A.E. Torma's research while affiliated with New Mexico Institute of Mining and Technology and other places
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Publications (64)
The present article illustrates the increased interest which is manifested in the microorganisms, Thiobacillus ferrooxidans, involved in the biohydrometallurgical extraction processes. The wide varieties of problems currently studied are very important in order to gain a better understanding about the factors which are governing the growth of micro...
The kinetics of aluminium extraction were investigated, using as-received and calcined fly ash samples and a pure culture of Aspergillus niger. This fungus metabolized sucrose to citric and oxalic acids, which were involved in the acidolysis of fly ash. Aluminium extraction from as-received fly ash was only 5–8%, whereas from calcined fly ash it wa...
The efficiency of Ca-alginate beads in the removal of barium, cadmium, uranyl and zinc contaminants from aqueous solutions was evaluated. Effects of process variables (initial metal ion and calcium alginate concentrations, pH and temperature) on the kinetics of the biosorption process were assessed. The maximum rate of metal sorption and the corres...
The theme of the International Biohydrometallurgy Symposium (IBS) held in Jackson Hole, Wyoming, August 22--25, 1993, is Biohydrometallurgy: An Industry Matures''. This is a developing technology which made important contributions to the minerals industry. The IBS-93 is focused on recent advances achieved in fundamental and applied aspects of resea...
The continuing depletion of high grade oxide gold deposits has created a need for new, economically viable and environmentally safe methods to treat refractory sulphidic ores. One of the alternative leaching processes uses micro-organisms, Thiobacillus ferro-oxidans, partially to oxidise pyrite and/or arsenopyrite containing finely disseminated, su...
The continuing depletion of high grade oxide gold deposits has created a need for new, economically viable and environmentally safe methods to treat refractory sulphidic ores. One of the alternative leaching processes uses micro-organisms, Thiobacillus ferro-oxidans, partially to oxidise pyrite and/or arsenopyrite containing finely disseminated, su...
In order to satisfy the high demand for gold, lower and complex grade resources must be treated in ever increasing amounts. This requires the development of new processing technologies, which are capable of recovering gold economically from these offgrade, difficult to process (refractory) ores, while safeguarding the environment. Within the novel...
The present article provides information on uses, mineral resources and production methods of gallium and germanium. Both of these metals are used in advanced technology. Gallium is mainly used in the production of high-speed computer chips (integrated circuits) and optoelectronic devices. Germanium is employed as semiconductor in electronics and i...
This article presents a brief overview of selected papers from a symposium on Precious and Rare Metals, which deal with automobile emission control catalysts and the recovery of platinum and other metals from spent catalysts.
A developing technology, the microbiological leaching of the less-common and rare metals has yet to reach commercial maturity. Still, although the data are preliminary in nature, the ultimate application of biotechnological principles may provide a potential solution for the valorization of many low-grade mineral resources. The development of these...
The apparent activation and deactivation energies and the corresponding frequency factors of coal desulfurization byThiobacillus ferrooxidans have been determined to be ΔE
a = 60.9 kJ,A
a = 1.45 s-1 and ΔEd = 178.3 kJ,A
d
= 5.65×1027 s-1, respectively. The thermo-dynamic values (AG‡, ΔH
‡, and ΔS‡) of the activated complex were calculated. Kinetic...
Currently the demand for gallium and germanium is continuously increasing from high tech industries. These metals are traditionally obtained as byproducts of aluminum and zinc processings. The article provides some information on the extraction of gallium and germanium from a complex ore using sulfuric acid and the reducing agents sulfur dioxide an...
The effect of sulfuric acid concentration, pulp density and particle size on the rate and extent of beryllium extraction was established. The order of reaction with respect to H//2SO//4 concentration is 0. 5 and the overall reaction rate constant is k equals 5. 1 multiplied by 10** minus **6 mol** one-half dm** minus **3**/**2 min** minus **1. A ps...
Biotechnology continued to gain importance in the mineral industry during the past four years. This upsurge of interest is especially expressed in the areas of biodesulfurization of coal, recovery of precious metals from pyrite- and arsenopyrite- containing minerals, biosorption processes and biogenetic engineering.
The present article provides information on the application of biotechnology in the valorization of mineral resources. Biohydrometallurgy is relatively a recent development but already employed in the copper, uranium and in a limited extent in precious metal processing industries. The basic principles of bioleaching and the mechanisms of bacterial...
