Abstract: A method for producing substantially pure alumina from kaolin clay by removing in a soluble form impurities which contaminate the alumina while the aluminum is maintained in an insoluble form. This is accomplished by leaching calcined kaolin clay with at least 36 weight percent hydrochloric acid to dissolve the impurities and convert the aluminum to insoluble aluminum chloride and maintaining the hydrochloric acid concentration in the leach liquor at at least 36 weight percent by the injection of hydrochloric acid gas. The insoluble aluminum chloride is then separated from the dissolved impurities and subjected to a second leaching step to solubilize and separate it from the silica gangue. Substantially pure AlCl.sub.3.sup.. 6H.sub.2 O crystals are recovered from solution and converted to alumina by conventional means. In an alternate embodiment, the process may be practiced on uncalcined clay and includes the addition of a source of fluoride ions, such as H.sub.2 SiF.sub.

Abstract: Spent asphaltic concrete is recycled by crushing, heating and admixing with sulfur at elevated temperature.

Abstract: A mine face ventilating method and apparatus are disclosed which serve to supply fresh air from a ventilated crosscut. A duct system containing a blower draws air from the crosscut and expels a jet of air out of a duct in the tunnel. Arcuately shaped troughs located at the end of the duct in the tunnel channel the air to the face of the tunnel. The troughs define an arc of between about 90.degree. and 180.degree. and provide substantially improved air "throw" as compared with conventional tubular ventilation piping.

Abstract: A multi-step process for recovering metal values from lead smelter matte. The matte is mixed with sulfuric acid and manganese oxide and leaching is effected at atmospheric pressure to form an aqueous solution including dissolved metal sulfates and a residue containing sulfur and lead sulfate. The sulfur is removable by conventional means and the lead sulfate may be returned to the smelter. The pH of the aqueous sulfate solution is adjusted to 3.5 to 4.5 to precipitate ferric iron and arsenic and pH is readjusted to about 3.0 to redissolve coprecipitated copper. After separation from the precipitate, the aqueous solution is mixed with a sulfiding agent, such as sodium sulfide at a pH of not more than 3 to selectively precipitate copper sulfide. After separating the copper sulfide, the aqueous solution is mixed with further sulfiding agent at a pH of 3 to 4.5 to form a cobalt-nickel sulfide precipitate in which the weight ratio of copper-nickel to sulfur is 1.8.

Abstract: Molybdenite (MoS.sub.2) is recovered from copper sulfide flotation concentrates by froth flotation utilizing steam-air injection into the concentrate flotation pulp at a temperature of about 70.degree. to 100.degree. C. in the presence of activated carbon and soluble sulfide reagents.

Abstract: Separation of zirconium and hafnium by solvent extraction with a tertiary amine from sulfuric acid solution is improved by addition of water-soluble .alpha.-hydroxycarboxylic acid to the aqueous phase.

Abstract: Improved efficiency of reverse-osmosis and ultrafiltration processes is achieved by backwashing membranes by means of electroosmosis. This is achieved by application of an electric potential across the membrane, thereby causing a backflow of water through the membrane.

Abstract: Organic and aqueous phases are separated from solvent extraction emulsions by treatment of the emulsions with diatomaceous earth at elevated temperature, whereby the emulsion-forming matter is sorbed by the diatomaceous earth.

Abstract: A method for immunizing fish against disease by spraying with vaccine or bacterin.

Abstract: An improved drafting instrument is provided for scribing small dots on a drafting medium comprising a substrate provided with a removable surface coating. The drafting instrument includes a drive motor and rotatable cutter which are slidably mounted as a unit for vertical movement toward and away from the drafting medium. A manually operable actuator is provided for moving the drive motor downward to bring the cutter into engagement with the surface coating of the drafting medium. A control switch responds to downward movement of the drive motor and cutter by a predetermined distance for automatically actuating the drive motor before the cutter is moved into engagement with the drafting medium. The drafting instrument includes an adjustable depth limit feature to control the depth of penetration of the cutter into the surface coating of the drafting medium. The operation of the drive motor and rotation of the cutter are automatically terminated when manual pressure on the actuator is released.

Abstract: A method and apparatus for in-situ leach mining which utilizes multiple dhole branch wells whipstocked off a single main generally vertical well. Initially the vertical well is drilled into the earth so that it may intersect the ore zone of material to be recovered. The vertical well may be cased and cemented after drilling. Thereafter from this same well a plurality of branch wells are whipstocked or drilled which intersect the vertical well at an angle from about 2 degrees to 60 degrees. These branch wells extend into the ore zone. A submersible pump and drop pipe are placed in the main well and at some point below the intersection of the main well with the branch wells a packer is placed around the drop pipe. The drop pipe carries solutions to the surface from the pump.

