발간논문

Home > KJMM 논문 > 발간논문

Chlorination processes of the oxides of main values contained in monazite, that is thorium, cerium, lanthanum and yttrium, were clarified by thermobalance method. The results indicated that the chlorination process is affected by the dehydration temperature of the hydrous oxide. On the chlorination of the oxides, the influence of a kind of carbonaceous materials was also examined; and the result showed that active carbon, sugarcoat were effective and graphite was not suitable.

keyword :

Dehydration processes of the hydrous oxides of thorium, lanthanum and yttrium obtained by addition of ammonium hydroxide to the chloride solutions were examined by thermogravimetric, differential thermal and x-ray diffraction analyses. It was observed that the hydrous oxides of thorium, cerium and yttrium were amorphous and belong to the group of aquated oxides, and hydrous oxide of lanthanum was lanthanum tri-hydroxide. The tri-hydroxide is dehydrated according to the process, La(OH)₃, 270℃ LaOOH 680℃ La₂O₃.

keyword :

keyword :

Forged alloy steel balls and cast chilled balls, which are widely used to crush ore, coal and cement clinker, are indispensably required excellent wearing-resistant and impact-resistant properties in order to increase crushing ratio. The forged alloy steel balls manufactured by Han Kuk Machine Industrial Company are time-water quenched by bucket conveyor, and self-tempered in drum can. In accordance with general making process, especially heat treatment of steel ball, the author attempted, in this paper, the experimental and theoretical research on the hardness slope and hardness distribution of steel balls. It was obserbed that proper chemical composition, hardness slope and micro structure of steel balls are desirable to bear wearing and cracking.

keyword :

keyword :

keyword :