返矿的物化特性及其对烧结过程的影响研究

Study on physicochemical properties of return fines and their influence on sintering process

对不同粒级的返矿进行化学成分分析、热重差热分析和软融试验，并配料进行烧结试验，结果表明：不同粒级的返矿化学成分存在差异，二次返矿与一次返矿相比，未烧透混合料少，返矿粒度越大，未烧透混合料越少；返矿中含有大量低熔点化合物，易产生液相，而1～5mm粒级返矿易作为核粒子，被粘附颗粒包裹，无法起到液相中心的作用，只有＋5mm粒级的返矿不易被粘附粒子包裹，易形成液相中心；＋5mm粒级返矿的均匀分布，有利于烧结过程液相区的均匀合理化发展，对烧结矿粒度的均匀化起着重要作用。

Chemical composition analysis, TG-DTA thermal analysis and soft melting test were made for different size of return fines, which were proportioned for sintering test. The result shows that, difference exists in chemical composition of different size of return fines, in view of secondary return fines compared with the primary return fines, there are few non-burnt through mixed materials, the bigger the size of return fines is, the fewer the non-burnt through mixed materials are. Return fines contain lots of low melting point compounds and they are easy to produce liquid phase, while 1 - 5 mm return fines as nuclear particles are easy to be wrapped by adhered particles and can＇ t act as the liquid phase centre, only ＋ 5 mm return fines can＇ t easily be wrapped by adhered particles and are easy to form the liquid phase centre. The uniform distribution of ＋ 5 mm return fines is conductive to uniform and reasonable development of liquid phase region during sintering process and it plays an important role in the homogenization of sinter size.