Recovery of niobium during comprehensive processing of pyrochlore-monazite-goethite ores

2021 ◽  
pp. 71-77
Author(s):  
N. A. Permyakova ◽  
M. V. Tsygankova ◽  
E. I. Lysakova
Keyword(s):  
Organic Phase ◽  
Tributyl Phosphate ◽  
Weight Ratio ◽  
Acid Leaching ◽  
Processing Technique ◽  
Pressure Leaching ◽  
High Concentration ◽  
Heat Treatment Mode ◽  
Efficient Processing ◽  
Comprehensive Processing

This paper looks at the pyrochlore-monazite-goethite ores of the Chuktukonsk deposit (0.98wt.% Nb2O5) and their processing with the help of acidbased (HNO3, H2SO4) and sulphatization techniques. Nitric-acid pressure leaching was found to be an efficient processing technique for this type of ore: ore size –0.074 mm; CHNO3 = 25%; CH2O2 = 5%; τ = 2 h; solid-to-liquid = 1:9; heat treatment mode: 1 h at 160 oC followed by 1 h at 230 oC. As a result, rare earth metals and manganese are leached to the solution while all of the contained niobium remains in the cake. Two different techniques were tested to recover niobium from the cake. One is based on the use of alkali (NaOH sintering), the other is an extractive leaching technique that combines acid leaching with liquid-liquid extraction of tributyl phosphate in one stage. It was established that niobium mi nerals can be efficiently decomposed when using a mixture of hydro fluoric and sulphuric acids with the concentrations of 4.08 and 8.46 mol/L, correspon dingly, as a leaching agent. At the weight ratio of 1:2:1 of the solid to aqueous to organic phase and after the slurry has been stirred intensively for 5 minutes, niobium fluorides, which form as a result of interaction between hydrofluoric acid and the cake components, can be recovered with a 50% solution of tributyl phosphate in octane. After that they transfer to an organic phase while impurities get accumulated in the solid residue. As niobium-containing cake has a high concentration of silicon, it is recommended to first remove silicon from the cake using a strong alkaline solution.

Spectroscopic Study of the Uranyl—Acetohydroxamate Adduct with Tributyl Phosphate

2007 ◽  
Vol 61 (7) ◽  
pp. 772-776 ◽  
Author(s):  
Peter Tkac ◽  
Alena Paulenova ◽  
Kevin P. Gable
Keyword(s):  
Acetic Acid ◽  
Organic Phase ◽  
Tributyl Phosphate ◽  
Chelate Ring ◽  
Spectroscopic Studies ◽  
Acetohydroxamic Acid ◽  
Ft Ir ◽  
Uranium Distribution ◽  
Ir Spectroscopic ◽  
Hydrolysis Of

The ultraviolet–visible (UV-Vis) and Fourier transform infrared (FT-IR) spectroscopic studies carried out for the system UO2(NO3)/AHA/TBP (uranyl–acetohydroxamate–tributyl phosphate) confirmed the presence of the adduct of UO2(NO3)(AHA) ·2TBP with 1:1 stoichiometry for UO2:AHA (acetohydroxamic acid). The spectrum of this complex is identical to the infrared spectrum of the organic phase formed in the uranium distribution experiments with 30% TBP/n-dodecane and AHA present in aqueous phase. Disappearance of the hydroxyl stretching band and a shift in the position of the carbonyl band in the infrared spectra revealed that both the hydroxyl and the carbonyl group of acetohydroxamic acid are involved in the chelate ring with uranium. Also, acetic acid, accrued after acidic hydrolysis of acetohydroxamic acid, was identified in the extraction organic phase.

