Sulfuric acid, collection

Proteins from tissue homogenates are precipitated by tungstic acid. Mix homogenates, which contain about 1% protein, with 1/10 of volume of 10% sodium tungstate (Na2W04 H2O) (w/v), and acidify with the same volume of 0.67 N sulfuric acid. Collect the precipitate after 10 min at RT by centrifugation. Nucleic acids are precipitated by tungstic acid to a minor extent. 

T. Trnka and M. Cerny, Syntheses with anhydro sugars. 10. Cleavage of the oxirane ring in 1,6 2,3- and l,6 3,4-dianhydro-/i-i)-hexopyranoses with potassium hydroxide and sulfuric acid, Collect. Czech. Chem. Commun., 36 (1971) 2216-2225. 

Wear nitrile rubber gloves, eye protection, and laboratory coat. Work in the fume hood. Dissolve the soluble cadmium salt (0.05 mol, e.g., 9 g of cadmium chloride) in water (50 mL) and add solution of sodium metasilicate (Na2Si03-5H20, 25 g, 0.12 mol) in water (200 mL). A white precipitate of cadmium silicate forms immediately. Heat the mixture to 80°C for 15 minutes to complete the reaction. Cool and adjust to pH 11 with 2 M sulfuric acid. Collect the precipitate by filtration or allow the supernatant liquid to... 

Identification Dissolve 500 mg of sample in 10 mL of 1 A sodium hydroxide, boil for 30 min, allow the solution to evaporate to a volume of about 5 mL, and cool. Acidify the solution with 2 A sulfuric acid, collect the crystals on a filter, wash several times with small portions of water, and dry in a desiccator over silica gel. The p-hydroxybenzoic acid so... 

The descending sulfuric acid collects below the tubes from where it is pumped to cooling, storage, and sale (Fig. 25.1). 

The main justification for diesel fuel desulfurization is related to particulate emissions which are subject to very strict rules. Part of the sulfur is transformed first into SO3, then into hydrated sulfuric acid on the filter designed to collect the particulates. Figure 5.21 gives an estimate of the variation of the particulate weights as a function of sulfur content of diesel fuel for heavy vehicles. The effect is greater when the test cycle contains more high temperature operating phases which favor the transformation of SO2 to SO3. This is particularly noticeable in the standard cycle used in Europe (ECE R49). 

With brisk stirring 75mL Everclear (ethanol) is poured into the reaction flask then 75mL concentrated sulfuric acid is slowly added until incorporated. The rest of the distillation apparatus is connected and the solution slowly heated to about 140°C. Next, 150mL Everclear is dripped in slowly so as to match the approximate distillation output that one can see condensing over into the collection flask. The temperature must remain between 140-150 C. After all the ethanol has been added (which should have taken approximately 90 min) the distillate that has collected is washed with 5% NaOH solution then with water (remember that the ether will form the top layer here). The ether can then be dried through sodium sulfate and used or can be distilled to purify. 

Precipitators are currently used for high collection efficiency on fine particles. The use of electric discharge to suppress smoke was suggested in 1828. The principle was rediscovered in 1850, and independently in 1886 and attempts were made to apply it commercially at the Dee Bank Lead Works in Great Britain. The installation was not considered a success, probably because of the cmde electrostatic generators of the day. No further developments occurred until 1906 when Frederick Gardiner Cottrell at the University of California revived interest (U.S. Pat. 895,729) in 1908. The first practical demonstration of a Cottrell precipitator occurred in a contact sulfuric acid plant at the Du Pont Hercules Works, Pinole, California, about 1907. A second installation was made at Vallejo Junction, California, for the Selby Smelting and Lead Company. 

A typical up-draft sinter machine (Fig. 2) has an endless belt of malleable iron pallets with grate bottoms upon which the charge is evenly spread. Beneath the pallets, wind boxes produce an up-draft of air through the charge. At the feed end, an ignition box starts the roasting. The combustion products, mostly SO2 and SO, are collected, usually for sulfuric acid production (see Sulfuric acid and sulfur trioxide). 

Battery breaking technologies use wet classification to separate the components of cmshed batteries. Before cmshing, the sulfuric acid is drained from the batteries. The sulfuric acid is collected and stored for use at a later stage in the process, or it may be upgraded by a solvent extraction process for reuse in battery acid. 

In the gum rosin process, pine trees are wounded to stimulate the flow of gum. V-shaped slashes are cut through the bark, and the exudate is collected in a bucket below the slash. Production is stimulated by painting sulfuric acid on the slashes. The oleoresin (exudate) is separated by distillation into gum spidts of turpentine and gum rosin. The gum turpentine industry has decreased in importance in the 1990s because it is labor-intensive. The process is carried out in Russia, the People s Repubflc of China, Indonesia, Portugal, Brazil, and Mexico. 

