Leaching Process of Cerium Extraction from Mixture of Cerite-Monazite Mineral

2006 ◽  
Vol 514-516 ◽  
pp. 1653-1657 ◽  
Author(s):  
José Cosme Cunha Gomes ◽  
C.P. Souza ◽  
Uilame Umbelino Gomes ◽  
Jean R. Gavarri ◽  
Jean P. Dallas ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Research Work ◽  
Sulfate Solution ◽  
Process Efficiency ◽  
Process Time ◽  
High Concentration ◽  
Acid Attack ◽  
Selective Precipitation ◽  
Leaching Process ◽  
Oxidation Of Hydrocarbons

Rare earth oxides have been widely investigated in catalysis as structured and electronic promoters to improve the activity and thermal stability of catalysts. Cerium has an important role in three-way catalysis and fluid catalytic cracking, two significant catalytic processes by their economic relevance and tonnage. Cerium and other rare earths have been studied as possible heterogeneous catalysts at selective oxidation of hydrocarbons. Cerite and monazite are minerals with high concentration of cerium element. Extraction of cerium metal using conventional leaching processes has shown low yields or high costs. The main purpose of this research work is to optimize the parameters in cerium purification stage from this mineral using leaching process. To separate particles with different granulometries, the mineral is ground and fractioned with sieves of 80, 200, 250 and 400 mesh. In order to put off organic components and oxidize cerium(III) to cerium(IV), samples were roasted at 1073K by twenty-four hours. The roasted samples were solubilized by acid attack (leaching) for approximately twenty-four hours; according to the acid used hydrochloric or sulfuric), cerium and other trivalent elements are solubilized as chloride or sulfate solution. Cerium was extracted by selective precipitation at pH~3,4 using ammonium or natrium hydroxide as pH changer. After filtration and drying, the precipitated product was characterized by XRD (x-ray diffraction), and then process efficiency was determined (cerium percentage and the different phases in the powder). Particles granulometry, roasting process (time and temperature), as well as leaching parameters (acid used, time, temperature and concentration of reagents) were the main variables studied.

Separation of Heavy Metal Ions from the Solution Obtained by Leaching Low-Grade Pyrolusite with Pyrite and H2SO4

2013 ◽  
Vol 773 ◽  
pp. 283-288
Author(s):  
Xing Zou ◽  
Xiang Quan Chen ◽  
Hai Chao Xie ◽  
Xiao Dan Qiu
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Separation Efficiency ◽  
Ph Value ◽  
Sulfate Solution ◽  
Ion Concentration ◽  
Manganese Sulfate ◽  
Low Grade ◽  
High Concentration

The manganese sulfate solution leached from low-grade pyrolusite with pyrite and H2SO4 contains heavy metal ions of high concentration, influencing the quality of the final products of manganese compounds and causing manganese ions not to be electrolyzed. The present study was focused on the separation of Co, Ni and Zn ions from the leached solution with BaS. By controlling the pH value at 5.0-6.5, temperature at 50-60°C, reaction time at 15 min and mixing velocity at 78 rpm, the heavy metal ions could be separated effectively. Under the above optimized conditions, the ion concentration of Co, Ni, and Zn in the solution was reduced to 0.06 mg.L-1, 0.27mg.L-1 and 0.01mg.L-1, and the separation efficiency was 99.72%, 99.18% and 99.9% respectively. The obtained pure solution meets the demands of manganese electrowinning.

Comparison of Bioleaching High Arsenic-Bearing Copper Sulphide Concentrate Using Thiobacillus Ferrooxidans and Sulfobacillus Thermosulfidooxidans

2012 ◽  
Vol 524-527 ◽  
pp. 1997-2003
Author(s):  
Hai Yun Xie ◽  
Zhuo Yue Lan ◽  
Shu Ming He ◽  
Li Kun Gao ◽  
Xiong Tong
Keyword(s):  
Thiobacillus Ferrooxidans ◽  
Arsenic Sulfide ◽  
High Concentration ◽  
Initial Concentration ◽  
Copper Concentrate ◽  
Leaching Process ◽  
Sulfobacillus Thermosulfidooxidans ◽  
Moderate Thermophile ◽  
Arsenic Copper ◽  
High Arsenic

The usage of high-arsenic sulfide copper concentrate were limited because the arsenic in the concentrate harms the qualities of copper product and pollutes the environment. In this paper an innovative process for high-arsenic copper sulfide concentrate with with bio-oxidation respectively Thiobacillus ferrooxidans and moderate thermophile Sulfobacillus thermosulfidooxidans has been studied out, and the influencing factors have been comparative studied during the leaching process, such as concentration particle size, leaching methods, pulp concentration, leaching time and the initial concentration of Fe3+, etc. Under the suitable leaching conditions, the experiments results show that the concentrate is leached 47.13% of Cu,50.09% of As and 52.46% of Fe by Thiobacillus ferrooxidans and 82.39% of Cu,78.21% of As and 40.38% of Fe by moderate thermophile Sulfobacillus thermosulfidooxidans. The high concentration initial Fe3+ has speeded leaching process up in the presence of moderate thermophile Sulfobacillus thermosulfidooxidans, and when the pulp initial concentration of Fe3+ is in the range of 0.08~0.32mol/L, the leaching rate of Cu is 86.34~97.06%, As 89.22~94.13%. It is concluded that Sulfobacillus thermosulfidooxidans have a better effect on bioleaching high-arsenic sulfide copper concentrate than Thiobacillus ferrooxidans.