The Application of Signal Processing Techniques in Improving Spectrometer Detection Limit

2011 ◽  
Vol 148-149 ◽  
pp. 1045-1050
Author(s):  
Zhi Ying Wu ◽  
Yi Zhang ◽  
Zuo Yuan Shen
Keyword(s):  
Signal Processing ◽  
Detection Limit ◽  
High Sensitivity ◽  
Processing Technique ◽  
Laser Source ◽  
Sampled Data ◽  
High Concentration ◽  
Signal Processing Technique ◽  
Processing Techniques ◽  
Lock In

Improving spectrometer detection limit using statistical principle and signal-processing technique are described simply in this work. In the detection of gas photoacoustic(PA) signal, accurate partitions of the sampled data affect on the detection limit to some extent although Lock-in amplification technique with high SNR and microphone sensor with high sensitivity have been used. A model and the resulting algorithm are proposed from PA-signal samples. The techniques are validated at ppb level on PA spectrometer for NH3 breath detection in high concentration of CO2 and H2O based on tunable erbium-doped fiber laser (TEDFL) or for multicomponent trace gas detection based on waveguide CO2 laser or on other laser source.

Comparison of the volumetric composition of lamellar bone and the woven bone of calluses

2018 ◽  
Vol 232 (7) ◽  
pp. 682-689 ◽  
Author(s):  
Javier Martínez-Reina ◽  
Javier García-Rodríguez ◽  
Juan Mora-Macías ◽  
Jaime Domínguez ◽  
Esther Reina-Romo
Keyword(s):  
Organic Phase ◽  
Formation Rate ◽  
Bone Transport ◽  
High Concentration ◽  
Woven Bone ◽  
Cortical Shell ◽  
Bone Callus ◽  
Low Stiffness ◽  
Water Contents

Woven tissue is mainly present in the bone callus, formed very rapidly either after a fracture or in distraction processes. This high formation speed is probably responsible for its disorganized microstructure and this, in turn, for its low stiffness. Nonetheless, the singular volumetric composition of this tissue may also play a key role in its mechanical properties. The volumetric composition of woven tissue extracted from the bone transport callus of sheep was investigated and compared with that of the lamellar tissue extracted from the cortical shell of the same bone. Significant differences were found in the mineral and water contents, but they can be due to the different ages of both tissues, which affects the mineral/water ratio. However, the content in organic phase remains more or less constant throughout the mineralization process and has proven to be a good variable to measure the different composition of both tissues, being that content significantly higher in woven tissue. This may be linked to the abnormally high concentration of osteocytes in this tissue, which is likely a consequence of the more abundant presence of osteoblasts secreting osteoid and burying other osteoblasts, which then differentiate into osteocytes. This would explain the high formation rate of woven tissue, useful to recover the short-term stability of the bone. Nonetheless, the more abundant presence of organic phase prevents the woven tissue from reaching a stiffness similar to that of lamellar tissue in the long term, when it is fully mineralized.

Preparation of Crystalline Hematite from Bauxite

2014 ◽  
Vol 936 ◽  
pp. 1153-1157
Author(s):  
Juan Liu ◽  
Qian Qian Jiang ◽  
Jing Wang ◽  
Li Chen ◽  
Xing Yao Wang
Keyword(s):  
Hydrochloric Acid ◽  
Organic Phase ◽  
Ferric Oxide ◽  
Acid Leaching ◽  
Nano Particles ◽  
Proof Of Concept ◽  
Primary Particles ◽  
Hydrochloric Acid Leaching ◽  
Loaded Organic Phase ◽  
Xrd Patterns

A novel of hydrothermal stripping technique is developed to synthesize nano-particles of ferric oxide from iron-loaded organic phase by ammonia. The iron-loaded organic phase was prepared by extracting simulated bauxite hydrochloric acid leaching liquors with N235 and then the iron is stripped by heating the organic phase up to 180°C to precipitate as ferric oxide. XRD patterns exhibits that the ferric oxide is composed of α-Fe2O3 and TEM images reveals that the particles of crystalline hematite powders are homogenous with quasi-spherical fine crystallites and its primary particles are about 150 nm. This process is a proof of concept for the removal and precipitation of iron from bauxite hydrochloric acid leaching liquors.

