Abstract: Toxic furnace dust having a low bulk density is densified into pellets by mixing the dust with ice, preferably by tumbling in a rotating drum. A six to eight-fold increase in bulk density may be realized, greatly facilitating the disposal of the toxic waste.

Abstract: A process for removing residual mercury from scrap fluorescent lamp exhaust tubulation or similar scrap glass is disclosed. A very small predetermined amount of finely divided silica or alumina powder is added to the mercury contaminated scrap glass and the mixture is agitated for a very short predetermined time during which the mercury is stripped from the tubulation. The separated mercury, powder and glass mixture is then decanted through a screen of suitable mesh to remove the separated mercury and powder from the glass and the mercury is then rinsed with a suitable solvent to remove the oxide powder from the mercury.

Abstract: A procedure is given for recovering yttrium and europium from phosphors or solutions which have become contaminated. An acid solution containing the yttrium, europium and impurities is passed through a cation resin exchange column until there is no longer a difference between the contaminated and effluent liquids. Yttrium and europium are then stripped from the resin exchange column using a concentrated hydrochloric acid solution. The hydrochloric acid solution containing the yttrium and europium is heated with oxalic acid to produce yttrium and europium oxalate and the oxalate is fired to produce yttrium and europium oxide.

Abstract: The in-line transmission of a translucent polycrystalline alumina arc tube for a high-pressure sodium discharge lamp is improved by as much as 50% by dipping the "green" tubular compact in an aqueous slurry containing finely-divided alumina particles and, after the slurry-dipped compact has been dried, subjecting it to the usual pre-sintering and sintering operations required to convert the compact into a dense ceramic body. The slurry is preferably prepared from the same slurry which contains the blended alumina powder, magnesia and other additives that comprise the raw-mix slurry which is spray-dried to produce the larger size generally spherical particles that are compressed or extruded to form the green compact.

Abstract: A procedure is given for recovering yttrium and europium from phosphors or solutions which have become contaminated. An acid solution containing the yttrium, europium and impurities is passed through a cation resin exchange column, the resin holding the yttrium, europium and certain impurities. The impurities are then eluted from the resin with a relatively weak hydrochloric acid solution. Yttrium and europium are subsequently stripped from the resin exchange column using a more concentrated hydrochloric acid solution. The hydrochloric acid solution containing the yttrium and europium is heated with oxalic acid to produce yttrium and europium oxalate and the oxalate is fired to produce yttrium and europium oxide.

Abstract: Rapid recovery of molybdenum from an acid solution containing dissolved molybdenum is accomplished by using a multiple batch method. A first batch of ammonium molybdate precipitate is formed by diluting a first portion of acid with 1.5 times that volume of water, adding anhydrous ammonia, and seeding with ammonium molybdate particles while maintaining a temperature between 90.degree. C. and boiling. Subsequent batches of precipitate are formed by dissolving the previous precipitate in additional acid, similarly diluting as above, and adding anhydrous ammonia while maintaining temperature as above. All precipitates are coarse and fast settling.

Abstract: For rapid and efficient recovery of dissolved molybdenum from spent acid, the spent acid solution is first diluted to a predetermined acid-water volume ratio and anhydrous ammonia added thereto to raise the solution temperature to at least about 90.degree. C. The solution temperature is maintained at less than boiling and the ammonia addition continued until the solution pH is from about 1.5 to about 3.5. The partially neutralized solution is then seeded with solid ammonium molybdate particles in order to hasten the onset of nucleation. The seeded solution is maintained at a temperature of at least about 90.degree. C. but less than the boiling temperature for a period of from about one hour to about four hours in order to precipitate substantially all molybdenum therefrom as ammonium molybdate. Thereafter, the precipitated ammonium molybdate is separated from the residual solution.

Abstract: A flash lamp array is disclosed including a plurality of flash lamps and a two-sided circuit board having sequencing circuitry affixed to one side thereof and having the lamps connected thereto to fire individually and in sequence. The array comprises solid-state thermally activated switches located externally of the lamp and affixed to one side of the circuit board forming a part of the sequencing circuitry. Each of the switches is located in close proximity to one of the flash lamps to receive thermal energy emitted by the proximate flash lamp upon its being fired, and thereby changes from a high resistance or non-conductive state to a low resistance or conductive state. The switches comprise a uniform mixture of predetermined proportions of finely divided silver carbonate, finely divided silver oxide and finely divided hydrophobic silica. Switches prepared from this mixture are reliable and have no tendency to crack. The mixture is easy to work with being very free flowing.

Abstract: An improved circuit board comprising a substrate having electrical conductor runs resistant to the formation of electrically non-conductive localized areas carried thereon. Such a circuit board is particularly adapted to use with a flash lamp array having a plurality of flash lamps and sequencing electrical circuitry for sequentially flashing the lamps. The sequencing electrical circuitry is formed in part by the conductor runs. The conductor runs comprise an organic polymer binder for attachment of the conductor runs to the substrate and silver-coated vitreous bead-like particles with a triazole-silver water-insoluble reaction product comprising the surface of the bead-like particles. The triazole-silver reaction product prevents the formation of non-conductive localized areas in the conductor runs.

Abstract: A method of preparing anhydrous dicalcium orthophosphate of predetermined and substantially uniform particle size for use in making fluorescent lamp phosphors. The method entails heating an acidified aqueous slurry of hydrated dicalcium orthophosphate in a reaction vessel and at the same time agitating the heated slurry. The heating and simultaneous agitation is continued until significant incipient formation of a gel-like material is manifested at the wall portions of the reaction vessel. At that point the application of heat to the slurry is discontinued. The agitation of the slurry within the vessel is continued until all the slurry is converted to meta-stable gel-like material. At that time the agitation is discontinued. The formed meta-stable gel-like material is then maintained in a quiescent state until it converts completely to crystals of dicalcium orthophosphate. The orthophosphate crystals are then permitted to settle to the bottom of the residual liquid in the vessel.

Abstract: A method of producing finely-divided phosphor grade calcium carbonate having a calcite crystalline structure and a very low sodium content. The calcium carbonate is produced from calcium chloride having a high sodium impurity content, such as calcium chloride which is a by-product of the Solvay process for producing soda ash.

Abstract: Phosphor grains coated with wax or plastic coating compositions comprising hydrocarbons are useful as tagging phosphors for explosives. The coating composition can incorporate UV opacifiers, coloring agents or antistatic agents, or mixtures of them.

Abstract: Method and apparatus are described for applying a wax or plastic coating to phosphor grains to be added to explosives for tagging purposes. The coating is obtained by spraying from a nozzle a homogenous mixture of molten coating material and phosphor grains and permitting the droplets thus formed to solidify during free fall through a cooling medium such as air. The coated phosphors thus obtained when incorporated into an explosive render the mixture less sensitive to friction and impact than the corresponding mixture employing uncoated phosphors.

Abstract: A method of preparing a halophosphate phosphor of controlled particle size with includes the step of compacting the calcium hydrogen orthophosphate di-hydrate crystals. The steps in the method include precipitating the calcium hydrogen orthophosphate di-hydrate crystals from a fluid formed by mixing a calcium chloride solution or a calcium nitrate solution and a diammonium phosphate solution, separating the precipitated di-hydrate crystals from the remainder of the fluid, compacting the di-hydrate crystals, converting the di-hydrate into de-hydrate crystals, preparing a raw mix containing the de-hydrate crystals, and firing the raw mix to form the halophosphate phosphor. The di-hydrate crystals may be separated from the remainder of the fluid by filtering, in which case, the compacting is preferably achieved by pressing the crystals against the filter.