scholarly journals Investigation of Molten Salt Phase Formation during Alkali Roasting of Titaniferous Minerals with Sodium and Potassium Hydroxide

2016 ◽  
Vol 16 (4) ◽  
Author(s):  
S. Parirenyatwa ◽  
L. Escudero-Castejon ◽  
S. Sanchez-Segado ◽  
Y. Hara ◽  
A. Jha
Keyword(s):  
Energy Consumption ◽  
Liquid Phase ◽  
Molten Salt ◽  
Phase Formation ◽  
Potassium Hydroxide ◽  
Salt Phase ◽  
Sodium And Potassium

Abstract The benefit of alkali roasting over existing processes is that it minimises waste and energy consumption compared with the current methods for the beneficiation of titaniferous minerals. Previous studies on the liquid phase formation during alkali roasting of titaniferous minerals were based on the use of Na

scholarly journals Formation of Chromium-Containing Molten Salt Phase during Roasting of Chromite Ore with Sodium and Potassium Hydroxides

2016 ◽  
Vol 16 (4) ◽  
pp. 215-225 ◽  
Author(s):  
Lidia Escudero-Castejon ◽  
Sergio Sanchez-Segado ◽  
Stephen Parirenyatwa ◽  
Animesh Jha
Keyword(s):  
Molten Salt ◽  
Extraction Yield ◽  
Water Soluble ◽  
Sodium Chromate ◽  
Water Leaching ◽  
Chromite Ore ◽  
Wide Range ◽  
Salt Phase ◽  
Sodium And Potassium ◽  
Equilibrium Calculations

AbstractChromium has a wide range of applications including metals and alloys manufacturing, pigments, corrosion resistance coatings and leather tanning. The production of chromium chemicals is based on the oxidative alkali roasting of chromite ores, which leads to the formation of water-soluble alkali chromates. Previous investigations reported that when chromite is roasted with soda-ash, a molten salt containing chromium, which is mainly composed of sodium carbonate and sodium chromate (Na2CO3-Na2CrO4 binary mixture), forms under typical roasting conditions. The physical properties of the liquid phase, which are dependent on the temperature, charge and gangue compositions, play an important role on the oxidation reaction and may limit the chromate recovery by hindering the oxygen transport to the reaction interface. This investigation focuses on the alkali roasting of chromite ore at 1,000 oC using NaOH and KOH, followed by water leaching. The influence of the alkali ratio on the chromium extraction yield is analysed, and the results obtained with both hydroxides are compared. Sample characterisation and thermodynamic analysis, including phase diagrams, equilibrium calculations and computation of liquidus curves, are combined with the purpose of studying the formation of the molten salt phase under different roasting conditions and its effect on the final chromium recovery.

Preparation of YBa2Cu3O7−x precursors from a fused eutectic of sodium and potassium hydroxides

1989 ◽  
Vol 4 (6) ◽  
pp. 1307-1311 ◽  
Author(s):  
Nicholas Coppa ◽  
Daniel H. Nichols ◽  
John W. Schwegler ◽  
J. E. Crow ◽  
G. H. Myer ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Potassium Hydroxide ◽  
Product Formation ◽  
Mechanical Grinding ◽  
Reaction Conditions ◽  
Fine Powders ◽  
Yttrium Barium ◽  
Sodium And Potassium

A method for preparing YBa2Cu3O7−x from the simultaneous thermal decomposition of the nitrates of yttrium, barium, and copper in an anhydrous fused eutectic of sodium and potassium hydroxide is described. This method eliminates the need for any mechanical grinding or the introduction of carbon containing anions. Products formed are fine powders (∼1 μm) having mole ratios 1.00Y:2.00Ba:3.06Cu.X-ray diffraction analyses reveal that the initial products are Y(OH)3, BaO2, and CuO, which when air calcinated/oxygen annealed at 900–950 °C form the superconducting YBa2Cu3O7−x A mechanism is postulated for product formation as a function of reaction conditions.

scholarly journals Fabrication of multi-layered structures for proton conducting ceramic cells

2021 ◽  
Author(s):  
Wendelin Deibert ◽  
Mariya E. Ivanova ◽  
Yuanye Huang ◽  
Rotraut Merkle ◽  
Joachim Maier ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Proton Conductivity ◽  
Phase Formation ◽  
Tape Casting ◽  
Transient Liquid Phase ◽  
Layered Structures ◽  
Proton Conducting

We show manufacturing of 25 cm2 BZCY half-cells by tape-casting of assemblies with electrolyte thickness 10–20 μm. BaY2NiO5 transient liquid phase formation is analysed and proton conductivity with values of σ = 0.003 S cm−1 at 600 °C is shown.

Effect of WC Addition on Phase Formation and Microstructure of TiC-Ni Composites

2008 ◽  
Vol 55-57 ◽  
pp. 353-356
Author(s):  
Nawarat Wora-uaychai ◽  
Nuchthana Poolthong ◽  
Ruangdaj Tongsri
Keyword(s):  
Liquid Phase ◽  
Tungsten Carbide ◽  
Phase Formation ◽  
Liquid Phase Sintering ◽  
Precipitation Process ◽  
Solid Solution Phase ◽  
Binder Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray

In this research, titanium carbide-nickel (TiC-Ni) composites, with tungsten carbide addition, were fabricated by using a powder metallurgy technique. The TiC-Ni mixtures containing between 0-15 wt. % tungsten carbide (WC), were compacted and then sintered at 1300°C and 1400°C, respectively. The phase formation and microstructure of the WC-added TiC-Ni composites have been investigated by X-ray diffraction and scanning electron microscopy techniques. Mechanical properties of these composites were assessed by an indentation technique. The X-ray diffraction patterns showed no evidence of tungsten rich phases in the sintered WC-added cermets. This indicates that during the sintering process, tungsten carbide particles were dissolved in metallic binder phase (Ni phase) via dissolution/re-precipitation process during liquid phase sintering. The liquid phase formed during sintering process could improve sinterability of TiC-based cermets i.e., it could lower sintering temperatures. The TiC-Ni composites typically exhibited a core-rim structure. The cores consisted of undissolved TiC particles enveloped by rims of (Ti, W)C solid solution phase. Hardness of TiC-Ni composites increased with WC content. Sintering temperature also had a slight effect on hardness values.

Effects of liquid phase formation on the order-disorder behavior of ba (ni1/3nb2/3)o3

1995 ◽  
Vol 173 (1) ◽  
pp. 125-137 ◽  
Author(s):  
In-Tae Kim ◽  
Su Jin Chung ◽  
Kug Sun Hong
Keyword(s):  
Liquid Phase ◽  
Phase Formation

Thermodynamic calculation and microscopic examination of liquid phase formation in MgO–C refractories contain calcium magnesium aluminate

2020 ◽  
Vol 256 ◽  
pp. 123723 ◽  
Author(s):  
Patrick Gehre ◽  
Theresia Preisker ◽  
Nora Brachhold ◽  
Stefan Guhl ◽  
Christoph Wöhrmeyer ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Phase Formation ◽  
Microscopic Examination ◽  
Thermodynamic Calculation ◽  
Magnesium Aluminate ◽  
Calcium Magnesium
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