摘要:
A method of transporting heavier than water particles such as coal from an elevated supply site to a delivery site at a substantial elevation below said elevated supply site comprising the steps of mixing the particles at the supply site with liquid such as water to form a slurry of particles and liquid, introducing slurry at the supply site into a confined path extending downwardly from the supply site to the delivery site, confining a volume of slurry material in energy transmitting relation to the slurry in the confined path such that the static head of the slurry in the confined path is transmitted to the confined volume, continuously withdrawing material from the confined volume at spaced first and second positions and introducing liquid into the confined volume in such a way as to (1) maintain the pressure conditions within the confined volume generally equal to the static head of the slurry in the confined path minus the friction losses and (2) enable slurry from the confined path to flow into the confined volume and the particles thereof to move within the confined volume such that the material at the first withdrawal position contains the larger particles of the slurry and the material at the second withdrawal position is substantially devoid of the larger particles of the slurry, continuously separating a liquid fraction from the material withdrawn from the confined volume at the second withdrawal position in such a way that the pressure of said liquid fraction is not materially lowered with respect to the pressure of the material in the confined volume, pumping the liquid fraction along a confined path extending upwardly to the supply site, and utilizing the liquid fraction pumped to the supply site as the liquid in the mixing step, and apparatus for carrying out the method.
摘要:
A method and apparatus are provided for the dehydration of low rank coal, such as lignite. The coal is formed into particles having a size of less than about 4 inches, is subjected to atmospheric steaming, and then preheating with steam at a pressure of about 20-100 psig. The particles are then entrained in liquid and fed to a high pressure feeder at which they are transferred to a high pressure circulation loop, at a pressure of between about 300-1500 psig. The particles and liquid are fed to a liquid/particles separator at the top of a vertical dehydrating vessel, and the particles at the top of the vessel are contacted by saturated steam. Condensed steam and particles flow downwardly in the dehydration vessel, and are subjected to a counter-current wash at the bottom of the vessel. A slurry of liquid and particles discharged from the bottom of the dehydration vessel has the pressure thereof gradually reduced in a second high pressure feeder, and is transferred to a low pressure loop at a pressure of between about 20-100 psig. The liquid and particles are separated, and then the particles are subjected to evaporative cooling.
摘要:
Methane is produced from peat by solubilizing the phenolic polymers therein, and oxidizing the solute to produce short chain molecules. The short chain molecules are fermented to produce a gas that this scrubbed to remove CO.sub.2 to produce methane. Solubilizing takes place in a vertically oriented pressurized vessel that is circular in cross-section and divided into a number of regular vertically elongated compartments, each comprising a circular sector in cross-section, and extending the majority the height of the vessel. Slurried peat is fed into the top of one compartment while another compartment is being emptied from the bottom, the compartment being filled or emptied being progressively changed in response to rotation of a central shaft in the vessel. Oxidation of solubilized peat takes place in a structure that transports the solubilized peat in a substantially vertical wave path from an inlet to an outlet with oxygen being introduced at the bottoms of segments of the wave path, and CO.sub.2 being withdrawn from the tops of segments of the wave path while the solubilized peat is maintained at a pressure above atmospheric. Coolant is circulated around the wave path to remove the exothermic heat of reaction, and the coolant is flashed into steam used elsewhere in the process.
摘要:
In gold and/or silver cyanide leaching-adsorption processes employing solid adsorbents such as activated charcoal, the overall efficiency in the recovery of gold and/or silver from ores or the like is greatly increased by contacting the cyanide slurry containing the gold and/or silver, with oxygen gas instead of normal air. A generally pure oxygen gas can be bubbled into a vessel containing the slurry, and a cover (e.g. a floating cover) may be provided on the vessel to reduce the oxygen transfer out of the solution and to facilitate pressurization of the system with an oxygen atmosphere. The procedures of the invention are applicable to carbon-in-pulp (CIP), and carbon-in-leach (CIL) processes and related processes using resins. Deaeration of the ore slurry can be practiced prior to the introduction of the oxygen.
