Uranium recovery from phosphate ores through sintering

1983 ◽  
Vol 61 (10) ◽  
pp. 2341-2343 ◽  
Author(s):  
L. A. Guirguis
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Carbonate ◽  
Sodium Phosphate ◽  
Moderate Temperature ◽  
Low Grade ◽  
Uranium Recovery ◽  
Phosphate Ores

The use of an alkaline reactant for phosphate processing is an alternative to the current methods of using acid reagents.In this work the possibilities of attacking low-grade phosphate ores by sintering with sodium carbonate at moderate temperature are considered. The carbonate liquor obtained by a water leach contains uranium in the form of uranyl tricarbonate complex, as well as the equivalent dissolved phosphate. Uranium from such liquor was recovered as sodium uranate on addition of sodium hydroxide, while pure sodium phosphate, useful as a chemical, was recovered by fractional crystallization.Finally, a flowsheet was designed for the proposed process.

Reduction of insecticide residues in grain dust by treatment with alkali

1978 ◽  
Vol 18 (92) ◽  
pp. 453 ◽  
Author(s):  
JM Desmarchelier ◽  
JP Hogan
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Carbonate ◽  
Pesticide Residues ◽  
Animal Feed ◽  
Pilot Scale ◽  
Liquid Sodium ◽  
Low Grade ◽  
Grain Dust ◽  
Commercial Applications ◽  
Stock Feed

A series of laboratory and pilot scale experiments was performed to reduce residues of dichlorvos and malathion in grain dust to levels below the maximum permitted for stock feed. Processing such as steaming or pelleting did not reduce pesticide residues sufficiently, but mixing grain dust with three alkaline materials, sodium hydroxide, sodium carbonate or ammonia, reduced residues considerably and this reduction was increased by subsequent processing. Reduction of residues was greater from use of liquid rather than solid alkalis, from use of the stronger (sodium hydroxide) rather than from the weaker (sodium carbonate) base and was proportional to the amount of liquid sodium hydroxide or ammonia that was used. Alkaline materials reduced pesticide residues in possible stock feed combinations of grain dust plus straw and grain dust plus lucerne meal. As these results are consistent with general base-catalyzed hydrolysis of organophosphorus esters, there is probably scope for considerable variations in procedure by use of different alkalis and different exposure times to alkali. In commercial applications amounts of base required (2 per cent w/w) were less than those used to increase the food value of low-grade animal feed.

Flexibility Modification of Konjac Glucomannan Film by Deacetylation

2009 ◽  
Vol 610-613 ◽  
pp. 1248-1251 ◽  
Author(s):  
Yan Chen ◽  
Xiao Yan Lin ◽  
Xue Gang Luo ◽  
Ying Ting Kang
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Calcium Hydroxide ◽  
Sodium Carbonate ◽  
Sodium Phosphate ◽  
Konjac Glucomannan ◽  
Glass Plates

Konjac glucomannan (KGM) were modified by deacetylation with sodium hydroxide, calcium hydroxide, sodium carbonate, sodium phosphate, respectively and mechanical properties of modified KGM films were investigated. The modification mechanism was explored by FTIR. Results show that deacetylation of KGM play an important role on the flexibility of the modified membranes, and the flexibilities vary with different modifiers. The flexibility of the films modified by sodium hydroxide is significantly higher than that of the others. The modified films with good flexibility were prepared by simple steps as follows: NaOH modifiers and KGM (1%) were added to water, stirred until the pH arrived at 9. And then the KGM swelled at the temperature of 50°C for 2 hours, the modified KGM sol was cast onto glass plates, the modified membranes were formed after dried at 50°C.

scholarly journals Extraction of Boron from Ludwigite Ore: Mechanism of Soda-Ash Roasting of Lizardite and Szaibelyite

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Energy Dispersive Spectrometer ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selective Activation ◽  
X Ray ◽  
Shed Light ◽  
Soda Ash ◽  
Scanning Electron

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.

The Effect of Different Oxidants on Extraction of Uranium from Low Grade Ore

2020 ◽  
Vol 299 ◽  
pp. 1104-1108
Author(s):  
Ashimkhan T. Kanayev ◽  
Khussain Valiyev ◽  
Aleksandr Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Potassium Permanganate ◽  
Ferric Sulfate ◽  
Low Grade ◽  
Acid Solutions ◽  
Uranium Recovery ◽  
Ammonium Persulphate ◽  
Uranium Extraction ◽  
Increase Rate ◽  
Sulfuric Acid Solutions

The effect of different oxidants on extraction of uranium from low grade ore was studied. Leaching was performed using sulfuric acid solutions at a concentration of 10 to 30%. Ferric sulfate Fe2(SO4)3, ammonium persulphate (NH4)2S2O8, and potassium permanganate KMnO4 at different concentrations were used as oxidants in different variants of the experiment. In addition, solutions collected at Vostok deposit containing 6.86 g/L Fe3+ and 106 cells/mL of the bacteria Acidithiobacillusferrooxidans were used for leaching. The rate of uranium extraction with sulfuric acid solutions without oxidants was low and did not exceed 19.4%. Addition of oxidants made it possible to increase rate of uranium extraction. In the presence of ferric sulfate, ammonium persulphate, and potassium permanganate rates of uranium extraction were up to 68, 95.2, and 69.6%, respectively. The rate of uranium leaching in the experiments with the AMD sample was high and reached about 95%. Therefore, it can be concluded that using not only oxidizing agents, but AMD, which are formed during the natural oxidation of sulfide minerals contained in the ore of the deposit, can significantly increase the rate of uranium recovery.

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