Acid-resistant materials

The dimensions of concentric-tube nebulizers have been reduced to give microconcentric nebulizers (MCN), which can also be made from acid-resistant material. Sample uptake with these microbore sprayers is only about 50 xl/min, yet they provide such good sample-transfer efficiencies that they have a performance comparable with other pneumatic nebulizers, which consume about 1 ml/min of sample. Careful alignment of the ends of the concentric capillary tubes (the nozzle)... 

Mention should also be made of glutamic acid and invert sugar which are used in foodstuffs and demand the use of hydrochloric acid-resistant material in manufacture, and of the essential flavouring oils which should preferably be stored and prepared in stainless steel and aluminium equipment. 

The structure of a SPE cell is shown in Fig. 2.3. The basic unit of a SPE electrolyzer is an electrode membrane electrode (EME) structure that consists of the polymer membrane coated on either side with layers (typically several microns thick) of suitable catalyst materials acting as electrodes [43,49,50], with an electrolyzer module consisting of several such cells connected in series. The polymer membrane is highly acidic and hence acid resistant materials must be used in the structure fabrication noble metals like Pt, Ir, Rh, Ru or their oxides or alloys are generally used as electrode materials. Generally Pt and other noble metal alloys are used as cathodes, and Ir, Ir02, Rh, Pt, Rh-Pt, Pt-Ru etc. are used as anodes [43,46]. The EME is pressed from either side by porous, gas permeable plates that provide support to the EME and ensure... 

Acid-Resistant Materials. As acid plants are usually attached to plants manufg expls, it is important to have some knowledge of acid-resistant materials, such as metals, bricks, plastics, gaskets, paints, cements and putties, etc.Basic info on this subject may be found in the refs listed below. A common type of acid-proof putty is one consisting of powd red iron oxide and asbestos fiber in a petroleum grease. During WW II, this type of putty was used at many US Ord Plants, including Wabash Ordnance Works... 

Following are examples of acid-resistant materials available in commerce and suitable for expls plants ... 

Lead is an acid-resistant material and the lead sulphate formed on the surface does not contaminate the product of nitration, merely forming a permanent protective layer against the corrosive effects of the nitrating acids. However, the cover of lead sulphate acts as a thermal insulator, which is undersirable since it lowers efficiency of operation, e.g. when leaden cooling coils are used. 

In Germany during World War II, cylindrical boilers, provided with mixers, of 10-14 m3 capacity, were used. The vessels were made of sheet-iron or of concrete lined internally with an acid-resistant material, for instance ceramic plates joined by means of a phenol-formaldehyde resin, asplit . 

Cement, Acid-Resistant, See under Acid-Resistant Materials in Vol l,pp A92-A93 of this Encyclopedia... 

Prime and seal with wax or other acid-resistant material. 

Chemical Abstracts, Decennial Indexes, under Acid-Resistant Materials and Sealing Compositions 8)M.H.Sandler, "Second Report on the Development of a Fuming Nitric Acid Resistant Paint," AberdeenPG, Md, Project No. TB4-006D 593 32/006(1958)... 

In Germany, this ether was manufactured by the same method as that described above for the laboratory preparation by the action of chlorosulphonic acid on formaldehyde. The reaction is carried out in iron vessels of 5 cu. m. capacity (about 1,100 gals.), coated internally with acid-resistant material and fitted with stirring apparatus and lead cooling coils. 

When the decision was reached to line the iron digester at Cedar Rapids with an acid-resistant material, a study was made of a number of metals. A consultation with the various purveyors indicated the use of 20-gage Monel, the edges being turned up and welded. The digester lining was finished, and the first digestion made in November 1921. 

In the acid gas scrubber, water is again sprayed into the gas stream. However, the gas is forced through a packed bed of acid-resistant material, such as polyvinylchloride, to increase its contact with the water. By forcing the gas through this tortuous path, larger amounts of HCl are absorbed by the water. Removal efficiencies of 70% are achievable when using plain water and 93-96% when using water with an alkaline... 

The performance of Pt plated YSZ electrolyte for SO3 electrolysis did not degrade during about 60 hour operation in 550°C gaseous sulfuric acid. Nevertheless, outlet piping of the SO, electrolysis cell was corroded by condensed sulfuric acid. Sulfuric acid resistant material should be used in the new experimental apparatus. 

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