摘要:
Particlized mineral material, such as gold ore, silver ore, or coal, is subjected to a leaching process in a manner to maximize treatment effectiveness even when the particlized mineral material contains small fines. The material is slurried with a flocculating material and fibers, such as cellulosic fibers, fiberglass fibers, or ceramic fibers, and a liquid, and then is passed to the top of a leaching reactor. The slurry is continuously passed downwardly in the reactor while the leaching liquid, such as a cyanide solution, is passed counter-current to the slurry. Leaching liquid is removed from the top of the leaching reactor by a stilling well, and then passed through a carbon adsorber and reintroduced into the reactor. Leached slurry is passed to a continuous washing station, with spent wash liquid from the top of the washing station being utilized as a slurrying liquid for the particlized mineral material.
摘要:
In carbon-in-pulp (CIP) and carbon-in-leach (CIL) processes, especially those utilizing pure oxygen instead of normal air to increase the overall efficiency of the cyanide leaching-adsorption process in the recovery of gold and/or silver from ores, the screen within each tank which surrounds the slurry outlet is kept clean. The cleaning action is accomplished by linearly reciprocating the screen first slowly in one direction, and then quickly in another (to cause back flushing); or by rotating a cleaning rotor on the inside of a cylindrical screen. The cleaning rotor may be connected to the same shaft as an agitator disposed above a draft tube within the tank. The screen surface is tapered in its direction of movement, and during movement has a tendency to transport and concentrate the carbon (charcoal) particles at the far end of the slow stroke, and the concentrated particles can be withdrawn and recirculated to other tanks in the system.
摘要:
A method and system for the percolation leaching of gold and silver ores applies a cyanide leaching liquid to a pile of gold and silver ore. Heap leaching, vat leaching, or the like may specifically be practiced. The cyanide leaching liquid is applied to the pile by spraying, flooding, or via a foam of oxygen gas and cyanide liquid on top of the pile. Gold and silver are recovered from the pregnant liquor. The leach rate is increased and/or the recovery of gold and silver from the ore is increased by supplying to the pile a gas containing oxygen at a significantly higher percentage than in ambient air (e.g. pure oxygen gas). The oxygen gas may be supplied to the leaching liquid, and/or into the pile itself (as with a plurality of perforated pipes adjacent the bottom of the pile).
摘要:
A method for produce both kraft pulp and alcohol from hardwood chips or the like. The chips are subjected to mild acid prehydrolysis following by mild caustic pre-extraction. The withdrawn hydrolysate has insufficient furfural to inhibit microorganism growth, and both the hexose and pentose sugars in the hydrolysate are fermented to ultimately produce ethanol, butanol, or the like. The chips - after caustic pre-extraction - are subjected to a sulphate cook, and wash, and the resultant pulp is kraft pulp and even has viscosity and tear strength characteristics more desirable than that of conventional kraft pulp. The pulp can be subjected to oxygen delignification, and achieve a higher K number in fewer subsequent bleaching stages than conventional kraft pulp.
摘要:
The waste heat from a steam turbine is condensed and used to desalinate sea water at the same time. The waste steam from a turbine is fed to a condenser through which cold sea water passes. As the cold sea water condenses the waste steam, it is warmed. It is then introduced into a first chamber which includes a number of spray heads disposed over fill (packing) that acts as an evaporator. Any water not evaporated is collected in a sump at the bottom of the first chamber, and the evaporated vapor is passed upwardly under the influence of a fan and ultimately to a second chamber. The second chamber may either be stacked above the first chamber, or in side-by-side relationship with it. A condenser, such as a number of dimpled metal plates, or plastic membranes defining a closed loop, or another set of spray heads and fill, are provided in the second chamber. Air typically recirculates from the bottom of the second chamber back into the first chamber. The product (fresh) water is collected at the bottom of the second chamber, and may be cooled by cold sea water and a portion of it introduced as the condensing liquid in the second chamber.
摘要:
An evaporator includes heating elements which are part of a thin skin providing the evaporator vessel wall, supporting the skin for internal and external pressure, and a top portion of the vessel. A liquor distributing plate is supported on the heating elements, with a liquor inlet donut-shaped conduit disposed above the liquor distributing plate. The heating elements are radially disposed within the vessel, and are supported at the bottom by a ring which engages the bottoms of the heating elements, and a vertical axis tube extending from the vessel bottom to the ring, the tube having a plurality of through-extending openings formed in it. The vapor outlet for the vessel is concentric with the heating elements and the liquor distributing perforated plate. Heating fluid (e.g. steam) is introduced into the interior volumes of the heating elements adjacent the tops thereof, and a vent is provided adjacent the bottoms.