Influences of pH Buffers on the Growth of Acidithiobacillus thiooxidans and Biodesulfurization Efficiency

2013 ◽  
Vol 825 ◽  
pp. 508-511
Author(s):  
Xiao Rong Liu ◽  
Chang Su ◽  
Sheng Cai Jiang ◽  
Yan Jun Liu ◽  
Hui Li
Keyword(s):  
Magnetic Separation ◽  
Phosphate Buffer ◽  
Metal Sulfides ◽  
Acidithiobacillus Thiooxidans ◽  
Iron Ores ◽  
Hydrogen Phosphate ◽  
Disodium Hydrogen Phosphate ◽  
Promising Alternative ◽  
Processing Technologies ◽  
Effects Of Ph

More than 90% of metal sulfides in vanadium-bearing titanomagnetite concentrates in Panzhihua (China) are pyrrhotite. It is difficult to remove pyrrhotite from iron ores through conventional mineral processing technologies as magnetic separation and flotation. Desulfurization with the help of microorganisms is a promising alternative way relating to the implementation in dissolution. The effects of pH buffers on growth of Acidithiobacillusthiooxidans and biodesulfurization efficiency of vanadium-bearing titanomagnetite concentrates were investigated. 61.86% of sulfur can be removed from the concentrates after bioleaching for 15 days for a 10% pulp density. While 10% of citric-disodium hydrogen phosphate buffer was added into the solution, Acidithiobacillusthiooxidans grew significantly faster and the biodesulfurization rate was increased by 12.34%, accompanying with pH stabilised at ~ 3.0. Boruitan-Luobisen buffer was helpful to keep pH in a good situation, whereas it inhibited the growth of Acidithiobacillusthiooxidans seriously and brought down the biodesulfurization efficiency.

Disodium Hydrogen Phosphate as an Efficient and Cheap Catalyst for the Synthesis of 2-Aminochromenes

2011 ◽  
Vol 41 (23) ◽  
pp. 3477-3484 ◽  
Author(s):  
Xin-Ying Meng ◽  
Hong-Juan Wang ◽  
Chun-Ping Wang ◽  
Zhan-Hui Zhang
Keyword(s):  
Hydrogen Phosphate ◽  
Disodium Hydrogen Phosphate

The Effect of Phosphatic Composite on Magnesium Phosphate Cement Performance

2014 ◽  
Vol 809-810 ◽  
pp. 477-484
Author(s):  
Zhao Qing Qi ◽  
Hong Tao Wang ◽  
Jun Liang Dang ◽  
Shi Hao Zhang ◽  
Jian Hua Ding
Keyword(s):  
Setting Time ◽  
Potassium Dihydrogen Phosphate ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Hydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Disodium Hydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Sodium Dihydrogen

The capacity of 10%, 30%, and 50% ammonium dihydrogen phosphate were replaced with an equal amount of three phosphate (potassium dihydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate) respectively. Magnesium phosphate cement was made by phosphate of replaced, which strength, setting time, fluidity, hydration temperature, and the hydration products was researched. The results show that: MPC was made that replaced with the equal amount of three kind of phosphate, which has good mechanical properties. Setting time and fluidity change along with the replacment. Three kind of phosphate replace ammonium dihydrogen phosphate, which change the hydration process of MPC. When ammonium dihydrogen phosphate was replaced by an equal amount of disodium hydrogen phosphate, the temperature of hydration is only 69.4 °C. XRD showed that the diffraction peaks of composite’s magnesium phosphate cement increases.

Laboratory-Based Bacterial Weathering of the Merensky Reef and Its Impact on Platinum Group Mineral Migration

2021 ◽  
Author(s):  
Ling Tan ◽  
Thomas Jones ◽  
Jianping Xie ◽  
Xinxing Liu ◽  
Gordon Southam
Keyword(s):  
Base Metal ◽  
Mineral Dissolution ◽  
Metal Sulfides ◽  
Acidithiobacillus Thiooxidans ◽  
Thin Sections ◽  
Secondary Minerals ◽  
Merensky Reef ◽  
Fe Oxides ◽  
Base Metal Sulfides ◽  
Platinum Group

