A numerical model was established by using LS-DYNA software and then used to simulate the influence of pre-split fracture with width of 3 cm and 5 cm, respectively, on blasting effect. It is found that wider pre-split fracture can bring a better effect of blasting vibration attenuation, with the maximum amplitude decay rate of 46%. Based on pre-split blasting tests with different borehole sizes, the on-site vibration monitoring results have verified the correctness of the rule. It is concluded that the parameters of pre-split blasting should be selected based on the actual working conditions in consideration of protection of surrounding buildings.

A Gamma-ray concentration meter based on Kalman filtering was designed, and the relationship between ray intensity attenuation and slurry concentration was established by analyzing the measurement principle of ray concentration meter. To suppress the disturbance of the results, an optimal estimation of ray intensity was actualized by using Kalman filtering. The corresponding concentration is segmentally simulated and calculated by using the least square method. The results show that the concentration meter can provide timely and accurate measurement, with a maximum error of 0.328 percentage points and a root mean square error of 0.194 percentage points, presenting effective improvement in accuracy.

Beneficiation tests were conducted to process the low-grade cobalt-nickel ore from Hebei Province by adopting an asynchronous flotation flowsheet consisting sequentially of staged grinding, flotation of sulfide minerals and flotation of sulfurized oxide minerals. In the study, combined depressants were used for better depressing of slime, while regrinding process was introduced to intensify the sulfurization effect. Finally, a cobalt-nickel sulfide concentrate with Co grade of 2.00% and Ni grade of 3.90% and a cobalt-nickel oxide concentrate with Co grade of 1.47% and Ni grade of 2.73% were obtained. The total Co recovery and total Ni recovery reached 77.61% and 79.20%, respectively. In this way, the preliminary enrichment and recovery of Co and Ni resources can be realized, laying a foundation for their further purification.

In response to the problems of high molybdenum loss and difficulty in molybdenum/talc separation existing in the desliming process of a high talc-type molybdenite ore from Henan, ZN-J1, a molybdenum depressant, was introduced in the desliming section to minimize efficiently the molybdenum loss. The feed ore with Mo grade of 0.116%, molybdenum sulfide percentage of 83.53% and talc content of 14.0% was processed by adopting a flowsheet, consisting of desliming, pre-flotation of molybdenum, regrinding, and molybdenum/talc separation, with a combination of sodium silicate and ZN-P1 as depressant. A closed-circuit test with the whole process produced a molybdenum concentrate with Mo grade of 47.68% and Mo recovery of 75.41%, respectively.

To utilize efficiently valuable metal resources containing lithium and beryllium, flotation experiments were conducted based on the study of ore properties. A lithium-beryllium bulk flotation process was used and the influences of dosages of regulator, activator and collector, and the stirring time of regulator on the flotation performance of lithium polymetallic ore were investigated. Based on the determined optimal dosages of calcium chloride and collectors of GYLZ and GYM3, a closed-circuit test produced a lithium concentrate with Li₂O grade and recovery of 6.10% and 94.01% respective, and BeO grade and recovery of 0.12% and 88.53%, respectively, achieving efficient recovery and utilization of lithium and beryllium resources in lithium polymetallic ores.

A vertical stirring mill was introduced for regrinding the graphite concentrate from the rougher in a graphite mine of Heilongjiang Province. Using ceramic ball as the grinding medium, the influences of processing parameters, including rotation speed of mill, diameter of medium ball and grinding time, on the grinding and flotation performances of graphite ore were investigated. The graphite ore was beneficiated adopting an open-circuit flotation process after it was milled with the optimized grinding parameters including alternating (slow-fast-slow) rotation speed, medium ball diameter of 8-10 mm and grinding time of 5 min. The as-obtained graphite concentrate, with the 24.51% in a size fraction of -0.045 mm, has a fixed carbon content of 95.83% and large-flake graphite content of 14.27%.

The occurrence state of iron minerals in a kind of kaolin ore in Guangdong is relatively complex. A portion of iron minerals is irremovable as they disseminate in the lattice of kaolinite, illite and other minerals in an isomorphic manner. For this reason, the calcined kaolin concentrate possesses a lower whiteness than the natural whiteness. In order to efficiently exploit and utilize the kaolin ore, a process consisting of slurry tamping, spiral classifier classification and hydrocyclone classification was adopted, resulting in a kaolin concentrate grading 30.02% Al₂O₃ at 61.70% recovery with the content of impurity Fe₂O₃ at 1.15%, which can reach grade III standard of kaolin for ceramic industry. The classification downflow was then subjected to a process consisting of grinding, magnetic separation and hydrocyclone classification, resulting in a quartz sand concentrate and a sericite concentrate. The quartz sand concentrate, containing 97.11% SiO₂ and 0.058% Fe₂O₃, can satisfy the standard for low quality quartz for glass industry, and the sericite concentrate, containing 7.07% K₂O, 31.22% Al₂O₃ and 48.32% SiO₂, with natural whiteness at 65.53%, can be used in the coating industry. The magnetic separation results in the tailings with a yield of 8.41% and SiO₂ content of 76.33%, which can be used as auxiliary materials for building sand. Through this process, different minerals can be effectively separated to achieve the purpose of comprehensive utilization of kaolin ore.

By means of X-ray diffraction, optical microscopy, scanning electronic microscopy, mineral liberation analysis and chemical analysis, the paigetite ore from Wengquangou mine in Liaoning Province was studied in terms of its chemical component, mineral composition and content, and the occurrence state of main minerals. After main dissemination characteristics of target minerals and key factors in mineralogy influencing beneficiation performance were ascertained, some corresponding separation techniques were proposed.

Based on the process mineralogy study, an experiment was performed on flotation of a phosphogypsum from Hubei Province for its purification. The experiment was run in stronger acid solution with T-609 as the collector, by adopting a process consisting of one roughing, one scavenging, and two cleaning, resulting in the final cleaning concentrate with the content of calcium sulfate dihydrate over 99%, with a whiteness of 75% at 200 ℃. It is shown that this processing flow is characterized by simplicity, high separation rate of phosphogypsum, less addition of agent. The obtained product, with low content of impurities, is up to the special grade in the national standard for gypsum, and can be used for preparation of high-end building materials and gypsum whiskers.

To examine the industrial feasibility of pre-discarding by using screening classification combined with gravity separation in processing of a scheelite ore from Hunan Province, industrial distributary and flotation trial tests were carried out. The results show that a process consisting of screening and spiral chute discarding under optimized conditions can discard tailings grading 0.034% WO₃ with a yield of 25.50% in mass, leading to tungsten loss of only 2.99%. With this pre-discarding before flotation process, both the grade and recovery of the final flotation concentrate are improved, compared to the concentrate obtained from direct flotation of overflow product.