Magnetic fluid static separation working medium
The magnetic fluid static separation beneficiation working medium is a paramagnetic strong magnetic liquid. It has the following three requirements: Timing Cover,Front Timing Cover,Timing Chain Cover,Timing Belt Cover Ningbo Maixun International Trade Co., Ltd , https://www.zjnbmachinery.com
(1) It should have a high susceptibility to produce a high magnetic buoyancy in an inhomogeneous magnetic field and increase the apparent density of the liquid.
(2) It has a low viscosity and good fluidity without precipitation and agglomeration in order to improve the sorting precision of minerals.
(3) It is non-toxic, odorless, cheap and easy to obtain, easy to use, easy to recycle and regenerate.
There are three types of magnetic fluids suitable for the above requirements:
(1) A paramagnetic electrolyte solution having a high magnetization coefficient. It is usually a true solution, but it is also colloidal. Its preparation is simple, i.e. a paramagnetic metal salts dissolved in an aqueous solution or an organic solvent together. These metal salts are nickel chloride, cobalt chloride several metals, manganese sulfate, manganese carbonate, manganese chloride, manganese nitrate, ferric chloride, and rare earths such as erbium (Er), terbium (Tb), dysprosium (Dy) And hydrazine (Ho) compounds.
Among these electrolytes, the aqueous solution of manganese chloride and manganese nitrate has a high magnetization coefficient, and is non-toxic, odorless, small in viscosity, good in transparency, and relatively inexpensive, and is an ideal working medium; It is brownish black, basically opaque, has a low susceptibility and is corrosive, but it is very inexpensive and has a wide range of sources, so it is still a promising working medium for industrial applications.
(2) Ferromagnetic colloidal suspension. It is a surface treatment of particles such as magnetite, so that it can be stably dispersed in the liquid phase, and does not cause aggregation or sedimentation under the action of gravity and magnetic force, but also has magnetic and non-display hysteresis. The phenomenon is characterized by lower viscosity. There are three methods of co-preparation:
1) pulverizing method (1965 Papell). This method is added oleic acid was placed magnetite organic solvent (e.g., kerosene) in a ball mill, after grinding time (20 days), and then after centrifugal classification Remove the coarse particles and, if necessary, concentrate the treatment;
2) Dispersion method (the next meal in 1966, Run Run 3). It is the adsorption treatment of oleic acid ions by the magnetite granules obtained by wet pulverization, so that the oleic acid ions are adsorbed on the surface of the magnetite in a single layer, and then in the water. Adding a long-chain ionic or non-ionic surfactant to form a second layer on the side of the oleic acid ion layer that forms a hydrophilic group toward the aqueous phase;
3) Peptization method (Khalafalla, 1972). This method is to add ammonia water to an aqueous solution containing Fe 2+ and Fe 3+ to precipitate magnetite particles. The ore particles are placed in a mixture of boiling kerosene and oleic acid, and after being transferred into the oil phase, the water is evaporated. The oil-based magnetic fluid produced by this method has the lowest cost.
(3) Liquid metal or low melting point metal. Such as Wood alloy (Bi50%, Pb25%, Sn12.5%, Cd12.5%), it melts at 65.5 ° C, its density is 9.7 g / cm 3 , the specific heat capacity is 0.167 J / g · ° C melting specific heat is 35.16 J / g, a boiling point of about 1600 ℃ when it was heated to 100 deg.] C, may be passed .1478 kilowatts of power at a current of 1 cm 3 of metal. The current density is equal to 1650 A / cm 3.
The liquid metal does not wet the ore. During the operation of the liquid metal, the ore particles can be completely separated by themselves, which not only avoids the loss of the metal solution, but also avoids the trouble of purification and regeneration of the metal solution. In addition, liquid metal does not undergo electrolysis, does not evaporate at 100 ~ 120 ° C; does not emit toxic gases polluting air and flammable gases cause fire; liquid metal density is high, can be as high as 11.5 g / cm 3 , which is very good for sorting favorable. The disadvantage is that the production cost is high and it is difficult to operate at high temperatures. But in general, liquid metal as a working medium is promising.