Rheological Properties Of Gangue Minerals In Scheelite Flotation

Scheelite is the main source of tungsten in China,but most scheelite occurs in skarn type tungsten deposits,with low average grade,fine Mosaic size,and complex gangue mineral composition.The difference of physical and chemical properties of gangue minerals will lead to complex rheological properties of pulp in flotation process.In the flotation system,the rheology of pulp can reflect the interaction between useful minerals and gangue minerals as well as their internal particles,and has a direct impact on the flotation microscopic processes such as the collision between bubbles and particles,the interaction between mineral particles,and the interaction between chemicals and minerals.Therefore,by studying the deformation and flow law of pulp under the action of mineral components,flotation agents,external force field and other factors,this paper analyzes the influence of the change of rheological properties of gangue minerals in the flotation process of scheelite on the flotation behavior,and puts forward improvement measures for the control of rheological properties of pulp in the actual ore flotation system.The results of slurry rheology test,foam stability measurement and mixed ore flotation test showed that the relationship of mineral type affecting slurry rheology was as follows:muscovite>tourmaline>quartz>scheelite/apatite.This was due to the fact that muscovite in the pulp will formed a three-dimensional network structure of end-surface and end-surface combination,which had a large apparent viscosity,while tourmaline and apatite in the pulp were only simple pile type structure,which had little influence on the viscosity of the pulp.In the flotation system of artificial mixed ore,Fe³⁺,Mg²⁺,Ca²⁺and PO₄^3-dissolved in water also increased with the increase of the content of turmaline and apatite,and these ions would be absorbed on the surface of scheelite,thus worsening the flotation.When the concentration was 60%,the concentrate grade decreased to 9.32%and 9.88%,respectively,and the recovery rate decreased to 52.22%and 47.43%.With the increase of muscovite content,the foam layer thickness increased with appropriate viscosity,which was conducive to the improvement of concentrate quality.When the content was 40%,the grade was 12.75%and the recovery was 68.54%.When the content of muscovite was increased to 60%,the higher pulp viscosity inhibited the collision between bubbles and particles and the mobility of bubble-particle aggregates,resulting in the concentrate grade decreased to9.68%and the recovery decreased to 54.59%.The results of mineral surface potential measurement,contact Angle measurement,flotation test and rheological test showed that the rheological properties of pulp could be controlled by adding dispersant,changing the stirring rate and ultrasonic pretreatment.The addition of flotation agents such as sodium silicate and sodium hemeretaphosphate increased the electronegative property of the surface of mineral particles in the sodium oleate system,enhanced the electrostatic repulsion between mineral particles,improved the dispersion degree of mineral particles in the pulp,and was conducive to the contact between reagent and mineral particles.The pulp viscosity decreased from 155.6 m Pa·s to 152 m Pa·s.The flotation concentrate grade increased from 1.21%to 2.29%,and the recovery rate first increased from 40.75%to 68.14%and then decreased to 47.55%.The increase of agitation rate increased the movement speed of mineral particles in the pulp,increased the collision probability between mineral particles,improved the internal friction of the pulp in the process of agitation,promoted the suspension of mineral particles and the uniform distribution of mineral particles and bubbles in the tank,increased the contact chance of mineral particles and bubbles,was conducive to the recovery of target minerals,but also improved the entraining of gangue minerals.The pulp viscosity increased from 52.47 m Pa·s to 65.74 m Pa·s,the concentrate grade decreased from 1.95%to 1.52%,the recovery rate increased from 60.11%to 68.14%, and then decreased to 62.64%.Ultrasonic pretreatment intensified the movement of mineral particle molecules,changed the structure of the pulp,and made the particles in the pulp disperse.However,long-term treatment would break the ore particles,increased the content of fine minerals in the pulp,which was not conducive to flotation.The viscosity of the pulp decreased from 158.72 m Pa·s to 143.09 m Pa·s.recovery first increased from 68.14%to 74.25%,and then decreased to 60.52%.