Sulfate ion precipitation

G. Effects of Barium. Barium sometimes is present in the salt in high enough concentration to be of concern. It is also used in some plants to precipitate sulfate ion from the brine. In the latter case, it must be used with care in order not to become a problem... 

Pyridine does not absorb carbon dioxide like ammonium hydroxide does. This reduces the possibility of carbonate Interference or of alkaline earth precipitation In a uranium separation. Ammonium nitrate facilitates uranium precipitation. Sulfate Ion hinders It. Separation can be made from alkali metals, alkaline earths, Mh, Co, Nl, Cu, and Zn. Zr, Tl, Pe,... 

The most common basic sulfate is 5Zr02 ASO 535. [84583-91-5] which is precipitated in good yield when a zirconium oxychloride solution is heated with the stoichiometric amount in sulfate ion. It is used to prepare high purity oxides and ammonium zirconium carbonate. 

The mother Hquor from the cmde ferrous sulfate crystallisation contains neady all the chromium. It is clarified and aged with agitation at 30°C for a considerable period to reverse the reactions of the conditioning step. Hydrolysis reactions are being reversed therefore, the pH increases. Also, sulfate ions are released from complexes and the chromium is converted largely to the hexaaquo ion. Ammonium chrome alum then precipitates as a fine crystal slurry. It is filtered and washed and the filtrate sent to the leach circuit the chrome alum is dissolved in hot water, and the solution is used as cell feed. 

The primary constituents to be measured are the pH of precipitation, sulfates, nitrates, ammonia, chloride ions, metal ions, phosphates, and specific conductivity. The pH measurements help to establish reliable longterm trends in patterns of acidic precipitation. The sulfate and nitrate information is related to anthropogenic sources where possible. The measurements of chloride ions, metal ions, and phosphates are related to sea spray and wind-blown dust sources. Specific conductivity is related to the level of dissolved salts in precipitation. 

The alcoholic filtrate is evaporated to 50 cc., and 50 g. of barium hydroxide and 150 cc. of distilled water are added (Note 4). The mixture is refluxed for two hours and the excess barium hydroxide is precipitated with carbon dioxide. The barium carbonate is removed by filtration and washed with hot distilled water. A slight excess of sulfuric acid is added to the filtrate to liberate the amino acid from its barium salt, and an excess of barium carbonate is added to remove sulfate ion. The mixture is digested on the steam bath until effervescence ceases, and it is then filtered and the precipitate is washed with hot distilled water. The filtrate and washings are concentrated on the steam bath to a volume of 100 cc., decolorized with i g. of active carbon, filtered, and concentrated to the point of crystallization (about 25 cc.). The amino acid is precipitated by the addition of 150 cc. of absolute alcohol and the product is collected and washed with absolute alcohol. 

It is convenient to titrate the suspended barium salt with 18 N sulfuric acid (approx. 12-14 ml.) to a pH. of 1.5 using a pH meter. After removal of the barium sulfate the slight excess of sulfate ion may be precipitated using barium chloride solution. The end point is taken when several drops of filtrate show no turbidity either upon addition of sulfuric acid or barium chloride solution. 

Components in the invading water-based filtrate and in the formation waters may react to form insoluble precipitates which can block the pores and give rise to skin damage. The scale can be formed by interaction of calcium-based brines with carbon dioxide or sulfate ions in the formation water. Alternatively sulfate ions in the invading fluid may react with calcium or barium ions in the formation water. Analysis of the formation water can identify whether such a problem may arise. 

When two solutions are mixed, a precipitate may form. For example, suppose solutions of calcium chloride, CaCl2, and sodium sulfate, Na2S04, are mixed. The mixture contains both calcium ions, Ca+1, and sulfate ions, S04-2, so solid calcium sulfate may form. The solubility product permits us to predict with confidence whether it will or not. 

A 50 ml volume of 0.04 M Ca(N03)2 solution is added to 150 ml of 0.008 M (NH4)2S04 solution. Show that a trial value of the calcium sulfate ion product is 6 X 10-6. Will a precipitate form ... 

Strong reducing agents such as sulfur dioxide, sodium bisulfite, sodium metabisulfite, and ferrous sulfate are used in the iron and steel finishing sites to reduce hexavalent chromium to the triva-lent form, which allows the metal to be removed from solution by chemical precipitation.21 23 Metal-containing wastewaters may also be treated by chemical precipitation or ion-exchange. 

Calculate how much 0.200 M Ba(N03)2 would be needed to totally precipitate all of the sulfate ion present in the alum solution. 

In order to answer this question, we will need the concentration of the barium ion and the sulfate ion before precipitation. These may be determined from the dilution relationship ... 

Slowly add a solution containing the sulfate ion (usually sodium sulfate) to the solution. Allow the precipitate to settle, and check for complete precipitation. 

