Sodium-strontium-hydroxide-water

If calcium chromate be treated with a soln. of potassium sulphate, the calcium chromate is converted into calcium sulphate, which is precipitated, and potassium chromate, which remains in soln. Instead of leaching the calcium chromate with a soln. of potassium sulphate, W. J. Chrystal showed that if ammonium sulphate is used, a soln. of ammonium chromate is produced, and J. J. Hood found that if the soln. of potassium salt be treated with sodium hydrosulphate, potassium sulphate crystallizes from the soln., while sodium dichromate remains in soln. According to F. M. and D. D. Spence and co-workers, if a mixtiu-e of ammonia and carbon dioxide be passed into the aq. extract of the calcium chromate. Calcium carbonate is precipitated while ammonium and alkali chromate remain in soln. If the liquid be boiled, ammonia is given off, and sodium dichromate remains in soln. S. Pontius used water and carbon dioxide under press, for the leaching ptocess. J. Brock and W. A. Rowell purified alkali chromite by treating the soln. with strontium hydroxide, and digesting the washed precipitate with a soln. of alkali sulphate or carbonate W. J. A. Donald used calcium hydroxide or barium chloride as precipitant. A mixture of chromite with calcium carbonate and potassium carbonate was formerly much employed. Modifications of the process were described by W. J. A. Donald, A. R. Lindblad, C. J. Head, 8. G. Thomas, W. Gow, J. Stevenson and T. Carlile, L. I. Popoff,G. Bessa, P.Weise, P. N. Lukianoff,... 

Uranium mineral first is digested with hot nitric acid. AH uranium and radium compounds dissolve in the acid. The solution is filtered to separate insoluble residues. The acid extract is then treated with sulfate ions to separate radium sulfate, which is co-precipitated with the sulfates of barium, strontium, calcium, and lead. The precipitate is boiled in an aqueous solution of sodium chloride or sodium hydroxide to form water-soluble salts. The solution is filtered and the residue containing radium is washed with boiling water. This residue also contains sulfates of other alkahne earth metals. The sohd sulfate mixture of radium and other alkahne earth metals is fused with sodium carbonate to convert these metals into carbonates. Treatment with hydrochloric acid converts radium and other carbonates into chlorides, all of which are water-soluble. Radium is separated from this solution as its chloride salt by fractional crystallization. Much of the barium, chemically similar to radium, is removed at this stage. Final separation is carried out by treating radium chloride with hydrobromic acid and isolating the bromide by fractional crystallization. 

High-gravity reactive precipitation (HGRP) has been extended to the production of aluminum hydroxide and strontium carbonate (57). Aluminum hydroxide fibrils precipitate from the reaction of sodium meta-aluminate (NaA102), water, and carbon dioxide and are formed in diameters of 1-10 nm and lengths of 50-300 nm. Rotor speed, gas- and liquid-flow rates, and initial reactant concentrations control particle size. Strontium carbonate particles of 40-nm mean diameter and narrow size distribution have been produced from the liquid-liquid reaction of strontium nitrate and sodium carbonate. 

Barium reacts with metal oxides and hydroxides in soil and is subsequently adsorbed onto soil particulates (Hem 1959 Rai et al. 1984). Adsorption onto metal oxides in soils and sediments probably acts as a control over the concentration of barium in natural waters (Bodek et al. 1988). Under typical environmental conditions, barium displaces other adsorbed alkaline earth metals from MnO2, SiO2, and TiO2 (Rai et al. 1984). However, barium is displaced from Al203 by other alkaline earth metals (Rai et al. 1984). The ionic radius of the barium ion in its typical valence state (Ba+) makes isomorphous substitution possible only with strontium and generally not with the other members of the alkaline earth elements (Kirkpatrick 1978). Among the other elements that occur with barium in nature, substitution is common only with potassium but not with the smaller ions of sodium, iron, manganese, aluminum, and silicon (Kirkpatrick 1978). 

The observed catalytic effect of the alkali metal carbonates and oxides and the alkaline earth oxides upon the gasification of the ESC deposit in water vapour again most probably derived from successive oxidation and reduction processes. A possible cycle carbonate-metal-hydroxide could be feasible at this temperature, at least for sodium, potassium and lithium (3) and conceivably also for cesium and rubidium. For barium and strontium the cycle could be between a higher and a lower oxide. Calcium, in contrast to barium and strontium, does not form a peroxide by oxidation of calcium oxide and in any case this would not be stable above 200°C, which could explain why calcium oxide was not an active catalyst. 

Evzhanov, Kh Andiyasova, G.I., and Beikelieva, L.K., Conditions of the isolation of calcium and strontium with sodium hydroxide in the high mineralized chloride based waters . Chemistry and Water Technology, 1986, (4), 36-38. 

To test for positive ions, add 300 milligrams of the sample to be tested to water and mix. Filter the slurry and divide the filtered solution into two parts. To one part of the solution add a drop of a saturated sodium sulfate solution. Barium or strontium will come out of the solution as a white precipitate. A flame test on a platinum wire, using the part of the solution that was not treated with sodium sulfate, identifies barium or strontium. A green flame is produced by barium salts and a red flame is produced by strontium salts. To find the quantities of barium and strontium, add sodium sulfate until no more precipitation is formed. Filter and weigh the precipitate. The untreated aqueous solution may be flame tested for sodium and potassium. A yellow and violet flame is produced respectively, although the potassium test is diffcult. NH4 can be detected by an ammonia smell after the solution has been made basic with sodium hydroxide. 

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