最近十年在经济发达国家里明显地出现一种趋势:把现有的再生原料吸引到经济周转中来。它的加工,有助于扩大原料来源,保护森林,保存矿业原料(如石油、煤气、黑色金属、有色金属和其他有用金属)和农产品(如羊毛、亚麻、棉花),更合理地利用水和土地。这样,不仅减少了原料的消耗,而且也减少了燃料、水、蒸汽的消耗,极大地降低了经营费用、劳动消耗以及交通运输费 There has been a clear trend in the last decade in economically developed countries: to attract the existing recycled feedstock into the economic turnover. Its processing helps to expand the sources of raw materials, protect forests, conserve raw materials such as oil, gas, ferrous, non-ferrous and other useful metals and produce (such as wool, linen, cotton) and make more rational use of water and land. This not only reduces the consumption of raw materials, but also reduce the consumption of fuel, water, steam, greatly reducing operating costs, labor and transportation costs