新西兰海沙矿含碳球团成型、还原实验研究

Experimental Study on Moulding and Reduction of Carbon-containing Pellets of Marine Placer in New Zealand

研究了新西兰海沙矿含碳球团冷固结成型和直接还原性能,结果表明,球团的抗压强度随粘结剂加入量的增加先增加后减小,随成型压力增加而增加。对比了A、B两种粘结剂的使用效果,B粘结剂制成的球团抗压强度高于A粘结剂的,在成型压力为18 MPa时,加入6%的B粘结剂制成的球团抗压强度可以达到2 642 N;但不同粘结剂对还原结果影响不大。相同还原时间下,温度越高,金属化率越高;增加还原时间金属化率也随之增加。球团中C/O为0.8～1.4时,还原初期(15 min内)对球团还原金属化率影响不大;C/O小于1.0,还原25 min后,金属化率增加较少,甚至出现二次氧化;C/O大于1.2,金属化率随时间增加一直增加。直接还原实验最佳结果是,1 350℃下弱氧化气氛中,C/O为1.4,还原30 min,此时金属化率为94.7%。

The performance of cold-bonded moulding and direct reduction of carbon-containing pellets of marine placer in New zealand were studied experimentally.The results showed that compression strength of the pellets first increased and then decreased with the increase of adding binders and increased with the increase of moulding pressure.The effects of two binders A and B were compared.The compression strength of the pellets prepared by binder B was higher than that of binder A.The compression strength of the pellets prepared by adding 6% binder B can reach 2 642 N when the moulding pressure was 18 MPa.But different binders had little influence on the reduction results.When reduction time was the same,the higher the temprature the higher the metalliztion degress was.When increasing reduction time,the metalliztion degree also increased with it.When C/O in the pellets was 0.8～1.4,it had little influence on the metallization degree at initial reduction（within 15 min）.When C/O was less than 1.0,after reduction for 25 min,the metallization degree increased little and re-oxidation even occurred.When C/O was more than 1.2,the metallization degree keeped increasing with the increase of time.The metallization degree reached 94.7% under the optimal conditions of direct reduction experiment under weak oxidation atmosphere that the temprerature was 1 350 ℃,C/O was 1.4 and reduction for 30 min.