The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Jianguang Li - One of the best experts on this subject based on the ideXlab platform.
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fine coal circuitry considerations in treatment of soft coal with difficult washabilities
Fuel Processing Technology, 2007Co-Authors: Jianguang LiAbstract:A typical process used in Chinese metallurgical coal preparation plants employs Heavy-Media Separation to treat the coal coarser than 0.5 mm. The − 0.5 mm fine coal is treated with froth flotation. A major disadvantage of this process is that a large quantity of fine coal is recycled in the Heavy-Media cyclone circuit, which results in high magnetite losses. The − 0.5 mm fine coal in the Media is a result of poor raw coal deslime screen efficiency and the continuous breakage associated with the processing of soft coal. Another disadvantage of this typical process is that some coarse clean coal particles are lost to the froth flotation tailings. This investigation focuses on the simulation of processing fine soft coal with water-only cyclone (WOC) and spirals. WOCs and spirals have become popular devices for treating fine coal. WOCs can operate at low specific gravity cut points to produce low ash clean coal while spirals tends to operate at high specific gravity cut points and act as a scavenger to rewash the underflow (refuse) from WOCs. The combination of WOCs and spirals can compete with a Heavy-Media cyclone with respect to both efficiency and clean coal yield when treating 1 mm × 100 Mesh fine coal. This fine coal processing circuit can subsequently increase the bottom size of the Heavy-Media cyclone feed from 0.5 mm to 1 mm which will reduce the loading of the Heavy-Media cyclone circuit. This change in circuitry thus reduces magnetite consumption without scarifying Separation efficiency of the 1 mm × 0 size fraction. Furthermore, the reduction of the nominal top size of the froth flotation feed from 0.5 mm to 0.15 mm will greatly decrease or eliminate the loss of clean coal to flotation tailings.
Hugh Morrow - One of the best experts on this subject based on the ideXlab platform.
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Kirk-Othmer Encyclopedia of Chemical Technology - Cadmium and Cadmium Alloys
Kirk-Othmer Encyclopedia of Chemical Technology, 2010Co-Authors: Hugh MorrowAbstract:Cadmium, Cd, a Group 12 (IIB) element occurring between zinc and mercury, is a soft, ductile, silver-white metal having a distorted hexagonal close-packed structure. The crustal abundance of cadmium is somewhere between 0.1 and 0.5 ppm, and several cadmium minerals have been identified, the most common being greenockite, CdS. Cadmium is generally encountered in zinc ores, zinc-bearing lead ores, or complex copper-lead-zinc ores, where, however, it forms an isomorphic impurity in the zinc mineral sphalerite, ZnS. For this reason, cadmium is almost invariably recovered as a by-product from the processing of zinc, lead, and copper ores. Its oxidation state in almost all of its compoumds is + 2, although a few compounds have been reported in which cadmium exists in the + 1 oxidation state. There are eight natural isotopes. Cadmium forms a fume of brown-colored cadmium oxide, CdO, when heated in air. Other elements which react readily with cadmium metal upon heating include the halogens, phosphorus, selenium, sulfur, and tellurium. Cadmium is rapidly oxidized by hot dilute nitric acid. Cadmium occurs primarily as sulfide minerals in zinc, lead-zinc, and copper-lead-zinc ores. Beneficiation of these minerals, usually by flotation or Heavy-Media Separation, yields concentrates which are then processed for the recovery of the contained metal values. Cadmium follows the zinc with which it is so closely associated. Air pollution problems and labor costs have led to the closing of older pyrometallurgical plants, and to increased electrolytic production. Cadmium production is dependent on the processing of zinc ores, which often contain 0.2 to 0.4% cadmium. Cadmium is classified as a toxic metal. Acute industrial poisoning by cadmium dust or fume can occur during the melting or pouring of cadmium metal; the welding, burning, or heating of cadmium-plated steel; or spraying, brazing, and overheating of cadmium metal. Protection should be provided by a properly designed exhaust ventilation system or by a suitable individual filter or air-supplied respirator. Industrial exposure to cadmium fumes and dust has been reported to result in emphysema, hypertension, kidney failure, osteomalacia, and perhaps an increased incidence of cancer. To help maintain the balance between supply and demand for cadmium, efforts can be made to recycle such cadmium-containing materials as spent nickel-cadmium batteries as well as dust and other residues from the pigment industry. Consumption of cadmium is in batteries, coating and plating, pigments, plastics and synthetic products, and alloys and other uses. Cadmium is an important component in brazing and low melting alloys, used in bearings, solders, and nuclear reactor control rods. Keywords: Occurrence; Cadmium; Sources; Recycling; Properties; Manufacture; Economics; Environmental Concerns; Specifications; Analytical Methods; Nealth & Safety; Uses; Minerals; Batteries; Nickel; Contamination; Pigments; Stabilizers; Coatings; Alloys; Cadmium Telluride; Cadmium Sulfide