Abstract: A system for detecting carbon monoxide, even in the presence of methane, using a catalytic sensor material having a perovskite crystal structure and a compositionA.sub.1-n B.sub.n CO.sub.3-mwhere A is a rare earth metal; B is an alkaline metal; C is a metal from the group consisting of cobalt, vanadium and maganese; O is oxygen; n is less than 0.1; and m is not greater than 0.5, which material is substantially free of oxides of A, B and C. The method of making the crystalline material involves firing appropriate amounts of mixed salts of A, B and C until substantially converted to the perovskite structure, and then leaching with a caustic to remove the undesired oxides.

Abstract: A lighting inverter for operating an electrical discharge lamp from a direct current power source. The inverter includes a resonant feedback inverter which converts the output of the d.c. power source to an alternating current output and regulates the a.c. inverter output voltage level by varying the frequency thereof. A ballast filter is coupled to the regulated output of the resonant feedback inverter and is formed by a series circuit of a ballast inductor and a ballast capacitor. Connected across the capacitor is the discharge lamp. Appropriate circuit parameters such as ballast inductance, ballast capacitance, inverter operating frequency, and the inverter resonant frequency are selected to maintain almost unity power factor at the input to the ballast filter.

Abstract: A system for measuring the resistance of an earth electrode such as a coal mine safety ground bed. Current is circulated between the bed and an auxiliary current probe installed approximately ten times the maximum linear dimension of the ground bed under test. By measuring the voltage level between the ground bed and an auxiliary voltage probe placed about 62 percent of the distance from the ground bed to the auxiliary current electrode along the straight line between them, the true resistance of the ground bed can be determined. To sense the current value of the current flowing into the ground bed, a current transformer is placed around the lead to the ground bed. Voltage measurements are made with a high impedance voltage amplifier connected between the ground bed and the auxiliary voltage probe. Continuous monitoring of the measurements obtained without the presence of operator is achieved by using an analog divider and filter with their output terminal being connected to a recorder.

Abstract: A portable calibrator for d.c. circuit breakers is provided which produces a low voltage, short duration current test pulse of a current level sufficient to trip the breaker under test. The current pulse is produced by a high power, high frequency d.c. to d.c. converter which is controlled by lower power signals. A static switch controlled by the converter output provides current protection for the converter. A feedback loop including a current transformer connected in an output transformer circuit provides control of the test pulse. A non-inductive shunt connected in a negative test lead monitors the test pulse during the period of application thereof, the shunt being connected to a sample and hold read-out circuit which includes metering for indicating the peak current value. A timer interlocked with the metering ensures that sufficient time is provided for the operator to read current value.

Abstract: Lanolin is employed as a modifier for froth flotation utilizing conventional collectors such as fatty acids, kerosene, and the like. Lanolin added to the system acts as a depressant which assists in the selectivity of the process for the desired mineral or inhibits the flotation of gangue materials. Scheelite ore flotation is substantially improved using lanolin in addition to a conventional collector such as tall oil.

Abstract: A dilution stable water based magnetic fluid is provided by dispersing magnetic particles in water with the aid of a C.sub.10 -C.sub.15 aliphatic monocarboxylic acid. The magnetic particles are preferably particles of magnetite, prepared by precipitation of dissolved iron chloride salts from aqueous solution by the use of ammonium hydroxide. The preferred acids used in preparing the dispersions are dodecanoic (C.sub.12) and tridecanoic (C.sub.13).

Abstract: Nickel, cobalt and manganese are selectively recovered from Atlantic deep sea nodules by means of a preliminary treatment with acetic acid, followed by leaching with sulfurous acid.

Abstract: Gold is desorbed from activated carbon by contacting, at a temperature of about 70.degree. to 160.degree. C., with a solution comprising about 20 to 30 percent by volume of a water soluble alcohol and about 80 to 70 percent by volume of an aqueous solution of a strong base.

Abstract: A vibrating wire stress meter and the method used to clamp its wire in position. The wire is highly tensioned diametrically across the sides of a hollow metallic cylinder and held there by two anchor tubes. A wedge and platen assembly in turn hold this cylinder in a rock borehole such that small stress changes in the surrounding rock cause the diameter of the cylinder to slightly change. This cylinder variation is transmitted to and measured by the preloaded wire by noting variations in its frequency or period of vibration. To cause the wire to vibrate a coil, magnet, and yoke are used as a plural pole electromagnetic plucker.Clamping of the wire is accomplished by highly tensioning the wire between two opposite hollow tubes that are seated in opposite aligned countersunk holes of the cylinder and then extruding the steel tubes around the wire. The wire extends through holes of those hollow tubes as well as the aligned holes in the cylinder walls which are diametrically opposite each other.