Another source of error in the investigation of the surface properties of titanium dioxide is its tendency to adsorb acids or ions. Phosphate ions are very strongly adsorbed (see Table XIX) as well as sulfuric acid. Commercial pigments often have considerable sulfate contents. When titania is precipitated from sulfate solution, sulfate ions are strongly adsorbed (308). They are carried through all further stages of pigment manufacture. 

As the zinc dissolves, more positive charge [i.e., Zn (aq)] is introduced into this side of the cell. As the copper precipitates, the concentration of positive charge declines on its side of the cell. To maintain electroneutrality throughout the cell, sulfate ions diffuse across a salt bridge from the copper to the zinc side of the cell. 

Chloride ions are easily washed away from the metallic surface by precipitation, while sulfate ions concentration remains more constant. It means that corrosion takes place under very variable concentrations of chloride ions and in the presence of less variable concentration of sulfate ions. Changes in the amount of chloride ions concentration should depend on the particular rain regime of the place. A notable difference has been found between chloride deposition rate determined by collectors protected from liquid precipitations and chloride content in corrosion products. 

Elemental composition Ce 42.18%, S 19.30%, O 38.53%. It is digested with nitric acid, diluted appropriately and analyzed for Ce by AA or ICP spectroscopy (see Cerium). The compound may be dissolved in small quantities of water (forms a basic salt when treated with large a volume of water). The solution is analyzed for sulfate ion by gravimetry following precipitation with barium chloride. Alternatively, the compound is dissolved in hot nitric acid and the solution analyzed for sulfate by ion-chromatography. 

Acid soluble rare earth salt solution after the removal of cerium may be subjected to ion exchange, fractional crystalhzation or solvent extraction processes to separate individual rare earths. Europium is obtained commercially from rare earths mixture by the McCoy process. Solution containing Eu3+ is treated with Zn in the presence of barium and sulfate ions. The triva-lent europium is reduced to divalent state whereby it coprecipitates as europium sulfate, EuS04 with isomorphous barium sulfate, BaS04. Mixed europium(ll) barium sulfate is treated with nitric acid or hydrogen peroxide to oxidize Eu(ll) to Eu(lll) salt which is soluble. This separates Eu3+ from barium. The process is repeated several times to concentrate and upgrade europium content to about 50% of the total rare earth oxides in the mixture. Treatment with concentrated hydrochloric acid precipitates europium(ll) chloride dihydrate, EuCb 2H2O with a yield over 99%. 

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. 

An aqueous solution of the salt may be analyzed for rubidium by AA, ICP-AES and flame photometry, and for sulfate anion by ion chromatography. Rb sulfate in solution also may be measured by gravimetry after adding barium chloride to precipitate sulfate as barium sulfate, BaS04. 

HPT Research, Inc., has developed the ionic state modification (ISM) process for the treatment of acid mine drainage (AMD). ISM is an ex situ treatment technology that uses magnets, electricity, and proprietary chemical to precipitate heavy metals, remove sulfate ions, and neutralize acidity from AMD and industrial wastewaters. The end products of the process are a metal hydroxide sludge, a calcium sulfate sludge, and treated liquid effluent. The vendor claims that the metal hydroxide sludge may have some value as an ore, the calcium sulfate may be used as an agricultural additive to soils, and the liquid effluent is free of metal contamination and has low sulfate concentrations. 

Initially, the antibodies should be purified prior to prepare the immunoaffinity column. Precipitation with ammonium sulfate, ion-exchange chromatography, gel filtration chraoma-tography or affinity chromatography may be employed with the aim of antibody purification. Activated beads which are coated with bacterial proteins A or G may be used as the support material. Some parameters may be changed for the elution of the sample solution for example the ionic conditions of mobile phase may be changed or chaotropic buffers may be used [11]. 

When a second sulfite or SO2, if you like, or H2SO3 attacks 03Cr0S02 2, it goes all in one fell-swoop to chromic ion, to which sulfate is attached at the end of the reaction, and an SCV - radical. One can t precipitate sulfate with barium immediately after the reaction. Coordination of the chromium (111) stabilizes the radical until it can react with another as was mentioned by Dr. Halpern. This mechanism accounts for both the stoichiometry and kinetics. 

Infrared spectra suggested that a sulfate ion coordinates to two titanium atoms as a bidentate in particles. The maximum particle size was found at Aerosol OT mole fraction of 0.35 in the mixtures. The particle size increased linearly with increasing the concentration of sulfuric acid at any Wo, but with increasing Wo the effect was the opposite at any sulfuric acid concentration. These effects on the particle size can be explained qualitatively in relation with the extent of number of sulfate ions per micelle droplet. These precursor particles yield amorphous and nanosized TiO particles, reduced by 15% in volume by washing of ammonia water. The Ti02 particles transformed from amorphous to anatase form at 400°C and from anatase form to rutile form about at 800°C. In Triton X-100-n-hexanol-cyclohexane systems, however, spherical and amorphous titanium hydroxide precursor were precipitated by hydrolysis of TiCl4 (30). When the precursor particles were calcinated,... 

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