Comparative Study on Removal of Fe, Al and Ca From MG-Si by Acid Leaching

2012 ◽  
Vol 581-582 ◽  
pp. 831-835
Author(s):  
Yi Mai ◽  
Wen Hui Ma ◽  
Ke Qiang Xie ◽  
Tong Wang ◽  
Hu Zhang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Hydrofluoric Acid ◽  
Removal Rate ◽  
Acid Leaching ◽  
Pressure Leaching ◽  
Impurity Removal ◽  
Mixed Acid ◽  
Iron Aluminum ◽  
High Impurity ◽  
Hydrometallurgical Method

In order to find the most effective hydrometallurgical method of removing iron, aluminum and calcium from MG-Si, a variety of acid leaching methods were presented. The research results show that the order of capacity of metallic impurity removal is HF, HCl, HNO3 and H2SO4. The most effective hydrometallurgical method is the leaching by mixed acid with hydrofluoric acid and sulfuric acid. Removal efficiency of hydrochloric acid pressure leaching can improved as the pressure increases. Sulfuric acid and nitric acid even using high pressure leaching cannot obtain high impurity removal rate. The leaching by hydrofluoric acid or mixed acid containing hydrofluoric acid and sulfuric acid is very effective on removal of iron and aluminum, but less effective on calcium.

Membrane Extraction of Penicillin G from a Synthetic Fermentation Media Using Sunflower Oil

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Md Monwar Hossain
Keyword(s):  
Organic Phase ◽  
Sunflower Oil ◽  
Tributyl Phosphate ◽  
Hollow Fiber Membrane ◽  
Aqueous Media ◽  
Environmentally Friendly ◽  
Membrane Extraction ◽  
Penicillin G ◽  
Percentage Extraction ◽  
Fermentation Media

The use of sunflower oil as an environmentally-friendly solvent was examined for the separation of penicillin G (Pen G) from a synthetic fermentation media to develop a cost-effective process. In order to evaluate this, equilibrium experiments were first carried out with solvent alone (sunflower oil/pegasol/tributyl phosphate) and then with the solvent containing dissolved Amberlite LA-2, an ionic carrier. The organic systems with the carrier gave better distribution of Pen G between the aqueous and organic phases. The values of the distribution coefficient were greater for tributyl phosphate (TBP) than the other solvents at the natural pH of Pen G. Sunflower oil gave a good distribution ratio and it can be recommended as an attractive option because of its low cost, minimal toxicity and moderate performance. The effectiveness of the carrier-sunflower oil (organic phase) was evaluated in a hollow-fiber membrane contactor by performing experiments with the organic phase on the shell side and the feed inside the fiber. With a small amount of carrier (approx. 5%) in the organic phase and at the natural pH of penicillin G, a good percentage extraction (approx. 40-45%) was achieved. The percentage extraction decreased (approx. 30-35%) when penicillin G was prepared in a synthetic fermentation media instead of pure aqueous media. These results are similar to those reported by many investigators; the main difference is that, in this report, an environmentally-friendly solvent was used instead of toxic solvents used in the literature, such as kerosene.

STUDIES ON THE URANIUM EXTRACTION EQUILIBRIA, PHOTOLYTIC, AND HYDROLYTIC REACTIONS IN SYSTEMS CONTAINING TRI-n-BUTOXYETHYL PHOSPHATE

1964 ◽  
Vol 42 (4) ◽  
pp. 878-884 ◽  
Author(s):  
M. Halpern ◽  
T. Kim ◽  
A. S. Kertes ◽  
N. C. Li
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Organic Phase ◽  
Acid Content ◽  
Tributyl Phosphate ◽  
Extraction Behavior ◽  
Initial Aqueous Solution ◽  
Hydrolysis Of ◽  
Ethereal Oxygen ◽  
Extraction Equilibria

The extraction equilibria in the system aqueous hydrochloric acid – uranyl chloride –undiluted tri-n-butoxyethyl phosphate, TBEP, were examined as a function of increasing uranyl concentration (0.44 to 4.41 M) in the initial aqueous solution, the acid content of the initial aqueous solution being kept constant at 6.76 M. The extraction behavior of TBEP is found to be different from that of tributyl phosphate. Evidence has been presented to show that the three ethereal oxygen atoms in the TBEP molecule are, under high organic phase loading conditions, available for participation in complexation. The hydrochloric acid promoted hydrolysis of TBEP and the instability toward light of the TBEP layer containing hydrochloric acid and uranium were also examined.

