Acid spray treatment

Acid spray treatment of pasted plates improves the plate manufacturing processes in the following ways ... 

Influence of acid-spray treatment on reserve capacity of automotive batteries [37],... 

Figure 6.39 presents capacity curves for batteries produced with and without acid sprajdng of plates after pasting [37], Plates subjected to acid-spray treatment preserve their reserve capacity, whereas the reserve capacity of untreated plates declines. 

Table II. The Increase in Ascorbic Acid Content of Pinto Bean Leaves Following Spray Treatment...

Acetic, citric, lactic, and tartaric acids and their salts (potassium sorbate, potassium or sodium benzoate, sodium propionate, sodium acetate or diacetate, and sodium lactate) have been tested and approved as dipping or spraying treatments (Geomaras et al., 2005). 

The number of separating vessels will depend upon the reservoir pressure and the oil-to-gas ratio, but the first one is always a three-phase separator yielding water, oil and gas. The water will still contain some oil droplets and further treatment will be required before it can be discharged to the sea. The amount of treatment will depend upon the quantity involved and governmental regulations. The gas passes through a demisting pad, similar to that described above for acid spray removal, and is then added to the gas streams from the other separators for further treatment. 

Spray and Witts (1952a,b) observed that the levels of folic acid in plasma and urine after the oral administration of 1 mg. and 5 mg. of pteroylglutamic acid were lower in untreated pernicious anemia than in normal persons, suggesting, perhaps, an increased demand for folic acid. After treatment with vitamin Bis this increased demand was no longer evident. 

Product from melt or suspension treatment is obtained directly as emmb or powder. Polymer recovered from solution treatment is obtained by precipitative cooling or spray drying. Polymer with now stable end groups may be washed and dried to remove impurities, especially acids or their precursors, prior to finishing operations. 

Dieldrin [60-57-1] or l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, Aro-5,8-dimethanonaphthalene (34) (mp 176°C, vp 0.4 mPa at 20°C) is formed from aldrin by epoxidation with peracetic or perben2oic acids. It is soluble in water to 27 / g/L. Aldrin and dieldrin have had extensive use as soil insecticides and for seed treatments. Dieldrin, which is very persistent, has had wide use to control migratory locusts, as a residual spray to control the Anopheles vectors of malaria, and to control tsetse flies. Because of environmental persistence and propensity for bio accumulation, registrations in the United States were canceled in 1974. 

Bakery Products. Sorbates are used in and/or on yeast-raised and chemically leavened bakery products. The internal use of sorbates in yeast-raised products at one-fourth the amount of calcium—sodium propionate that is normally added provides a shelf life equal to that of propionate without adversely affecting the yeast fermentation. Sorbates added at one-tenth the propionate level reduce the mix time by 30% (126). This internal treatment combined with an external spray of potassium sorbate can provide the same or an increased shelf life of pan breads, hamburger and hot-dog buns, English muffins, brown-and-serve roUs, and tortillas. The total sorbate useful in or on these baked goods ranges from 0.03 wt % for pan breads to 0.5 wt % for tortillas 0.2—0.3 wt % sorbic acid protects chemically leavened yellow and chocolate cakes (127). Emit-pie fillings and icings can be protected with 0.03—0.1 wt % sorbates. 

The dry powder process has several additional advantages over the wet process. For example, much less waste of enamel occurs because the dry over-spray is airborne and recycled in a closed system. No-pidde ground coats have broadened the apphcation of both wet-process and dry-process systems. These enamels are appHed over cleaned-only metal. Thus the problems of disposing of pickling acid wastes containing iron sulfates and nickel wastes are eliminated (see Metal surface treatments) (7). 

Liquid Dispersion Spray columns are used with slurries or when the reaction product is a solid. The absorption of SO9 by a hme slurry is an example. In the treatment of phosphate rock with sulfuric acid, offgases contain HF and SiF4. In a spray column with water, solid particles of fluorosilic acid are formed but do not harm the spray operation. The coefficient /cl in spray columns is about the same as in packed columns, but the spray interfacial area is much lower. Considerable backmixing of the gas also takes place, which helps to make the spray volumetri-caUy inefficient. Deentrainment at the outlet usually is needed. 

Not many operating data of large-scale hquid/hquid reactions are published. One study was made of the hydrolysis of fats with water at 230 to 260°C (446 to 500°F) and 41 to 48 atm (600 to 705 psi) in a continuous commercial spray tower. A small amount of water dissolved in the fat and reacted to form an acid and glycerine. Then most of the glycerine migrated to the water phase. Tlie tower was operated at about 18 percent of flooding, at which condition the HETS was found to be about 9 m (30 ft) compared with an expec ted 6 m (20 ft) for purely physical extrac tion (Jeffreys, Jenson, and Miles, Trans. In.st. Chem. Eng., 39, 389-396 [1961]). A similar mathematical treatment of a batch hydrolysis is made by Jenson and Jeffreys (In.st. Chem. Engrs. Symp. Ser, No. 23 [1967]). 

Such care includes washing of the filter material with the spray jets after every period of use, removal of grease and fats with warm soap solution if clogged, treatment with diluted hydrochloric acid for removal of lime encrustations, maintenance of scraper bade in careful adjustment to filter drum to prevent tearing of the filter material. 

Note The pre- and post-treatment of the chromatograms with the basic tri-ethylamine solution, which can be replaced by an alcoholic solution of sodium hydroxide [1,4] or a phosphate buffer solution pH = 8.0 (c = 0.2 mol/1) [5], serves to stabilize the fluorescence of the amino derivatives [2]. A final spraying with methanolic hydrochloric acid (chci = 5 mol/1) or 70% perchloric acid renders the detection reaction highly specific for histamine [4] and for catecholamines and indolamines [5]. 

A low acid polyvinyl butyral-based pretreatment primer ( etch or wash primer are alternative names) is usually advantageous as the first treatment of a metal-sprayed surface before painting. Up to an equal volume of spirit soluble phenolic resin is used as a diluent to the polyvinyl butyral of conventional pretreatment primers. This has an incidental, but particularly valuable effect, in reducing the free acid available to penetrate into the pores of the coating. The modified pretreatment primer is highly water resistant and this helps to avoid damage due to condensation. 

---