1 - 25 of 279
Number of results to display per page
1 Miller, Jan D.Metal ion activation in xanthate flotation of quartzQuartz cannot be floated with potassium amyl xanthate as collector at any pH. Complete flotation is achieved with certain minimal additions of amyl xanthate and Pbtt from pH 5.8 to 8.5 and with amyl xanthate and Znt+ from pH 7.5 to 8.1. The active species of these metal ions responsible for activ...pH (Chemistry); Xanthate flotation; Metal ions1965
2 Miller, Jan D.Chrysocolla flotation by the formation of insoluble surface chelatesPure chrysocolla is floated with chelating agents that form insoluble complexes with copper at ambient temperature. Complete flotation is obtained with potassium octyl hydroxamate as collector at pH 6. Flotation response is enhanced with increased temperature when low additions of h ydroxamate are ...Chrysocolla; Copper chelating compounds; Flotation systems1965
3 Miller, Jan D.Role of the hydrocarbon chain in anionic flotation of calciteThe response of calcite to flotation with saturated fatty acids and alkyl sulfonates of various chain lengths is presented. The amount of collector required for flotation is shown to decrease systematically with increasing carbon content from 8 to 12-carbon atoms per molecule. This systematic flot...Hydrocarbon chain; Calcite; pH (Chemistry); Carbon1967
4 Miller, Jan D.Selective flotation of iron oxideThe response of pure goethite and two natural iron ores to flotation with potassium octyl hydroxamate is presented. The ores contained 12.5% and 39.7% iron; concentrates containing 69.5% and 61.5% iron, respectively, were obtained with additions of 0.4 lb/ton hydroxamate.Goethite; Iron; Flotation; Iron Oxide1967
5 Brown, Francis HaroldSome early pleistocene deposits of the lower Omo valley: the Usno formationEarly Pleistocene deposits of the Rudolf Basin have been described by E. Brumpt (Bourg de Bozas, 1903: 107 ff.), Arambourg (1943: 190 ff.), Fuchs (1939), Patterson (1966), and Butzer and Thurber (1969). These include the Omo Beds, first recognized by Brumpt in 1902 and subsequently studied by Arambo...1969
6 Miller, Jan D.ConcentrationThe most startling development in concentration processes this past year would have to be the results obtained after magnetic treatment of aqueous systems. Beneficial effects were reported in both flotation and thickening on an industrial scale following the application of a magnetic field to ...Concentration; Aqueous systems; Pulp; Magnetic treatment1969
7 Brown, Francis HaroldHorizontal sediments of the lower Omo valley: the kibish formationThe existence of old lacustrine deposits in the Lake Rudolf Basin was first recognized by Hohnel et al. (1891 : 20f., 134) and subsequently confirmed by the work of M. Sacchi (Angelis and Millosevich, 1900) and E. Brumpt (Bourg de Bozas, 1903: 107ff.), Fuchs (1935, 1939), Champion (1937), and Aramb...1969
8 Brown, Francis HaroldObservations on the stratigraphy and rediometric age of the omo beds, lower omo basin, southern EthiopiaDuring September and October, 1966, the author measured a stratigraphic section for a portion of the Omo Beds, as exposed north of Kalam, Ethiopia. Additional field observations were also made at the time in other parts of the lower Omo Basin. Samples were collected for analysis and for radiometric ...1969
9 Miller, Jan D.Minerals beneficiation in '69 steps up tonnage, engineering, environmental control and automation: size analysis and flotation chemistry highlighted by basic science researchersThe application of computers to the control and study of mineral processing operations such as grinding, classification and notation has created an interest in simulation studies of these operations with mathematical models. Evidence of this interest is confirmed by papers presented at the 1969 Int...Mineral processing; Computer simulations; Mathematical models1970
10 Miller, Jan D.Hydroxamate vs. fatty acid flotation of iron oxideData were obtained with hematite with octyl hydroxamate and oleate as collectors to determine the mechanism of collector adsorption and also to establish the roles that conditioning time and temperature assume in this system. The presence of hydroxy complexes of iron are apparently necessary for che...Iron ore; Iron; Fatty acid; Hydroxy complexes1970
11 Miller, Jan D.Adsorption mechanisms in nonmetallic activation systemsAdsorption of lead and ferric iron on quurtz and alumina is presented as a function of pH. Only the hydrolyzed species of these metal ions, FeOHt+ and PbOH', adsorb significantly on each of these minerals. Zeta potentials of quartz were measured as a function of pH in the presence of various additio...Ferric iron; Quartz; Lead; Alumina; Adsorption; pH (Chemistry)1970
12 Brown, Francis HaroldPliocene/pleistocene formations in the lower omo basin, southern EthiopiaFollowing a two month geological reconnaissance by one of us (FHB) in 1966, four seasons of fieldwork by members of the Omo Research Expedition has added greatly to our previous, scanty knowledge of the late Cenozoic history of the lower Omo basin in southern Ethiopia. Eduard Suess (in: von Hohnel ...1970
