The Optimization And Performance Testing Of Novel Flotation Machine With Double Impeller Structure

Floatation is a kind of ore dressing method which has been paid much attention by the general ore dressing workers.Flotation machine is a kind of important flotation equipment,which has been paid much attention to the researchers.Now,the mechanically flotation machine is one of the most sophisticated and widely used flotation devices in the world.Up to now,the structure has been greatly developed,but the "1+1 mode" of one rotor(impeller)and one stator has never been changed.Air intake and slurry suspension are greatly limited by the speed of the impeller.It is difficult to achieve adequate air charging in a suitable static flow separation environment.So,in order to improve the separation performance of flotation machines,we need to make some improvements.In this paper,the mixing system of the flotation machine is improved,we use the double impeller control system(2+1 mode)to replace the traditional "1+1 mode" to improve its separation performance.Different centrifugal impeller,mixing impeller,flow guide cylinder(stator)and flotation tank were designed for this experiment.The cavitation strength of different centrifugal impeller was tested to optimize the performance of the centrifugal impeller to produce mineralized bubbles.The critical speed of different impeller to keep slurry suspended and dispersed was determined to optimize the structural parameters of the impeller.In this paper,a comparative experiment was carried out between a double-impeller flotation machine and a conventional mechanical stirring self-priming flotation machine to evaluate the influence of the structural characteristics and working parameters of the double-impeller flotation machine on the separation performance.Based on that,We determine the structure of flotation machine.The influence of double impeller on the flow field of flotation equipment was studied.The relationship between stirring impeller and critical suspension speed,the direction and velocity of gas-liquid flow field in flotation tank and the relationship between centrifugal impeller and cavitation foaming were investigated.The result show that the suspension height of slurry mineral particles and the turbulence intensity of slurry are taken into account.The inclination Angle and diameter of the impeller should not be too large or too small.There is cavitation foaming in the equipment,the effect of square flotation tank is slightly better than circular flotation tank.No.2 centrifugal impeller with a diameter of 30mm+20mm and a length of 30mm+30mm has good effect.With the design of mixing impeller and centrifugal impeller,the new double-impeller system flotation machine can obtain a reasonable distribution of liquid flow direction and speed in the mixing zone,separation zone,foam zone and provide a better separation environment for mineral flotation.In the structure optimization experiment of double impeller flotation machine,the influence of different mixing impeller,centrifugal impeller,flotation tank and diversion tube structure on the flotation was investigated.The results show that no.2 stirring impeller,no.1 diversion cylinder and no.2 centrifugal impeller have better effect,no.1 square floation tank has the same effect as no.2 columnar flotation tank.In the comparison test,the new double-impeller flotation machine has a better effect than the traditional flotation machine on concentrate grade or recovery of different types of colloidal phosphate ores.The effect has been greatly improved.In the end,a new type of flotation machine consisting of no.2 mixing impeller?no.1 diversion cylinder?no.2 centrifugal impeller and no.1 square flotation tank.The results showed that: for yichang mine 3,Adopt one rough-one concentrate-one scavenging direct flotation and one rough reverse flotation closed-circuit test,under the condition of optimum medicament,achieve the concentrate grade P2O5 34.55%?R2O3 2.34%?Mg O 0.52% and the recovery rate of phosphorus concentrate 93.56% of good separation indexes.Adopting one rough-one concentrate-two scavenging reverse flotation closed-circuit test in yichang mine 2.Under the condition of the best reagent,achieve the concentrate grade P2O5 34.08%?Mg O 0.55% and the recovery rate of phosphorus concentrate 91.37% of good separation indexes.