Flotation enhancement of low-grade bauxite using oxalic acid as surface pretreatment agent

2021 ◽  
pp. 151964
Author(s):  
Huaxia Li ◽  
Wencui Chai ◽  
Yijun Cao ◽  
Shichong Yang
Keyword(s):  
Oxalic Acid ◽  
Low Grade ◽  
Surface Pretreatment

Recovery of Lanthanides from Indonesian Low Grade Bauxite Using Oxalic Acid

2018 ◽  
Vol 929 ◽  
pp. 171-176 ◽  
Author(s):  
Eny Kusrini ◽  
Zakaria Jaka Bahari ◽  
Anwar Usman ◽  
Arif Rahman ◽  
Eko Adi Prasetyanto
Keyword(s):  
Rare Earth ◽  
Optimum Condition ◽  
Oxalic Acid ◽  
Rare Earth Elements ◽  
Acid Leaching ◽  
Experimental Result ◽  
Low Grade ◽  
Icp Oes ◽  
Temperature Dependent ◽  
Economical Method

The present work describes the extraction of lanthanide (rare earth elements, REE) from low grade bauxite using acid leaching method. The aim of this study is to obtain the best condition for extraction of lanthanides from low grade bauxite. The effect of different parameters such as temperatures and concentration of oxalic acid in leaching process were investigated. The content of La, Ce and Y elements were determined using ICP-OES. The experimental result shows that the efficiencies of lanthanide leaching are the temperature-dependent. Increasing leaching temperature from 45°C to 85°C did not improve recoveries of lanthanides. The most optimum condition was found at oxalic acid leaching of 1 mol/L, leaching temperature at 40°C, and time for 2 hours. The obtained results show that the lanthanides can be leached using oxalic axid. This finding may lead to more effective and economical method to separate lanthanides from low grade bauxite.

Leaching kinetics of iron from low grade kaolin by oxalic acid solutions

2011 ◽  
Vol 51 (4) ◽  
pp. 473-477 ◽  
Author(s):  
A. Martínez-Luévanos ◽  
M.G. Rodríguez-Delgado ◽  
A. Uribe-Salas ◽  
F.R. Carrillo-Pedroza ◽  
J.G. Osuna-Alarcón
Keyword(s):  
Oxalic Acid ◽  
Low Grade ◽  
Acid Solutions ◽  
Leaching Kinetics ◽  
Kinetics Of

Kinetic Study of Iron Dissolution from Low Grade Kaolin Using Oxalic Acid Solutions

2012 ◽  
Vol 1380 ◽  
Author(s):  
A. Martínez-Luévanos ◽  
L. E. Serrato-Villegas ◽  
M. G. Rodríguez-Delgado ◽  
F. R. Carrillo-Pedroza
Keyword(s):  
Oxalic Acid ◽  
Acid Concentration ◽  
Industrial Applications ◽  
Product Layer ◽  
Low Grade ◽  
Acid Solutions ◽  
Iron Dissolution ◽  
Bearing Materials ◽  
Kaolinitic Clay ◽  
Kinetics Of

ABSTRACTKaolin is an important material that is used in industrial applications, including ceramics, paper, paints, fiberglass, inks, pharmaceuticals, and cement. The presence of impurities, particularly iron and titanium bearing materials, imparts color to kaolin. During weathering or hydrothermal alteration, significant levels of iron oxides can be deposited that leave a concentrated kaolinitic clay unusable for industrial application. Therefore, several chemical methods have been applied to kaolin beneficiation in order to reduce these contaminants. Ferric oxide dissolution is of particular interest for producers of industrial minerals such as kaolin. The objective of this work was to examine the kinetics of iron dissolution form low grade kaolin using oxalic acid solutions. The effects of acid concentration and reaction temperature were studied. It was determined that the iron dissolution rate increases with oxalic acid concentration, temperature. Leaching data showed that iron dissolution from low grade kaolin is due to diffusion through the product layer. The activation energy of the process was 46.32 kJ/mol.

scholarly journals High Efficiency Stabilization of Lead in Contaminated Soil by Thermal-organic Acid Activated Phosphate Rock

2021 ◽  
Author(s):  
Ziwen Song ◽  
Zhuo Zhang ◽  
Canyu Luo ◽  
Likun Yang ◽  
Jin Wu
Keyword(s):  
Oxalic Acid ◽  
Organic Acid ◽  
Contaminated Soil ◽  
Phosphate Rock ◽  
High Efficiency ◽  
Fold Increase ◽  
Low Grade ◽  
Rock Powder ◽  
Composition And Structure ◽  
Stabilization Effect

Abstract Phosphate rock powder (PR) has been shown to possess the potential to stabilize lead (Pb) in soil. Most of the phosphorus (P) minerals in the world are low-grade ores, which makes it difficult to achieve the expected stabilization effect on heavy metals. This study compared the changes in the phase composition and structure of PR and three kinds of activated phosphate rock powder (APR) (organic acid activated PR, thermal activated PR, and thermal-acid activated PR), and used APR for the stabilization of Pb-contaminated soil. PR/APR was characterized by different methods. The stabilization effectiveness of APR on Pb-contaminated soil was evaluated by toxicity leaching procedure, the Pb products adsorbed on APR and stabilization mechanism of APR on Pb were analyzed. The results showed that the crystallinity of fluorapatite phase decreased after all the activation treatments. The APR showed decreased crystallinity and 3.4-fold increase in specific surface area, and a 53.07% and 49.32% increase in soluble P content in oxalic acid activated PR and citric acid activated PR, respectively, when compared with those of PR. These changes improved the stabilization effect of APR on Pb-contaminated soil, and the stabilization effectiveness was as follows: thermal-acid activated PR > organic acid activated PR > thermal activated PR. In particular, oxalic acid-600℃ activated PR showed the best effect, presenting 94.0%-99.8% reduction in Pb leaching concentration following addition of 2%-10% modifier. Product characterization after Pb adsorption on APR showed that Pb was adsorbed onto APR by forming pyromorphite precipitation with APR.

Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

1977 ◽  
Vol 35 ◽  
pp. 162-163
Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck
Keyword(s):  
Crystallite Size ◽  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Low Grade ◽  
X Ray ◽  
Graphitized Carbon ◽  
Transmission Electron ◽  
Heat Treated ◽  
Commercial Carbon ◽  
Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

1973 ◽  
Vol 31 ◽  
pp. 468-469
Author(s):  
N.C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nitric Acid ◽  
Oxalic Acid ◽  
Light Microscopy ◽  
Epidermal Cell ◽  
Cell Walls ◽  
Plant Viruses ◽  
Plant Leaves ◽  
Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

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