Uranium is extracted from its ores either by acidic or alkaline leachants. In order to achieve an almost complete extraction, uranium has to be oxidized to its hexavalent form which is soluble. This is accomplished by the industry, for example, by adding sodium chlorate or manganese dioxide to the leach suspensions. However, these oxidants are cons...
The present work reports on kinetic data of hydrochloric acid leaching of a low-grade uranium ore and on the preliminary information regarding the removal of radium-226 and thorium-230 from the leach residues. The importance of enviromentally and radiochemically safe tailing is discussed.
The kinetics and practical aspects of the applicability of a new uranium leaching method — the HSS (H2O2Na2SO4H2SO4) system — in the extraction of uranium from a typical New Mexico ore was investigated in the temperature range 30–80°C and at constant pH of 4.0–6.0 ± 0.1. The effect of Na2SO4 and H2O2 concentrations, pH, temperature and Fe2+ addit...
Black zinc oxide surfaces produced in an alkaline bath on leaf zinc, electroplated zinc on mild steel and hot-dip zinc coated mild steel substrates show high (6–9) selectivity () values for solar collection applications. These overgrowths are seen to maintain their physical integrity as well as optical properties following exposure to 250°C (2 h) i...
Plating parameters for black-chrome overgrowth deposition were optimized with respect to selectivity (αs/ε100°C) utilizing simplex evolutionary operation procedures (EVOP) in sixteen sets of experiments. Overgrowths produced with optimized parameters were then evaluated for optical, structural, thermal stability and mechanical properties. It is obs...
The microbiological desulfurization of a high sulfur New Mexico (Carthage) coal has been investigated using an adapted strain of Thiobacillus ferrooxidans. Optimum conditions for this leaching were determined as: pH, 2.0; particle-size, -400 mesh (-37 ..mu..m); pulp density, 25%; and temperature, 35/sup 0/C. Under these conditions approximately 90%...
The physiological responses of Thiobacillus ferrooxidans, Thiobacillus thiooxidans, and the facultatively thermophilic microbe TH3 to simulated deep solution mining conditions (elevated hydrostatic pressures and oxygen tensions) have been studied. Maximum hydrostatic pressures permitting growth of T. ferrooxidans and TH3 on ferrous sulfate were 30....
Nucleation and growth characteristics of electrodeposited zinc and anodically produced zinc oxide overgrowths on atomically smooth steel field emission end forms were investigated through field ion microscopy (FIM) and scanning electron microscopy. The zinc oxide overlayers attained in an alkaline bath through the application of an a.c. were seen t...
The present study is the investigation of the kinetics of uranium extraction from a low-grade ore using a mixed Na2CO3-NaHCO3 leachant at various air pressures from one to 68 atmospheres and temperatures ranging from 29 to 70°C. The yield and rate of uranium extraction were found to increase as a function of temperature and pressure. The highest ur...
Plating parameters for black chrome system were optimized with respect to selectivity utilizing simplex evolutionary operation procedures in sixteen sets of experiments. Overgrowths produced with the optimized parameters were evaluated for optical, structural, thermal stability and mechanical properties. It is observed that the coatings produced po...
Literature on the possibility of desulfurizing coal by microbiological leaching is limited. The earliest report was that of Zarubina et al. (1959) who indicated that 23 to 27% of sulfur was removed from their coal samples in 30 days. Other investigators (Silverman et al. 1961, 1963; Lorenz and Tarpley 1963; Clark 1966) commented on the beneficial e...
In previous studies (Torma and Subramanian, 1974; Torma and Guay, 1976) we have demonstrated that a decrease in the particle size of the solid metal sulfide results in an increase in the rate/or extent of the metal extraction by the chemolithotrophic Thiobacillus ferrooxidans. The use of fractions of a lead-zinc sulfide concentrate (Torma and Subra...
The present preliminary study has demonstrated that the kinetics of uranium extraction from a low-grade ore will be improved in the presence of hydrogen peroxide at moderate temperature using conventional tank leaching technique. Yield improvements of 6% and higher reaction rates were observed in the presence of H//2O//2.
The growth characteristics of thin copper deposits grown through cementation, electrodeposition and vapor deposition were evaluated through imaging the coated samples in the field ion microscope at 78 K utilizing a 90% He-10% Ne gas mixture. Although the thicknesses of overgrowths were found to be varied with the method and time of deposition, copp...
