Study On The Reaction Milling Of Cu-H₂O Binary System And Cu-Cl-H₂O Ternary System

Based on the principle of mechanochemistry, nanosized oxides and H2 as the side product can be obtained by ball milling metal powders (Zn, Mn etc.) in water solution using high-energy ball mill. The metal powders used rank before H in the list of metal activity sequence. However, the study on ball milling metal powders which rank after H in water solution is not available. The Cu powder which ranks after H was selected as the raw material in this experiment to study the phenomenon and principles of Cu-H2O binary and Cu-Cl-H2O trinary reaction ball milling. XRD,SEM and TEM were employed to examine the phase composition,microstructure of the final products. The experimental results were as follows:(1) By ball milling Cu powder in pure distilled water solution, Cu2O was formed by the reaction between Cu and oxygen which was dissolved in water. But the amount of Cu2O was quite limited due to the limited amount of oxygen in the ball milling system. While in the results of mechanical alloying, the reaction between Cu and oxygen was hard to occur, little amount of Cu2O was gained after 110h ball milling, which was less than in the former experiment.(2) By ball milling Cu powder in distilled water solution with a high oxygen pressure, the reaction between Cu powder and oxygen would be activated continuously. The Cu powder can be oxidized to CuO completely due to the sufficient oxygen in system. The pure CuO obtained after 110h ball milling was uniform with the particle size of 100-200nm.(3) By ball milling Cu powder in HCl solution with pH value of 2, a large amount of Cu2O was obtained after 3h milling, together with a little amount of Cu2(OH)3Cl and CuCl. While high purity Cu2O was formed after 70h milling. No other phases were examined. The particle size of Cu2O was 50-100nm.(4) Ball milling Cu powder in CuCl2 solution with [Cl-] of 1.5×10-2mol/L and 7.5×10-2mol/L, complete Cu2O were gained after 25h and 80h milling respectively. Most of the particles were cubic or hexagonal in shape and 50-150nm in size. When the [Cl-] was adjusted to 0.3mol/L, the milling time needed for forming pure Cu2O was 100h. And the particles were apparently larger in size and more abnormal in shape than the former results. When the [Cl-] reached 0.75×10-2mol/L and 0.3×10-2mol/L, pure Cu2O was hard to form in a certain period. It can be concluded that different concentration of Chloride ion would affect the reactions in different milling periods, the needed time for forming pure Cu2O and the size,shape of Cu2O particles.(5) A large amount of Cu2O was obtained after 80h ball milling CuCl in water solution. Most of the Cu2O particles were abnomal in shape and 20-80nm in size. There were also partial particles of cubic and hexagonal shapes.