Research on classification, recycling and reuse of

The continuous improvement of social productivity has promoted the rapid development of modern packaging industry, resulting in the characteristics of large number of modern packaging and short life. Most modern packaging products are disposable consumer goods, and the cycle from raw materials to product molding, consumption and waste is relatively short. Most products reach the hands of consumers, and the life of packaging is over. The packaging waste generated from this has caused great pollution to the environment and seriously affected the quality of human life. Statistics show that the environmental pollution caused by packaging waste is second only to water pollution, marine and lake pollution, and air pollution, ranking fourth. Therefore, it has become a global topic of common concern to establish relevant laws and regulations to forcibly reduce the production of packaging waste and improve its recycling and utilization technology. This paper attempts to classify packaging waste according to its materials, and study their recycling and utilization

I. recycling and utilization of paper packaging waste

paper packaging materials, which are the fastest-growing packaging materials, have become the focus of development and utilization because of their obvious ecological and economic benefits. At present, paper packaging waste is usually recycled by recycling paper and developing new products

1. Recycled papermaking from paper packaging waste

recycled papermaking from waste paper mainly has two processes: pulping and papermaking. The technological process of pulping is: crushing, purification, screening and concentration; Papermaking is to transport the reduced cost pulp of waste paper to the paper machine, which is processed, pressed, dried and calendered to make barrel paper or flat paper

① shredding of waste paper

after preliminary selection, waste paper is generally shredded by hydraulic pulper

② screening, dredging and concentration of waste paper

screening after shredding of waste paper is mainly to remove sundries (plastic chips, wood chips, nylon ropes, binding lines, etc.) in the shredded waste paper by using rotary screen (aperture 10mm) and 25L screen (aperture 2.5mm). Uncluttering is to continue to disintegrate the partially disintegrated waste paper (such as the part around the staples) by the unclutterer, and further separate the residual ink on the pulp fiber. Concentration refers to the dehydration and concentration of low concentration paper pulp by using concentration equipment (such as circular thickener, vacuum filter and tilting filter)

③ remove asphalt, hot melt adhesive and other sundries from the slurry

if the slurry contains asphalt and wax, it needs to be heated and melted, and then it is evenly dispersed in the slurry with a cyclone separator. Due to the fine dispersion, the finished paper is not easy to detect. The hot melt adhesive in the slurry will block the plug hole, dirty the dyeing press roll and dryer during the paper making process, resulting in paper breakage. Therefore, the hot dispersion method, cold screening method and hot spraying method should be used to remove it

④ waste paper deinking

waste paper deinking is usually carried out in the hydraulic pulper with intermittent operation until the product is fully formed. In order to achieve good deinking effect, we must pay attention to the following problems; Feeding sequence; The deinking agent is first added to the hot water of the pulper and dissolved before adding waste paper; Appropriately raise the temperature to promote ink diffusion (depending on the nature of waste paper and deinking agent, the low temperature is about 40 ~ 600 ℃, and the high temperature is about 80 ~ 900 ℃); Extend the time appropriately to promote waste paper release and ink dispersion (usually, the deinking time of each tank of pulp is 1 ~ 1.5h; wash the deinked pulp in time to prevent fiber color reversion.

⑤ bleaching of pulp

after the waste paper is stored for a period of time, the whiteness of the fiber will decline, and the deinked pulp needs bleaching to restore the original whiteness. Factories use bleaching machines to bleach the pulp. If the bleaching agent is bleaching powder, the effective chlorine content is 7%, and the bleaching time is about 2H. If you want to improve the whiteness of the waste paper, The following measures can also be taken: first, strengthen washing and screen out micro fibers; 2、 Bleach according to the length of fiber; 3、 Enzyme pretreatment was used before bleaching

how to carry out environmental protection treatment for the mixing treatment, activation treatment, sizing, filling, color matching, strengthening and papermaking of pulp? The process is basically the same as that of ordinary papermaking, which will not be repeated here

2. Paper packaging waste development of new products

① manufacturing of pulp molded products

pulp molded products are formed by quickly and evenly depositing the waste pulp without sundries onto the shape model through vacuum molding, hydraulic molding and air compression molding. The technological process includes: waste paper sorting, grinding and beating, compounding ingredients, pulp sizing, blending concentration, product molding, cold extrusion and shape correction. This product has the characteristics of light weight, low price, shock resistance, good air permeability and no pollution to the environment, so it is widely used in the packaging of eggs, fruits, glass and so on

② manufacturing composite board

waste paper can produce glued cardboard with relatively high strength. The method is to press the waste paper together with phenolic resin or urea formaldehyde resin (the pressing temperature of phenolic resin is 170 ℃, and the pressing temperature of urea formaldehyde resin is 140 ℃). Waste paper can also be used to make asphalt corrugated board by molding waste paper, cotton yarn, coconut fiber, asphalt and other raw materials. The product has good heat insulation, impermeability, portability, fire prevention and corrosion resistance, and can be used as building materials

③ making paper scraps paste

also makes the market of recycled plastic granulator more and more optimistic. Waste paper scraps are hydrolyzed to produce paste with strong adhesion. The method is to soak clean and ink free paper scraps (1 part) in sodium hydroxide (0.1 part) for 24h, stir and dissolve them, add chloroacetic acid (0.35 part) and sodium carbonate (0.1 part), and finally add water to stir them into a slurry. In order to prevent mildew and discoloration, a small amount of hydrochloric acid can be added to adjust the pH value to neutral

④ production of livestock feed

waste paper can produce livestock feed. The method is to cut up the waste paper, add water and 2% hydrochloric acid, and then boil it for 2h. Under the action of high temperature and acid, the cellulose breaks down, and then add it to the feed (the addition amount is 20% - 40%), which is used to feed cattle, sheep and other animals. Its nutritional effect is 1/3 higher than that of ordinary feed. Cattle and sheep fed with this kind of feed have less disease and more fat