Strontium sulfate , solubility

In another process, strontium sulfate can be converted to strontium carbonate direcdy by a metathesis reaction wherein strontium sulfate is added to a solution of sodium carbonate to produce strontium carbonate and leave sodium sulfate in solution (6). Prior to this reaction, the finely ground ore is mixed with hydrochloric acid to convert the calcium carbonates and iron oxides to water-soluble chlorides. 

Elemental composition Sr 47.70%, S 17.46%, O 34.84%. Strontium sulfate can be characterized by x-ray crystallography. A nitric acid extract is analyzed for strontium. An aqueous solution (the salt is only slightly soluble) is filtered or decanted from insoluble material and measured by ion chromatography. 

Write the solubility product dissociation constants for silver (I) chromate (Ag2CrO ) and strontium sulfate (SrSO ). 

White precipitate of strontium carbonate White precipitate of strontium sulfate White precipitate of strontium sulfate Yellow precipitate of strontium chromate White precipitate of strontium oxalate, which is soluble in mineral acids... 

Calculate the molar solubility of strontium sulfate, SrS04, in 0.25 M sodium sulfate, Na2S04. Ksp for strontium sulfate is 3.44 X 10 7. 

Barium and strontium form sulfate scales that are not readily soluble. In fact, barium is the least soluble of all the alkaline-earth sulfates. It can act as a catalyst for strontium and calcium sulfates scale.4 Analyses of the ion product with the solubility constants for barium and strontium sulfates is necessary to determine the potential for scaling with these species. If the ion product (IP) for barium sulfate exceeds the solubility constant, scale will form. Note that in the case of strontium sulfate, if IP > 0.8Ksp, scaling is likely. However, the induction period (the time it takes for scale to form) is longer for these sulfate-based scales than it is for calcium carbonate scale. 

Calcium sulfate is a sparingly-soluble salt. As with barium and strontium sulfate, the potential to scale with calcium sulfate is high when the ion product exceeds 80% of the solubility constant. Antisealants or sodium... 

Eniistiin BW, Turkevitch J (1960) Solubility of fine particles of strontium sulfate. J Phys Chem 82 4503-4509... 

In addition, precipitation of fission-product elements has been demonstrated. The addition of sodium carbonate or sodium sulfate to molten equimolar sodium-potassium nitrate containing soluble strontium nitrate results in precipitation of strontium carbonate or strontium sulfate, respectively. Molybdenum trioxide, M0O3, added to an equimolar sodium-potassium nitrate melt resulted in evolution of nitrogen dioxide and dissolution of the molybdenum, presumably as the molybdate anion, MogOy (14). Addition of soluble strontium nitrate to this nitrate melt produced an insoluble precipitate that was also insoluble in water. The existence of an aqueous insoluble strontium molybdate is known, and it is believed that a similar species is formed in the melt. 

Plan For each pair of solutions, we note the ions present in the reactants, write the cation-anion combinations, and refer to Table 4.1 to see if any are insoluble. For the molecular equation, we predict the products. For the total ionic equation, we write the soluble compounds as separate ions. For the net ionic equation, we eliminate the spectator ions. Solution (a) In addition to the reactants, the two other ion combinations are strontium sulfate and sodium nitrate. Table 4.1 shows that strontium sulfate is insoluble, so a reaction does occur. Writing the molecular equation ... 

Strontium Sulfate. Strontium sulfate, SrS04, occurs as celestite deposits in beds or veins in sediments or sedimentary rocks. Celestite has a specific gravity of ca 3.97, a Mohs hardness of 3.0—3.5, and is colodess-to-yellow and often pale blue. Strontium sulfate forms colorless or white rhombic crystals with a specific gravity of 3.96 and an index of refraction of 1.622—1.631. It decomposes at 1580°C and has a solubility of 0.0113 g per 100 mT, of water at 0°C. 

Strontium sulfate is the more soluble of the two compounds. Therefore, we can assume that all of the SO4 ions come from SrS04. 