Acid Functionalized Hydrochar as Heterogeneous Catalysts for Solventless Synthesis of Biofuel Precursors

2021 ◽  
Author(s):  
Tripti Chhabra ◽  
Prachi Dwivedi ◽  
Venkata Krishnan
Keyword(s):  
Renewable Energy ◽  
Heterogeneous Catalysts ◽  
Research Work ◽  
Fundamental Solutions ◽  
High Density ◽  
Energy Resources ◽  
Alkylation Reaction ◽  
Renewable Energy Resources ◽  
Solventless Synthesis

Synthesis of high density fuel precursors via hydroxyalkylation alkylation reaction is one of the fundamental solutions to the depletion of renewable energy resources. This research work examines the preparation of...

scholarly journals Polymeric Heterogeneous Catalysts in the Hydroformylation of Unsaturated Compounds

2020 ◽  
Author(s):  
D. P. Zhuchkov ◽  
M. V. Nenasheva ◽  
M. V. Terenina ◽  
Yu. S. Kardasheva ◽  
D. N. Gorbunov ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Polymer Structure ◽  
Organic Polymer ◽  
Synthesis Methods ◽  
Special Focus ◽  
Organic Media ◽  
High Concentration ◽  
Catalyst Synthesis ◽  
Unsaturated Compounds ◽  
Highly Active

Abstract This review deals with heterogeneous hydroformylation catalysts, specifically metal complexes fixed in an organic polymer structure. It describes the main catalyst synthesis methods, provides data on hydroformylation of unsaturated compounds (including asymmetric hydroformylation), and shows how those compounds can be used. The special focus is on the systematization of data on heterogeneous catalysts developed on the basis of porous organic polymers. Due to their porous structure, resistance to organic media and the high concentration of heteroatoms they contain, these materials can be considered promising for developing highly active, selective and stable heterogeneous catalysts for hydroformylation of unsaturated compounds, particularly higher linear olefins.

scholarly journals A fast-acting elastase inhibitor in human monocytes.

1985 ◽  
Vol 162 (6) ◽  
pp. 2142-2155 ◽  
Author(s):  
E Remold-O'Donnell
Keyword(s):  
Proteinase Inhibitor ◽  
Sodium Dodecyl ◽  
Human Monocyte ◽  
Sulfate Solution ◽  
Cell Protein ◽  
Human Monocytes ◽  
High Concentration ◽  
Elastase Inhibitor ◽  
Nucleophilic Cleavage ◽  
Fast Acting

A proteinase inhibitor active against neutrophil and pancreatic elastase was detected in extracts of cultured human monocytes and the human monocyte-like cell line U937. This component forms a covalent complex with the active site of elastase; the complex is stable in boiling sodium dodecyl sulfate solution, and is susceptible to nucleophilic cleavage. The activity of the elastase inhibitor is not detected in extracts of freshly isolated monocytes, but becomes detectable when the monocytes are allowed to mature in culture, with maximum levels occurring at 5-7 d. The monocyte inhibitor is fast-acting; its reaction with 125I-labeled elastase is complete in less than 1 min at 37 degrees C. Analysis by electrophoresis and studies using a heteroantiserum to alpha 1-proteinase inhibitor demonstrated that the elastase inhibitor of monocytes/U937 cells is not identical to alpha 1-proteinase inhibitor, the major elastase inhibitor of blood plasma. The extent of conversion of 125I-elastase to the 125I-elastase-inhibitor complex is proportional to the amount of U937 extract or cultured monocyte extract, indicating that this reaction can serve to quantify the elastase inhibitor. The elastase inhibitor is an abundant component in mature monocytes, with greater than or equal to 1.5 X 10(6) molecules/cell (greater than or equal to 12 micrograms per 10(8) cells, greater than 0.1% of total cell protein). Its mol wt is estimated at 50,000. Thus, the monocyte inhibitor should be classified as a putative regulator of neutrophil (and monocyte) elastase activity at inflammatory sites. This designation is based on the properties of the molecule, including its high concentration in maturing monocytes, its affinity for elastase, and its fast reaction with this enzyme.

