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随着矿物资源的不断贫化及新的能源危机,废旧金属的回收,在国外逐渐引起人们的重视。1971年美国的斯潘德洛夫提出了“在城市开矿”的口号,各种金属回收新工艺、新设备、诸如各种传送带,粉碎机,筛分器,磁力分离器等相继问世,“城市矿山”已发展成为一门新兴的工业。据报道,1970年下半年,美国因资源不足,大量回收再生有色金属,回收量约占其产量的49％,由于再生有色金属的费用比生产原生金属低,如铝低40～50％,铜35～40％,锌25～30％,且能耗低(再生金属的能耗与原生金
With the continuous depletion of mineral resources and the new energy crisis, the recovery of scrap metal has gradually attracted people’s attention in other countries. In 1971, the United States proposed Spartandrov’s slogan “mining in the cities”, new technologies for metal recycling, and new equipment such as various conveyor belts, shredders, sifters and magnetic separators. The “urban mine” Has developed into a new industry. It is reported that in the second half of 1970, due to insufficient resources, the United States recovered and regenerated non-ferrous metals in large quantities, accounting for about 49% of its output. As the cost of regenerating non-ferrous metals is lower than the production of primary metals such as aluminum by 40-50% 35 ~ 40%, zinc 25 ~ 30%, and low energy consumption (energy consumption of renewable metals and primary gold