A NEW METHOD FOR EFFICIENT AND SUSTAINABLE PRODUCTION OF MAGNESIUM OXIDE ORE-chloride developed by the Russian steel industry.
On AVISMA Titanium and Magnesium Works, a new method of producing magnesium, which can not only reduce the specific consumption rates of raw materials in its production, but also to dispose of excess chlorine from the electrolysis process, reduce the emission of gases into the atmosphere, reducing the yield of solid and liquid waste in the production of magnesium at 40 %.
Known methods of dehydration of magnesium chloride solutions have considerable drawbacks, which are manifested in the fact that in solutions in the dewatering of the fluidized bed furnace, it is difficult to remove water, which leads to a high degree of hydrolysis product obtained by reducing the process temperature, and this ultimately reduces the quality of anhydrous carnallite required for the electrolysis process, and requires additional processing of raw materials. Alternatively, dehydration in an oven synthetic carnallite formed multicomponent mixture, resulting in a low drainage rate and reduce the efficiency of the process. In addition, these methods do not provide for the integrated use of raw materials, have increased specific consumption rates of raw material for the subsequent process of electrolysis or inefficient technology.
Researchers AVISMA - Penske AV Shundikovym NA, Kurnosenko VV, Eltcova BI, Artamonovs VV and desolate position, IN, have developed the technology of production, it was possible to eliminate these drawbacks and, by increasing the agglomeration of the particles, reducing the degree of hydrolysis and the formation of a homogeneous mixture at the molecular level, the lower the specific norms of raw materials, which will reduce the cost of production of magnesium. This technology provides recycling excess chlorine electrolysis process reduces emissions of gases into the atmosphere due to their return to the leaching step, and reduces the output volume of solid and liquid wastes.
The essence of this technology consists in grinding chloride oxide material, its exhaust gases leaching to obtain a solution of magnesium chloride, purification, concentration and treatment of salt solutions containing potassium and magnesium chloride. Further step is to obtain a homogeneous mixture of synthetic carnallite composition and mixing the mixture with natural enriched carnallite. First two-step dehydration is carried out in a fluidized bed to obtain carnallite, anhydrous, and then - the chlorination of dehydrated to yield anhydrous carnallite.
Electrolysis carnallite to give anhydrous magnesium chloride and spent electrolyte, followed by the return of chlorine to both dehydration step and the spent electrolyte is in the mixing step. Capture dust from flue gases of furnaces followed COP direction flue gases produced in the leaching step of the oxide material, wherein the concentration of lead in the solution tank, its circulation through the scrubber to the magnesium oxide content in the solution is not more than 10 g / l.
This will reduce the costs of the concentration step and get the necessary quality of the finished product.
The resulting magnesium chloride solution is separated into two streams in a ratio of 1: (1-5). One stream is fed to the fluidized bed, the other thread - by treating a solution of salts when heated in a homogeneous mixture with a salt solution at a particular ratio. This can improve the agglomeration of particles in the fluidized bed and thereby enhance the quality of the product and reduce the specific consumption rate of raw materials to obtain magnesium oxide-chloride materials.
The resultant mixture is mixed with the enriched natural carnallite and fed simultaneously with the step of dehydration in solution in a fluidized bed at a flow rate of flue gas necessary to create the above fluidized bed.
Furthermore, a first dehydration step is carried out in a multi-chamber fluidized bed furnace and the temperature in the first fluidized bed furnace chamber is maintained at +130-170 | C and +220-250 | C, which allows to increase the conversion in synthetic carnallite and carnallite dehydrated thereby reducing the cost of its production.
The long chain of processes is justified.
The only extra costs are that the chlorine oxide feedstock prior to drying require grinding.
Contact information:
618421, Perm region. Berezniki, JSC AVISMA Titanium and Magnesium Works, Engineering Department