The biodegradation of an aluminum-bearing (basalt) rock by Penicillium simplicissimum has been investigated. This organism grows on a sugar substrate and releases organic acid compounds. These acids interact with the mineral matter and cause their partial decomposition. The dissolved metals are then complexed by the excess organic acids. The activi...
The reduction of stibnite by hydrogen in the absence and in the presence of sulfur acceptors has been investigated at atmospheric pressure and at temperatures of 200 – 600 °C. The activation energy of these processes has been found to be 17.4 kcal mol−1 (−7.2 × 104 J), 20.4 kcal mol−1 (−8.5 × 104 J), and 27.7 kcal mol−1 (−11.6 × 104 J), in the abse...
The effect of hydrostatic pressure on the activity of Thiobacillus ferrooxidans grown on chalcopyrite concentrate has been investigated. It was found that bacterial activity, measured by conventional respirometry, was little affected by subjecting these microorganisms to a pressure of 100 lbs/in2 (690 kPa). The total cooper concentration was as hig...
Recent bacterial leaching studies indicate that zinc, copper, and cadmium values can selectively be removed from off-grade lead sulfide concentrates without producing any air pollution. The bacterial leaching technique is based on the difference in the solubility of the metal sulfates which are resulted in this process. The leach residue is an up-g...
The nucleation and growth characteristics of electroplated layers of nickel on 303 stainless steel and of black chrome on nickel emission tips have been investigated at liquid nitrogen imaging temperatures. The overgrowths were observed to possess the strength of bonding to the substrate necessary for such a study under field-induced stresses. The...
The bacterial oxidation of naturally occurring gallium-bearing chalcopyrite concentrate and a pure synthetic gallium (III) sulfide has been investigated at pH 1.8 and 35 degree C, using an active culture of Thiobacillus ferrooxidans. This oxidation process may proceed by direct or by indirect bacterial action. The highest dissolved gallium and copp...
Lithium chloride extraction with n-butanol has been studied using synthetic solutions containing different quantities of lithium chloride, sodium chloride, potassium chloride and calcium chloride. Based on distribution coefficients, separation factors and McCabe-Thiele representation of the results, a process has been proposed for separation and re...
The variety of support media for securing geological specimens to SEM stubs available depending on the size, texture and fragility of the specimen and the purpose for its examination is discussed together with the methods and materials available to render specimens electrically conductive if so required.
The microbiological oxidation of ferrous iron in batch and continuous systems has been investigated in relation to uranium extraction from a low-grade ore by Thiobacillus ferrooxidans. The influence of the parameters, agitation, and aeration on oxygen saturation concentration, rate of oxygen mass transfer, and rate of ferrous iron oxidation was dem...
Optimum pH, temperature and pulp density for microbiological leaching of museum-grade stibnite mineral has been investigated using a stibnite-adapted strain of Thiobacillus ferrooxidans. Optimum conditions were found to be pH 1.75, 35 C and 12g solid substrate per 100 ml of basal salts medium as the initial dose. The energy of activation was determ...
It has been shown that organic solvents used primarily for the extraction of metals from aqueous leach liquors decrease both the surface tension of the aqueous phase and the chalcopyrite oxidation ability of Thiobacillus ferrooxidans. For the reagents and modifiers investigated, the order of inhibition was found to be LIX 70 < LIX 73 < LIX 71 < LIX...
The present study indicates some anomalies with respect to the DNA base composition of Thiobacillus ferrooxidans when it is cultured on different substrates. The % GC of the DNA of this bacterium has been calculated by three different methods (melting temperature, CsCl density gradient centrifugation and ultra-violet absorbancy ratios) using Escher...
The microbiological leaching of low-grade uranium ore has been investigated using a pure strain ofThiobacillus ferrooxidans. It has been shown that only minute quantities of iron are required to achieve a maximum effect on uranium release. The ore sample contained enough iron (3.23%) to produce this effect, consequently, very little influence has b...
This investigation has demonstrated that the chalcopyrite oxidation ability of Thiobacillus ferrooxidans is considerably reduced in presence of the surface active agents, such as Tween 20, 40, 60 and 80. The bacterial activity, the surface tension of the medium and the oxygen concentration at saturation were inversely proportional to the concentrat...
The microbiological oxidation of synthetic chalcocite and covellite has been investigated using an adapted strain of Thiobacillus ferrooxidans. Biodegradation of chalcocite was found to be 90 to 100% and that of covellite 45 to 60%. Optimum conditions for the oxidation of chalcocite were: pH, 1.7 to 2.3; temperature, 35 C; and ferric iron concentra...
