The Northern Laboratory has published bulletin AIC-336, "Dry Grinding Agricultural Residues, A New Industrial Enterprise" that summarizes the research conducted to date. This is the first time that such data on engineering and design has been assembled and published to cover this field. Copies of the bulletin may be obtained by addressing requests to the Northern Regional Research Laboratory, Peoria, Illinois. Plants designed to produce at least 1-1/2 tons per hour of ground shell products will cost upwards of $60,000. A well-engineered plant of such size will require three to five men per shift. Among other factors, the working capacity of a grinding plant depends upon the quantity of shells available and the ability of the organization to merchandize its products. The plant should be located in an area in which at least 5,000 tons of nut shells or fruit pits are annually available at low transportation costs. Uses of Shell Products The more important uses for nut shell products, together with their specifications for particle size, are shown in Table 1. Table 1.--Uses for ground nut shells and fruit pits +------------------------------------------------+--------------------+ | Applications | Size | | | | | Deburring, cleaning, burnishing and polishing | | | in metal stamping, electroplating and | No. 10 to No. 50 | | plastics industries | | | Soft-grit blasting | No. 10 to No. 30 | | Fillers for plastics and plywood adhesives | Finer than No. 100 | | Insecticide diluents and carriers | Finer than No. 140 | | Explosives | No. 10 to No. 100 | | Fur cleaning | No. 10 to No. 100 | | Poultry litter and mulch (almond and peanut) | 1/4 to 3/4 inch | | Fillers for fertilizers (almond and peanut) | Finer than No. 20 | +------------------------------------------------+--------------------+ Experience shows that no matter how nut shells or fruit pit shells are ground both under- and oversize particles will be produced. The hard, friable character of most of the nut shells makes their reduction to fine size particles less difficult than for tough materials, such as corncobs, or fibrous materials such as woods. Shells from almonds because of their bulk and very fibrous nature are somewhat less convenient to handle than other shells. Good business practice shows that sales outlets should be found for each fraction so that grinding expenses can be kept at a minimum. Because there are some differences in physical characteristics of nut shells and fruit pits all shell products do not necessarily meet the same specifications, nor have the same uses. Industrial Cleaning and Finishing