All sulfates are soluble except those of barium, lead(II), and silver. Calcium and strontium sulfate are moderately soluble. 

The osmotic pressure of a saturated solution of strontium sulfate at 25 °C is 21 torr. What is the solubility product of this salt at 25 °C ... 

As an example, we consider the measurement of the solubility of strontium sulfate which, at 298 K, is O.llOgdm". Naturally occurring strontium contains four isotopes, none of which is radioactive. The radioisotope °Sr (f = 28.1 yr) is produced from the fission of and is commercially available. A uniform mixture of °SrS04 and the inactive salt SrS04 is prepared and the radioactivity of the combined sample is measured this gives a standard value for the... 

Strontium - Strontium sulfate (SrS04) has a minimum solubility in 40% phosphoric acid. SrS04 forms a scale in the heat exchangers of phosphoric add concentrators. An extremely thin film of this precipitate causes pronounced reductions in the capacities of such units 137]. 

Strontium and lanthanides (rare earths), found in igneous rocks, inhibit rehydration of the hemihy-drate to gypsum, which can cause problems in certain phosphoric acid processes. Moreover strontium causes problems in the concentration sections because strontium sulfate has a minimum solubility in 40% P2O5 acid. An extremely thin film of SrS04 causes a very pronounced reduction in the capacity of the concentration unit. 

One problem in calculating the solubility of small particles is that the surface energy is not accurately known. There are very few substances of which the solubility of particles of uniform size and less than 100 A diameter have been measured. According to Walton (174), a combination of these requirements has not previously been achieved, but recently using radiotracer measurements and the electron microscope, such measurements have been made on strontium sulfate particles, from which the solid-water interfacial energy was calculated to be 84 8 ergs cm". ... 

Strontium is quite common in seawater. Some organisms use strontium sulfate as a skeletal material. Strontium is added to the water in aquariums, as the decorative stony corals need it. Strontium has no function in the human body. (It is the most abundant element in the human body without a known function there.) Nor is barium essential for Hfe indeed it is toxic. The symptoms of barium poisoning are colic, diarrhoea, vomiting and paralysis. The content of barium in food plants is as a rule low (part per million levels) but there is an exception Brazil nuts may contain as much as 1% barium. The metabolism is stimulated by barium, but to such a high degree that the heart begins to beat erratically (ventricular fibrillation). Barium salts are thus toxic to humans, but the use of barium sulfate as an X-ray contrast medium is accepted because of its very low solubility. 

In contrast to the much less soluble barium and strontium sulfates, calcium sulfate reacts with an alkaline solution of sodium rhodizonate to give a violet basic salt. Compare page 160. 

Barium and strontium form sulfate scales that are not readily soluble. In fact, barium is the least soluble of all the alkaline-earth sulfates. It can act as a catalyst for strontium and calcium sulfate scales." Analyses of the ion product with the solubility constants for barium and strontium sulfates is... 

Calcium sulfate is a sparingly-soluble salt. As with barium and strontium sulfate, the potential to scale with calcium sulfate is high when the ion product exceeds 80% of the solubility constant. Antisealants or sodium softening to remove calcium can be used to control calcium sulfate scale. Calcium phosphate has become a common problem with the increase in treatment of municipal waste-water for reuse. Surface waters can also contain phosphate. Calcium phosphate compounds can also contain hydroxyl, chloride, fluoride, aluminum, and/ or iron. Several calcium phosphate compoimds have low solubility, as shown in Table 7.3. SolubiUty for calcium carbonate and barium sulfate are also shown by comparison. The potential for scaHng RO... 

Figs 9.9 and 9.10 can be used to obtain K, Pca and PaDc for the stability index. Similar indices may be used to predict bariiun sulfate or strontium sulfate or calcium sulfate deposition. If the product of concentration of Ca ions and SO4 ions exceeds the solubility products ( p) of CaS04, calcium sulfate would be precipitated. The solubility of calcium sulfate decreases with an increase in the temperature. CaCOj and CaS04 scaling cause major problems in plants and equipment encountering salt water. 

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