摘要:
A method of selectively leaching zinc from a source material containing zinc in sulphide form and iron, comprises the steps of subjecting the source material to bioleaching with a strict sulphur oxidizing micro organism or a mixed culture of sulphur oxidizing and iron oxidizing micro organisms, in the presence of a nutrient solution containing less than about 15 mg/L phosphate ions. In another embodiment, the source material is in the form of a slurry having a solids concentration of at least about 25% on a weight per volume basis and a nutrient solution containing from about 1 mg/L to less than about 100 mg/L ammonium ions, from about 0.5 mg/L to less than about 40 mg/L magnesium ions and from about 2 mg/L to less than about 60 mg/L phosphate ions.
摘要:
In one embodiment, a method of electrowinning a metal from an electrolyte comprises the steps of measuring the redox potential of the electrolyte to obtain a measured value, comparing the measured value with a predetermined optimum value and adding a redox agent to the electrolyte to adjust the redox potential of the electrolyte to the optimum value. One embodiment of apparatus (10) for carrying out the method comprises a redox potential measuring device (20) having a housing for the flow of electrolyte therethrough and including a pair of electrodes (22, 24) for measuring the redox potential of an electrolyte flowing through the housing to produce an output measurement value and a redox controller (26) responsive to the output measurement value for controlling the addition of redox agent to the electrolyte of an electrolysis cell (12).
摘要:
The strip is cast on a chilled casting surface of a rotating drum from a pool of the molten metal contained in a tundish having a graphite lip insert seated therein cooperating with, the casting surface adjacent to the tundish to form and contain the pool of the molten metal. The tundish preferably contains a feed chamber, a return chamber, and a diverting chamber, the feed chamber and the diverting chamber effectively removing turbulence from the molten feed and the return chamber having a vertically adjustable weir dividing the return chamber from the diverting chamber for controlling the surface level of the pool of molten metal in the diverting chamber and the lip insert and for diverting a flow of molten metal to the return chamber. A preferred lead alloy is a low antimony-lead alloy which is cast into strip and is subjected to a heat treatment to permit expansion and shaping in subsequent production of expanded mesh battery grids. The battery grids produced by the method have improved electrochemical properties such as corrosion resistance and resistance to growth.
摘要:
Copper arsenate, substantially free from impurities that form sludge in wood preservatives such as chromated copper arsenate, is prepared by adding a solution of soluble arsenate to copper sulfate solution, either or both solutions containing sludge-forming impurities, to form a copper and arsenic-containing solution without precipitating copper arsenate. The pH during the adding is controlled at a value in the range of 1.8 to 2.2 to precipitate impurities. Precipitated impurities are removed, and the copper and arsenic-containing solution is neutralized with a suitable alkaline substance to pH 3.5 to 5.0 to precipitate copper arsenate. Arsenate solution is derived from arsenic oxides, soluble arsenic salts and compounds and metallurgical materials capable of yielding water-soluble arsenate. Copper sulfate solution is derived from crystals and compounds and metallurgical materials cable of yielding copper sulfate. In a preferred embodiment, sodium arsenate is derived by aqueous caustic oxidative pressure leaching of flue dusts and copper sulfate is derived by aqueous acid oxidative pressure leaching of copper matte.
摘要:
Gallium is zone refined in a stationary, vertical, double annulus refiner. Impure gallium is contained between walls of a first annulus that are made of a material that does not impart impurities to the gallium. At least one of the walls is made of a flexible material. A cooling fluid is circulated through a second annulus enveloping the first annulus. The gallium is zone refined by moving through the gallium ingot one or more molten zones formed by radio frequency waves from at least one reciprocating radio frequency heating induction coil. After the necessary number of passes, the ingot is cropped without introducing contaminants and refined gallium with purities between 79 and 89 is recovered. LEC single crystal GaAs made with the so refined gallium has very uniform electrical characteristics.
