Multi-scale impact crushing characteristics of polymetallic sulphide ores

The effects of crushing energy, ore hardness and particle size of cassiterite polymetallic sulphide ore and lead-zinc polymetallic sulphide ore on the crushing characteristics during impact crushing were investigated by mineral liberation analyzer(MLA) and drop weight test. The results show that both ores contain pyrrhotite, sphalerite, jamesonite, gangue mica and quartz except cassiterite. Cassiterite is closely associated with sulphide and quartz to form aggregates, which are mixed with each other in the form of intergrowth or symbiotic disseminated fine grains. Cassiterite has a significant impact on ore crushing characteristics. Ore hardness is negatively correlated with the product of crushing parameters of A and b, i.e. A×b, the effect of crushing energy on crushing fineness is related to crushing parameters A and b, and the influence degree increases with the increase of A. The influence degree increases with the increase of b when crushing energy ECS is less than 1 kW·h/t, and the influence degree decreases with the increase of b when crushing energy ECS is greater than 1 kW·h/t. The impact of crushing energy on crushing fineness is greater than that of ore particle size when the crushing energy is lower;on the contrary, the impact of ore particle size on crushing fineness is greater than that of crushing energy when crushing energy is higher.

Sulfuric acid leaching of high iron-bearing zinc calcine

Sulfuric acid leaching of high iron-bearing zinc calcine was investigated to assess the effects of sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, and the stirring speed on the leaching rates of zinc and iron. The results showed that the sulfuric acid concentration, liquid-to-solid ratio, leaching time, and leaching temperature strongly influenced the leaching of zinc and iron, whereas stirring speed had little influence. Zinc was mainly leached and the leaching rate of iron was low when the sulfuric acid concentration was less than 100 g/L. At sulfuric acid concentrations higher than 100 g/L, the leaching rate of iron increased quickly with increasing sulfuric acid concentration. This behavior is attributed to iron-bearing minerals such as zinc ferrite in zinc calcine dissolving at high temperatures and high sulfuric acid concentrations but not at low temperatures and low sulfuric acid concentrations.

MnS–MnO heterogeneous nanocube@N,S-doped carbon as a highly efficient bifunctional water splitting electrocatalyst

A stable,efficient,and economical bifunctional electrolytic catalyst would be incredibly beneficial for the development of hydrogen production by electrocatalytic water splitting.In this study,we synthesized a novel MnS–MnO heterogeneous nanocube@N,S-doped carbon(MnS–MnO@NSC).MnS–MnO nanocubes possess rich heterogeneous interfaces and plentiful catalytic active sites to promote electrochemical reactions,while the N,S-doped carbon shell possesses excellent conductivity and catalytic properties and protects the nanocubes.MnS–MnO@NSC exhibited excellent electrochemical properties as an effective bifunctional electrocatalyst for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in KOH solution.In the HER,the overpotential was as low as 124 mV at a current density of 10 mA·cm^(-2)while in the OER,it was only 340 mV at 100 mA·cm^(-2)under the same conditions.In addition,a MnS–MnO@NSC||MnS–MnO@NSC electrolyzer exhibited almost comparable activity and higher steadiness than those exhibited by the state-of-the-art Pt/C||RuO_(2)/C system for full water splitting in KOH solution.