Cotton yarns spun from natural fibers are widely used in the apparel industry. Most of waste cotton goods are now disposed by incineration or landfill, which brings resource and environmental challenges to the society. Using the waste cotton to spin yarns is an alternative way to forward a more sustainable future. In this research, two scenarios for the environmental impacts of yarns spun from corresponding fibers are investigated, including recycled cotton fibers and virgin cotton fibers. The life cycle assessment (LCA) has been conducted according to the collected data from on-site investigation of typical production factories. The life cycle for the recycled cotton yarn production is divided into five stages, i.e., raw material acquisition, transportation, breaking, mixing, and spinning. The life cycle of virgin cotton yarn production is been divided into four stages, i.e., raw material acquisition, transportation, mixing, and spinning. The functional unit is 1000 kg produced yarns which are used for weaving into the fabrics. Notable impacts on climate change, fossil depletion, water depletion, and human toxicity were observed. The life cycle impact assessment (LCIA) results show that environmental impacts of recycled cotton yarns are far less than those of virgin cotton yarns, except for climate change and water depletion. The reason is that the land occupation and irrigation water have great impact on environmental impacts of cotton cultivation. In spinning, the electricity is the key factor whose environmental impacts account for the most in the virgin cotton yarn scenario, while the electricity and water consumptions are the key factors for the recycled cotton yarn scenario in the life cycle of yarn production. The sensitivity analysis indicates that improving energy efficiency can significantly reduce environmental burdens for both the two scenarios. The uncertainty distribution of water depletion, human toxicity, fossil depletion, and climate change of the two scenarios were determined with a 90% confidence interval. The LCIA results reveal recycled cotton yarn is a viable alternative to relieve resource and environmental pressure. About 0.5 ha of agricultural land can be saved, 6600 kg CO2 eq can be reduced, and 2783 m3 irrigation water can be saved by using 1000 kg of the recycled cotton yarns. It can be concluded that the recycled cotton fibers can be served as a substitute for virgin cotton fibers to reduce agricultural land and avoid environmental impacts generated from the cotton planting.

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再生纱能否替代纯棉纱：比较 LCA

由天然纤维纺成的棉纱广泛用于服装行业。现在大部分废棉制品通过焚烧或填埋处理，这给社会带来了资源和环境挑战。使用废棉纺纱是实现更可持续未来的另一种方式。在这项研究中，研究了由相应纤维纺成的纱线对环境影响的两种情况，包括再生棉纤维和原棉纤维。生命周期评估（LCA）是根据对典型生产工厂的现场调查收集的数据进行的。再生棉纱生产的生命周期分为原料获取、运输、破碎、混纺、纺纱五个阶段。原棉纱生产的生命周期分为原料获取、运输、混纺、纺纱四个阶段。功能单元是 1000 公斤生产的纱线，用于织成织物。观察到对气候变化、化石消耗、水资源消耗和人类毒性的显着影响。生命周期影响评估（LCIA）结果表明，除气候变化和水资源枯竭外，再生棉纱对环境的影响远小于纯棉纱。原因是土地占用和灌溉用水对棉花种植的环境影响有很大影响。在纺纱过程中，电力是对环境影响最大的关键因素，在初棉纱方案中，而电力和水的消耗是纱线生产生命周期中再生棉纱场景的关键因素。敏感性分析表明，提高能源效率可以显着减少两种情景的环境负担。两种情景的水资源枯竭、人类毒性、化石枯竭和气候变化的不确定性分布均以 90% 的置信区间确定。LCIA 结果表明，再生棉纱是缓解资源和环境压力的可行替代方案。使用1000公斤再生棉纱，可节约农地约0.5公顷，减少二氧化碳当量6600公斤，节约灌溉用水2783立方米。