Sulfate impurities

Beryllium Oxide. Beryllium oxide [1304-56-9], BeO, is the most important high purity commercial beryllium chemical. In the primary industrial process, beryllium hydroxide extracted from ore is dissolved in sulfuric acid. The solution is filtered to remove insoluble oxide and sulfate impurities. The resulting clear filtrate is concentrated by evaporation and upon cooling high purity beryllium sulfate, BeSO 4H20, crystallizes. This salt is... 

Barium perchlorate colorimetric titration. This colorimetric titration procedure is used in the determination of inorganic sulfate impurities in complex systems of water-soluble sulfonates and sulfonic acids. Sulfonates are precipi-... 

The Nature of Exposed Co In CoMo Catalysts. Figure 1 shows typical original spectra for NO adsorbed on 2% Co/alumlna. Spectra were recorded after reduction at 600°C, after admission of 8 Torr of NO, and again after 5 min. evacuation at 50°C. With the pure alumina the main NO/Co bands were 10 to 20 wavenumbers higher In frequency than those observed when using alumina with sulfate Impurity. 

Zinc also may be produced by electrolysis of zinc sulfate solution. The zinc oxide in the roasted concentrate is leached with sulfuric acid. The oxide is converted to soluble zinc sulfate. Impurity metals, such as iron, copper, cadmium, arsenic, tin, and cobalt are removed by precipitation, floe formation, and other methods. The purified zinc sulfate solution is electrolyzed using aluminum cathodes and lead anodes. Zinc is deposited on the cathode. 

Remember that an arrow pointing upward indicates a gas that has been released and an arrow pointing downward indicates a precipitate. The Greek letter delta over the arrow shows heat. Magnesium sulfate also makes water hard, but you can t soften this type of hard water by boiling it. You must add another chemical to react with the sulfate impurity which prevents the soap from forming suds. Sodium tetraborate and potassium carbonate are chemicals that will do this. Here are the equations showing how they act ... 

Figure 3.127 Determination of sulfate in sodium sulfite. Separator column lonPac AS3 eluent 2.8 mmol/L NaHCOs + 2.2 mmol/L Na2C03 flow rate 23 ml7min detection suppressed conductivity injection volume 50 pL peaks (1) 500mg/L sulfite and (2) sulfate impurity.

The sodium hydroxide solution from the mercury process is the purest of the three the amounts of NaCl and NaClOs are especially low. However, the quality of caustic from the membrane process is almost as good. A main drawback of the diaphragm process is the high concentration of NaCl and NaClOs in the caustic solution. This sodium hydroxide solution cannot be used for some processes. A chloride-free grade, commonly referred to as rayon-grade caustic, is required for 20-30% of the demand in industrialized countries. Even the use of purification processes (see p. 73) does not reduce the NaCl content below 0.03 wt%. In addition to the NaCl and NaClOs, the levels of Si, Ca, Mg, and sulfate impurities are higher than for the mercury and membrane processes. 

The ether sulfate can be determined by two-phase titration. However, interference from sulfated impurities (sulfated alcohol/alkylphenol and sulfated PEG) in the titration requires that a preliminary separation step be performed first for high accnracy. This analysis may also be performed by HPLC, as described in Chapter 7. 

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