Study On Performance Of Magnesia And Magnesia-spinel Refractories Containing Rare Earth Oxides

With the reinforcement of environmental awareness, more attentions have been paid to the pollution of chrome, resulting in the gradual replacement of magnesia-chrome brick. Magnesia and magnesia-spinel refractories are important basic refractories,. On the purpose of eliminating chrome pollution, the effects of added rare earth oxides on the properties of the magnesia and magnesia-spinel refractories were studied in this paper.Magnesia refractories were prepared using MgO and rare earth oxides(Y2O3, La2O3, Nd2O3, CeO2) power as raw materials and waste solution of pulp as binder. The effects of rare earth oxides addition on physical performance, the coating adhering performance and slag resistance performance of magnesia refractories were studied. The results indicated that the addition of rare earth oxides was beneficial to the sintering densification of magnesia refractories, and the best was CeO2; mechanical performance of samples can be improved by the proper addition of rare earth oxides, and the mechanical performance at room temperature can be improved by addition of a small quantity of Y2O3, CeO2, Nd2O3; however, the best adding quantity for La2O3 was 1.5wt.%; The highest HMOR of samples containing 1wt.% Y2O3 was 8.19 MPa, and the next were La2O3 and Nd2O3, but for CeO2 there is no significant improvement on the HMOR. The coating adhering performance of magnesia refractory has highly increased by adding Y2O3, no obvious improvement by addition of CeO2, and a little improvement with La2O3 and Nd2O3. The RH slag resistance performance of magnesia refractories increased with the addition of rare earth oxides.Magnesia-spinel refractories were prepared using MgO,α-Al2O3, MA power and rare earth oxides(Y2O3, La2O3, Nd2O3, CeO2) as raw materials and waste solution of pulp as binder. The effects of rare earth oxides addition on physical performance, coating adhering performance and slag resistance performance of magnesia-spinel refractories were studied. The results showed that the addition of rare earth oxides were beneficial to the sintering densification of magnesia-spinel refractories, and the addition of Y2O3 with a better outcome; the mechanical performance at room temperature of samples could be improved by the proper addition of rare earth oxides;The addition of rare earth oxides were beneficial to the thermal shock resistance of magnesia-spinel refractories, the sample with 1wt.% CeO2 has the highest HMOR of 3.76MPa. The coating adhering performance of magnesia-spinel refractory has highly increased by adding Y2O3, no obvious improvement by addition of CeO2, and a little improvement with La2O3 and Nd2O3. The RH slag resistance performance of magnesia-spinel refractories increased with the addition of rare earth oxides.The coating adhering performance and slag resistance performance of magnesia and magnesia-spinel refractories were compared. The results showed that the coating adhering performance of magnesia refractories were better than that of magnesia-spinel refractories, and the RH slag resistance performance of magnesia-spinel refractories were better than that of magnesia refractories.