Molten sulfate mixture

Similarly to the discnssed nitrate melts, molten sulfate mixtures are characterized by the upper limit of acidity that is seemingly defined by both the limited solubility of SO3 in these melts at temperatures near 800°C and its instability under these conditions. This conclusion may be obtained from the data found elsewhere. There is shift in pO (emf) of acidic solution towards the nentrality point of the melt. This process was found by Lux to be caused by evaporation of SO3 from acidic solutions K2S04-Na2S04 eqnimolar mixture and by its possible decomposition according to the following scheme ... 

In the molten carbonate process a molten eutectic mixture of lithium, sodium, and potassium carbonates removes sulfur oxides from power plant stack gases. The resulting molten solution of alkali metal sulfites, sulfates, and unreacted car bonate is regenerated in a two-step process to the alkali carbonate for recycling. Hydrogen sulfide, which is evolved in the regeneration step, is converted to sulfur in a conventional Claus plant. A 10 MW pilot plant of the process has been constructed at the Consolidated Edison Arthur KiU Station on Staten Island, and startup is underway. 

In the molten carbonate process, a molten eutectic mixture of lithium, sodium, and potassium carbonates is used to scrub the power plant gas stream. The sulfur oxides in the gas stream react with the carbonates to form sulfites and sulfates which remain dissolved in excess unreacted carbonate melt. The molten carbonate-sulfite-sulfate mixture is then... 

The first study of the oxoacidic properties of molten sulfates was performed by Lux [17] on an equimolar K2S04-Na2S04 mixture at 950 °C. The measurements of activity of oxide ions in the melt were made by the potentiometric method with the use of an Au(C>2) gas oxygen electrode. 

Commonly, lipids like glycerides (mono-, di-, or tri-), waxes (e.g., camauba wax, beeswax, cetyl alcohol, emulsilying wax, cholesterol, cholesterol butyrate, etc.), and vegetable oils are nsed as carriers to dissolve/disperse the drug molecules. The surfactants (e.g., polysorbates, sodium dodecyl sulfate, castor oil, bile salts, etc.) and cosurfactants (e.g., alcohols, polyethylene glycol, cranophor, poloxamer, etc.) are used to emulsify the molten lipid mixture in aqneons media The SLNs can then be lyophilized with excipients to obtain the dried powder. The list of excipients and formnlations of the marketed products is found in Mehnert and Mader and Pardeike et... 

The process operates with a closed absorbent cycle in which a molten eutectic mixture of sodium, potassium, and lithium carbonate is circulated to react with the sulfur oxides in the flue gas. The sulfur compounds are absorbed at about 800°F, forming sulfites and sulfates in the melt. The molten salt is next processed in a reducer, operating at about 1,400°F, which uses petroleum coke to convert oxidized sulfur species to the sulfide form. Heat is provided in the reducer by oxidation of a portion of the coke with air. 

Traditionally, sodium dichromate dihydrate is mixed with 66° Bh (specific gravity = 1.84) sulfuric acid in a heavy-walled cast-iron or steel reactor. The mixture is heated externally, and the reactor is provided with a sweep agitator. Water is driven off and the hydrous bisulfate melts at about 160°C. As the temperature is slowly increased, the molten bisulfate provides an excellent heat-transfer medium for melting the chromic acid at 197°C without appreciable decomposition. As soon as the chromic acid melts, the agitator is stopped and the mixture separates into a heavy layer of molten chromic acid and a light layer of molten bisulfate. The chromic acid is tapped and flaked on water cooled roUs to produce the customary commercial form. The bisulfate contains dissolved CrO and soluble and insoluble chromic sulfates. Environmental considerations dictate purification and return of the bisulfate to the treating operation. 

Bromine (128 g., 0.80 mole) is added dropwise to the well-stirred mixture over a period of 40 minutes (Note 4). After all the bromine has been added, the molten mixture is stirred at 80-85° on a steam bath for 1 hour, or until it solidifies if that happens first (Note 5). The complex is added in portions to a well-stirred mixture of 1.3 1. of cracked ice and 100 ml. of concentrated hydrochloric acid in a 2-1. beaker (Note 6). Part of the cold aqueous layer is added to the reaction flask to decompose whatever part of the reaction mixture remains there, and the resulting mixture is added to the beaker. The dark oil that settles out is extracted from the mixture with four 150-ml. portions of ether. The extracts are combined, washed consecutively with 100 ml. of water and 100 ml. of 5% aqueous sodium bicarbonate solution, dried with anhydrous sodium sulfate, and transferred to a short-necked distillation flask. The ether is removed by distillation at atmospheric pressure, and crude 3-bromo-acetophenone is stripped from a few grams of heavy dark residue by distillation at reduced pressure. The colorless distillate is carefully fractionated in a column 20 cm. long and 1.5 cm. in diameter that is filled with Carborundum or Heli-Pak filling. 4 hc combined middle fractions of constant refractive index are taken as 3-l)romoaccto])lu iu)nc weight, 94 -100 g. (70-75%) l).p. 75 76°/0.5 mm. tif 1.57,38 1.5742 m.]). 7 8° (Notes 7 and 8). 

