Abstract: A process and system for simultaneously cooling shale ash fines and flue gas produced during the combustion of spent shale. The flue gas and fine solids are introduced into a heat exchange zone for contact with conventional heat exchange tubes. Heat transfer particles are introduced into the heat exchange zone for mixing with the flue gas to provide increased heat transfer rates between the flue gas and heat exchange equipment. The heat transfer solids are also of a sufficient size to provide continual scrubbing of the heat exchanger surfaces to prevent the build up of an insulating layer of fine dust particles. A staged cooling system and process is also disclosed.

Abstract: A solar cell includes a semiconductor wafer of one conductivity type with a front radiation receiving surface having a plurality of pyramidal apertures therein. The spacing of adjacent apertures is selected to maximize the escape of undesired radiation. A material with a high index of refraction fills the apertures and further enhances radiation escape. The surfaces of the wafer are provided with thin regions of opposite conductivity type. Two sets of electrodes are provided at selected locations on the rear side of the wafer. One set of electrodes contacts the region of opposite conductivity type on the rear side. The other set of electrodes contacts the wafer through openings in the region of opposite conductivity type.

Abstract: Pyrolysis process and system for recovering product gases and liquids from solid carbonaceous particles.Dual stage fluidized bed retort is disclosed having frusto-conical stages serially connected to promote uniform pyrolysis. Product gases and oil are removed from final fluid bed stage in series. Process includes various energy efficient aspects involving recycle of dilute phase combusted solids as the heat carrier, heavy oil recycle and use of steam and/or product vapors as the source of fluidizing gas for the staged retort.

Abstract: A dual stage combustion system and process for achieving high fuel combustion efficiency and reduced nitric oxide emissions. Combustion is carried out in two stages. A first partial combustion carried out in an oxygen deficient atmosphere followed by a second complete carbon combustion in an oxidizing atmosphere. The second combustion step achieves complete fuel utilization, but generates a nitrogen oxide containing flue gas. The nitrogen oxide containing flue gas is passed to the first combustion step where it is removed by interaction with the partially combusted solids.

Abstract: An improved method for producing hydrogen fluoride from fluoride bearing ores, such as fluorospar and fluorapatite, by reaction of the ore as a slurry in fluorosulfonic acid. The slurry is heated by the exothermic heat of the reaction to vaporize volatile phosphorous compounds and substantial quantities of hydrogen fluoride. The calcium fluoride is substantially reacted to form hydrogen fluoride. High silica fluorospar ores can be used since silicon tetrafluoride is not formed with fluorosulfonic acid. Another feature provides for addition of calcium fluoride to the slurry to react with the by-product sulfuric acid in the residual solids to eliminate the sulfuric acid recovery step in the process. Hydrogen fluoride produced is recovered, together with the hydrogen fluoride produced from the hydrolysis or pyrolysis of the intermediate fluorophosphorous compounds. Additionally, at least a portion of the hydrogen fluoride can be reacted with sulfur trioxide to form fluorosulfonic acid for makeup in the process.

Abstract: A solar cell which has high efficiency and which can be fabricated at low cost is described. The cell includes a semiconductor wafer with a front radiation-receiving surface which is entirely open and free of current conducting grids and also includes an array of interconnection paths which carry photocurrent from the front surface through the cell to metal electrodes on the rear surface of the cell.

Abstract: An elongated body of monocrystalline semiconductor material is provided with a first region of one conductivity type entirely enclosed within a second region of the opposite conductivity type. Ohmic contacts are made to ends of the elongated body.

Abstract: An improved method for treating calcium phosphate sources such as bone phosphate and phosphate rock with fluorosulfonic acid in the presence of a limited amount of moisture whereby over 98.00% of the phosphorous is converted to volatile compounds that can be subsequently hydrolyzed. A substantial excess of fluorosulfonic acid is utilized to contact the phosphate ore as a slurry. The phosphorous products are primarily phosphorous pentafluoride and phosphorous oxyfluoride, and to a limited extent difluorophosphoric acid. A trace of water apparently catalyzes the reaction. The production of phosphorous pentafluoride is favored by up to one part of water to eight parts of ore by weight in the presence of excesses of fluorosulfonic acid. The method includes the hydrolysis of the volatile compounds to phosphoric acid and hydrogen fluoride. Hydrogen fluoride is then recycled to react with the required sulfur trioxide to make the requirement of fluorosulfonic acid for the process.

Abstract: Germanium radiation detectors are manufactured by diffusing lithium into high purity p-type germanium. The diffusion is most readily accomplished from a lithium-lead-bismuth alloy at approximately 430.degree. and is monitored by a quartz half cell containing a standard composition of this alloy.Detectors having n-type cores may be constructed by converting high purity p-type germanium to n-type by a lithium diffusion and subsequently diffusing some of the lithium back out through the surface to create a deep p-n junction.Coaxial germanium detectors comprising deep p-n junctions are produced by the lithium diffusion process.

Abstract: Germanium radiation detectors are manufactured by diffusing lithium into high purity p-type germanium. The diffusion is most readily accomplished from a lithium-lead-bismuth alloy at approximately 430.degree. C. and is monitored by a quartz half cell containing a standard composition of this alloy.Detectors having n-type cores may be constructed by converting high purity p-type germanium to n-type by a lithium diffusion and subsequently diffusing some of the lithium back out through the surface to create a deep p-n junction.Coaxial germanium detectors comprising deep p-n junctions are produced by the lithium diffusion process.

Abstract: Heat from spent shale combustion is removed from shale ash and combustion gases by direct contact thereof with raw shale particles wherein the fine raw shale particles not easily separable from the shale ash are removed prior to contact of the raw shale with the shale ash and combustion gases.