Figure 9 shows the sampling train for sulfuric acid mist collection (13). The first impinger contains 80 wt % isopropyl alcohol and the second and third contain 3 wt % H2O2. The first impinger and filter retain the acid mist and SO the next two retain the SO2. After sampling, the filter is added to the contents of the first impinger and the total acid is titrated and reported as sulfuric acid. 

Packed fiber bed mist eliminators can be designed to operate at almost any desired particle collection efficiencies, depending on the allowable pressure drop and cost. A good discussion of sulfuric acid mist generation, control, and mist eliminator design is available (109,110). 

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

Typical applications in the chemical field (Beaver, op. cit.) include detarring of manufactured gas, removal of acid mist and impurities in contact sulfuric acid plants, recovery of phosphoric acid mists, removal of dusts in gases from roasters, sintering machines, calciners, cement and lime Idlns, blast furnaces, carbon-black furnaces, regenerators on fluid-catalyst units, chemical-recoveiy furnaces in soda and sulfate pulp mills, and gypsum kettles. Figure 17-74 shows a vertical-flow steel-plate-type precipitator similar to a type used for catalyst-dust collection in certain fluid-catalyst plants. 

Sulfur Dioxide EPA Method 6 is the reference method for determining emissions of sulfur dioxide (SO9) from stationary sources. As the gas goes through the sampling apparatus (see Fig. 25-33), the sulfuric acid mist and sulfur trioxide are removed, the SO9 is removed by a chemical reaction with a hydrogen peroxide solution, and, finally, the sample gas volume is measured. Upon completion of the rim, the sulfuric acid mist and sulfur trioxide are discarded, and the collected material containing the SO9 is recovered for analysis at the laboratory. The concentration of SO9 in the sample is determined by a titration method. 

The reaction mixture is then transferred to a 2-I. round-bottom flask with wide neck, and to this is added all at once 300 g. of cracked ice, and the mixture is rapidly agitated by a rotary motion until the decomposition is complete (Note 7). Sufficient 30 per cent sulfuric acid is added to dissolve the magnesium hydroxide, and the mixture is then steam-distilled until oil no longer collects on the surface of the distillate. The distillate, which amounts to 1500-2500 cc., is saturated with sodium chloride and the upper layer separated. The aqueous layer is extracted with two loo-cc. portions of ether and the ether extract added to the alcohol layer. The ether solution is dried over anhydrous potassium carbonate, filtered, and heated carefully on the steam cone until all the ether is distilled. The crude alcohol is warmed one-half hour with about 5 g. of freshly dehydrated lime (Note 8). After filtering again and washing the lime with a little ether, the ether is distilled and the alcohol is distilled in vacuo from a Claisen flask (Note g). The carbinol distils at 88-93 /18 mm. (practically all distilling at 91°). The yield is 70-74 g. (61-65 P r cent of the theoretical amount) (Note 10). 

The salt is dissolved in 800 cc. of water (Note 3) and transferred to a 5-I. round-bottom flask. To the solution is added with constant stirring a solution of 200 g. of lead nitrate (0.6 mole) in 400 cc. of water. Lead sulfide separates as a heavy brown precipitate which soon turns black. The mixture is then distilled with steam into a receiver containing 5-10 cc. of. i N sulfuric acid as long as any oil comes over (Note 4). About 2-3 1. of distillate is collected. The product is separated from the water and weighs 63-66 g. 

A widely used type of scrubber for mists and droplets is the venturi scrubber. It has been used for the collection of sulfuric acid and phosphoric add mists with very high effidency. The scrubbing contact is made at the... 

Particulate emissions from zinc processing are collected in baghouses or ESPs. SO2 in high concentrations is passed directly to an acid plant for production of sulfuric acid by the contact process. Low-concentration SO2 streams are scrubbed with an aqueous ammonia solution. The resulting ammonium sulfate is processed to the crystalline form and marketed as fertilizer. 

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. 

The catalyst is separated by filtration, and the aqueous solution is extracted with three 30-ml. portions of ether (Note 6), acidified with 30% sulfuric acid, boiled for 45 min. (Note 7) with 6-7 g. of carbon, then filtered hot. The filtrate is cooled to 0° and allowed to stand at this temperature for 1 hour or longer. The 2-furoic acid, which separates as pale pink needles, m.p. 130-132°, is collected by suction filtration and washed with small portions of ice water (Note 8). The yield is 96-101 g. (86-90%). 

The product is again collected by filtration, washed with water, resuspended in 225 ml. of water, collected, and pressed as dry as possible. The filter cake is thoroughly dispersed in 160 ml. of absolute alcohol, then filtered, air-dried, and finally dried in a vacuum desiccator over concentrated sulfuric acid. The bright-yellow solid is pulverized and redried. The yield is 115-135 g. (60-71%). When this product is inserted in a bath preheated to 210 and the temperature is increased at a rate of 1° per 10 seconds, decomposition with evolution of gas occurs at 219-220° (cor.) (Note 13). 

---