Investigation of Phthalocyanine Catalysts for the Aerobic Synthesis of meso-Substituted Porphyrins

1997 ◽  
Vol 01 (04) ◽  
pp. 385-394 ◽  
Author(s):  
M. RAVIKANTH ◽  
CATALINA ACHIM ◽  
JOHN S. TYHONAS ◽  
ECKARD MÜNCK ◽  
JONATHAN S. LINDSEY
Keyword(s):  
Trifluoroacetic Acid ◽  
Room Temperature ◽  
Heterogeneous Catalysts ◽  
Mossbauer Spectroscopy ◽  
Oxidation Process ◽  
Aerobic Oxidation ◽  
Heterogeneous Reactions ◽  
High Concentration ◽  
Neutral Conditions ◽  
Homogeneous Reactions

The aerobic oxidation process for the synthesis of porphyrins, previously performed using 5 mol % p-chloranil (TCQ), 5 mol % iron(II) phthalocyanine ( FePc ) and stoichiometric amounts of O 2, has been refined using new phthalocyanine catalysts. Four phthalocyanine catalysts have been prepared, characterized by Mössbauer spectroscopy and examined for efficacy in the high concentration (0.1 M) synthesis of tetraphenylporphyrin at room temperature. Each phthalocyanine has been identified to be a μ-oxo dimer. Two catalysts are soluble (the μ-oxo dimers [(t-butyl)4 FePc ]2 O and [(n- C 6 H 13 O )4 FePc ]2 O ) and enable homogeneous reactions, while two are insoluble (the μ-oxo(1) and μ-oxo(2) dimers of FePc , ( FePc )2 O ) and give heterogeneous reactions. These four phthalocyanine compounds provide efficient catalysis at the 0.3–1 mol % level using only 1 mol % quinone or hydroquinone ( TCQ , DDQ , TCQH 2 or DDQH 2), affording ~25% yields of tetraphenylporphyrin in 60 min of oxidation. There are no discernible advantages of the homogeneous versus heterogeneous catalysts. The μ-oxo dimers are active, but FePc is inactive, at the 0.3 mol % level. The activity of the FePc sample at the 5 mol % level is attributed to residual μ-oxo dimer impurity. This aerobic oxidation process is superior to stoichiometric oxidation with TCQ or DDQ , and can be performed in the presence of BF 3· O ( Et )2, trifluoroacetic acid, or under neutral conditions.

Degradation of wine industry wastewaters by photocatalytic advanced oxidation

2005 ◽  
Vol 51 (1) ◽  
pp. 113-120 ◽  
Author(s):  
P. Navarro ◽  
J. Sarasa ◽  
D. Sierra ◽  
S. Esteban ◽  
J.L. Ovelleiro
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Heterogeneous Catalysts ◽  
Suspended Solids ◽  
Advanced Oxidation ◽  
Wine Industry ◽  
Biological Processes ◽  
H2o2 Concentration ◽  
High Concentration ◽  
Promising Technology

Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.

Self-Cleaning TiO2/SiO2 Thin Film Prepared by a Simple Sol-Gel Method

2014 ◽  
Vol 804 ◽  
pp. 157-160
Author(s):  
Wen Xiu Liu ◽  
Jun Na Xu ◽  
Jun Zhang ◽  
Xue Mei Liu ◽  
Wen Bin Cao
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Sulfate Solution ◽  
Ultraviolet Region ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Titanyl Sulfate ◽  
Glass Substrates ◽  
Light Region ◽  
Vis Spectroscopy

TiO2 thin films were prepared on SiO2-coated glass substrates using sols deriving from high concentration titanyl sulfate solution by the spin-coating technique. The calcined films were characterized by X-ray diffraction, UV-Vis spectroscopy, scanning electron microscopy. The film exhibited high transmittance in the visible light region and high absorption in the ultraviolet region. The contact angle of SiO2/TiO2 decreased to below 5° under 30 min of UV light irradiation and can sustain for 1 weeks.

scholarly journals Growth response of pigeon pea (Cajanus cajan L. Millsp) on saline and alfisol soils

2021 ◽  
Vol 306 ◽  
pp. 01010
Author(s):  
M. Soedarjo
Keyword(s):  
Growth Retardation ◽  
Saline Soil ◽  
Growth Parameters ◽  
Research Work ◽  
Dry Weight ◽  
Pigeon Pea ◽  
Saline Soils ◽  
Growth Responses ◽  
High Concentration ◽  
Shoot Dry Weight

As an archipelago country, Indonesia is surrounded by abundant saline soils which could be potential for growing food crops. The research work was conducted to study the growth responses of some pigeon pea genotypes on saline soils. The genotypes of Pigeon pea (LG Kidul, Mega, 90024, 91043 and 94028), as treatment, were grown on Alfisol soil (non-saline) and on saline soil. The experiment was carried out using completely randomized design and replicated three times. All data observed were analyzed by employing standard deviation from 3 replicates. The results of present research work revealed a significant growth retardation of pigeon pea when grown on saline soil. All growth parameters, plant height, plant diameter, root dry weight, and shoot dry weight were significantly lower on saline soil than on Alfisol soil. High concentration of Na+ was observed in roots, shoots and leaves of pigeon pea indicating growth retardation and toxicity symptoms of pigeon pea on saline soil was due to Na+.

Sign in / Sign up

Export Citation Format

Share Document