Carbon blowing

Bromine test. Dissolve 0 2 g. or 0 2 ml. of the compound in 2 ml. of carbon tetrachloride, and add a 2 per cent, solution of bromine in carbon tetrachloride dropwise until the bromine colour persists for one minute. Blow across the mouth of the tube to detect any hydrogen bromide which may be evolved (compare Sections III,6 and 111,11). 

Fillers (qv) are occasionally used in flexible slab foams the two most commonly used are calcium carbonate (whiting) and barium sulfate (barytes). Their use level may range up to 150 parts per 100 parts of polyol. Various other ingredients may also be used to modify a flexible foam formulation. Cross-linkers, chain extenders, ignition modifiers, auxiHary blowing agents, etc, are all used to some extent depending on the final product characteristics desired. 

Injection stretch-blow molding may be performed on a single one-stage machine in sequence or on two independent sequential two-stage machines. PET carbonated beverage botties are usually produced by injection stretch blow molding. 

Phenyl-3,6-dihydro-l,3,4-oxadiazin-2-one (50) is a high temperature blowing agent used primarily for polycarbonates (qv). It is prepared by the reaction of a-hydroxyacetophenone and methyl carbazate (52), made from hydrazine and dimethyl carbonate (175) ... 

In the calendering method, a PVC compound which contains plasticizers (qv) (60—120 phr), pigments (qv) (0—10 phr), fillers (qv) (20—60 phr), stabilizers (10—30 phr), and other additives, is kneaded with calender roUs at 150—200°C, followed by extmsion between clearance-adjusted roUs for bonding onto the substrate. This method is employed for products with thick PVC layers, ie, of 0.05—0.75 mm thickness. The main plasticizer used is di-2-ethylhexyl phthalate (DOP). For filler to reduce cost, calcium carbonate is mainly used. A woven or knit fabric made of cotton, rayon, nylon, polyester, and their blend fiber is used as substrate. For foamed vinyl-coated fabrics, the bonded materials are heated in an oven to decompose the foam-blowing... 

The laser spray process uses a high power carbon dioxide laser focused onto the surface of the part to be metallized. A carrier gas such as belium blows metal particles into the path of the laser and onto the part. The laser melted particles may fuse to the surface, or may be incorporated into an aHoy in a molten surface up to 1-mm thick. The laser can be used for selective aHoying of the surface, for production of amorphous coatings, or for laser hardening. 

The three classes of PE, designated as A, B, and C, specify the color, amount, and type of antioxidants and other additives. Class A refers to naturally colored PE, Class B includes white or black polymer, and Class C covers weather-resistant black polymer containing no less than 2% carbon black. Typical characteristics of resins used for film manufacture, injection mol ding, and blow mol ding are given in Table 5. 

No external heat source is required. In all types of steelmaking that employ pig iron, which melts at temperatures well below low carbon steel, the heat balance between exothermic oxidation of elements, such as C, Si, and Mn, and the cooling provided by scrap or sometimes other endothermic coolants, such as iron ore, are critical issues. The numerical factors are well understood and are routinely contained in computer programs used by operators. If the balance is such that the temperature after blowing is too high, refractory consumption is increased significantly. 

In the CIS pitch coke is made by carbonizing a hard coke-oven pitch in modified coke ovens. The hard pitch has an R-and-B softening point of 140—150°C and is made by air-blowing a mixture of medium-soft pitch and recycled coking oils. This feedstock is charged in the molten state over a period of 5 h and coked for 17—18 h at 1250—1300°C. The coke yield is 70%. Oils, which are recycled, amount to 20% by weight of the pitch fed. The gas yield... 

Stable oxides, such as those of clrromium, vanadium and titanium cannot be reduced to the metal by carbon and tire production of these metals, which have melting points above 2000 K, would lead to a refractoty solid containing carbon. The co-reduction of the oxides widr iron oxide leads to the formation of lower melting products, the feno-alloys, and tlris process is successfully used in industrial production. Since these metals form such stable oxides and carbides, tire process based on carbon reduction in a blast furnace would appear to be unsatisfactory, unless a product samrated with carbon is acceptable. This could not be decarburized by oxygen blowing without significairt re-oxidation of the refractory metal. 

Basic oxygen furnaces (BOFs) have largely replaced open hearth furnaces for steelmaking. A water-cooled oxygen lance is used to blow high-purity oxygen into the molten metal bath. This causes violent agitation and rapid oxidation of the carbon, impurities, and some of the iron. The reaction is exothermic, and an entire heat cycle requires only 30-50 min. The atmospheric emissions from the BOF process are listed in Table 30-16. 

Azocarbonamide (I) Carbonamide N2, CO, CO2 190-230 220 Most widely used blowing agent in PVC and polyolefins. High decomposition temperature reduced by a variety of metal salts and oxides such as lead carbonate, lead phosphite and zinc oxide. High gas yield. Reaction products show little odour or discoloration. ... 

---