Barium sulfate-water system

Available Forms. Phthalocyanines are available as powders, in paste, or Hquid forms. They can be dispersed in various media suitable for aqueous, nonaqueous, or multipurpose systems, eg, polyethylene, polyamide, or nitrocellulose. Inert materials like clay, barium sulfate, calcium carbonates, or aluminum hydrate are the most common soHd extenders. Predispersed concentrates of the pigments, like flushes, are interesting for manufacturers of paints and inks (156), who do not own grinding or dispersing equipment. Pigment—water pastes, ie, presscakes, containing 50—75% weight of water, are also available. 

Chemical scaling is another form of fouling that occurs in NF and RO plants. The thermodynamic solubility of salts such as calcium carbonate and calcium and barium sulfate imposes an upper boundary on the system recovery. Thus, it is essential to operate systems at recoveries lower than this critical value to avoid chemical scaling, unless the water chemistry is adjusted to prevent precipitation. It is possible to increase system recovery by either adjusting the pH or adding an antisealant, or both. 

Appreciable levels of barium sulfate occur because natural water often contains high sulfate concentrations. Since the solubility of barium sulfate is low, only trace amounts of barium dissolve in surface water (Bodek et al. 1988 NAS 1977). At pH levels of 9.3 or below, barium sulfate may limit barium concentrations in natural waters (Bodek et al. 1988). The solubility of barium sulfate increases considerably in the presence of chloride (Cf) and other anions (e.g., NO and CO ), and at pH levels of 9.3 or below, the barium ion (Ba ) is the dominant species (Bodek et al. 1988 NAS 1977). The Ba+ ion is stable under the pH-Eh range of natural systems. However, natural and treated waters usually contain sufficient sulfate so that a barium ion concentration of more than 1,000-1,500 mg/L cannot be maintained in solution (EPA 1983a Hem 1959 Lagas et al. 1984 McCabe et al. 1970). 

An interesting case in mineral equilibria is the presence in a soil-water system of two minerals with a common ion. An example of such a case is barium sulfate (BaS04) plus calcium sulfate (CaSO. Which mineral would be controlling SOj- in the system Two conditions would need to be met in such a system one is mass-balance while the second is charge balance. The mass-balance is given by... 

Critical sizes characteristic of different substances vary from less than ten to several hundred molecules. The earliest measurements were made by Ostwald (01), who found lO-10 g. to be the limiting mass of sodium chlorate in initiating crystallization from water solution. Volmer and Flood (V8) have shown that the critical nucleus in water vapor condensation is about 80 molecules. Extensive studies of barium sulfate precipitation (C4, L2) indicate that in this system the critical nucleus is no more than the unit cell, consisting of four sulfate and four barium ions. 

More than a century ago, Pickering [2] and Ramsden [3] investigated paraffin-water emulsions contains solid particles such as iron oxide, silicon dioxide, barium sulfate, and kaolin and discovered that these micron-sized colloids generate a resistant film at the interface between the two immiscible phases, inhibiting the coalescence of the emulsion drops. These so-called Pickering emulsions are formed by the self-assembly of colloidal particles at fluid-fluid interfaces in two-phase liquid systems (Fig. 1). 

D14. Barium sulfide is produced by reacting barium sulfate ore with coal. The result is barium black ash, which is BaS plus insoluble solids. Since BaS is soluble in water, it can be leached out with water. In thickeners the insoluble solids in the underflow typically carry with them 1.5 kg liquid per kg insoluble solids. At equilibrium the overflow and underflow liquids have the same BaS concentrations fTreybal. 19801. We want to process 350 kg/h of insoluble solids plus its associated underflow liquid containing 0.20 mass fraction BaS. Use a countercurrent system with 2075 kg/h of water as solvent. The entering water is pure. We desire the outlet underflow liquid to be 0.00001 mass fraction BaS. Find ... 

Compatibility concerns. THPS is not compatible with oxidizing biocides, but is compatible with most other commonly used nonoxidizing oilfield microbicides such as QACs or glutaraldehyde. THPS is more stable under anaerobic conditions than aerobic conditions. This is due to its tendency of the THP molecule to be oxidized to the phosphine oxide in the presence of oxygen. It works faster in alkaline systems than acidic systems, since the active THP is formed faster under alkaline pH s. In anaerobic oilfields, THPS is extremely stable and has been observed to travel through a formation and reemerge in the produced water (Bryan et al, 1995). Also, being the sulfate salt, solutions of THPS have been observed to react with divalent ions such as calcium and barium in oilfield produced waters to form insoluble calcium sulfate and barium sulfate precipitates. 

Hydrogenation of hulupone and cohulupone in the presence of platinum(IV) oxide or palladium(il) chloride as catalysts affords in both cases a hexahydroderivative and an octahydroderivative (2,16,22). With palladium on barium sulfate only a hexahydrohulupone or a hexahydrocohulupone is formed (87%). Thus hexahydrocohulupone gives 2-(3-methylbutanoyl)-5,5-bis(3-methylbutyl)-3,4-di-hydroxy-2-cyclopentenone (211, Fig. 88), which also may be considered as 5-(3-methylbutyl)dihydrocohumulinic acid. Cohulupone leads to 5,5-bis(3-methylbutyl)-3,4-dihydroxy-2-(2-methylpropanoyl)-2-cyclopentenone or 5-(3-methylbutyl)dihydro-cohumulinic acid (210, Fig. 87). This compound is identical to that obtained by sequential oxidation, reduction and alkaline treatment of hexahydrocolupulone (see 13.1.1.2.2.). Compound 210 (melting point 48°C) is isolated from the band with distribution coefficient 0.475 after 450 transfers in the two-phase system iso-octane acetate buffer in methanol water 58 42 with pH 5.45 (8). The molecular formula is C19H32O4 and the pK/ value in methanol water 1 1 is 4.1. In the H NMR spectrum... 

It is advisable to include a silane appropriate for the curing system employed in order to achieve lower compression set and water resistance plus higher modulus. Some fillers, including clays, talc, and sihca, have a silane already incorporated in them and are suggested for electrical and low water swell applications. If the product is meant for acid resistant uses carbon black and acid resistant non-black fillers such as barium sulfate should be selected. 

Barium perchlorate colorimetric titration. This colorimetric titration procedure is used in the determination of inorganic sulfate impurities in complex systems of water-soluble sulfonates and sulfonic acids. Sulfonates are precipi-... 

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