13 Miller, Jan D.Mineral processing fundamentalsThe reported claims in several Russian articles that magnetic fields change the viscosity and other basic properties of water and as a result produce beneficial effects such as increased flotation rate, improved grades and recovery, and increased settling rates appear to be unfounded. This conclusi...Minerals; Processing; Magnetic fields; Metallurgy; Water1971
14 Miller, Jan D.Removal of dissolved contaminants from mine drainageEleven mill tailing samples from locations throughout the Rocky Mountain region were tested for their effectiveness in removal of dissolved contaminants from mine drainage . With the exception of the sample of the Blaine Mill tailing, the average capacity of the tailings tested was 9.8 mg of iron p...Mine drainage; Mill tailing; Adsorption; Precipitation; Rocky Mountain Region1972
15 Miller, Jan D.HydrometallurgyThe science and technology of hydrometallurgy and chemical processing continues to advance both at the laboratory level and in plant practice. In past decades, hydrometallurgy was rather limited in scope and received relatively little attention, being largely a laboratory curiosity. But curiosity i...Hydrometallurgy; Chemical processing; Environment; Laboratory practice; Plant practice1972
16 Miller, Jan D.Screening and classificationThe processing of minerals almost invariably involves the reduction in size of the minerals contained in an ore to effect liberation of disseminated values or, in other instances, to effect increased surface area. Separation of solids according to size usually is undertaken to promote maximum produc...Mesh; Mechanical; Separation1973
17 Miller, Jan D.Structure and composition of commercial copper chelate extractantsThe structure, properties, and composition of commercial chelating-type copper extractants are examined. Characterization of these extractants was accomplished using organic separation techniques and analytical tools such as NMR and infrared spectroscopy. Results indicate that only the trans isomer ...LIX® reagents; stoichiometry; reaction mechanism1973
18 Miller, Jan D.Analysis of the surface potential developed by non-reactive ionic solidsThe sign of the surface potential for complex non-reactive ionic solids cannot be predicted solely from consideration of the hydration energy of gaseous ions which constitute the ionic lattice. Accurate analysis of these systems must involve the hydration energy of surface ions, which requires knowl...Lattice; dipole; Madelung Constants1976
19 Brown, Francis HaroldRadiometric dating and tuff mineralogy of omo group depositsThrough the efforts of the Omo Research Expedition and the East Rudolf Research Group, a large number of vertebrate fossils have been collected from the sedimentary deposits near the northern end of Lake Rudolf in Kenya and in the lower Omo valley in Ethiopia. The hominid fossils collected in this a...1976
20 Miller, Jan D.Determination of Madelung constants for infinite and semi-infinite lattices by direct summationLattice sums for the electrostatic interactions in ionic crystals, first evaluated by Madelung, are now known to high degrees of accuracy. The problem of conditional convergence has been solved either by manipulations of a mathematical model of the lattice, or by directly summing over neutral group...Lattices; Madelung constants1976
21 Miller, Jan D.Bismuth dissolution from smelter flue dust residuesEffective bismuth removal from flue dust residues has been accomplished for flue dusts from both zinc and copper smelters. Selective dissolution of bismuth, with respect to silver and lead, can be achieved by the proper manipulation of temperature, sulfuric acid addition and sodium chloride addition...Technique; Distribution; Chloride1976
22 Brown, Francis HaroldMagnetostratigraphy of the shungura and usno formations, lower Omo Valley, Ethiopia1976
23 Miller, Jan D.Reaction kinetics of bismuth dissolution from lead cake by sulfuric acid leachingLead cake, a zinc smelter flue dust residue, consists primarily of lead sulfate. Characteristic properties of lead cake were determined in order to aid the understanding of reaction mechanisms involved in bismuth removal from lead cake by sulfuric acid digestion. Sp gr (specific gravity) measuremen...Lead cake; Smelter flue; Lead sulphate; Bismuth; Sulfuric acid1978
24 Miller, Jan D.Separation of bitumen from Utah tar sands by a hot water digestion-flotation techniqueTar sand deposits in the state of Utah contain more than 25 billion bbl of in-place bitumen. Although 30 times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion bbl). Based ...Tar sand; Utah; Bitumen; Hot water separation; Froth flotation1978
25 Brown, Francis HaroldPleistocene rhyolite of the mineral mountains, Utah geothermal and archeological significance1978
1 - 25 of 279