The microbiological oxidation of ferrous ion and the extraction of uranium from a low-grade ore has been studied using an adapted strain of Thiobacillus ferrooxidans. The effect of temperature, pH, volumetric oxygen transfer coefficient, K1a, and aeration number, Ia, on the activity of the microorganism has been determined. The activation energy fo...
The sulphuric and nitric acid leaching of natural and synthetic nickel sulphides has been investigated. Optimum leaching conditions of the factors influencing the extraction of metals (Ni, Cu, Co) from a pentlandite bearing-concentrate have been determined. These factors are: temperature, time concentration and sulphuric and nitric acids and pulp d...
The applicability of the pressure leaching technique in the recovery of lithium from a beta-spodumene bearing concentrate has been investigated using sodium chloride as reactant in alkaline medium. Factors such as the concentration of sodium chloride and calcium hydroxide, the temperature, the pulp density, the reaction time and the particle size,...
The applicability of the pressure leaching technique in the recovery of lithium from a beta-spodumene bearing concentrate has been investigated using sodium chloride as reactant in alkaline medium. Factors such as the concentration of sodium chloride and calcium hydroxide, the temperature, the pulp density, the reaction time and the particle size,...
The sulphuric and nitric acid leaching of natural and synthetic nickel sulphides has been investigated. Optimum leaching conditions of the factors influencing the extraction of metals (Ni, Cu, Co) from a pentlandite bearing-concentrate have been determined. These factors are: temperature, time concentration and sulphuric and nitric acids and pulp d...
The microbiological oxidation of cadmium, cobalt, nickel and zinc sulphides has been investigated using a pure strain of Thiobacillus ferrooxidans. Kinetic parameters (Vm and K) have been derived regarding the effect of initial total surface area of these substrates. A relationship is suggested to exist between the rate of sulphide oxidation and th...
Leaching with Thiobacillus ferrooxidans has been used for selectively extracting Cu, Zn and Cd values from a PbS concentrate. The PbS is partly oxidized to the sulphate form. A scheme has been proposed for the recovery of the metal values from the leach liquor.
Thiobacillus ferrooxidans, grown on either ferrous sulfate, lead sulfide concentrate, or chalcopyrite concentrate demonstrated oxygen uptake and CO2 fixation in the presence of ferrous sulfate, chalcopyrite ore, pyrite ore, and red antimony trisulfide. Lead suifide-grown cells could oxidize lead sulfide ore and galena, using the energy obtained for...
Thiobacillus ferrooxidans can derive its energy from the oxidation of copper selenide. In this metabolic oxidation process, copper goes into solution and elemental selenium is deposited.
The effects of carbon dioxide-enriched air on the rate of zinc extraction during the microbiological leaching of a, high-grade zinc sulfide concentrate by Thiobacillns ferrooxidans have been studied. Under normal air-aeration conditions, the leach rate is limited initially by the availability of solid substrate surface area per unit volume of leach...
The microbiological extraction of zinc from a high-grade zinc sulfide concentrate has been investigated, using a pure strain of Thiobacillus ferrooxidans. Conditions such as temperature, pH, pulp density, nutrient, concentration, and specific surface of solids have been studied in terms of their effects on zinc extraction rate and in some instances...
Bibliogr. na konci kapitol
Microorganisms were evaluated for use in recovery of uranium under conditions of in-situ solution mining. The cultures tested were Thiobacillus ferrooxidans, the faculative-thermophilic TH3 strain, and two Sulfolobus species. Growth of the organisms occurred in the presence of 0.34 to 5.0 mM uranyl ion with higher concentrations being inhibitory. U...
Citations
... Acidity of the environment controls the bacterial activity within a system. The H + ion is in fact vital for acidophilic microorganisms since bacteria utilize it as a proton source for the reduction of O 2 [19]. Also optimum activity of each type of bacteria takes place in a relatively well-defined range of temperature at which these microorganisms grow with maximum efficiency. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/430918608396291-1479750410784_Q64/Lawrence-Murr.jpg)
... To maintain the rate of uranium oxidation, the ferrous ions have to be oxidized back to the ferric state. Conventional oxidants used for this purpose include manganese dioxide (Edwards and Oliver, 2000), oxygen (Mamilov et al., 1980), nitric acid (Litvinenko et al., 2013), hydrogen peroxide (Eligwe and Torma, 1986) and sulfur dioxide (Ho and Quan, 2007). Oxidation of uranium can be accelerated by ultrasonic irradiation (Avvaru et al., 2008) and mechanical agitation of the uranium-containing pulp (Kovacheva et al., 2004). ...
