At the end of Guangzhou's old clothing recycling chain, a new destination has emerged: old clothes that recycling companies have picked over and that can no longer be worn are shredded into rags of about 10 square centimeters, then pressed into cloth bales about 1 meter square and sold to cement plants to replace part of their coal. A project manager at an old clothing sorting and shredding company in Huijiang Village, Panyu District, said cement companies' demand for these cloth scraps is considerable. Of the old clothes delivered by truck, about 85% can be sorted and utilized; the rest, contaminated and unusable, can generally only serve as fuel for waste-to-energy incineration.

Key points

  • An old clothing shredding company in Panyu District shreds collected garments and sells them to cement plants as fuel, replacing 10%–20% of coal.
  • Tan Dihua, manager of the Suihuishou operations center, said buying 1 ton of coal costs about 800-plus yuan, while 1 ton of old clothing waste costs only 300–400 yuan, and the ash left after burning can also be used as cement material.
  • At present, cement companies' annual demand for its old clothing powder is 30,000 tons, but the company cannot supply enough.

Sorting process and current capacity

On September 13, a reporter saw at this company in Huijiang Village, Panyu District, that bales of old clothes are weighed on a weighbridge and sent to the sorting center, where workers separate them according to whether they can still be used: usable ones are placed on one side of the workshop, unusable ones on the other. The usable portion is then fed by conveyor into a shredder, turning into rags about 10 square centimeters in size, which are then machine-pressed into bales and stacked by forklift as finished products.

Why do cement plants value these cloth scraps? Tan Dihua explained that cement production requires crushing raw materials such as limestone, sand and iron, then heating them at high temperature in a kiln, reaching 1,450°C to 1,600°C, which used to rely mainly on coal. Coal is a non-renewable resource, whereas mixing in a certain proportion of clothing scraps does not affect the calorific value and can also lower costs and reduce greenhouse gas emissions. This has also driven growth in old clothing processing volume—in the past, apart from donations and exports, old clothes were mostly landfilled or incinerated; today the increased demand is mainly due to companies' need for energy substitution. Besides Guangzhou, the company also collects old clothes in Wuhan, Fuzhou and other places.

Where different materials go

Old clothes that do not meet donation standards but are still of decent material go the recycling route. Tan Dihua said cotton garments can be shredded and spun into recycled cotton; although it is downgraded compared with virgin cotton and has poorer extensibility, it can still be used for labor protection products such as cotton gloves and cloth bags, as well as agricultural insulation sheds, roadbed padding and machine-wiping cloths. Denim garments of good quality can be made into soundproof cotton for automotive noise reduction. After old clothes enter the plant, workers first cut off zippers and buttons, then sort by color and fabric; down from down jackets is extracted and made by grade into lower-priced down quilts and down jackets. Recycled cotton material sells downstream for about 1,000 yuan per ton; a person long engaged in recycling student living supplies at universities said an old down quilt can sell for 100 yuan. Leather is the hardest to handle—incineration requires high technical standards for exhaust treatment, so harmless treatment is usually adopted.

Dirty means devalued; recycling and sorting must also prevent contamination

Old clothing recycling differs from ordinary scrap recycling in that it is sensitive to contamination—once clothing gets dirty, it basically loses its recycling value, which is one reason recyclers prefer door-to-door appointment pickups. Tan Dihua said some residents do not understand the value of old clothes and throw them out mixed with other garbage; collected together, they cannot be used and can only end up at waste incineration plants, because even if sent to cement plants as alternative fuel, there are strict requirements on moisture and impurities. Therefore, waste sorting is equally necessary in old clothing recycling; only if uncontaminated can it generate maximum value.

Policy background and industry significance

The Implementation Opinions on Accelerating the Recycling of Waste Textiles, jointly issued by the National Development and Reform Commission, the Ministry of Commerce and the Ministry of Industry and Information Technology, points out that China's total textile fiber processing accounts for more than 50% of the world's total and that large amounts of waste textiles are generated every year. It also proposes developing Internet Plus recycling, exploring new models such as one-bag door-to-door recycling and campus collection during graduation season, and cultivating leading recycling enterprises. The Opinions require that by 2025 the recycling rate of waste textiles reach 25% and recycled fiber output reach 2 million tons; by 2030 the recycling rate reach 30% and recycled fiber output reach 3 million tons. This channel of alternative fuel for cement kilns is providing an outlet for old clothes that are hard to wear again—and a new disposal path beyond export.

Source: Shredding old clothes, mixing them into coal to burn cement, helping companies save energy and reduce emissions · Originally published 2022-09-15