Shot tower

The As content may range from 0.3 to 0.8% and may be added either in the form of white As or arsenical dross. The As imparts a greater fluidity to the metal and increases its tendency to assume a spherical shape in passing thru the air when dropped from the top of a Pb shot tower into cold w. About 0.025% Na sulfide is added to the w in order to prevent oxidation of the shot... 

If properly proportioned and preheated, the reaction can be run continuously to produce molten ammonium nitrate containing very little water (1 to 5%), which can be formed into small spheres (prills) by dropping the reaction product through a shot tower or into flakes by cooling it on belts or drums. By fluidized bed treatment, it is possible to obtain a dry granular material as product batch processes have also been used. 

Shot tower at Trinity Site in the desert north of Alamogordo, N.M., where Los Alamos prepared in the spring of 1945 to test the plutonium bomb. 81. Base Camp. 

In a final postwar celebration the British mission at Los Alamos pantomimed the war years. A stepladder stood in for the Trinity shot tower. Note Otto Frisch (third from left) in skirt playing housemaid. 

Exothermic processes, with cooling through heat transfer surfaces or cold shots. In use are sheU-and-tube reactors with smaU-diameter tubes, or towers with internal recirculation of gases, or multiple stages with intercoohng. Chlorination of methane and other hydrocarbons results in a mixture of products whose relative amounts... 

These arresters consist of a tower or honsing filled with varions sizes of metal shot (halls) in ahont nine zones. The size of the halls varies from 4 to 7 mesh for the larger halls and 40 to 60 mesh for the smallest halls. The... 

In most cases air is used as the cooling medium but other gases or liquids may also be used. In the manufacture of lead shot, molten lead is prilled into water. The prilling of calcium nitrate into mineral oil has been described [5], Prilling into liquid medium requires shorter towers because of the improved cooling by liquids but an extra step to remove the liquid cooling medium is necessary. 

Arsenic is used with lead (0.5% As) in making lead shot. It makes the metal harder than pure lead, and also improves the properties of the molten metal—the shot are made by pouring the metal through a sieve at the.top of a tall tower, which permits the liquid drops to assume a spherical form and then to harden before falling into water at the base of the tower. 

In other sulfur recovery operations, better control of product particle size is obtained. The molten sulfur is chilled on a steel belt to produce a roughly 0.5-in.-thick flake sulfur, or sprayed into water or even tumbled in drums to obtain granulated sulfur. Pelletized sulfur, similar in particle size range to the granulated variety, is also obtained when a melt is sprayed into the top of a tower to form droplets of molten sulfur which harden into shot-sized beads as they fall through a current of air. In this form, it is referred to as prills [20]. The narrow size range of particles of prilled sulfur, as well as the negligible dust content in this form, makes it more convenient to use. It normally commands a price premium. 

The steam produced is removed from the molten ammonium nitrate (m.p. 170°C) via the vortex finder of a cyclone separator, and the 99+% molten salt proceeds to either a cooled stainless steel belt to produce a flaked product (Fig. 11.10), or to a 30-m-high prilling tower where droplets of melt fall through a countercurrent dry air stream to produce shot-sized prills (beads) of ammonium nitrate. A hot concentrated solution of ammonium nitrate is explosively sensitized by traces of acid so care is taken to add sufficient ammonia to the wet melt to keep the pH above about 5. 

For a variety of applications, spherical particles are required. Many of these are associated with the field of powder metallurgy. While it is relatively easy to produce spherical particles from low melting materials by conventional techniques, such as shot or prilling towers (see Chapter 5), refractory solids in general and, specifically, high melting point metals can not be converted by these techniques. However, if the solid is available in powder form, various methods are available to produce spherical particles by agglomeration. 

Right-o, they have, the policeman said. He pointed at the tall beautiful tower of the Y.M.C.A. Building, close by. "Why, just last week an Arab sniper sneaked up into that tower and fired half a dozen shots into this building. The Warwicks went up after the blighter, but he got away. ... 

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