Microbial generation of sulfuric acid from granular elemental sulfur in laboratory-scale bioreactors

2019 ◽  
Vol 190 ◽  
pp. 105152 ◽  
Author(s):  
Eva Pakostova ◽  
D. Barrie Johnson
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Laboratory Scale

scholarly journals Nitrogen mineralization and microbial activity as influenced by sulfur sources in an alkaline calcareous soil

1970 ◽  
pp. 14-18
Author(s):  
Tufail Shah ◽  
Zahir Shah ◽  
Syed Atizaz Ali Shah ◽  
Nazir Ahmad
Keyword(s):  
Organic Matter ◽  
Sulfuric Acid ◽  
Microbial Activity ◽  
Calcareous Soil ◽  
Bacterial Population ◽  
Elemental Sulfur ◽  
Microbial Population ◽  
Organic Matter Content ◽  
Matter Content ◽  
Fungal Population

A study was performed to check the effects of various sources of sulfur on microbial activity, microbial population, N mineralization and organic matter content in an alkaline calcareous soil by using soil samples collected from Malakandher Farm at 0-20 cm depth, and analyzed for microbial activity, total mineral nitrogen, bacterial and fungal population and organic matter content. The results showed that the rate of CO2 evolution and cumulative CO2 production were higher in soils amended with elemental sulfur followed by sulfuric acid and gypsum treated soils. The microbial activity decreased with incubation period in all treatments, and the microbial population was greatly affected by sulfur sources. Generally, the bacterial population decreased in soils amended with elemental sulfur, but the population was higher in soils amended with gypsum. Bacterial population was suppressed in soils treated with sulfuric acid. However, the fungal population was higher in soils amended with sulfuric acids was less in soil amended with elemental sulfur. The sulfur amendments promoted immobilization of N. The net N immobilized was higher in soil amended with gypsum followed by soils amended with sulfuric acid and elemental sulfur. The percent organic matter was higher in soils amended with gypsum and was decreased compared with that amended with elemental sulfur or sulfuric acid. These results suggested that soil microbiological properties changed with sulfur amendments during laboratory incubation.

scholarly journals Corrosion in CO2 Systems with Impurities Creating Strong Acids

CORROSION ◽  
10.5006/3110 ◽  
2019 ◽  
Vol 75 (11) ◽  
pp. 1307-1314
Author(s):  
Bjørn H. Morland ◽  
Morten Tjelta ◽  
Arne Dugstad ◽  
Gaute Svenningsen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Steel ◽  
Stainless Steels ◽  
Elemental Sulfur ◽  
Experimental Studies ◽  
Visual Observation ◽  
Low Concentrations ◽  
Strong Acids ◽  
Safety And Environment

There are several proposed specifications for CO2 transport regarding how much impurities that can be allowed in the CO2 stream. Many of these specifications are based on health, safety, and environment (HSE) considerations in case of accidental spill, and only limited focus has been on the pipeline integrity. Previous work has demonstrated that many of the impurities that are expected to be present in CO2 captured from flue gasses may react and form corrosive species. The present paper studied impurity reactions and corrosion under simulated transport conditions (25°C and 10 MPa of CO2). An experiment was performed in a transparent autoclave which allowed for in situ visual observation. Chemical reactions between the impurities were observed even at very low concentrations (<100 ppmv). These reactions contributed to the production of nitric and sulfuric acid together with formation of elemental sulfur. Corrosion was observed on coupons of carbon steel, but not on stainless steels. The corrosion rate of carbon steel was low, but the amount of acids and solids (corrosion products) produced cannot be accepted from a pipeline integrity perspective. Further experimental studies are needed to determine specific limits for impurity concentrations in captured CO2 for transport.

scholarly journals Effect of Surface Modification with Different Acids on the Functional Groups of AF 5 Catalyst and Its Catalytic Effect on the Atmospheric Leaching of Enargite

2019 ◽  
Vol 3 (2) ◽  
pp. 45 ◽  
Author(s):  
Jahromi ◽  
Ghahreman
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Elemental Sulfur ◽  
Catalytic Properties ◽  
Copper Recovery ◽  
Pre Treatment ◽  
Sulfur Adsorption