... The capacity of T. ferrooxidans to oxidize ZnS has been well demonstrated using naturally occurring sulfide-bearing minerals (5,13,16) or chemically prepared synthetic zinc sulfides (10,14,15). Semi-industrial studies (2,17) resulted in very rapid zinc extraction and high soluble zinc concentration. ...
... The bioleaching experiments demonstrated only 32% Al dissolution by P. simplicissimum. Mehta et al. [52,53] used biogenically produced citric acid by P. simplicissimum for Al recovery from basalt rock. The highest yield was 20% after 30 days. ...
... It is interesting to note that despite the stated benefits of using nitric acid as a lixiviant, there are few published studies into nitric acid leaching of nickel sulfide concentrates which are summarized in this series. Ouellet, Torma, and Bolduc (1975) studied the leaching of a copper-nickel sulfide concentrate and ore (refer to Table 4) containing pentlandite, pyrrhotite, and chalcopyrite, in a mixed sulfuric acid-nitric acid lixiviant. The Ni and Cu grade in the concentrate used by Ouellet, Torma, and Bolduc (1975) was 5.14% Ni and 11.50% Cu. ...
... It was found that with 15-30% HNO 3 , all the nickel and copper went into solution, while elemental sulphur and iron oxide remained in the residue after 8 hours. Similar work was also conducted elsewhere by Ouellet and Shukla (24,25). The reaction of nitric acid with molybdenite concentrates has also been extensively studied under autoclave conditions (26)(27)(28)(29)(30)(31)(32)(33). ...
Reference: Applications of NSC Pressure Leaching
... The analcime process operates at elevated pH, typically > 11, temperatures of around 220 • C, and pressures high enough to contain the water vapour generated at this temperature. It can admit NaCl, Na 2 CO 3 and Na 2 SO 4 as the reactants (Archambault, 1963, Gabra et al., 1975Chen et al., 2011;Kuang et al., 2018;Alhadad et al., 2023), and it proceeds by fast dissolution of β-spodumene and precipitation of analcime, either in situ at the reacting front in particles or as de novo from the leach solution (Alhadad et al., 2023). It requires NaOH for pH controls, with Ca(OH) 2 delivering lesser amounts of extracted lithium (Gabra et al., 1975;Alhadad et al., 2023). ...
... 50 A previous study utilizing NaCl for the extraction of Li from spodumene has been, similarly, performed on β-spodumene, producing LiCl and Na 2 O·Al 2 O 3 ·4SiO 2 after autoclaving with NaCl. 51 Thermodynamic Analysis. To further study the mechanism of the roasting process, the Equilib module in FactSage 8.1 42 was run to calculate equilibrium of the roasting process. ...
... Improved extraction techniques for these refractory gold-bearing concentrates (Figure 7) consist of oxidative pre-treatments including low-alkalinity high-pressure cyanidation (Davis et al., 1986;Haque, 1987;Morizot and Ollivier, 1993), bioleaching with At. Ferrooxidans (de Carvalho et al., 2019;Haque, 1987;Morizot and Ollivier, 1993;Torma, 1989;Ubaldini et al., 2000) and other microorganisms (Haque, 1987;Solozhenkin and Alekseev, 2010a;van Aswegen et al., 2007), nitric acid digestion and roasting, as Hu (1988); Lager and Forssberg (1989b); Morizot and Ollivier (1993); Richards (1977); Schwarz-Schampera (2014); Wu et al. (2019). Solid arrows represent the simplest processing route. ...
Reference: Stibnite froth flotation: A critical review
... When 100 mg/L Tween-20 was added, the cells density in solution was only 4.80 × 10 7 cells/mL at 72 h, which was far lower than that in the solution without Tween-20 (16.07 × 10 7 cells/mL), suggesting that microbial growth was inhibited in the presence of Tween-20 with high concentration. Similar phenomenons were also found in the previous studies (Peng et al., 2012;Liu et al., 2018), which were probably attributed to the poisonousness of surfactant leading to the limitation in the bacterial activity (Torma et al., 1976;Rebello et al., 2014). While when Tween-20 concentration was low (such as 2 mg/L), cell density was 16.93 × 10 7 cells/mL, indicating that low concentration of Tween-20 would not affect the growth of A. manzaensis YN-25. ...