摘要:
Method and apparatus for the agitation of base metal on alloy melts, and for the agitation and alloying of base metal melts with at least one alloying metal. A rotatable device is suspended in a melt of base metal and the device is rotated to draw at least a partial vortex in the melt. The device comprises a hollow cylinder having an open top and a closed bottom. An array of openings in the cylinder side wall is adapted to allow melt of the base metal to pass through. In the agitation of a base metal or alloy melt, the amount of dross formed on the melt is reduced. In alloying, the at least one alloying metal may be added directly to the melt or may be added in particulate form into the vortex in the device, the latter being particularly useful when the melting point of the alloying metal is higher than that of the base metal or alloy. When added into the device, the openings in the cylindrical wall are adapted to retain the particulates in the device to be washed with base metal until the particulates are substantially dissolved. Alloys produced using the device have narrow standard deviations from their specification. The alloying proceeds more efficiently with formation of less dross and less off-specification material, proceeds faster and in less time than heretofore possible, and allows production on a continuous basis.
摘要:
A method for controlling the electro-deposition of metal from an aqueous electrolyte containing two organic polarizing agents is disclosed. The method requires measuring the nucleation overpotential, the plating overpotential, and the difference between these potentials. By relating these measurements to predetermined values, optimum process control can be obtained by changing the concentration of the various organic polarizing agents in the process electrolyte.
摘要:
A method for the heat treatment of cadmium mercury telluride homogeneous single crystals is disclosed wherein the crystals are heated and maintained at a temperature in the range of from about 300 K to below the solidus temperature of the composition treated in the presence of mercury, the vapor pressure of mercury being less than the saturation vapor pressure of mercury.
摘要:
A cutting apparatus for slicing semiconductor materials into wafers is disclosed.The cutting apparatus broadly comprises a pair of spaced-apart co-planar rotatable wheels, a continuous metallic band passing over said wheels, means for driving one of said wheels to move said band unidirectionally through a path encompassing said wheels and through a linear cutting region, means for moving the other wheel towards and away from the driven wheel for tensioning the metallic band, workpiece support means stationed in the cutting region adapted to raise a workpiece to the metallic band at a controlled speed, means for supplying an abrasive slurry to said metallic band in the cutting region upstream of the workpiece, and guide-wipers upstream and downstream of the cutting region each comprising a pair of opposed, laterally and linearly offset wipers for dampening lateral motion of the metallic band, maintaining the band in alignment across the workpiece and wiping the band of abrasive slurry before the band passes over the driven wheel.
摘要:
Embodiments of a method are disclosed for producing large size cadmium mercury telluride (CMT) sputtering targets of a homogeneous composition. Sputtering targets of CMT having a general formula Cd.sub.x Hg.sub.1-x Te wherein x has values in the range of about 0.14 to 0.60 are prepared by compacting finely divided CMT of a particle size smaller than 150.mu. in a die into a coherent compact having a density of at least 97% theoretical density. CMT with an x value of about 0.14 to about 0.20 preferably is compacted at a die preheat temperature of about 100 to 300.degree. C. and at a compacting pressure of at least about 400 MPa. CMT having an x value of about 0.20 to about 0.60 preferably is compacted at a die preheat temperature of about 300.degree. C. and a compacting pressure of about 160 to 275 MPa. The die may be evacuated to a pressure of less than about 133 Pa absolute prior to compacting.
摘要翻译:公开了用于生产均匀组合物的大尺寸碲化汞镉(CMT)溅射靶的方法的实施方案。 具有通式Cd x Hg 1-x Te的CMT的溅射靶,其中x具有在约0.14至0.60范围内的值,通过将模具中的小于150μm的粒度的细碎CMT压实成密度为 至少97%的理论密度。 具有约0.14至约0.20的x值的CMT优选在约100至300℃的模具预热温度和至少约400MPa的压实压力下压实。 具有约0.20至约0.60的x值的CMT优选在约300℃的模具预热温度和约160至275MPa的压实压力下压实。 在压实之前,模具可以被抽真空至小于约133Pa绝对压力。