Powder black

Though the theoretical of black powder is less than that of single-base, doublebase, and AP-based composite propellants, black powder is useful for short-duration operation of simple propulsive systems. The advantages of the use of black powder are its low cost, its minimal deterioration with age, and simple regulation of the propulsive force by adjustment of the quantities used. 

Black powder is a mechanically mixed material consisting of KN powder (60-80%), charcoal (10-25%), and sulfur (8-25%), which is pressed, granulated, and packed into the desired shape for use. When black powder is ignited, the combus- 

The first chemical explosive was invented in China around 1300 years ago and was originally used exclusively for military purposes. Black powder was not used industrially until the seventeenth century when it was adopted to blast out mines in Europe. In order to detonate black powder, it must be ignited by flame or intense heat. 

Special types of gunpowders which contain no sulfur are known as sulfurless gunpowders. They are used where any corrosion due to sulfur is undesirable. The powders for pyro-devices are often of the sulfurless variety. 

By about the eighth century ad, Chinese alchemists, amongst others, were preoccupied with discovering the elixir of life. Concoctions were made containing all manner of substances including oils, honey and 

These dangerous early experiments led to many secret or banned recipes, but enough information was disseminated to enable the details of the discovery to be brought to Europe. However, the place and date of the invention of true gunpowder are still unknown and have been the subject of extensive but inconclusive investigation. 

Once the reactive tendencies of potassium nitrate were unleashed it was simply a matter of time before the third vital ingredient, charcoal, was added to complete the famous gunpowder recipe of charcoal, sulfur and potassium nitrate. Needless to say, much time and effort were expended before the alchemists produced a successful product. 

More peaceful uses of these crude articles appeared in the form of fire crackers - the first fireworks One mixture corresponded quite closely to modern gunpowder in that it contained saltpetre, sulfur and willow charcoal. The fire cracker was said to consist of a loosely-filled parchment tube tied tightly at both ends and with the introduction of a small hole to accept a match or fuse. All of these incendiary mixtures, presumably containing saltpetre, are mentioned in Chinese work dating from the eleventh century ad. Thus, in theory at least, the Battle of Hastings could have been one of Greek Fire , incendiary rockets and grenades. 

Skipping about two centuries, the activities of one experimenter typify the development of early black powder. His work took place between about 1235 and 1290ad and he is reputed to have been the first scholar in Northern Europe who was skilled in the use of black powder. In essence. 

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Thallium( ) oxide, TI2O. Black powder formed by heating TIOH, gives T1(I) salts with acids. 

Tiianium ll) chloride, TiCl2- Black powder (TiCl4 plus Ti or heat on TiCl3). Strong reducing agent, immediately reduces water. Forms some complexes. 

Vanadium trioxide, V2O3. Black powder (V2OS plus Hj under heat). Readily reoxidized to VjOj. Stable down to VO,.35. 

Amorphous boron has not been obtained in the pure state. Crystalline boron is a black powder, extremely hard, with a metallic appearance but with very low electrical conductivity. 

It is a black powder, often pyrophoric, and is non-stoichiometric. the formula Feo.950 more correctly representing its average composition. 

Copfierilh axUle. CuO. is a black powder, insoluble in water il is prepared by heating either the hydroxide, or the hydrated nitrate. 

Boron exists naturally as 19.78% lOB isotope and 80.22% IIB isotope. High-purity crystalline boron may be prepared by the vapor phase reduction of boron trichloride or tribromide with hydrogen on electrically heated filaments. The impure or amorphous, boron, a brownish-black powder, can be obtained by heating the trioxide with magnesium powder. 

Black phosphorus Black powder Black reactive dyes Black Rubber 3773... 

Black Powder. Black powder is mainly used as an igniter for nitrocellulose gun propellant, and to some extent in safety blasting fuse, delay fuses, and in firecrackers. Potassium nitrate black powder (74 wt %, 15.6 wt % carbon, 10.4 wt % sulfur) is used for military appHcations. The slower-burning, less cosdy, and more hygroscopic sodium nitrate black powder (71.0 wt %, 16.5 wt % carbon, 12.5 wt % sulfur) is used industrially. The reaction products of black powder are complex (Table 12) and change with the conditions of initia tion, confinement, and density. The reported thermochemical and performance characteristics vary greatly and depend on the source of material, its physical form, and the method of determination. Typical values are Hsted in Table 13. 

The performance of black powder is critically dependent on the degree of intimacy of the components in the product. The manufacture of black powder is essentially a procedure for bringing the ingredients into maximum mutual contact. A detailed flow chart for the conventional process is presented in Figure 10. 

Typically, dry potassium nitrate is pulverized in a ball mill. Sulfur is milled into cellular charcoal to form a uniform mix in a separate ball mill. The nitrate and the sulfur—charcoal mix are screened and then loosely mixed by hand or in a tumbling machine. Magnetic separators may be used to ensure the absence of ferrous metals. The preliminary mix is transferred to an edge-mimer wheel mill with large, heavy cast iron wheels. A clearance between the pan and the wheels is required for safety purposes. The size of this gap also contributes to the density of the black powder granules obtained. Water is added to minimize dusting and improve incorporation of the nitrate into the charcoal. The milling operation requires ca 3 to 6 h. 

D. R. Mouta and co-workeis, Mayards Analysis of the Final Design of the Improved Black Powder Process, Vols. 1—2, Rpt. J6329, Illinois Institute of Technology, Chicago, 1963. 

In the absence of air, TEE disproportionates violently to give carbon and carbon tetrafluoride the same amount of energy is generated as in black powder explosions. This type of decomposition is initiated thermally and equipment hot spots must be avoided. The flammability limits of TEE are 14—43% it bums when mixed with air and forms explosive mixtures with air and oxygen. It can be stored in steel cylinders under controlled conditions inhibited with a suitable stabilizer. The oxygen content of the vapor phase should not exceed 10 ppm. Although TEE is nontoxic, it may be contaminated by highly toxic fluorocarbon compounds. 

Tungsten tribromide [15163-24-3] WBr, prepared by the action of bromine on WBr2, in a sealed tube at 50°C (17), is a thermally unstable black powder that is insoluble in water. 

Tungsten dibromide [13470-10-5] WBr2, formed by the partial reduction of the pentabromide with hydrogen, is a black powder that decomposes at... 

Iodides. Tungsten tetraiodide [14055-84-6] WI, is a black powder that is decomposed by air. It is prepared by the action of concentrated hydriodic acid on tungsten hexachlotide at 100°C. 

Uranium [7440-61-17 is a naturally occurring radioactive element with atomic number 92 and atomic mass 238.03. Uranium was discovered in a pitchblende [1317-75-5] specimen ia 1789 by M. H. Klaproth (1) who named the element uranit after the planet Uranus, which had been recendy discovered. For 50 years the material discovered by Klaproth was thought to be metallic uranium. Pnligot showed that the uranit discovered by Klaproth was really uranium dioxide [1344-57-6] UO2, and obtained the tme elemental uranium as a black powder in 1841 by reduction of UCl [10026-10-5] with potassium (2). 

Shock Synthesis. When graphite is strongly compressed and heated by the shock produced by an explosive charge, some (up to 10%) diamond may form (26,27). These crystaUite diamonds are small (on the order of 1 llm) and appear as a black powder. The peak pressures and temperatures, which are maintained for a few microseconds, are estimated to be about 30 GPa (300 kbar) and 1000 K. It is beheved that the diamonds found in certain meteorites were produced by similar shock compression processes that occurred upon impact (5). 

Graphite oxide may explode when heated above 200°C. Below this temperature it converts to a black powder once known as pyrographitic acid. 

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