Monium Sulphate Precipitation Using Gypsum

Solubility of Gypsum (CaSO4)

2020-8-9 · The correct formula of gypsum is CaSO 4:2H 2 O. To keep the notation simple, we use the short form CaSO 4 here. ↩ Here and in the following, the notation ''log x'' is used for the decadic logarithm ''log 10 x''. ↩ Tables of K sp values are given here. ↩ Here we approximate K sp by the stoichiometric solubility product (Strictly speaking, this only applies for ideal solutions …

Prediction the Amount of Barium Sulfate Scale Formation …

BARIUM SULPHATE SCALE. BaSO 4 scale (barite) in oil fields can be precipitated easily on the basis of already available information relating to the thermodynamic condition and the kinetics (Collins and Leinweber, 1956; Davis and Collins, 1971; Hunton and Gilbert, 1982; Nancollas and Liu, 1975; Templeton, 1960; Weintritt and Cowan, 1967) of precipitation.

Influence of additives on the precipitation of gypsum in ...

The kinetic of precipitation of calcium sulfate dihydrate (gypsum) in sodium chloride solutions was investigated at various supersaturation from 1.05–2.49, pH = 8.50, 25°C and ionic strength 0.5 M. The rate of precipitation showed a quadratic dependence upon the relative supersaturation which suggests a surface-controlled growth mechanism. Influence of a number of amino acids on the …

A new precipitation pathway for calcium sulfate dihydrate ...

This work investigates the early stages of precipitation of calcium sulfate from aqueous solution at room temperature and shows for the first time that amorphous calcium sulfate (ACS) and calcium sulfate hemihydrate are sequentially precipitated prior to calcium sulfate dihydrate (gypsum).

Lime & gypsum

2016-5-18 · In the high-rainfall parts of the KZN interior, aluminium toxicity due to subsoil acidity can severely restrict root development. Both the calcium and the sulphate in gypsum help to improve root growth in acid subsoils. exchange sites The sulphate ion ameliorates aluminium toxicity by: precipitating aluminium- and sulphate-

Kinetic and morphological investigation of calcium …

2018-5-6 · the gypsum crystals grown in the presence of anionic polymeric additives show that structures of these crystals are highly modified. Results on the performance of various surfactants and biocides are presented. Key words: calcium sulfate dihydrate, gypsum, scale, maleic acid polymers, heat exchanger, crystal morphology.

Application Note Titanium Dioxide

2020-6-18 · Titanium Dioxide - Sulfate Process 2 Gypsum Production - Sulfate Process Titanogypsum (CaSO 4) production can be a unique by-product of the sulfate process. The process is analogous to flue gas desulfurization used for SO 2 reduction in coal-fired power plants. White titanogypsum is highly desirable for use in plasterboard and cement. Red ...

Ravensdown Gypsum (calcium sulphate)

Gypsum is used as a source of soluble calcium and sulphate, with the added advantage of not increasing soil pH (in contrast to lime as a calcium source). Gypsum is typically used in horticulture e.g. kiwifruit, apples and pipfruit …

Sulfate removal from waste chemicals by precipitation ...

2009-1-1 · Sulfate precipitation procedureChemical precipitation of sulfate before and after Fenton''s oxidation was performed using barium and calcium ions. Firstly, the effects of pH on sulfate precipitation were investigated at a pH range of 2–8 using non-treated wastewaters without solids separation. NaOH (∼30% w/v) was used for pH adjustments.

A New Process For Sulfate Removal From Industrial Waters

1. Initial precipitation of sulfate as gypsum 2. Precipitation of metals as hydroxides in a gypsum matrix 3. Additional sulfate removal via ettringite precipitation 4. pH reduction using recarbonation. Figure 1 shows the simplest version of the process where only final sulfate …

An integrated limestone/lime process for partial sulphate ...

