The experiment study of using industrial waste red mud to manufacture foamed blocks
Red mud foamed block is prepared using waste of aluminum oxide production—red mud, soft burning magnesium powder (MgO), bischofite (MgCl<inf>2</inf>·6H<inf>2</inf>O) and various addition agents. The influence of each factor on strength and density of red mud foamed block is analyzed by orthogonal experiment in this paper. The best ratio is obtained as follows: red mud 30%, MgO 40%, F-3 high efficiency composite foaming liquid 3.0 kg, MgCl<inf>2</inf>·6H<inf>2</inf>O 20% and fine sand 5% (all dry ingredients about 700 kg).
Basic properties of red mud and engineering characteristics of it
In this paper, the writer starts from the angle of engineering application, rather comprehensively analyses and studies basic properties, engineering characteristics of a kind of characteristic earth-red mud by using viewpoint of engineering geology. They are beneficial to further utilizing and improvement of red mud. The writer concretely elaborates and introduces material composition, felit, physical and chemical characteristics, physical and water mechanism properties, mechanical property, structural formation and characteristics, etc. They indexes are rather accurate, can be selected and used for reference. The writer puts forward that it is very necessary to study and grasp properties, engineering characteristics of red mud for development of it in engineering application.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.