D. S. Carr - One of the best experts on this subject based on the ideXlab platform.
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Kirk-Othmer Encyclopedia of Chemical Technology - Cadmium and Cadmium Alloys
Kirk-Othmer Encyclopedia of Chemical Technology, 2000Co-Authors: D. S. CarrAbstract:Cadmium, Cd, a Group 12 (IIB) element occurring between zinc and mercury, is a soft, ductile, silver-white metal having a distorted hexagonal close-packed structure. The crustal abundance of cadmium is somewhere between 0.1 and 0.5 ppm, and several cadmium minerals have been identified, the most common being greenockite, CdS. Cadmium is generally encountered in zinc ores, zinc-bearing lead ores, or complex copper–lead–zinc ores, where, however, it forms an isomorphic impurity in the zinc mineral sphalerite, ZnS. For this reason, cadmium is almost invariably recovered as a by-product from the processing of zinc, lead, and copper ores. Its oxidation state in almost all of its compounds is , although a few compounds have been reported in which cadmium exists in the oxidation state. There are eight natural isotopes. Cadmium forms a fume of brown-colored cadmium oxide, CdO, when heated in air. Other elements which react readily with cadmium metal upon heating include the halogens, phosphorus, selenium, sulfur, and tellurium. Cadmium is rapidly oxidized by hot dilute nitric acid. Cadmium occurs primarily as sulfide minerals in zinc, lead–zinc, and copper–lead–zinc ores. Beneficiation of these minerals, usually by flotation or Heavy-Media Separation, yields concentrates which are then processed for the recovery of the contained metal values. Cadmium follows the zinc with which it is so closely associated. Air pollution problems and labor costs have led to the closing of older pyrometallurgical plants, and to increased electrolytic production. Cadmium production is dependent on the processing of zinc ores, which often contain 0.2 to 0.4% cadmium. Cadmium is classified as a toxic metal. Acute industrial poisoning by cadmium dust or fume can occur during the melting or pouring of cadmium metal; the welding, burning, or heating of cadmium-plated steel; or spraying, brazing, and overheating of cadmium metal. Protection should be provided by a properly designed exhaust ventilation system or by a suitable individual filter or air-supplied respirator. Industrial exposure to cadmium fumes and dust has been reported to result in emphysema, hypertension, kidney failure, osteomalacia, and perhaps an increased incidence of cancer. To help maintain the balance between supply and demand for cadmium, efforts can be made to recycle such cadmium-containing materials as spent nickel–cadmium batteries as well as dusts and other residues from the pigment industry. Consumption of cadmium is in batteries, coating and plating, pigments, plastics and synthetic products, and alloys and other uses. Cadmium is an important component in brazing and low melting alloys, used in bearings, solders, and nuclear reactor control rods.
K. Anast - One of the best experts on this subject based on the ideXlab platform.
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Bench scale testing of micronized magnetite beneficiation. Quarterly technical progress report 4, October--December, 1993
1994Co-Authors: K. AnastAbstract:This project is aimed at development of a process that, by using ultra fine magnetite suspension, would expand the application of Heavy Media Separation technology to processing fine, {minus}28 mesh coals. These coal fines, produced during coal mining and crushing, are separated in the conventional coal preparation plant and generally impounded in a tailings pond. Development of an economic process for processing these fines into marketable product will expand the utilization of coal for power production in an environmentally acceptable and economically viable way. This process has been successfully researched at PETC but has not been studied on a continuous bench-scale unit, which is a necessary step towards commercial development of this promising technology. The goal of the program is to investigate the technology in a continuous circuit at a reasonable scale to provide a design basis for larger plants and a commercial feasibility data.
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Bench scale testing of micronized magnetite beneficiation. Quarterly technical progress report No. 1, January--March 1993
1993Co-Authors: K. AnastAbstract:This project is aimed at development of a process that, by using ultra fine magnetite suspension, would expand the application of Heavy Media Separation technology to processing fine, {minus}28 mesh coals. These coal fines, produced during coal mining and crushing, are separated in the conventonal coal preparation plant and generally impounded in a tailings pond. Development of an economic process for processing these fines into marketable product will expand the utilization of coal for power production in an environmentally acceptable and economically viable way. This process has been successfully researched at PETC but has not been studied on a continuous bench-scale unit, which is a necessary step towards commercial development of this promising technology. The goal of the program is to investigate the technology in a continuous circuit at a reasonable scale to provide a design basis for larger plants and a commercial feasibility data.
R.w. Breault - One of the best experts on this subject based on the ideXlab platform.
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Storage, transportation, and atomization of CWF for residential applications. Final report, September 27, 1989--November 15, 1991
1991Co-Authors: M.p. Grimanis, R.w. Breault, F.j. Smit, M.c. JhaAbstract:This project investigated the properties and behavior with regard to handling, storage, and atomization in small-scale applications of different CWFs (coal water fuels) prepared from different parent coals and various beneficiation techniques as well as consideration for bulk storage and distribution. The CWFs that were prepared included Upper Elkhorn No. 3, Illinois No. 6, and Upper Wyodak coal cleaned by Heavy Media Separation. Also, several CWFs were prepared with Upper Elkhorn No. 3 coal cleaned by Heavy Media Separation with filtration, chemical cleaning, oil agglomeration, and froth flotation.
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Storage, transportation, and atomization of CWF for residential applications
1991Co-Authors: M.p. Grimanis, R.w. BreaultAbstract:The properties and behavior with regard to handling, storage, and atomization in small-scale applications of different coal-water fuels (CWFs) prepared from different parent coals and various beneficiation techniques, were investigated. The CWFs that were prepared included Upper Elkhorn No. 3, Illinois No. 6, and Upper Wyodak coal cleaned by Heavy Media Separation. Also, several CWFs were prepared with Upper Elkhorn No. 3 coal cleaned by Heavy Media Separation with filtration, chemical cleaning, oil agglomeration, and froth flotation. Pressure drop measurements in tubes and viscometer measurements were used to construct rheograms of the seven CWFs that were prepared for shear rates up to 1000 1/s. Analysis of each CWF included proximate, ultimate and ash fusion temperatures. A fully automatic demonstration storage facility was designed and fabricated. The viscosity at higher shear rates (150,000 1/s) will be measured in a capillary viscometer to determine the viscosity at shear rate typically obtained with atomizers. The demonstration storage/handling facility will be tested. A cost analysis of a residential facility will be conducted. The seven CWFs will be burned in the residential combustor developed by Tecogen under contract DE-AC22-87PC79650. 41 figs., 12 tabs.