2009-8-27 · sulphate removal of acidic/sulphate-rich water to sulphate levels of less than 1 500 mg/l due to precipitation of magnesium and removal of the associated sulphate fraction (through gypsum crystallization). Neutralized mine water of this quality may be suitable for irrigation. The process consists of the following stages: 1.

Calcium sulfate crystallization in phosphoric acid

2020-10-13 · calcium sulfate as semihydrate. Unfortunately, in the development of the process, as in the past for gypsum processes, fundamentals of crystalliza­ tion and the theory of crystallizers have been ignored completely. Con­ sequently, problems encountered by TVA are not very different from :hose existing in gypsum processes.

SHORT COURSE: MINE WATER TREATMENT …

2017-5-3 · • Lime precipitation using HDS • Waste stream must have an acidic pH (less than 6 S.U.) • Waste stream must contain soluble metals • Primary metals; iron, chromium, zinc, copper, nickel or aluminum • Control pH to minimize conventional precipitation • Applicable for CaCO3 and CaSO4 precipitation . 10

The potential of gypsum speleothems for …

2020-9-9 · Using stable isotopes (δ 17 O, δ 18 O and δD) of gypsum hydration water to ascertain the role of water condensation in the formation of subaerial gypsum speleothems. Chem. Geol. 452 …

Ammonium Sulfate

Sulfate removal from waste chemicals by precipitation ...

Gypsum Crystallization during Phosphoric Acid …

2015-5-12 · Gypsum Crystallization during Phosphoric Acid Production: Modeling and Experiments Using the Mixed-Solvent-Electrolyte Thermodynamic Model You Peng,†,‡ Zhilong Zhu,†,‡ Richard D. Braatz,† and Allan S. Myerson*,† †Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States S …

Removal of High-Concentration Sulfate Ions from the …

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 dosage, solution temperature, anions (Cl −, NO 3 − and F −), and heavy metal ions (Mg2+ and …

Sulphate removal from mine water with chemical, …

2018-3-6 · 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 gypsum pre …

[PDF] A new precipitation pathway for calcium sulfate ...

DOI: 10.1039/c1cc14210k Corpus ID: 20628891. A new precipitation pathway for calcium sulfate dihydrate (gypsum) via amorphous and hemihydrate intermediates. @article{Wang2012ANP, title={A new precipitation pathway for calcium sulfate dihydrate (gypsum) via amorphous and hemihydrate intermediates.}, author={Yun-wei Wang and Yi-Yeoun Kim and H. Christenson …

Calcium Sulfate and Calcium Carbonate Simple and Mixed ...

2021-8-18 · The study of gypsum precipitation by the double decomposition method shows that the QCM response as well as monitoring [Ca 2+] is the most appropriate method to detect the exact time of the start of gypsum germination. 3.3 Co-precipitation . Gypsum and CaCO 3 mixed precipitation Kinetics have been studied by the double decomposition method and ...

Chapter 12 Calcium Sulfate Precipitation Throughout Its ...

2017-1-23 · 12 Calcium Sulfate Precipitation Throughout Its Phase Diagram 229 Fig. 12.1 Structural motifs of the three main calcium sulfate phases, gypsum, bassanite, and anhydrite (AII form). Tetrahedra are sulfate ions, large spheres are Ca ions, and arrows indicate water sheets and channels in the gypsum and bassanite structures, respectively (Images ...

Effect of bacteria and salinity on calcium sulfate ...

2012-2-15 · This paper presents interactive effects of biological matter, Pseudomonas Fluorescence ( PF ), on precipitation of calcium sulfate, a sparingly soluble salt and an inorganic foulant. Experiments were conducted in isothermal (25 °C) batch tests. The effect of PF and its concentration on CaSO 4 precipitation and deposit structure at varying ...

The behaviour of the rare earth elements during gypsum ...

