Mineral oleate

Sorbitan oleate and the monolaurate are pale yeUow Hquids. Palmitates and stearates are light tan soHds. Sorbitan esters are not soluble in water but dissolve in a wide range of mineral and vegetable oils. They are lipophilic emulsifiers, solubiHzers, softeners, and fiber lubricants that find appHcation in synthetic fiber manufacture, textile processing, and cosmetic products. Sorbitan esters have been approved for human ingestion and are widely used as emulsifiers and solubiHzers in foods, beverages, and pharmaceuticals. 

Certain small-volume injections are available where the dmg is dissolved in a viscous oil because it is insoluble in water non-aqueous solvent must be used, hi addition, drags in non-aqueous solvents provide a depot effect, for example for hormonal compounds. The intramuscular route of injection must be used. The vehicle may be a metabolizable fixed oil such as arachis or sesame oil (but not a mineral oil) or an ester such as ethyl oleate which is also metabolizable. The latter is less viscous and therefore easier to administer but the depot effect is of shorter duration. The dmg is normally dissolved in the oil, filtered under pressure and distributed into ampoules. After sealing, the ampoules are sterilized by dry heat, for example, at 160°C for 2 hours. A bactericide is probably ineffective in such a medium and therefore offers very httle protection against contamination in a multidose oily injection. 

Extending oils for compounds crosslinked with peroxides have to be carefully selected. Synthetic ester plasticisers such as phthalates, sebacates and oleates may be used in combination with crosslinking peroxides without affecting the crosslinking reaction. Some derivatives of alkylated benzenes are also known for their very low consumption of free radicals, which is clearly desirable. Mineral oil with double bonds, tertiary carbon atoms or containing heterocyclic aromatic structure may react with radicals paraffinic mineral oils are more effective than naphthenic types, which usually require extra treatment in order to guarantee optimum results when used in peroxide crosslinked blends. 

The adjuvanticity of oil emulsions was first recognized in the early 1900s. However, the first such product to gain widespread attention was Freund s complete adjuvant (FCA), developed in 1937. This product essentially contained a mixture of paraffin (i.e. mineral) oil with dead mycobacteria, formulated to form a water-in-oil emulsion. Arlacel A (mannide mono-oleate) is usually added as an emulsifier. 

Figure 23.1 Effect of level of sodium oleate on recovery of tantalite, columbite and associated gangue minerals.

Fatty Oil, etc.—Mixtures of colophony (or other resin, especially copal) with resinates, oleates and linseed oil are sold for the preparation of varnishes, and mixtures of colophony with mineral oils, resin oils, fatty oils, solid fats, paraffin wax, ceresine or wax for use as brewers pitch. For the recognition of such mixtures, the following tests may be made. 

Dixit and Biswas124 dealt with the relationship between H+ an OH- concentrations and adsorption of an anionic collector on a mineral surface and its flotability. They used the system zircon-Na oleate. If Na oleate is dissolved in water the following equilibrium sets up ... 

Akhtar and Lai128) infer the adsorption mechanism of a collector on a mineral surface from the mutual position of IPpH and PZC which they determine by electrophoresis. Their deduction is based on experiments performed with hematite in solutions of Na oleate (NaOl) and dodecylamine hydrochloride (DDA-HC1). The surface of hematite is assumed to consist of MeOHj, MeOH and MeO-. Chemisorption of the collector is discussed according to Table 3 which is based on Eq. 72 for charge density at the inner Helmholtz plane ... 

The study of adsorption kinetics of a surfactant on the mineral surface can help to clarify the adsorption mechanism in a number of cases. In the literature we found few communications of this kind though the adsorption kinetics has an important role in flotation. Somasundaran et al.133,134 found that the adsorption of Na dodecylsulfonate on alumina and of K oleate on hematite at pH 8.0 is relatively fast (the adsorption equilibrium is reached within a few minutes) as expected for physical adsorption of minerals with PDI H+ and OH". However, the system K oleate-hematite exhibits a markedly different type of kinetics at pH 4.8 where the equilibrium is not reached even after several hours of adsorption. Similarly, the effect of temperature on adsorption density varies. The adsorption density of K oleate at pH 8 and 25 °C is greater than at 75 °C whereas the opposite is true at pH 4.8. Evidently the adsorption of oleic acid on hematite involves a mechanism that is different from that of oleate or acid soaps. 

A number of phenols, especially chlorinated phenols and certain metal-organic compounds, such as copper naphthenate and phenyl mercury oleate, are effective preservatives. Pentachlorophenol and copper naphthenate are most commonly used, and are carried into the wood in 1-5 percent solutions in petroleum oil. Pentachlorophenol is colorless, and can be applied in clear volatile mineral oils to mill-work and window sash requiring a clean, nonswelling, and paintable treatment. 

Polysorbate 80 occurs as a yellow to orange colored, oily liquid. It is a mixture of oleate partial esters of sorbitol and sorbitol anhydrides condensed with approximately 20 moles of ethylene oxide (C2H40) for each mole of sorbitol and its mono- and dianhydrides. It is very soluble in water, producing a nearly colorless solution, and it is soluble in alcohol, in fixed oils, in ethyl acetate, and in toluene. It is insoluble in mineral oil. 

