Regarding the relationship between surface chemical properties of mineral crystals and flotation behavior, researchers at home and abroad mainly focus on surface fracture bonds, surface energy, wettability and adsorption. By calculating the number of fracture bonds and surface energy of the mineral surface, the cleavage properties and crystal habits of the mineral can be predicted, and the wettability and adsorption properties are indirectly explained. By analyzing the arrangement characteristics of mineral surface active particles, the difference between the different exposed surfaces of minerals and flotation agent can be explored by computer simulation, and the flotation mechanism is revealed.
Study on the properties of the fracture bond of mineral surface
Research shows that Hu et al., A diaspore, kaolinite, illite and pyrophyllite isoelectric point and point of zero charge gradually decreases with the order of arrangement, the surface properties of the Al- its electrochemical properties and minerals The O bond cleavage is closely related to the Si-O bond. The crystal structure, crystal chemistry and surface properties of the kaolin indicate that the soft kaolin has a higher crystallinity index than the hard kaolin and the flotation performance is also excellent.
Liu Xiaowen systematically analyzed the crystal structure of siliceous gangue minerals such as diaspore, kaolinite, illite and pyrophyllite, calculated the number of surface fracture bonds of each mineral, and analyzed the solutions of four minerals. The relationship between the properties and the wettability of each crystal plane and the flotation behavior.
Gao Zhiyong analyzed the crystal structure of three kinds of calcium-bearing minerals such as scheelite , calcite and fluorite . The cleavage properties and crystal habits of three calcium-containing mineral crystals are related to the electrical properties, interlayer spacing, fracture bond density and surface energy of the mineral surface. . Rai et al. used molecular dynamics simulations to confirm that the oleate ion and the spodumene {110} surface are more negative than the {001} plane and have a stronger effect.
B Mineral surface energy research
The surface free energy of minerals is directly related to mineral wettability, adsorption and interface kinetics. At present, researchers mainly use computer simulation to calculate mineral surface energy. There have been many studies in recent years on the surface energy of different crystallographic directions of oxidized ore.
Oviedo et al calculated cassiterite (SnO 2) four Bu {110} crystal plane, {100}, {101}, {001} surface energy, were 1.04J / m 2, 1.14J / m 2, 1.33 J / m 2, 1.72J / m 2, show {110} plane of the crystal plane is the most stable. Perron et al., Calculated rutile (TiO 2) four crystal planes {110}, {100}, {101}, {001} surface energy, were 0.89J / m 2, 1.12J / m 2, 1.39 J/m 2 and 1.65J/m 2 , the surface energy of each crystal surface is in the same order as the cassiterite. This is because rutile and cassiterite have similar crystal structures, which belong to the tetragonal system.
The surface free energy, polar component, and polar component of the {112} cleavage surface and calcite {104} cleavage surface account for the surface free energy ratio of the former is greater than the latter, and the Ca-O fractures of the two The number of keys is related to the difference in bond energy. Gao also calculated the bond energy density of the three surfaces of calcite cleavage on six surfaces and fluorite cleavage. It is believed that the common cleavage planes of calcite are {10-14}, {21-34} and {01-18}, {111} The common cleavage surface of fluorite and the linear relationship between surface fracture bond density and surface energy.
C Mineral surface adsorption study
In recent years, studies have shown that mineral surface active density and its spatial orientation distribution may be the key factors affecting the adsorption behavior of chemical molecules on mineral surfaces. Regarding the adsorption behavior of water molecules and small organic molecules collectors on different mineral faces, Steve Parker of the University of Bath in the United Kingdom and Nora de Leeuw of the University College of London have conducted a large number of computer simulation studies. Their research ideas can be summarized as: cutting and modeling a series of crystal faces of minerals, and then exploring and determining the minimum energy adsorption model of water molecules and small molecule collectors on these crystal faces and calculating the adsorption energy.
Taking mica as an example, Satoshi Nishimura et al. studied the adsorption characteristics of dodecylamine hydrochloride on the bottom of mica. The measurement of the dynamic potential of the mineral surface, the adsorption isotherm and the contact angle gave a significant decrease in the dynamic potential of the mineral surface. At the concentration of dodecylamine hydrochloride, the adsorption isotherms and contact angles of the mica surface increased, and the dodecyl double layer adsorption was formed on the surface of the mica. Mark Rutland et al. studied the effect of pulp pH on the adsorption of dodecylamine on the surface of mica. The results show that under the condition of low pH value (pH less than 8), dodecylamine in the slurry exists in the form of dodecylamine cation. The dodecyl cation is mainly adsorbed on the mica anion charge by electrostatic action, so that there are some positions on the mica surface. It is adsorbed by the collector; in the range of pH 8-9, dodecylamine is mainly in the form of dodecyl cation and dodecylamine molecule, and dodecyl cation and dodecylamine molecule are simultaneously adsorbed on the surface of mica. All the positions on the surface of the mica are adsorbed by the collector to form a tight monolayer adsorption, and the hydrophobic group is exposed on the surface of the mica to make the mica hydrophobic.