Carbon-based catalysts can assist the oxidative leaching of sulfide minerals. Recently, we presented that AF 5 Lewatit® is among the catalysts with superior enargite oxidation capacity and capability to collect elemental sulfur on its surface. Herein, the effect of acid pre-treatment of the AF 5 catalyst was studied on the AF 5 surface, to further enhance the catalytic properties of AF 5. The AF 5 catalyst was pretreated by hydrochloric acid, nitric acid and sulfuric acid. The results showed that the acid treatment drastically changes the surface properties of AF 5. For instance, the concentration of quinone-like functional groups, which are ascribed to the catalytic properties of AF 5, is 45.4% in the sulfuric acid pre-treatment AF 5 and only 29.8% in the hydrochloric acid-treated AF 5. Based on the C 1s X-ray photoelectron spectroscopy (XPS) results the oxygenated carbon is 30.6% in the sulfuric acid-treated AF 5, 29.2% in the nitric acid-treated AF 5 and 28.3% in the hydrochloric acid-treated AF 5. The nitric acid pre-treated AF 5 resulted in the highest copper recovery during the oxidative enargite leaching process, recovering 98.8% of the copper. The sulfuric acid-treated AF 5 recovered 97.1% of the enargite copper into the leach solution. Among different leaching media and pre-treatment the lowest copper recovery was achieved with the HCl pre-treated AF 5 which was 88.6%. The pre-treatment of AF 5 with acids also had modified its elemental sulfur adsorption capacity, where the sulfur adsorption on AF 5 was increased from 30.9% for the HCl treated AF 5 to 51.1% for the sulfuric acid-treated AF 5.

scholarly journals Copper metallurgy at the crossroads

2007 ◽  
Vol 43 (1) ◽  
pp. 1-19 ◽  
Author(s):  
F. Habashi
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Copper Production ◽  
Pressure Leaching ◽  
Copper Industry ◽  
Hydrothermal Conditions ◽  
The Past ◽  
Copper Metallurgy ◽  
Horizontal Furnace ◽  
Sulfide Concentrates

Copper technology changed from the vertical to the horizontal furnace and from the roast reaction to converting towards the end of the last century. However, the horizontal furnace proved to be an inefficient and polluting reactor. As a result many attempts were made to replace it. In the past 50 years new successful melting processes were introduced on an industrial scale that were more energy efficient and less polluting. In addition, smelting and converting were conducted in a single reactor in which the concentrate was fed and the raw copper was produced. The standing problem in many countries, however, is marketing 3 tonnes of sulfuric acid per tonne of copper produced as well as emitting large amounts of excess SO2 in the atmosphere. Pressure hydrometallurgy offers the possibility of liberating the copper industry from SO2 problem. Heap leaching technology has become a gigantic operation. Combined with solvent extraction and electrowinning it contributes today to about 20% of copper production and is expected to grow. Pressure leaching offers the possibility of liberating the copper industry from SO2 problem. The technology is over hundred years old. It is applied for leaching a variety of ores and concentrates. Hydrothermal oxidation of sulfide concentrates has the enormous advantage of producing elemental sulfur, hence solving the SO2 and sulfuric acid problems found in smelters. Precipitation of metals such as nickel and cobalt under hydrothermal conditions has been used for over 50 years. It has the advantage of a compact plant but the disadvantage of producing ammonium sulfate as a co-product. In case of copper, however, precipitation takes place without the need of neutralizing the acid, which is a great advantage and could be an excellent substitute for electrowinning which is energy intensive and occupies extensive space. Recent advances in the engineering aspects of pressure equipment design open the door widely for increased application. .

scholarly journals The influence of sulfur addition on the hazard-type reaction of ilmenite ores with sulfuric acid

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maciej Jabłoński ◽  
Krzysztof Lubkowski ◽  
Sandra Tylutka ◽  
Andrzej Ściążko
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Raw Materials ◽  
Thermal Power ◽  
Process Conditions ◽  
Process Safety ◽  
Type Reaction ◽  
Thermokinetic Parameter ◽  
Sulfur Addition ◽  
Titanium Raw Materials

Abstract The paper presents results of thermokinetic investigation of the hazard-type reaction of Norwegian and Australian ilmenite ores with sulfuric acid, modified by the addition of elemental sulfur, to increase the process safety in industrial conditions. In the reactions of both ilmenite ores the addition of sulfur caused a reduction of the thermal power generated in the reaction and a decrease in the value of the thermokinetic parameter ΔTmax/Δτ for almost the whole range of initial concentrations of sulfuric acid. It was also found that the addition of sulfur to the reaction did not negatively affect the degree of ilmenite leaching. The interpretation of the obtained thermokinetic curves allowed to determine safe process conditions for both types of titanium raw materials.