Many metal oxo-compounds (nitrates, oxides and particularly sulfates) and sulfides are reduced violently or explosively (i.e. undergo thermite reaction) on heating an intimate mixture with aluminium powder to a suitably high temperature to initiate the reaction. Contact of massive aluminium with molten salts may give explosions [1], Application of sodium carbonate to molten (red hot) aluminium caused an explosion [2]. 

Molten Carbonate A flue-gas desulfurization process in which the sulfur dioxide contacts a molten mixture of inorganic carbonates. These are converted to sulfates and sulfides and then reduced to hydrogen sulfide, which is treated in a Claus kiln. The advantage of this process over most others is that it does not cool the flue-gases. Not commercialized. Oldenkamp, R. D. and Margolin, E. D., Chem. Eng. Prog, 1969, 65(11), 73. 

Ru metal is quite refractory. It is not significantly soluble in any single acid even aqua regia has little effect. At room temperature, the metal does not react with O2, but, when heated in air, a film of the dioxide appears. The metal is insoluble in fused sulfates. Molten alkali slowly dissolves the metal. The rate of attack is rapid under oxidizing conditions, and a molten mixture of NaOH and Na20s will readily dissolve the metal. 

A slurry of sodium bicarbonate comprising 39.8 g sodium bicarbonate and 254 ml water was placed in an autoclave. 96.3 g hexadecyl bromide and 635 ml acetone were then added. The autoclave was sealed and while stirring (590 r.p.m.) it was heated to a temperature of 218°C over a period of 1 hour 15 min. The temperature was maintained at 218-220°C for an additional hour. At the end of the reaction the autoclave was cooled to about 50°C, that is, to a temperature at which the alcohol remains molten. The autoclave was then rinsed with acetone and 1 N hydrochloric acid add to neutralize the sodium bicarbonate. The reaction mixture was diluted with an equivalent volume of water and then extracted with n-pentane. (Other suitable water insoluble solvents such as benzene, carbon tetrachloride, chloroform, petroleum ether and the like can be used for extraction). The pentane extract was washed with water and then dried over magnesium sulfate. The dried solution was filtered and evaporated. The residue was melted and a vacuum applied to remove the last traces of pentane. On distillation a yield of 94.8% of the theoretical yield white crystals of hexadecanol was recovered M.P. 49°C, B.P. 344°C, nD79 = 1.4283. 

Vitreous materials can be formed by undercooling certain molten salts consisting of mixtures of nitrates, acetates, and sulfates, which contain discrete anions such as NO3, 204 , S04 , and so on. 

Although compounds of the platinum metals are commercially available, many workers, for reasons of economy, prefer to prepare them from the elements. Rhodium, one of the rarest and most expensive of the platinum metals, is not attacked by acids (even aqua regia), and its dissolution in alkaline fusion mixtures (e.g., fused sodium carbonate and potassium nitrate mixtures) or in molten salts (e.g., molten potassium hydrogen sulfate) is inefficient and tedious. Chlorination during heating yields a mixture of water-insoluble chlorides, but in the presence of sodium... 

Volcanic smog (known as vog) is a mixture of atmospheric gases and suspended liquid and solid particles. It forms by the reaction of sulfur dioxide and other volcanic gases with atmospheric moisture, gases, dust, and sunlight (Sutton et al, 1997). Vog consists primarily of sulfuric acid and other sulfate compounds, and can contain a variety of heavy metals, including selenium, mercury, and arsenic (Sutton et al, 1997). Laze, a volcanic haze, forms when molten lava flows into the sea and vaporizes seawater (Sutton et al, 1997). It has many of the same characteristics as vog, with the exception that it probably contains higher levels of chloride and hydrochloric acid derived from seawater. 

The molten salt stream containing carbonate (M2CO3, where M = the mixture of Na, and Li), sulfite (M2SO3), sulfate (M2SO4), and ash from the scrubber is pumped to a pui cation system and filtered... 

This reaction can be carried out both in concentrated aqueous solution and, preferably continuously, in the molten state. In the latter case, sodium dichromate is mixed with sulfuric acid in a twin screw and the mixture fed into an externally heated rotary tube furnace. The water first evaporates, then the. sodium hydrogen sulfate melts (at I70°C) and finally the chromium(VI) oxide is formed (I98°C). Temperature control is critical, since chromium(Vl) oxide decomposes at temperatures slightly above this temperature. The reacted mixture then separates in a settling tank. Chromium(Vl) oxide is taken off from below and liquid sodium hydrogen sulfate is taken off from above, both being converted into solid material by cooling rollers. 

Several molten salts are volatile under the applied conditions. Chlorides for example are known for their high vapom pressure. Nitrates, usually forming low melting point eutectic mixtures, are unstable and will decompose. Another point of interest is the reaction of the origineil salts into, for example, carbonates and sulfates with components in the exhaust gas, eg. carbon dioxide or sulfirr dioxide, respectively. This could influence the composition of the melt and, thereby, increase the melting point and subsequently reduce or even destroy the activity. 

The incineration is accomplished by injecting the hazardous material and air beneath the surface of a pool of molten salts. Typically, sodium carbonate with a small amount (1 to 10%) of sodium sulfate is used as the molten salt, however, other alkali metal carbonates or mixtures of alkali metal carbonates can be employed. Sodium carbonate is used because it reacts instantly with acidic gases to form sodium salts. The small amount of sodium sulfate is used to catalyze the combustion of carbon. Temperatures of the molten salts are usually in the 700° to 1000°C range. 

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