DIRECT RECOVERY OF METALLIC ZINC FROM STEEL-MAING DUST WITHOUT CARBON DIOXIDE FORMATION

为了处理电炉粉尘，采用铁还原汽化法进行了小型和大型试验。在小型试验中，电炉粉尘中铅、铜、镉、钾、氯、氟等杂质经1000℃、120 min热处理后均可去除。同时，加入1后，粉尘中的锌也完全蒸发。经1000 ~ 1100℃减压保温60 ~ 40 min后，废铁粉的5倍量。为了为该工艺的产业化提供参考，计划了大规模的试验，并成功地利用炼钢粉尘制取锌锭。反应容器由直径120毫米、长460毫米的不锈钢管组成。将石墨储层和镁质坩埚组成的内部结构插入容器中。将电炉粉尘与废铁粉和少量石灰粉混合后，在自动压块机下进行压块。在干燥机中干燥24小时后。在坩埚中装煤，然后抽真空，加热至1050℃。保持1小时后冷却。在规定的温度下，从容器中取出固体锌。锌蒸发后，将残渣粉碎成粉末，用磁选机分离成两部分。磁性材料中含有80%以上的金属铁，可重复用作锌汽化还原剂。该工艺的产业化将为电炉除尘工艺带来巨大的经济效益。

For the treatment of EAF dusts, some small and larger scale experiments have been carried out applied the iron reduction vaporization method.In the small scale tests, it was conformed that impurities in EAF dusts, lead, copper, cadmium, potassium, chlorine and fluorine etc. would be removed by heat treatment of dust at 1000℃、 for 120 min. . Also zinc in dust was evaporated completely by adding 1. 5 times quantity of waste iron powder after holding under reduced pressure at 1000〜1100℃, 60〜40 min. .To get an information for industrialization of the process, larger scale experiments were planned and succeeded to make a zinc ingot from steel-making dust.The reaction vessel consisted of stainless steel pipe of 120 mm diameter and 460 mm long. Inner construction made of graphite reserver and magnesia crucible was inserted into vessel. EAF dust was briquetted after mixed with waste iron powder and small quantities of powder lime under automatic briquetting press. After dried in drier for 24 hrs. briquetts were charged in crucible and then evacuated and heat it up to 1050℃.Cool it down after holding 1 hr. at specified temperature, solid zinc was taken out from the vessel.After zinc vaporization, residues were crushed into powder and separated to two parts by using magnetic separater. Magnetic materials contains more than 80 percent of metallic iron, it can be reused for reducing agent for zinc vaporization.The industrialization of the process would be brought a big economical effect to EAF dust treating process.