scholarly journals PRODUCTS OF THE OXIDATION OF THIOSULFATE BY BACTERIA IN MINERAL MEDIA

1935 ◽  
Vol 18 (3) ◽  
pp. 325-349 ◽  
Author(s):  
Robert L. Starkey
Keyword(s):  
Sulfuric Acid ◽  
Sodium Sulfate ◽  
Elemental Sulfur ◽  
Heterotrophic Bacteria ◽  
Sodium Thiosulfate ◽  
Initial Reaction ◽  
Primary Reaction ◽  
Sulfate Sulfur ◽  
Autotrophic Bacteria ◽  
Secondary Chemical

Various cultures (previously described), which oxidize thiosulfate in mineral media have been studied in an attempt to determine the products of oxidation. The transformation of sodium thiosulfate by Cultures B, T, and K yields sodium tetrathionate and sodium hydroxide; secondary chemical reactions result in the accumulation of some tri- and pentathionates, sulfate, and elemental sulfur. As a result of the initial reaction, the pH increases; the secondary reactions cause a drop in pH after this initial rise. The primary reaction yields much less energy than the reactions effected by autotrophic bacteria. No significant amounts of assimilated organic carbon were detected in media supporting representatives of these cultures. It is concluded that they are heterotrophic bacteria. Th. novellus oxidizes sodium thiosulfate to sodium sulfate and sulfuric acid; the pH drops progressively with growth and oxidation. Carbon assimilation typical of autotrophic bacteria was detected; the ratio of sulfate-sulfur formed to carbon assimilated was 56:1. It is calculated that 5.1 per cent of the energy yielded by the oxidation of thiosulfate is accounted for in the organic cell substance synthesized from inorganic materials. This organism is a facultative autotroph. The products of oxidation of sodium thiosulfate by Th. thioparus are sodium sulfate, sulfuric acid, and elemental sulfur; the ratio of sulfate sulfur to elemental sulfur is 3 to 2. The pH decreases during growth and oxidation. The elemental sulfur is produced by the primary reaction and is not a product of secondary chemical changes. The bacterium synthesizes organic compounds from mineral substances during growth. The ratio of thiosulfate-sulfur oxidized to carbon assimilated was 125:1, with 4.7 per cent of the energy of oxidation recovered as organic cell substance. This bacterium is a strict autotroph.

Leaching of Indium from Indium-and Iron-Bearing Sphalerite Concentrate in Sulfuric Acid–Ferric Sulfate Solution

2019 ◽  
Vol 17 (10) ◽  
Author(s):  
Huang Hui ◽  
Zhang Fan ◽  
Deng Zhigan ◽  
Wei Chang ◽  
Li Xingbin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Control Process ◽  
Dissolution Kinetics ◽  
Sulfate Solution ◽  
Ferric Sulfate ◽  
Ferric Ion ◽  
X Ray ◽  
Mixed Control ◽  
Iron Bearing

Abstract Leaching of indium from an indium-and iron-bearing sphalerite concentrate in sulfuric acid– ferric sulfate solution was examined. The effects of various parameters were studied. Increases in the stirring speed, temperature, ferric ion and sulfuric acid concentrations, and decreases in the particle size, enhanced the indium leaching rate. Scanning electron microscopy/energy-dispersive X-ray spectroscopy and X-ray diffraction analyses of the unreacted and reacted sphalerite concentrate particles showed that elemental sulfur was formed and precipitated at the particle surfaces. The results show that dissolution was controlled by a mixed-control process. In the initial stage, the dissolution kinetics was chemically controlled. When more elemental sulfur was present on the particle surfaces, the dissolution kinetics was controlled by mass transfer though the sulfur layer. The activation energy of the chemically controlled step was 33.9 kJ/mol. The reaction orders with respect to the initial sulfuric acid and ferric ion concentrations were approximately 0.74 and 0.60, respectively.

scholarly journals Mesoporous Knitted Inverse Vulcanised Polymers

2021 ◽  
Author(s):  
Samuel Petcher ◽  
Bowen Zhang ◽  
Tom Hasell
Keyword(s):  
Sulfuric Acid ◽  
Crude Oil ◽  
Elemental Sulfur

Elemental sulfur is generated in large quantities when crude oil is refined. This elemental sulfur has limited use other than the production of sulfuric acid. Recently, attention in research has...

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