Some barriers to the use of materials recovered from municipal solid waste
Abstract Municipal solid waste (MSW) contains materials which could be put to good use, yet it continues to be discarded, which suggests that it contains little or nothing of value under current conditions. This paper discusses the technical reasons for the lack of commercial interest in recovering materials from MSW. After examining the nature of the salvage industry and trends in the use of materials, the paper considers the characteristics of secondary materials, the properties required of them, and the scope for increased salvage activity. The market prospects are described for waste paper, ferrous and non- ferrous scrap, glass and polymers.
Waste glass as a flux for brick clays
This investigation was undertaken to demonstrate how waste glass might be utilized to lower the required firing temperature and firing time of structural clay products. Mixtures of waste glass and common clays were formed by stiff-mud extrusion and fired to the temperature required to produce a body having 6 to 7% absorption. Substitution of glass for one-half of the clay in a red body reduced the firing temperature 500/sup 0/F, which made possible a 30% increase in production; in a tan body, the firing temperature was reduced 400/sup 0/F, which made possible a 23% increase in production. Work was done in cooperation with the University of Alabama.
Deterrents to the Recycling of Ferrous Scrap from Urban Refuse
Although predictions indicate that the demand for ferrous scrap will shortly exceed supplies, resistance exits to the use of the ferrous fraction of urban refuse. Reasons for this resistance include lack of reliable supplies and the deleterious effects of contaminants, such as aluminum, copper, and tin. Aluminum can cause slag foaming in the BOF and pinholes in cast iron, while copper and tin promote a pearlitic structure thereby increasing ferrous alloy strength while decreasing ductility. With proper processing these problems can be overcome. Detinning of unburned cans removes the tin and aluminum (because they have not been incinerated they do not contain copper). Densification of the detinned steel produces a premium furnace feed. Alternatively, the unprocessed scrap can be used in amounts ranging up to 10 percent of the cast iron or steel produced.