| Zinc is one of strategic nonferrous metal resources in China,which is widely used in industries such as zinc plating,batteries,aerospace,metallurgy,chemical engineering,and machinery.With the increasing demand for zinc and the depletion of zinc sulfide ore,researchers are turning their attention to the development and utilization of zinc oxide ore resources.However,due to the large amount of impurity metals,alkaline gangue,and silicate components in low-grade zinc oxide ore,using traditional acid leaching can lead to high acid consumption and increased difficulty in subsequent purification processes,making the acid leaching process unsuitable.The NaOH leaching process can avoid the disadvantage of acid leaching,but the zinc leaching effect is not good when dealing with zinc silicate minerals such as zinc silicate ore and hemimorphite,so a strengthening method is urgently needed to improve.In this paper,a low-grade lead-zinc oxide ore from Lanping,Yunnan Province,was used as raw material,NaOH solution as leaching agent,and a basket grinder as mechanical activation equipment to study the grinding leaching synergistic（MCL）process.The raw ore and leaching residue were analyzed through characterization methods such as XRD,SEM,particle size analysis,and EPMA to explore the strengthening mechanism of the MCL process.The main conclusions are as follows:（1）The MCL process can enhance the effect of alkaline leaching for zinc extraction and shorten the reaction time.The optimal leaching conditions for MCL process are:leaching temperature of 75℃,NaOH concentration of 3 mol/L,leaching time of 60 min,liquid-solid ratio of 10:1,and stirring speed of 800 rpm;Under these conditions,the leaching rate of zinc reaches 92.33%,which is 7.21%higher than the conventional stirring leaching（CSL）process.The residual zinc containing components in the leaching residue exist as difficult to leach zinc phases such as Zn S and Zn Fe2O4,which hinder the further improvement of zinc leaching rate.（2）The optimal grinding process parameters for MCL process optimization experiment are:the agitator type is a toothed disc turbine type agitator,the grinding ball is a steel ball with a diameter of 2mm,the amount of grinding ball added is 100 g,and the grinding speed is 1000 rpm.Under these conditions,the zinc leaching rate,energy consumption during the grinding leaching process,and MCL grinding efficiency are all at relatively optimal levels.（3）The kinetic research results of the alkaline leaching process of zinc show that it conforms to the Avrami model equation.The apparent activation energy of the alkaline leaching reaction of zinc oxide ore under the MCL process is 8.04 k J/mol,and the reaction order is 0.284.The reaction is controlled by internal diffusion.In summary,the use of MCL process can achieve efficient extraction of zinc from low-grade zinc oxide ore,reduce reaction conditions,improve process flow,and provide new ideas for the resource utilization of low-grade refractory zinc oxide ore in the Lanping area of China. |
