At present, most of the materials that can be recovered and used in our country are thermoplastic because they are soluble and plastic. Different sources of recycled plastic particles lead to different use degree and price of waste plastics. First of all, the lighter the color (even colorless and transparent), the wider the scale of use. For example, white can be adjusted into a variety of other colors, and can also be used as white products, so the price is high. Secondly, because of the needs of the product, various ingredients have been added to the material.

　　At present, the use value of waste plastics is mainly determined by the content of CaCO3 (stone powder). The higher the content of CaCO3, the lower the price. From the naked eye, if the product is not bright and lusterless (matte is outside), the content of CaCO3 is high, and it can be felt heavy from the handle. If the product is burned with fire, the burned part will turn red and ash after calming down. In addition, we should pay attention to the reinforced products (glass fiber). The only reinforcement products that can be used now are PA, PBT, P, etc., and the prices are not high. There are also a variety of alloy materials, now only ABS + PC has a domestic market. Then, according to the relative density of recycled plastic particles to determine whether the data can be reused. At present, the most common problems are ABS and PS mixing, PC and PMMA mixing, PVC sheet (bottle material) and PET sheet mixing, PE and PP mixing in half. After mixing these materials, because the density difference is not much, it is difficult to separate them by common methods.