Study of Some Factors Which Influence Froth Flotation of Deinked Stock

Mineral and fiber were concurrently reclaimed from coated waste stock with the froth flotation process. Percentages of ash and fiber reclaimed are included along with the brightness of the deinked stock. A suitable cooking formula and two flotation systems were discovered which respond favorably to froth flotation and yield a relatively high brightness before bleaching

Ferric chloride leaching of the Delta sulfide ores and gold extraction from the leaching residue

Conventional differential and bulk flotation processes have difficulties in achieving high recoveries with acceptable grades far zinc, lead and copper from the complex sulfide ores found at Tok, Alaska. Furthermore, gold and silver, which account for a significant fraction of total value of the ores, are distributed evenly in the flotation tailings and concentrate. Therefore, processing both flotation tailings and concentrate would be necessary to obtain high recoveries of gold and silver. A mineralogical study revealed that the economic sulfide minerals are interstitially associated with a large preponderance of pyrite. The economic sulfide minerals are 10 to 40 microns in size. These mineralogical facts explain the difficulties encountered in the flotation process. A hydrometallurgical method involving ferric chloride leaching and subsequent steps to recover lead, zinc, silver and copper from the leach liquor has been studied at the Mineral Industry Research Laboratory, University of Alaska Fairbanks for the treatment of Delta ores. This alternative is attractive for processing complex sulfide ores which conventional flotation and smelting cannot handle. In addition, the liberation of sulfur in the environmentally acceptable elemental form, rather than as sulfur dioxide, may prove a major advantage of this hydrometallurgical method because of stringent environmental regulations

Stock market liquidity and the rights offer paradox.

This paper contributes to the resolution of the rights offer paradox, using a database of French SEOs. We first document higher direct flotation costs, but also improved stock market liquidity after public offerings and standby rights relative to uninsured rights. We find that blockholder renouncements to subscribe to new shares and stock market liquidity are important determinants of flotation method choice. After controlling for endogeneity in the choice of flotation method, we find that public offerings are cost effective and more liquidity improving than standby rights whereas an uninsured rights offering is the best choice for low liquidity, closely held firms. Our results provide new insights as to why firms choose public offerings despite apparently higher costs.bid-ask spread; Security offering; SEO; flotation method; flotation costs; rights issues; public offerings; liquidity;

Stock market liquidity and the rights offer paradox.

This paper contributes to the resolution of the rights offer paradox, using a database of French SEOs. We first document higher direct flotation costs, but also improved stock market liquidity after public offerings and standby rights relative to uninsured rights. We find that blockholder renouncements to subscribe to new shares and stock market liquidity are important determinants of flotation method choice. After controlling for endogeneity in the choice of flotation method, we find that public offerings are cost effective and more liquidity improving than standby rights whereas an uninsured rights offering is the best choice for low liquidity, closely held firms. Our results provide new insights as to why firms choose public offerings despite apparently higher costs.Bid-ask Spread; Public Offerings; Rights Issues; Flotation Costs; Flotation Method; SEO; Security Offering; Liquidity;

