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

采用铁还原蒸发法对电炉烟尘进行了处理的小型和大型试验，小型试验确定了电炉烟尘在1000℃下热处理120 min，可除去烟尘中的铅、铜、镉、钾、氯、氟等杂质。此外，通过添加1，粉尘中的锌被完全蒸发。在1000 ~ 1100℃、60 ~ 40 min的条件下，采用直径120 mm、长460 mm的不锈钢管作为反应容器，对炼钢烟尘进行了大规模的工业化试验，并成功地将炼钢烟尘转化为锌锭。将石墨储罐和氧化镁坩埚制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，在自动压块机上压块。在干燥器中干燥24小时后。将压块装入坩埚中，抽真空，加热至1050℃，在规定温度下保持1小时后冷却，从容器中取出固体锌，锌蒸发后，残渣粉碎成粉末，用磁选机分离成两部分。磁性材料中金属铁含量在80%以上，可作为蒸发锌的还原剂回收利用，该工艺的工业化将给电弧炉烟尘治理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.