A flowsheet consisting of pre-reduction magnetic roasting and magnetic separation was introduced to process a refractory weakly-magnetic iron ore from Jiangsu Province. The results show that after 60 min roasting at 750 ℃ by adding coal as a reducing agent at an amount of 3%, the pre-reduced iron ore was ground to a fineness of 75% -0.074 mm and then subjected to low intensity magnetic separation consisting of one roughing, one cleaning and one scavenging, resulting in a high quality iron concentrate grading 65.05% Fe at 96.19% recovery. The research results can provide technical reference for the mineral processing of refractory weakly-magnetic iron ore.

The interaction mechanism of kyanite group minerals and quartz in cationic flotation system was studied by using an extended DLVO (EDLVO) theory combined with microscopy analysis. The results show that, under conditions including pH value of 8, FeCl₃·6H₂O dosage of 30 mg/L and dodecylamine dosage of 80 mg/L, there is interaction between quartz and kyanite group minerals in various size fraction, and the adhesive coating among particles is one of the main reasons for the interaction between kyanite group minerals and quartz amidst flotation process. Besides, the adsorption force between kyanite group minerals and quartz is in the following descending order：andalusite/quartz ≥kyanite/quartz ≥ sillimanite/quartz, indicating that it is relatively difficult for andalusite to be separated from quartz by flotation.

The west slope of SCM copper cobalt mine in DRC was taken as an example for determining the shear strength parameters of rock mass by a laboratory triaxial compression test, back analysis of landslides, evaluation of rock mass quality and strength conversion with Hoek-Brown criterion, and then the obtained strength parameters were verified. The results show that due to the size effect of the samples, there may be deviation in the cohesion of rock mass shear strength obtained from the laboratory triaxial compression tests. It is found that with the obtained parameters used in slope stability analysis, more accurate evaluation results can be obtained from the slope model with higher sensitivity to friction angle, while lower accuracy from the slope model with higher sensitivity to cohesion. Under the same working condition, the parameters of slope rock mass obtained from the back analysis of shallow landslides can be used for analyzing local or single bench stability, and the parameters of slope rock mass from back analysis of deep-seated landslides or the landslides due to weak structural planes can be used for overall stability analysis. It is found that the shear strength parameters obtained based on Hoek-Brown failure criterion are close to the results from laboratory triaxial compression test, also easy to operate and more accurate, which can have a wide application.

A kind of ore from Inner Mongolia containing 1.89% Pb, 1.84% Zn and 125 g/t Ag was taken in a flotation experiment for recovering the valuable elements therein. From the process mineralogy study, it is found that the Pb and Zn therein exist mainly in the form of galena and sphalerite, while Ag is in the form of freibergite. A preferential flotation process was adopted for treating this ore, in which zinc sulfate and sodium sulfite were taken as sphalerite depressants, propyl xanthate, ammonium dibutyl dithiophosphate and 25^# dithiophosphate were taken as the collector for lead flotation, and then copper sulfate was taken as the activator and butyl xanthate was taken as the collector for zinc flotation from the tailings of lead flotation. A lead concentrate grading 52.71% Pb, 2.29% Zn, containing 3 182.00 g/t Ag was produced at 94.22% Pb recovery and 82.00% Ag recovery, and a zinc concentrate grading 46.11% Zn, 0.76% Pb, containing 255 g/t Ag was also yielded at 87.31% Zn recovery and 6.78% Ag recovery, showing that silver was mainly pulled into lead concentrate. It is concluded that this processing technique can bring not only a good Pb/Zn separation effect, but also an effective recovery of Ag.

