Mineral-alkali interactions

Nylon fibers are semicrystalline, that is, they consist of crystallites separated by amorphous regions. Hydrogen bonding is an important secondary valence interaction in nylon-6 and nylon-6,6. Individual chains in the microcrystalline regions of nylons are held together by hydrogen bonds. Nylons are resistant to aqueous alkali but deteriorate more readily on exposure to mineral acids. 

Evolution of phosphine is slow in contact with water or alkali, but explosively violent in contact with dilute mineral acids [1], However, reports of violent interaction with concentrated or dilute hydrochloric acid, and of explosive reaction with 1 1 aqua regia, have been questioned [2],... 

Diamorphine Hydrochloride Diamorphine interacts with mineral acids and alkalis and with chlorocresol. Concentration-dependent precipitations were observed in mixtures of diamorphine hydrochloride with cyclizine and haloperidol, and color changes were observed with mixtures containing metoclopramide and diamorphine.44... 

Fedele, L., Tarzia, M., Belkin, H. E., De Vivo, B., Lima, A., and Lowenstern, J. B. (2006). Magmatic-hydrothermal fluid interaction and mineralization in alkali-syenite nodules from the Breccia Museo pyroclastic deposit, Naples, Italy. In Volcanism in the Campania Plain Vesuvius, Campi Flegrei and Ignimbrites (B. De Vivo, ed.). Developments in Volcanology, 9, pp. 125-161. Elsevier, Amsterdam, The Netherlands. 

It has been postulated [10] that silicate minerals as feldspar exposed to atmospheric agents undergo hydration and decay through the polarization and the ensuing dissociation of the water dipole into and OH due to the attractive forces of the free valencies. In this interaction the oxygens are converted to hydroxyl groups and part of the potassium is removed in solution. A partial or total cationic (K, Na, Ca ) depletion decomposes the feldspar. Since the neutral water now reaches an increased pH, introduction of acids neutralizes these alkali and facilitates a further decay of these minerals. 

Ba (Dove and Nix, 1997). Rate enhancements in single salt solutions can be predicted by equations that follow the form of Langmuir-type isotherms, whereas in mixed salt solutions, behavior follows a competitive cation-surface interaction model (Dove, 1999). Dove and co-workers argue that the alkali and alkaline earth cations enhance dissolution by modifying characteristics of the solvent at the mineral-solution interface. 

Other products of interaction of various rocks with bat excreta are taranakite (Sakae and Sudo, 1975), dittmarite (Mrose, 1971), mirabilite (Hutchinson, 1950), biphosphammite (Hutchinson, 1950 Pryce, 1972), phosphammite, struvite, newberyite, bobierrite, schertelite, hannayite, stercorite, monetite, whitlockite and brushite. It is noticeable (Table 3.1.1) that most of these mineral include the ammonium ion, which results from decomposition of urea and/or uric acid, and later the more stable minerals (Bobierrite, for example) persist after leaching of alkali ions (including NHJ) has been accomplished. 

A large number of studies have now been reported on the measurement of diffusion coefficients of isotopic species (e g. 0/ 0) in silicates, oxides and carbonates at elevated temperatures and pressures (see Tables 2, 3 and 4 in this study, or Brady 1995). Those of most relevance, geologically, involved the experimental interaction of a mineral (melt, glass) and either pure water, an alkali chloride solution that is in approximate chemical equilibrium with the solid (e.g. albite and NaCl), or a dry gas such as O2 or... 

Dissolution rate constants for major elements are summarized as a function of temperature in Fig. 2. Apparent activation energies have the same relationship as dissolution rate. Alkali metal and alkali earth metal ion have -20 to 40 kJ/mol apparent activation energy, due to a diffusion effect from the mineral surface. The existing reaction condition does not correspond to the critical reaction rate, but this condition is more applicable for natural water-rock interactions, because the nature of incongruent dissolution on the mineral surface controls fluid chemistry and metastable reaction processes. 

Interaction of alkali with rock minerals in reservoir sand is complicated. Somerton and Radke (11) classified these interactions into surface exchange and hydrolysis, congruent and in congruent dissolution reactiaiSr and insoluble salt formation by reaction with hardness ions in the pore fluids and exchanged from sand surfaces. These interactions may also be classified into reversible adsorption or non-reversible chemical consurrp-tion, and kinetic controlled or instantaneous reactions. 

Under the activated complex theory, chemical interaction of most minerals with a solution has mostly acid-alkali nature and depends on relative concentrations of complexes X-OH, X-OH and X-O" on their surface. That is why ions H " (HjO" ) and OH" are most active components in water composition, which serves as catalyst or inhibitor. Their relative role is defined by the pH value of the solution. As a rule, this correlation rate of dissolution vs. pH has a trough-like shape (Figure 2.33). At the same temperature, the slowest dissolution rate is usually observed in neutral water (pH = 7 2). As pH decreases or increases, the dissolution rate increases... 

PVC is resistant to most aqueous solutions, including those of alkalis and dilute mineral acids. The polymer also has a good resistance to hydrocarbons. The only effective solvents appear to be those which are capable of some form of interaction with the polymer. These include cyclohexanone and tetrahydrofuran. 

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