Sulfuric acid fluxes

Tests were also run with simulated brackish agricultural drainage water, as illustrated in Table 4. A feedwater composition containing sodium, calcium, chloride, sulfate, and bicarbonate ions was prepared in such a way as to duplicate the water in the Mohawk-Wellton drainage canal at Yuma, Arizona. Salt rejections were relatively poor toward this synthetic feedwater, but when this water was line-softened and acidified to pH 5.5 with sulfuric acid, salt rejection of the 90 10 copolyamide improved markedly. However, the membrane s water flux declined by nearly 50 percent. Salt rejection and flux were found in this and other examples to be markedly dependent on pH. As the pH approached the pKa of... 

Minerals of economic importance within sedimentary formations include, hut are not limited to fluorite, barite, phosphorite, and oolitic hematite. Fluorite is utili/ed us a flux in steelniakiitg and when of high quality as lenses and prisms in the optical industry. Barite is an essential mineral used m gas- and oil-well drilling. Phosphorite, a product of chemical precipitation from seawater, when ircaled with sulfuric acid, produces superphosphate fertilizer, (.killtic hematite deposits of extensive size are important sources of iron ore. 

Fusion with anhydrous potassium fluoride in a platinum dish is undoubtedly the simplest, most effective and reliable method available for the complete dissolution of a wide variety of siliceous materials. The potassium fluoride cake can then be transposed in the same container to a pyrosulfate fusion with rapid and complete volatilisation of both hydrogen fluoride and silicon tetrafluoride [54]. Except for a small quantity of barium sulfate, the pyrosulfate cake will dissolve completely in dilute hydrochloric acid. The resulting pyrosulfate fusion is one of the simplest and most effective methods available for rapid, complete and dependable dissolution of nonsiliceous materials, particularly high-fired oxides. This fusion has the distinct advantage that the flux can be obtained by simply adding easily purified alkali metal sulfates to sulfuric acid, and the fusion can be carried out in either borosilicate flasks or platinum vessels with very little contamination from either reagents or containers. 

Figure 12.8 shows a correlation between the solar flux and H2SO4 deposition (Faust, 1994). The correlation observed is consistent with the hypothesis that the deposition of sulfuric acid over the northeastern United States is limited by... 

Cziczo DJ, Thomson DS, Murphy DM (2001) Ablation, flux, and atmospheric implications of meteors inferred from stratospheric aerosol. Science 291 1772-1775 Dachs J, Eisemeich SJ (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ Sci Technol 34 3690-3697 Dalleska NF, Colussi AJ, Hyldahl AM, Hoffmaim MR (2000) Rates and mechanism of carbonyl sulfide oxidation by peroxides in concentrated sulfuric acid. J Phys Chem A 104 10794-10796 D Almeida GA, Schitz L (1983) Number, mass, and volume distributions of mineral aerosol and soils of the Sahara. J Clim Appl Meteorol 22 233-243... 

Use Flux for decomposing minerals substitute for sulfuric acid in dyeing disinfectant manufacture of sodium hydrosulfide, sodium sulfate, and soda alum liberating C02 in carbonic acid baths, in thermophores carbonizing wool manufacture of magnesia cements, paper, soap, perfumes, foods, industrial cleaners, metal pickling compounds lab reagent. 

Potassium pyrosulfate is a potent acidic flux that is particularly useful for attacking the more intractable metal oxides. Fusions with this reagent are performed at about 400°C at this temperature, the slow evolution of the highly acidic sulfur trioxide takes place ... 

MHS) consisted of two cation-exchange polymer membranes Nafion-120. The feed chamber contained the equimolar solutions of Zn(II), Cu(II), Mn(II), Ni(II), and Co(II) sulfates, 2 x 10 mol/dm each the strip was 0.1 niol/dm solution of sulfuric acid. The feed and strip solutions were circulated using a multichannel peristaltic pump. Experiments showed that after a transient period (up to 15 h), the output fluxes have attained their constant value and assumed to be quasistationary. Examples of the values of the fluxes are listed in Table 6.9. 

An excellent fit to the experimental data was found assuming a first-order process (Fig. 18). This is further illustrated by Figure 19 for a saturated copper sulfate solution containing 3.6 mol dm-3 sulfuric acid, which clearly shows that discrimination between n = 1 and 2 is possible. The dissolution flux from this region of the surface was described by the following rate law ... 

When furfuryl alcohol was added as a comonomer to the THEIC, water fluxes were increased tenfold. In addition, the extremely high salt rejections characteristic of NS-200 were obtained, while the high organic rejections characteristic of the isocyanurate moiety were retained. A typical patent example of membrane fabrication uses a water solution of 1 2 2 1 weight percent THEIC fur-furyl alcohol sulfuric acid dodecyl sodium sulfate, deposited on microporous polysulfone and cured at 150°C for 15 minutes. This membrane, possessing a thin active layer 100 to 300 angstroms thick, showed 99.9% rejection and 12 gfd flux under seawater test conditions at 1,000 psi. 

---