Beneficiation of rare earth minerals from Bokan Mountain: Dotson Ridge ore

Thesis (M.S.) University of Alaska Fairbanks, 2014The purpose of this research work was to study the beneficiation of rare earth ore of the Bokan Mountain -- Dotson Ridge deposit, located near Ketchikan, Alaska. Rare earth element (REE) composite ore samples from the Bokan Mountain -- Dotson Ridge deposit were tested using gravity concentration, magnetic separation, flotation, and leaching techniques to separate the REE. The composite ore sample was a product of a preliminary x-ray sorting process. Qualitative electron microprobe analysis of the ore showed that most of the REE minerals in the ore were silicate minerals. Since the electron microprobe analysis samples were coated with carbon during sample preparation, the carbon element was inactivated for analysis. Because of this, carbonate compounds of minerals' particles could not be detected. 95% of the REE mineral particles appear to be smaller than about 10 μm in size (about 100 μm² in area). For the gravity concentration, light rare earth elements (LREE) and heavy rare earth elements' (HREE) individual elemental recovery values were in the ranges of 49.6-52.8% and 46.3-48.8%, respectively, at 25% of mass yield. In order to separate a larger amount of the REE, a wet high intensity magnetic separation (WHIMS) test was carried out on tailings of the gravity concentration tests. The HREE individual elemental recovery values ranged from 56.3-63.1% at 37% mass yield, while LREE individual elemental recovery values were in the 57.9% - 59.1% range. For the combined gravity and magnetic separation processes, the net individual elemental recovery values of the LREE and the HREE were in the range of 79.6-80.5% and 76.5-80.9%, respectively. The combined mass yield of the gravity and magnetic separation processes was 3%. Direct leaching tests conducted on the composite ground ore feed yielded high individual elemental recovery values of 90-92% of the LREE. The HREE individual elemental recovery values ranged from 56.5-87.3%. In the leaching, 20% HCl was used in the 1st and 2nd stages with a duration of 2 hrs in each stage at 90°C. The solid percentage of the leach slurry was 20% w/w. The composite ground ore sample was tested in conventional flotation using a 2.0 L capacity Denver cell. In the flotation, 0.05 kg/tonne of Cytec Aero 6493 collector, 0.05 kg/tonne of Cytec Aero Froth 88, and 0.1 kg/tonne of sodium metasilicate as a depressant were used. Pulp pH was set around 9. Results showed individual elemental recovery values in the range of 44.6-50.4% or the LREE. The HREE individual elemental recovery values ranged from 27.9-44.5%. The mass yield of the flotation was 23%. The flotation recoveries reported here are significantly lower than what was achieved previously. For the Leach after flotation process, leaching was conducted on the first concentrate of flotation. Individual elemental recovery values of the LREE and HREE were 94.7-96.5% and 61.1-90.5%, respectively. The concentrate was leached using 20% HCl in both the 1st and 2nd stages, with a duration of 2 hrs in each stage at 90°C. Flotation/Leach process net recoveries of LREE by individual elemental values ranged from 42.2-48.5%. HREE net recoveries by individual elemental values ranged from 17.1-41.4%.Chapter 1 Introduction and Objectives -- Chapter 2 Literature Review -- 2.1 Gravity separation of REE ore -- 2.2 Magnetic separation of REE ore -- 2.3 Froth flotation of REE ore -- 2.4 Leaching of REE -- 2.5 Mineral processing of Bokan Mountain: Dotson Ridge REE ore -- 2.5.1 Mineralogical property -- 2.5.2 Froth flotation -- 2.5.3. Leaching -- 2.5.3.1 Direct leaching -- 2.5.3.2 Leach after flotation -- Chapter 3 Methods and Materials -- 3.1 Materials -- 3.2 Gravity separation tests -- 3.3 Wet high intensity magnetic separation tests -- 3.4 Froth flotation tests -- 3.5 Leaching tests -- 3.5.1 Direct leaching -- 3.5.2 Leach after flotation -- 3.6 Electron microprobe analysis of REE mineralogy -- Chapter 4 Results and Discussion -- 4.1 Gravity separation -- 4.2 Wet high intensity magnetic separation -- 4.3 Froth flotation -- 4.4 Leaching -- 4.4.1 Direct leaching -- 4.4.2 Leach after flotation -- 4.5 Electron microprobe analysis -- 4.5.1 Mineralogy of the ore -- 4.5.2 Mineralogy of flotation concentrate -- Chapter 5 Conclusions and Recommendation -- 5.1 Conclusions -- 5.2 Recommendation for future work -- References -- Appendices

Utilization of flotation in copper extraction from polymetallic ore

The aim of this study was to examineflotation of utility metals from poor polymetallic ores and verify the potential for profitable yields in connection withpotentially economic deposits of non-ferrous metals.The paper describes results in flotation concentrate research to recover copper from polymetallic ore. The polymetallicore from Zlate Hory deposit (Czech Republic) was subjected to crushing, grinding, and screening to prepare feed for separation with mesh size under 200 microns. The heavy medium separation was performed in tetrabromethane with a density of 2.967 g.cm-3. The float and sink products were obtained and tested for chemical composition. Next, the treated polymetallic ore sample was subjected to flotation. In flotation,various dosages of collector (PAX) and various pH were tested, at which pyrite was depressed. The recovery of metallic copper in the concentrate increased with the collector dose. As the pH of the medium increased, the pyrite content in the concentrate dropped. The lowest contentof pyrite, i.e. 4.01%,was obtained at pH 10. In the original polymetallic ore, the Cu content was 0.41% after subsequent treatment and flotation tests, the Cu content increased to 1.38 % with Cu recovery 86.18%