scholarly journals Kinetics Study of Al Extraction from Desilicated Coal Fly Ash by NaOH at Atmospheric Pressure

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7700
Author(s):  
Andrei Shoppert ◽  
Irina Loginova ◽  
Dmitry Valeev
Keyword(s):  
Fly Ash ◽  
Atmospheric Pressure ◽  
Inductively Coupled Plasma ◽  
Coal Fly Ash ◽  
Acid Leaching ◽  
Emission Spectrometry ◽  
Pressure Leaching ◽  
Water Leaching ◽  
X Ray ◽  
Promising Source

The most promising source of alumina in the 21st century is the coal fly ash (CFA) waste of coal-fired thermal plants. The methods of alumina extraction from CFA are often based on the pressure alkaline or acid leaching or preliminary roasting with different additives followed by water leaching. The efficiency of the alumina extraction from CFA under atmospheric pressure leaching is low due to the high content of acid-insoluble alumina phase mullite (3Al2O3·2SiO2). This research for the first time shows the possibility of mullite leaching under atmospheric pressure after preliminary desilication using high liquid to solid ratios (L:S ratio) and Na2O concentration. The analysis of the desilicated CFA (DCFA) chemical and phase composition before and after leaching has been carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The morphology and elemental composition of solid product particles has been carried out by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). An automated neural network and a shrinking core model (SCM) were used to evaluate experimental data. The Al extraction efficiency from DCFA has been more than 84% at T = 120 °C, leaching time 60 min, the L/S ratio > 20, and concentration of Na2O-400 g L−1. The kinetics analysis by SCM has shown that the surface chemical reaction controls the leaching process rate at T < 110 °C, and, at T > 110 °C after 15 min of leaching, the process is limited by diffusion through the product layer, which can be represented by titanium compounds. According to the SEM-EDX analysis of the solid residue, the magnetite spheres and mullite acicular particles were the main phases that remained after NaOH leaching. The spheric agglomerates of mullite particles with non-porous surface have also been found.

scholarly journals The Influence of Glycerol Monostearate Concentration and Storage Condition on Tomato Powder’s Contents Using Foam Mat Drying Method

REAKTOR ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 1-10
Author(s):  
Putri Ramadhany ◽  
Abigail Fern Pramana ◽  
Arabella Febiola ◽  
Tony Handoko
Keyword(s):  
Vitamin C ◽  
Moisture Content ◽  
Shelf Life ◽  
Room Temperature ◽  
Weight Ratio ◽  
Aluminium Foil ◽  
Drying Method ◽  
High Concentration ◽  
Tomato Production ◽  
Tomato Powder

Tomato is a seasonal horticultural product that has beneficial effects on human health. It contains a high concentration of lycopene and vitamin C. However, tomato production, which continues to increase in Indonesia, is not balanced with its consumption. Due to its high moisture content, harvested tomato relatively has a short shelf-life. Resultantly, the unconsumed tomato will end up being wasted. One way to prolong tomato’s shelf-life is by converting it into powder form. In this research, the tomato was shifted into tomato powder using a foam mat drying method. The weight ratio of GMS to tomato juice was varied: (1) 4%-w/w, (2) 5%-w/w, and (3) 6%-w/w. Tomato powder was then stored in two types of materials (sealed brown glass bottle and laminated aluminium foil (LAF) resealable zipper) and three conditions (refrigerator ( ± 4 ℃), room temperature (± 25.2 ℃) and sun-exposed  (± 30 ℃)). According to the results, foam mat drying could maintain the nutrients of the tomato powder. Increasing GMS larger than 5%-w/w had no big impact on reserving lycopene and vitamin C. At 5%-w/w GMS, tomato powder consisted of 1.09%/w/w moisture, 42.58 mg/100 g lycopene, and 123.28 mg/100 g vitamin C. It was found that moisture and vitamin C on tomato powder content was influenced by storage conditions, while lycopene content was influenced by storage material. Moisture content and vitamin C were best maintained at the sun-exposed condition and room temperature, respectively. While lycopene was best stored in the laminated aluminium foil (LAF) resealable zipper.

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