Basic principle and main technical indexes of tungsten mineral NaF leaching method
First, the basic principle The NaF leaching method reacts as follows: At 225 ° C, the concentration equilibrium constant is 24.5. The leaching rate of tungsten than white with CO 3 2 - -, PO 4 3 - other large (see FIG. 1) F. Figure 1 Reaction rate of CaWO4 with different anions (PB Kui) At less than 100 ° C, a CaF 2 film is formed on the surface of the ore particles, which hinders the reaction. Above 100 ° C, the film falls off. The apparent activation energies were 63.54 kJ∕mol and 89.03 kJ∕mol, respectively, at stirring speeds of 830 r∕min and 510 r∕min, respectively. Second, the main technical indicators When a Russian scholar treats a white tungsten ore containing 33.7% to 41.5% WO 3 , when the temperature is 225 ° C and the amount of NaF is 1.8 times the theoretical amount, the decomposition rate is 99.2% to 99.8%, and SiO 2 ∕ WO 3 = in the leachate. 0.2% to 0.5%. Yao Zhengang waited for the treatment of Shizhuyuan white tungsten concentrate under industrial conditions. When the amount of NaF was 1.2 times the theoretical amount and 1.5 hours at 190 °C, the decomposition rate was 98.87%, and the obtained Na 2 WO 4 solution contained P0.002g. L, As 0.017 g ∕ L, SiO 2 0.055 g ∕ L. The disadvantage of the NaF leaching method is that the solubility of NaF is limited, that is, the F - concentration in the leaching agent is limited, and accordingly the unit production capacity is low.
Fluorocrystalline mica, also known as Fluorphlogopite Mica, synthetic mica, artificial mica, synthetic mica crystal, belongs to the silicate type artificial mica crystal, is under the high temperature condition of 1500°C, through strict process conditions and material ratio, in platinum The mica crystals smelted in the yttrium have a chemical formula of KMg3(AISi3O10)F2(OH)-, and do not contain (OH)-. The (OH)-hydroxyl group is replaced by F-(fluoro), which is similar to the fluorite mica. Materials commonly used in the general industry are natural mica. Natural mica is an underground ore naturally formed and belongs to the class of silicates. Most of the industrial mica used is phlogopite (brown) and muscovite. Its ideal chemical formula is KAI2(AISi3O10)(OH)2. OH)-(Hydroxy), due to the presence of hydroxyl (water molecules), its performance in all aspects is far lower than that of fluorocrystalline mica.
The main characteristics of fluoride crystal mica:
1, high temperature: can work long-term in the 1100 °C environment.
The testing department of the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (nationally recognized testing institute) tested the thermal weight loss of 8% at 1100°C for 48 hours, and the melting and devitrification temperature was 1375°C.
2. Electrical insulation: The volume resistivity is 10 times higher than natural mica. Electrical breakdown strength is PTFE
Lean 10 times.
3, hot and cold blasting stability is very good
5 cycles of -40°C~70°C at the 5th Saibao Lab of the Ministry of Information Industry
Inspection, all qualified.
4, anti-corrosion:
Fluorophlogopite does not react with acid and alkali solutions, and does not react with water. Under the long-term (2 to 3 years) scouring of high-temperature and high-pressure water (including acid and alkali), the original clarity and transparency can still be maintained.
5, high frequency performance:
The dielectric constant of fluorite mica is 4.6 ε, and the dielectric loss is (1~4)×10 −4 tg δ, and the dielectric loss is very low. And because of the pure texture, all parameters are extremely stable.
6, optical properties
Since the fluorite mica contains less impurities, its light transmittance is compared from infrared to ultraviolet.
High, the transmittance is close to 100%.
7, Mosaic (Mosaicity):
The Mosaicite of fluorocrystalline mica is less than 0.25 degrees, which was produced in the experiment.
The neutron flame is not high enough to absorb multi-band light beams and is an ideal neutron monochromator test material.
8, vacuum deflation performance:
The evaporative volume of fluorite mica is low, and it is measured with a mass spectrometer and the trace gas released is only
O2, N2, Ar and other adsorbed gases. Since the H2O vapor is not released, this is extremely valuable for use as an electrical vacuum insulation material, which can greatly increase the service life of the vacuum device.
9, excellent physical properties:
Fluorocrystalline mica has atomicity flatness, transparency, separability and elasticity, not aging
It is not brittle and so on.
Due to the high temperature resistance, corrosion resistance, low frequency loss, and high bulk resistivity
Absorb multi-band light beam, excellent light transmittance and other advantages. Therefore it has become an ideal new material in the high-end area.
Fluorocrystalline mica Available in:
In the range of 180mm×53mm or ∮76mm, it can be processed into various shapes according to user requirements. Thickness within the range of 0.02mm~1.0mm can be allocated according to user requirements. The conventional thickness is 0.04~0.2mm.
Fluorine crystal (fluorphlogopite, artificial mica) mica film for observation window of high pressure boiler water level gauge in thermal power plant
Fluorphlogopite Mica Fluorophlogopite Mica,Fluorophlogopite Sheet,Synthetic Fluorophlogopite Mica,Fluorophlogopite Mica Fragments Changchun City Taiyuan FluorphlogopiteCo. Ltd. , https://www.micaslice.com