Abstract Weathering of the Merensky reef was enhanced under laboratory conditions by Fe- and S-oxidizing bacteria: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans. These bacteria preferentially colonized pyrrhotite and pyrite, versus pentlandite and chalcopyrite (all of which were common within the rock substrate), promoting weathering. Weathering of base metal sulfides resulted in the precipitation of Fe oxides, Fe phosphate, and elemental sulfur as secondary minerals. Fe pyroxene weathered readily under acidic conditions and resulted in mineral dissolution, while other silicates (orthopyroxene and plagio-clase) precipitated Fe phosphate spherules or coatings on their surface. The deterioration of the platinum group metal (PGM) matrix (base metal sulfides and silicates) and the occurrence of a platinum grain associated with platinum nanoparticles observed in the biotic thin sections demonstrate that biogeochemical acid weathering is an important step in the active release of intact PGM grains. A platinum grain embedded in secondary Fe oxides/phosphate that had settled by gravity within the weathering solution demonstrates that secondary minerals that formed during weathering of PGM-hosting minerals also represent targets in PGM exploration by trapping and potentially slowing PGM migration. Dispersion halos surrounding or occurring downstream from PGM occurrences will likely produce two physical target classes—i.e., grains and colloids—under surficial weathering conditions.

Processing of Lean Iron Ores by Dry High Intensity Magnetic Separation

2015 ◽  
Vol 50 (11) ◽  
pp. 1689-1694 ◽  
Author(s):  
Huifen Zhang ◽  
Luzheng Chen ◽  
Jianwu Zeng ◽  
Li Ding ◽  
Jian Liu
Keyword(s):  
Magnetic Separation ◽  
High Intensity ◽  
Iron Ores

Osmolarity of Human Serum and of Chemical Solutions of Biologic Importance

1961 ◽  
Vol 7 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Edward B Hendry
Keyword(s):  
Human Serum ◽  
Freezing Point ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Hydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Disodium Hydrogen Phosphate ◽  
Normal Human ◽  
Chemical Solutions ◽  
Sodium Dihydrogen

Abstract With the use of the Fiske Osmometer, the mean total osmolarity of normal human serum was found to be 289 mOsM (S.D., 4), which is equivalent to a mean freezing point of -0.537°. The isosmotic concentrations of some important biologic solutions were determined. It was also found that M/15 solutions of disodium hydrogen phosphate and of potassium dihydrogen phosphate are very hypotonic, and that 3.8% sodium citrate is hypertonic. Hemolysis of erythrocytes in isosmotic ammonium chloride solution can be considerably delayed by the addition of 3.0% glucose to the solution. Isosmotic concentrations of disodium hydrogen phosphate and sodium dihydrogen phosphate were precisely determined, as were pH levels of buffer solutions made from these two salts. The cause of the slight changes in osmolarity that occur when these two isosmotic solutions are mixed is discussed.

Effects of pH on the Transformation of Gypsum to Carbonate Apatite in the Presence of Ammonium Hydrogen Phosphate

2006 ◽  
Vol 309-311 ◽  
pp. 199-202 ◽  
Author(s):  
Ishikawa Kunio ◽  
Yumiko Suzuki ◽  
Shigeki Matsuya ◽  
Masaharu Nakagawa ◽  
Kiyoshi Koyano
Keyword(s):  
The Other ◽  
Dicalcium Phosphate ◽  
Carbonate Apatite ◽  
Compositional Change ◽  
Hydrogen Phosphate ◽  
Detailed Mechanism ◽  
Effects Of Ph ◽  
Ammonium Hydrogen ◽  
Ammonium Hydrogen Phosphate ◽  
Ph Dependent

Effects of pH on the transformation of gypsum to apatite in the presence of ammonium hydrogen phosphate was studied using NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4. When set gypsum was immersed to ammonium hydrogen phosphate, pH of the solution decreased regardless of the solution. Although pH of the solution decreased, no significant compositional change was observed when gypsum was immersed in NH4H2PO4. On the other hand, apatite and small amount of dicalcium phosphate anhydrous (CaHPO4) was formed when gypsum was immersed in (NH4)2HPO4 solution. Only apatite was formed when gypsum was immersed in (NH4)3PO4 solution. Although the detailed mechanism for the pH dependent products has not been clarified, one of the causes may be the different thermodynamical difference between gypsum and apatite. We would like to recommend the use of (NH4)3PO4 solution since this provides higher pH and thus larger thermodynamical difference between apatite and gypsum and resulting pure apatite block.

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