Monistat-Derm Miconazole nitrate, 2% Water-miscible base consisting of pegoxol 7 stearate, peglicol 5 oleate, mineral oil, butylated hydroxyanisole... 

Miller et al. (73) determined the kinematic viscosity of soybean oil at temperatures of 170°C, 180°C, and 190°C, and obtained values of 3.151 cm /sec, 2.880 cm /sec, and 2.614 cm /sec, respectively. The viscosities of soybean oil-hex-ane (Skellysolve B) mixmres at temperatures between —20°C and 40°C were investigated by Magne et al. (84). Ibemesi and Igwe (95) examined the reduced viscosity (viscosity/concentration) of solutions of soybean oil in toluene, xylene, cyclohexane, and tetrahydrofuran. They found an anomalous reduced viscosity increase at concentrations below about 0.12 g/mL that they attributed to clustering of the fat molecules in the solvent. Erhan et al. (96) determined the kinematic viscosity of blends of typical soybean oil with polyalphaolefins and isobutyrl oleate and high-oleic soybean oil with isotrideceyl adipate and mineral oil to achieve viscosities suitable for lubricants. 

Fig. 2.9. Flotation recovery of the minerals using oleate as a function of pH 1—fluorite, 2—spodumene, 3—augite (Fuerstenau, 1977, 1980 Pugh and Stenius, 1985).

Fig. 2.10. Flotation recovery of additional minerals using oleate as a function of pH 1—scheelite, 2— taconite and 3—wolframite (Somasundaran and Ananthapadmanabhan, 1979b Li and Li, 1983 Hu, 1984).

In mineral-reagent systems, surface precipitation has been proposed as another mechanism for chemisorption. The solubility product for precipitation and the activities of the species at the solid-liquid interface determine the surface precipitation process. Under appropriate electrochemical conditions, the activity of certain species can be higher in the interfacial region than that in the bulk solution and such a redistribution can lead to many reactions. For example, the sharp increase in adsorption of the calcium species on silica around pH 11 has been shown to be due to surface precipitation (Somasundaran and Anan-thapadmanabhan, 1985 Xiao, 1990). Similar correlations have been obtained for cobalt-silica, alumina-dodecylsulfonate, calcite/apatite/dolomite-fatty acid, francolite-oleate and tenorite-salicylaldoxime systems. The chemical state of the surfactant in the solution can also affect adsorption (Somasundaran and Ananthapadmanabhan, 1985). 

Correlation of oleate adsorption and flotation maximum at about pH 7.5 for a variety of minerals and high abstraction (adsorption + surface precipitation) below this pH with the species distribution diagram (Fig. 4.9) suggests that the role of acid-soap dimer and precipitated oleic acid can be significant in controlling the adsorption and resultant flotation behavior. 

Various types of flotation agents are used for selective hydrophobization of minerals in froth flotation. Oleic acid is the most common collector used commercially in the flotation processes of salt-type mineral because of its low cost and availability. In the case of complex ores containing similar constituent minerals such as calcium carbonate and calcium phosphate, the selectivity of flotation using oleate as a collector is usually poor and the reagent consumption is generally high (Lawver et al., 1982 Hanna and Somasundaran, 1976). In order to achieve improvements in the separation, it is helpful to identify various interactions between the dissolved mineral species and the oleate species. These interactions are discussed below. 

Competition of the dissolved mineral species with similarly charged collector species for adsorption sites can result in the depression of mineral flotation. For example, in the case of flotation of apatite and calcite with oleate as collector, the floatability is usually lower in saturated mineral supernatants than in pure water (Fig. 4.27). This is partly due to the competition by dissolved species such as PsO and CO which are present in saturated apatite and calcite supernatants (10 to 10 mol/1) in concentrations close to that of the anionic oleate ions. Similar effects are also observed in the case of flotation of fluorite with dodecyl amine (Fig. 4.28). Floatability of fluorite in its saturated solution is lower than that in water. The concentration of dissolved Ca species in the fluorite saturated solution is about 10 " mol/1 and only when the amine concentration is higher than 10 mol/1, the flotation obtained in it is similar to that obtained in water. 

Floatabilities of francolite and dolomite using oleate as collector are shown in Figs. 4.28 and 4.29 as a function of oleate concentration and pH. It can be seen that the floatabilities of dolomite and francolite are quite similar with a sudden increase at an oleate concentration of 1.6 X 10 mol/1. Selective flotation of francolite from dolomite might be expected only above pH 9 or below pH 5. However, flotation of a binary mixture of dolomite and francolite (50 50) with 1.7 x 10 mol/1 oleate at pH 5.2 and 9.0 yielded poor separation. The loss of selectivity during flotation may be attributed to the interactions among the dissolved mineral species from minerals and oleate as well as the formation of oleate precipitates (Amankonah and Somasundaran, 1985). Depletion isotherms for labeled oleate on francolite and dolomite are shown in Fig. 4.30. Both francolite and dolomite show a two-region (II and III) linear isotherms with a break at a residual concentration of... 

At a concentration of >10 mol/1 (Region II), the slope of both curves increases significantly. This increased adsorption is attributed to possible precipitation of oleate on the mineral surface as well as in the bulk solution. The equation for both the isotherms is given below ... 

---