An accumulative bauxite ore in Yunnan containing 42.13% Al₂O₃, 15.73% SiO₂ and 17.44% TFe, namely, with an Al/Si ratio of 2.68, was taken in a flotation for Al/Si separation, and the effects of pH regulator dosage, type and dosage of depressant, collector dosage and grinding fineness on desilication performance of flotation were all investigated. A closed-circuit flotation test performed with the optimized parameters produced an aluminum concentrate with Al₂O₃ grade and recovery of 52.16% and 70.30%, Al/Si ratio of 7.69, and TFe grade of 20.89%, respectively. Then, a flowsheet consisting of magnetic roasting and magnetic separation was introduced to treat this aluminum concentrate for Al/Fe separation, which produced a final aluminum concentrate containing 69.34% Al₂O₃ with Al/Si ratio of 8.70, and a rough iron concentrate grading 52.34% TFe with a process recovery of 76.03%.

The concentration of plume caused by hydraulic collecting system during deep-sea polymetallic nodules mining under different working conditions were analyzed. Test results show that the concentration of discharged plume from conveying system is much higher than that of sediment plume caused by the disturbance of capture system, which is one of the main causes of turbidity current in the sea. In the test, the curve of slurry concentration presented a steep upward trend line followed by a steep downward line. Increasing oil pressure of the pump of capture system will lead to higher concentration of slurry. However, the oil pressure of the pump of conveying system won't result in obvious variation in slurry concentration.

The spent cathode carbon block after aluminum electrolysis was treated by acid leaching with a mixed solution of sulfuric acid and ammonium sulfate, and the effects of factors, such as molar ratio of sulfuric acid to ammonium sulfate, liquid-solid ratio, leaching temperature and time, on the leaching rate of cryolite from this spent cathode carbon sulfate were investigated. The results show that at a leaching temperature of 70 ℃, with liquid-solid ratio of 8 mL/g, sulfuric acid and ammonium sulfate in a molar ratio of 4, a 120-min leaching process can lead to the leaching rate of cryolite up to 99.48%. The leaching residue, being composed of carbon and calcium fluoride and free of leaching toxicity, can be treated as a general solid waste.

With sodium oxalate and D401 chelating resin as impurity removal materials, impurities of calcium and magnesium in crude lithium solution were removed by adopting a process consisting of chemical precipitation and ion exchange. In an experiment, reaction was firstly run at 25 ℃ for 60 min by adding sodium oxalate at an amount of 17.6 times the theoretical value, with pH of 6.5 and stirring rate of 300 r/min. And then, the lithium solution after filtration flowed through a resin column at a rate of 8 BV/h. As a result, the removal rates of calcium and magnesium reached 98.21% and 83.36%, respectively, and the lithium loss rate was 5.34%. The purified lithium solution was then recrystallized and purified, and the obtained lithium phosphate powder, with regular morphology and uniform dispersion, has its purity higher than 99.5%.

An orthogonal experiment was performed for laser welding of 5 mm ZL114A and 6061 aluminum alloys, and the influences of welding parameters on the microstructure and mechanical properties of welded joint were investigated. It is shown that the influences of three parameters of laser welding power, defocus and welding speed are in a descending order. With laser welding power of 3 kW, welding speed of 16 mm/s and the defocus of -3 mm, the welded joint has an average tensile strength of 208.03 MPa and the elongation of 5.16%. Compared to ZL114A and 6061 aluminum alloy, the tensile strength is reduced to 64.14% and 65.60%, respectively, while the elongation is reduced to 41.38% and 33.70%, respectively. The welded joint presents a mixed mode of brittle and ductile fracture when failing under tensile.

A complex precipitation method was adopted to synthesize CuO nanoparticles, and its morphology and structure were characterized. Then, the CuO nanoparticles were taken as the activator in the degradation of ofloxacin with persulfate. Based on the advanced technology of activated persulfate oxidation, the influences of different parameters, including concentration of K₂S₂O₈ and an initial pH of the ofloxacin solution, on the degradation activity of ofloxacin in the wastewater were investigated. It is found that the degradation rate can reach 95.6% with 10 mg/L of ofloxacin in the wastewater with an initial pH of 3.5, by adding 0.003 0 g/L CuO and 1.0 mmol/L K₂S₂O₈. The experiments on capturing free radicals show that SO₄^-· and O₂^-· are active species for the catalytic degradation of ofloxacin, which is possibly the catalytic reaction mechanism.