 2H 2 O), which is either mined from the earth or produced through more controlled chemical processes (Randolph, 1971).Gypsum and …

Calcium sulfate | chemical compound | Britannica

Other articles where calcium sulfate is discussed: ale: …brewed with water rich in calcium sulfate, are made with top-fermenting yeast, and are processed at higher temperatures than the lagers popular in the United States. Pale ale has up to 5 percent alcohol content, while India pale ale—a variety of pale ale—typically has more; both usually have even …

A REVIEW OF SULFATE REMOVAL OPTIONS FOR MINE WATERS

Direct transformation of FGD gypsum to calcium sulfate …

Formation of calcium sulfate whiskers is usually influenced by reaction temperature, reagent concentration, reaction time, and stirring speed (Song et al., 2011).To prepare calcium sulfate whiskers with good morphology and performance, different sets of reaction conditions were examined (Table 1).The transformation from CSD to CSH did …

Barium Carbonate process for sulphate and metal …

The purpose of this study was to demonstrate the performance of the integrated barium carbonate process, consisting of the following stages: Sulphate precipitation as BaSO4 …

Calcium Mining

Calcium carbonate is used in the production of cement, steel, and glass, and as a filler in rubber and plastics. Calcium sulfate is employed in the creation of plaster and drywall. Calcium is also used in agriculture to adjust soil pH and in water treatment to remove impurities. Historical records of calcium mining date back thousands of years.

THE SOLUBILITY AND SURFACE ENERGY OF CALCIUM SULFATE

THE SOLUBILITY AND SURFACE ENERGY OF CALCIUM SULFATE. Merle L. Dundon; and ; Edward Mack Jr. Cite this: J. Am. Chem. Soc. 1923, 45, 11, 2479–2485. Publication Date (Print): November 1, 1923. ... You've supercharged your research process with ACS and Mendeley! Continue. STEP 1: Login with ACS ID Logged in Success Click to create …

South Sudan Calcium sulfate Market (2024-2030) | Trends, …

7 South Sudan Calcium sulfate Market Import-Export Trade Statistics. 7.1 South Sudan Calcium sulfate Market Export to Major Countries. ... Peru Construction and Mining Machinery Market (2024-2030) | Industry, Analysis, Revenue, Forecast, Size, Growth, Outlook, Trends, Value, Share & Companies ...

A new approach of aluminum extraction from drinking water …

A new approach of aluminum extraction from drinking water treatment sludge using ammonium sulfate roasting process. Author links open overlay ... and low contents of calcium (0.64 %), magnesium (0.16 %), aluminum (2.75 %), and manganese (0.05 %), which confirm the efficiency of the developed process. ... its licensors, and contributors. …

Impact of C3A Polymorphism, Lignosulfonate Admixture, …

The effect of C 3 A polymorphism, the calcium sulfate source, and the addition of limestone on the hydration kinetics and rheology of cement pastes and their interaction with a lignosulfonate-based admixture were analyzed. Two clinkers produced in industrial cement rotary kilns using the same raw materials and process were produced; …

Barium Mining

MINING: The chief ore of barium, barite, is mined from the surface using the open-pit mining method. The presence of barite is initially confirmed through an initial analyzing process, and the distribution of the ores is …

Calcium sulfate precipitation pathways in natural and …

The solution-mediated formation of calcium sulfate minerals, i.e. gypsum, anhydrite and bassanite, is a common process in both natural and engineered settings. …

Sustainable Production and Physicochemical Characteristics of Calcium …

Gypsum products (calcium sulfate dihydrate, CaSO4·2H2O) were synthesized through an eco-friendly and low-cost process by two different renewable calcium carbonate sources (CaCO3), hen and duck eggshell wastes, with product yields obtained of 84.73 and 87.74%, respectively. The X-ray fluorescence results indicated …

Understanding the effect of sulphate in mining-process …

Formation of calcium sulphate (gypsum) by the interaction of calcium ions with sulphate ions in the pulp produces fines slime coatings on the sulphide minerals …

Gypsum | Properties, Formation, Uses and …

Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4·2H2O). It is commonly found in sedimentary rock formations and is often associated with other minerals such as …

Preparation of alpha-calcium sulfate hemihydrate from …

This work develops a new class of salt solution method to prepare alpha-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum in trace K 2 SO 4-contained 4.0 M Ca(NO 3) 2 aqueous solution at 95 °C under atmospheric pressure. The driving force for the phase transition is provided by the concentrated Ca(NO 3) 2 …

Application of microbially induced calcium carbonate …

MICP refers to a natural microbially mediated process in which CO 3 2− and then CaCO 3 precipitate can be produced during microbial metabolism processes in the presence of dissolved calcium, and this process can be utilized for specific remediation purposes. Several types of bacteria can be utilized to perform MICP, including urease …