2 Interfacial interaction force of fine-grained oxidized minerals
DLVO theory and extensions DLVO (EDLVO) theory suggests: mineral slurries floating potential energy and the total effect of particle size, shape, distance between the particles, the surface potential of the particles, the electrolyte concentration, flotation agents macromolecules relative molecular mass between particles, adsorption Thickness, pulp temperature, etc. are related to the cause. Using DLVO theory and extended DLVO theory can better explain the interaction between particles in different flotation pulp systems: such as cohesive and dispersive behavior between homogenous particles and heterogeneous particles in bauxite flotation system, microorganisms in microbial leaching adsorption and between ore particles, between the iron minerals, manganese as well as various gangue minerals and gangue aggregation and dispersion behavior.
Liu studied the aggregation and dispersion behavior between homogenous particles and heterogeneous particles in bauxite flotation system, and believed that the aggregation of particles is the main influencing factor of flotation under low pH conditions. Monfared studied the adsorption equilibrium, kinetics and thermodynamics of nano-silica particles adsorbed on the surface of calcite, and explained the factors affecting the interaction between the two particles by DLVO: surface electrical properties, particle size, surface wettability.
Zhang Guofan, who explore the interaction between the titanium from ilmenite, pyroxene and DLVO theory. As the surface electronegativity of the mineral decreases, the wettability decreases, and the particle size of the mineral particles decreases, the gravitational force between the two minerals increases. The theoretical calculation results of DLVO show that when the pH value is 5.9, the total interaction energy between the two mineral particles is negative, which is mutually attractive. The fine-grained titanite will adhere to the surface of ilmenite, making titanium The recovery rate of iron ore is significantly reduced; when the pH is 8.5, the total interaction shows a strong repulsive force due to the large electrostatic repulsion, and the fine-grained diopside can not adhere to the surface of ilmenite. Yin studied the effect of smectite particle size and particle interaction on flotation. According to the test results and EDLVO theory, it is known that the fine particles and the coarse particles have an interfacial action, which reduces the energy of the system and reduces the recovery rate. In the process of studying the new process and mechanism of pre-de-ironing-de-mudging-black-and-white tungsten mixing of tungsten ore, the interaction energy of scheelite and slime is calculated by expanding DLVO theory. The results show that between scheelite and slime The EDLVO potential energy is always negative, which is characterized by the mutual attraction behavior of scheelite and slime. The slime cover covers the surface of tungsten ore and affects the flotation of tungsten ore.
Feng Bo et al. calculated the pH value of 9, when there is no CMC, the interaction energy between pyrite and serpentine is negative, indicating that there is a strong mutual attraction between the two, easy Heterogeneous condensation occurs. After the addition of CMC, the interaction energy between serpentine and pyrite becomes positive, and there is a strong mutual repulsion between the two, and no heterogeneous coagulation occurs.
At pH 9, sodium hexametaphosphate in an amount of 100mg / L under the conditions, serpentine and talc and chlorite over a substantial range of distances, the total mutual action between the particles can be represented by a repulsive force, which It is because the addition of sodium hexametaphosphate causes the surface potential of the serpentine particles to change from positive to negative, resulting in the same surface charge of serpentine and talc and chlorite, which are mutually repelled by electrostatic interaction, so that the cover is covered in talc and green mud. The serpentine on the surface of the stone particles falls off, and sodium hexametaphosphate acts to disperse the serpentine.
Zhu Yangge et al. calculated the potential energy curve of the interaction between fine-grained ilmenite and coarse-grained ilmenite. If the hydrophobic interaction is not considered, there is a higher energy barrier between the fine-grained mineral and the carrier, fine-grained minerals. It is difficult to adhere to the surface of the carrier; after the addition of sodium oleate, the surface of the fine-grained mineral and the carrier mineral are hydrophobic, and the hydrophobic interaction causes the repulsive force to become attractive to the two, and the coarse and fine mineral particles are easy to adhere. It can be seen that the hydrophobic interaction is the premise of the adhesion of fine-grained ilmenite to the carrier in the system, and plays an important role in the flotation of ilmenite from the carrier.
The Cutting Table is up to your workpiece max length and width.
if you have more bigger materials want to cut,can ask us about customized table.
we offered customized including 6m*2M 8m and so on.
Cutting Table,Cnc Plasma Table,Plasma Cutting Table,Cnc Plasma Cutting Machine
FOSHAN YUANLI PRECISION MACHINERY CO.,LTD , https://www.ylwaterjet.com