Drying by warm air

Boric acid crystals are usually separated from aqueous slurries by centrifugation and dried in rotary driers heated indirecdy by warm air. To avoid overdrying, the product temperature should not exceed 50°C. Powdered and impalpable bode acid are produced by milling the crystalline matedal. 

The bottle is thoroughly cleaned and dried by warming and aspirating air through it, after which it is allowed to cool and weighed. It is then filled with the liquid, which is poured in... 

A glass surface to be silvered by a ing-on process should be cleaned with soap and water or detergents. For metallizing with platinum, gold and palladiiun, improved results are sometimes obtained with glass which has been stored when, after cleaning, it is immersed in 5 per cent acetic acid (cold) for six hours. The special preparation is then applied. If necessary it is mixed before use with a suitable thinner. The preparation is allowed to dry this may be accelerated by warm air. Dust should not be allowed to settle on the surface before firing. 

Brattice driers, incorporating a device for removing the dried material (Fig. 44) have been used in Germany. The moist material, spread in a thin layer over cloth stretched on wooden frames (1), is dried in warm air supplied via the ducting (2) at a rate of about 0.5 m/sec. Next to the frame on which the material is dried there is a tin funnel (3) with a built-in sieve in its base. This funnel is connected with the ventilating duct by a flexible tube. Each frame (7) contains about 1.2 kg of fulminate (dry substance). To dry a batch of fulminate at 65-70°C takes... 

In a 2-liter Erlenmeyer flask a solution of 55g of copper sulfate 5-hydrate is mixed with one of 25g of hydroxy] ammonium chloride (No. 55) in 125ml water. While cooling the mixture in a cold water bath and swirling well, a solution of 40g of sodium hydroxide in 750ml water is added. The precipitate is allowed to settle and the supernatant liquid is poured off. The oxide is transferred with a little water to a smaller vessel (250ml) and washed by repeated decantation until the rinsings are chloride-free, then suction filtered and the residue washed with 95% alcohol and with ether. The product is dried in warm air. 

Filtering water samples (say, 100 ml) though a Whatman 41 filter paper (or equivalent), followed by drying in warm air for 20 to 30 minutes, is a good practical test to conduct. A subsequent comparison of the papers provides a simple but effective visual indication of the progress of the cleaning program for the benefit of the customer. 

Ray and Kumar-De [54] described an HPTLC method and a TLC method for the rapid quantification and identification of omeprazole. Ground powder (omeprazole powders, capsules, or tablets) equivalent of 25 mg omeprazole was warmed for 10 min with shaking with 25 ml methanol. After cooling the solution was made up to 50 ml with methanol, mixed and filtered. The filtrate was spotted (2 ji ) on to HPTLC plates (20 x 20 cm) coated with Kieselgel 60 GF254 activated at 110 °C for 30 min. The plates were developed to 16 cm with methanol-water (2 1) as mobile phase. After development, the plates were dried in warm air and the spots were visualized at 302 nm. The calibration graph was linear from 2.5 to 10 jig omeprazole and the RSD was <0.60%. The recovery was 99.42%. Results compared well with those obtained by elution of the spots with methanol following TLC and spectrophotometric detection at 302 nm. 

Vacuum Drying Books. (A) Frozen (or wet) books are placed in a chamber and heated by warm air. Vacuum is applied to remove water vapor as the ice thaws (5, 7). This is sometimes called the purged air system. (B) Frozen (or wet) books are placed in an unheated chamber. Moist air is evacuated and replaced with dry heated air (0% r.h.). When the replacement air becomes saturated with moisture, it is evacuated and the process repeated until the books are dry (4, 5). (C) Thawing books are put in a chamber. Vacuum is applied and then controlled at a pressure of about 5 torr. Heat is then applied to books through shelves to replace latent heat of vaporization. As moisture is released from books in vapor form (outgassing), it is collected by pumps and reverted to ice on cooled condensers in the chamber. After most of the water leaves the books, the book temperature is increased gradually from 32 °F to 80°-85°F the chamber is opened after 48 hr, the books are removed from the shelves, and the condensers are defrosted (4,5,10). 

The polymer product is recovered by filtration, washing with water to remove any adhering stabilizer(s), and then dried with warm air. 

The processing cycle of the samples consisted of immersing the fabric in an aqueous solution of aniline hydrochloride (Ani.HCl). After draining and drying in warm air at 60°C, polymerisation was initiated close to the fabric surface by immersing it in an oxidant solution obtained by dilution of potassium dichromate (K2Cr207) in 2M HCl. The fabric was then drained and the reaction was allowed to continue until a final washing with 2M HCl. Finally, the fabric was dried under warm air at 60°C. 

A further enhancement in aluminum/epoxy joint durability in a moist environment is obtained by anodizing the aluminum after FPL treatment (80). Typically, samples are anodized for several minutes in an aqueous solution of phosphoric acid (phosphoric acid anodization or PAA) before rinsing and drying in warm air. The process produces a thin, uniform oxide layer near the bulk metal and a... 

Starch is a widely distributed material, occurring in the roots, seeds and fruits of plants. Seeds usually contain 40—70% starch whilst roots and fruits contain about 5-25%. The principal commercial source of starch is com sources of lesser importance include tapioca, wheat and potato. In the extraction of starch, the plant material is ground with water the resulting slurry is filtered to remove coarse tissue fragments, and a suspension of starch granules is obtained. The granules are collected by centrifuging and dried in warm air. 

Dry sheet in warm air stream dipping into reagent c for 20 sec to develop red color of diazo compound. Remove excess reagent by blotting with filter paper immediately followed by dipping into reagent d for 40 sec. Blot excess hydrochloric acid and dry in warm air stream. Colors are as indicated under section Rp. Quantitative determinations can be done by densitometric scan at 500-520 nm... 

---