The refractory lead oxide ore has become an important source of lead metal with the continuous depletion of lead sulfide minerals. Lead oxide ore is of poor floatability and there are few cases to concentrate it successfully. In this study, the sulfidization-xanthate flotation method is applied for the beneficiation of lead oxide ore in Yunnan Province (China) with sodium hexametaphosphate and carboxymethyl cellulose as depressant. Chemical analysis and phase analysis was performed to explore the physicochemical property of raw ore, which provides a research basis for process design and operational control. The main influencing factors during the process, including grinding fineness, reagent types, and dosage, etc., have been studied through flotation tests. Zeta potential measurements and Fourier transfer-infrared spectrometry (FTIR) analysis were conducted to reveal the function mechanism of the reagents. Based on the determined experimental conditions, open circuit tests and closed circuit tests with one stage rougher, three-stage scavenger, and two-stage cleaner flotation, were carried out with the run-of-mine ore with a lead grade of 4.57%. Through close circuit bench test, the lead concentrate with a lead grade of 64.08% and recovery of 92.30% was obtained. This study is of special value, as it provides referencing significance for economically exploiting lead oxide ore.

The continuous centrifugal concentration for heavy minerals of high mass weight has been a major challenge in the development of centrifugal concentrators. A pilot-scale fluidized hydrocyclone concentrator operating on hydrocyclone and fluidized bed separation was developed for continuous centrifugal concentration of a magnetite–feldspar mixture. It realized a continuous centrifugal concentration for the mixture and achieved an apparent concentration for heavy minerals; its separation performance is greatly related to the feed and water inlet pressures, the number of concentrating rings and the feed solid concentration, which is accordance with the theoretical description on the concentration process. It was concluded that this novel method may provide a potential in the continuous centrifugal concentration for heavy minerals.

The Cyclonic Continuous Centrifugal Separator (CCCS) is a new type of separation equipment developed based on cyclonic continuous centrifugal separation technology and combined with the separation principle of the fluidized bed. Taking hematite as the research object, the main parameters and conditions of t he best hematite classification were determined through the classification test by using CCCS. Based on the classification test, the significance order of each process parameter and their interaction with hematite classification efficiency of the underflow products was analyzed with the Response Surface Methodology, the optimal process parameter of hematite classification was obtained and a multiple regression equation was established. The optimized process conditions were as follows, feeding pressure 55.48 kPa, backwash pressure 9.79 kPa, and underflow pressure 31.94 kPa. Under these conditions, the average hematite ore classification efficiency of coarse fraction (-2~+0.15mm), medium fraction (-0.15~+0.074mm) and fine fraction (-0.074mm) were 85.08%, 65.10% and 51.41%, respectively, and the relative errors with the predicted values were 1.6%, 4.0% and 2.5%, respectively. The results showed that the analytical model has good predictive performance. This research provides a certain prospect for the application of Cyclonic Continuous Centrifugal Separation to hematite ore classification. it provides a reference for the application of the Response Surface Methodology in the classification of hematite by Cyclonic Continuous Centrifugal Separation.

There are abundant diasporic bauxite resource in China. The gravity separation and flotation process are utilized for treating this kind of ore. When the ore grinding fineness is -200 mesh 80%, the qualified bauxite concentrate can be obtained, and it contains Al2O3 71.62%, SiO2 8.94%, and its Al2O3 recovery rate is 75.43%, A/S is 8.02.Compared with single flotation process, it can be reduced for the dosage flotation reagent and the cost of mineral processing.