The influence of Al-10.5%Sr master alloy, which is much cheaper than Mg-Sr master alloys, on the as-cast microstructure of the AZ31 alloy was investigated. The research results revealed that the Al-10.5%Sr master alloy produced obvious modification of the as-cast microstructure of the AZ31 alloy, and the modification efficiency increased with the holding time from 0min to 60min and the amount of Sr from 0.01% to 0.1%. Moreover, the results also showed that the Al-10.5%Sr master alloys of different states had different modification efficiency on the as-cast microstructure of the AZ31 alloy. The Al-10.5%Sr master alloys in extrusion deformation state and rapid solidification state had better modification efficiency than the Al-10.5%Sr master alloys received and in heat treatment state, which could be related to the microstructure of the Al-10.5%Sr master alloys with different states.

The as-cast microstructures and solidification behaviours of Mg-Zn-Al ternary magnesium alloys with different Zn/Al mass ratios were investigated and compared. The results indicate that, when the Zn/Al mass ratio is less than 2, the alloys are composed of a-Mg and Mg32(Al,Zn)49 phases, and with the increase of the Zn/Al mass ratio, the amount of the second phase gradually decreases and its distribution changes from continuous net to quasti-continuous net. However, when the Zn/Al mass ratio is more than 2, the alloys are composed of a-Mg, Mg32(Al,Zn)49 and MgZn phases, and with the increase of the Zn/Al mass ratio, the amount of the second phase gradually increases and its distribution changes from quasti-continuous net to uniform particles. In addition, the onset and the peak temperatures of the second phase transformation for the alloys with the Zn/Al mass ratio of less than 2, are higher than that of the alloys with the Zn/Al mass ratio of more than 2, which results in the different reactions during the second phase transformation and the different types of the second phase.

In the present paper, the effects of treating processes on the microstructure of commercial Al-10Sr master alloy and its refinement efficiency to AZ31 magnesium alloy are investigated. The results indicate that the solution heat treatment, rolling and remelting have significant effects on the morphology and/or size of Al 4 Sr phase in the commercial Al-10Sr master alloy. After being solutionised at 773 K for 4 h and followed by water quenching, the Al 4 Sr phases evolve from coarse blocks to relatively fine blocks. However, after being rolled at 573 K for a total reduction level of 50% or remelted and followed by rapid cooling, the Al 4 Sr phases respectively exhibit fine particles or fibre shapes. In addition, after the commercial Al-10Sr master alloy is solutionised, rolled or remelted, its refinement efficiency to AZ31 alloy is improved, and the improvement resulting from the remelting is the most significant, the next is rolling and solutionisation respectively.

On the basis of the contrastive research into the flotation performance of several vegetable oil fatty acids, the rapeseed oil fatty acid with better performance was screened out from many fatty acids, and its linolenic acid C18:3content is15.81%, then through modifying and compounding, new magnesium removal collector EM-LS-01was obtained. With the use of this agent in certain low-grade high-Mg phosphorite, the phosphate concentrate indexes of single reverse flotation are grade of 30.25% P2O5, recovery of 90.63% and content of 0.99% MgO.

The as-cast microstructures and mechanical properties of Mg-3Ce-1.2Mn-0.9Sc and Mg-3Ce-1.2Mn-1Zn magnesium alloys were investigated and compared. The results indicate that the as-cast microstructure of Mg-3Ce-1.2Mn-0.9Sc alloy was mainly composed of -Mg, Mg12Ce and Mn2Sc phases, and that the as-cast microstructure of Mg-3Ce-1.2Mn-1Zn alloy was mainly composed of -Mg, Mg12Ce and MgZn phases. In addition, the as-cast tensile and creep properties of Mg-3Ce-1.2Mn-0.9Sc alloy were higher than that of the Mg-3Ce-1.2Mn-1Zn alloy. The difference of the two alloys in as-cast tensile and creep properties may be related to the initial microstructures of the two alloys.