2017-12-1 · A series of experiments was also carried out to identify the ''best" sulphate reagent for the gypsum precipitation experiments. Those experiments were done in the presence of 5 g/L Pr 3 +, and using 0.2 mol of CaCl 2 and 0.2 mol of one of Li 2 SO 4, Na 2 SO 4 or MgSO 4 .

The kinetics of the precipitation of gypsum, CaSO4·2H2O ...

2020-9-3 · Uncontrolled gypsum precipitation can also cause hardships during reverse osmosis processes; this issue was also addressed in the literature [9, 41, 42]. Gypsum precipitation as a side-product during the neutralization of some wastewaters was also investigated [3, 43]. From these examples, one may conclude that the precipitation kinetics of ...

The High Density Sludge (HDS) Process and Sulphate …

2015-4-17 · sulphate concentrations, the recent trend shows that HDS plants have been constructed with considerably higher retentions times in the neutralisation reactors. The reason for this increase in retention time is due primarily to the slow gypsum-precipitation reactions that are the key to minimising sulphate concentrations.

Unraveling the Sulfate Sources of (Giant) Gypsum Crystals ...

2020-9-5 · Gypsum was precipitated in the laboratory from CaSO 4-NaCl-H 2 O solutions across a broad temperature range to establish the isotopic fractionation behavior of the sulfate molecule between the solid and dissolved phase. Oxygen isotopes show a significant fractionation dependence on temperature, with the solid phase more depleted in light ...

SODIUM SULPHATE: ITS SOURCES AND USES

2011-6-15 · the anhydrous sulphate, thenardite, and it is a constituent of a num­ ber of compound minerals, such as glauberite, vanthoffite, bloedite, and aphthitalite, and of the waters of many natural brines and playa lakes. In areas where rainfall is scanty sodium sulphate is termed white

Effect of bacteria and salinity on calcium sulfate ...

2012-2-15 · Research Highlights Interactive effects in composite fouling that are mostly ignored. Interactive effects of biological matter Pseudomonas Fluorescence (PF) on calcium sulfate precipitation. PF influencing CaSO 4 crystallization which was suppressed and S levels increased. The generally ignored interactive effects are of significant importance. Interactive effects are …

Gypsum: an old product with a new use | Integrated Crop ...

2021-9-24 · Gypsum: an old product with a new use. Gypsum is calcium sulfate (CaSO 4 ). Refined gypsum in the anhydrite form (no water) is 29.4 percent calcium (Ca) and 23.5 percent sulfur (S). Usually, gypsum has water associated in the molecular structure (CaSO 4 ·2H2O) and is approximately 23.3 percent Ca and 18.5 percent S (plaster of paris).

Carboxylic acids: effective inhibitors for calcium sulfate ...

2018-7-5 · Precipitation reactions were followed at pH 7 in the pure CaSO 4 system and in experiments with 0–20 ppm carboxylic acids added using in situ UV-VIS spectrophotometry (turbidity). The solid products were characterized in terms of their mineralogical composition, using X-ray diffraction, during and at the end of each reaction, and in terms of ...

Standard Test Methods for Chemical Analysis of Gypsum …

2015-2-21 · 4.7 Gypsum Board—Cut or break the dried sample into small pieces. Using a mortar and pestle, strike the pieces of the sample to loosen the paper face. Remove the pieces of paper by hand as they are separated from the core of the gypsum board. Carefully scrape any remaining powder from the paper. When

Chemical sulphate removal for treatment of construction ...

Construction and demolition debris (CDD) is a product of construction, renovation or demolition activities. It has a high gypsum content (52.4% of total gypsum), concentrated in the CDD sand (CDDS) fraction. To comply with the posed limit of the maximum amount of sulphate present in building sand, e …

Sulfate Removal Process

Operation. Our flexible sulfate removal process consists of a sulfate precipitation stage at pH 11–13 using lime milk and aluminum, followed by a final neutralization stage using carbon dioxide. Gypsum precipitation can be included before the sulfate removal stage when required. The process, built on easy-to-understand chemistry, can be ...