Foam generator Patent

Plastic foam generator for space vehicle instrument payload package flotation in water landin

Recycling Of Auriferous Ore Flotation Tailings In Slag-alkaline Cement

Research analysis aimed at stabilizing processes in industrial waste and other, similar hazardous ion containing materials, shows that these materials can be successfully stabilized, if they are bound as a mineral component in cement. Considering that auriferous ore flotation waste contains heavy metals that are useless for any production and accumulated in dumps, storages and sumps, this impairs the ecology of the country. This is why current study is conducted on recycling of auriferous ore flotation tailings by binding it as a cement component, which is also can be one of its effective applications. For heavy metal bonds stability evaluation in the composition of the cement matrix, the method of leaching elements by atomic spectroscopy was applied.According to the research it was found that application of slag-alkaline viscid systems for recycling of auriferous ore dump flotation tailings provides considerable advantages over traditional Portland cement systems based on PC I-500. It was shown that along with the physical blocking in the artificial stone matrix, based on slag-alkaline viscid systems, elements of heavy metals were also bound chemically as a part of structure-forming compounds. In this regard use of auriferous ore dump flotation tailings (10…30 %) in the compound of slag-alkaline cement results in the prolonged solidification and provides the same level of cement stone durability as the check sample compound

Prevalence of Enteropathogens in Dogs Attending 3 Regional Dog Parks in Northern California.

BackgroundThe prevalence and risk factors for infection with enteropathogens in dogs frequenting dog parks have been poorly documented, and infected dogs can pose a potential zoonotic risk for owners.Hypothesis/objectivesTo determine the prevalence and risk factors of infection with enteropathogens and zoonotic Giardia strains in dogs attending dog parks in Northern California and to compare results of fecal flotation procedures performed at a commercial and university parasitology laboratory.AnimalsThree-hundred dogs attending 3 regional dog parks in Northern California.MethodsProspective study. Fresh fecal specimens were collected from all dogs, scored for consistency, and owners completed a questionnaire. Specimens were analyzed by fecal centrifugation flotation, DFA, and PCR for detection of 11 enteropathogens. Giardia genotyping was performed for assemblage determination.ResultsEnteropathogens were detected in 114/300 dogs (38%), of which 62 (54%) did not have diarrhea. Frequency of dog park attendance correlated significantly with fecal consistency (P = .0039), but did not correlate with enteropathogen detection. Twenty-seven dogs (9%) were infected with Giardia, and genotyping revealed nonzoonotic assemblages C and D. The frequency of Giardia detection on fecal flotation was significantly lower at the commercial laboratory versus the university laboratory (P = .013), and PCR for Giardia was negative in 11/27 dogs (41%) that were positive on fecal flotation or DFA.Conclusions and clinical importanceEnteropathogens were commonly detected in dogs frequenting dog parks, and infection with Giardia correlated with fecal consistency. PCR detection of Giardia had limited diagnostic utility, and detection of Giardia cysts by microscopic technique can vary among laboratories

The effect of flotation cell shape on deinking behaviour

Studies were undertaken to investigate the deinking behaviour of different shaped deinking cells of the same volume. For comparative purposes, most oprational variables were kept constant, and the same injector was used throughout the study. The position of the injector, however, was varied in some cases to go along with the particular cell shape being studied. Three types of cell shapes were studied, (1) cylindrical with tangential air injection, (2) rectanular with vertical injection, and (3) rectangular with horizontal injection. Eucalyptus/toner slurries and news/mag wastepaper slurries were deinked. Flow patterns in the cells and the corresponding deinking efficiencies were measured. It was found that strong and excessive re-circulatory flows within the cells could under certain conditions be a major factor in reducing brightness lift. Vertical injection into a rectangular cell gave stable flow patterns, non-wavy froth removal and sustained brightness lift for a wide range of feed and airflow rates. Horizontal injection into a similar rectangular shaped cell exhibited quite different characteristics. High brightness lift was possible for certain conditions and not for others. Wavy froth and excessive recirculation flow patterns varied with feed and airflow. The cylindrical cell with tangential injection gave stable circulatory flow and stable froth removal at low flow rates but was unable to deink at high flows