Page 16 - Materials Chemistry, Second Edition

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6.11 Plastics.................................................................................................................................151
6.11.1 Plastics Manufacture .............................................................................................152
6.11.2 Extrusion................................................................................................................152
6.11.3 Blow Molding........................................................................................................153
6.11.4 Injection Molding.................................................................................................154
6.11.5 Compression Molding ...........................................................................................154
6.11.6 Plastics Recycling..................................................................................................154
6.11.7 Processing for Recycling......................................................................................155
6.12 Yard Waste...........................................................................................................................157
6.13 Food Waste..........................................................................................................................157
6.14 Tires and Rubber.................................................................................................................157
6.14.1 Design and Manufacture ......................................................................................158
6.14.2 Disposal and Recycling........................................................................................158
6.14.3 Recycling..............................................................................................................160
6.14.4 Crumb Rubber......................................................................................................161
6.14.5 Retreaded Tires.....................................................................................................161
6.15 Goals for the Nation............................................................................................................164
References ......................................................................................................................................164
Suggested Readings .......................................................................................................................165
Questions........................................................................................................................................166

Chapter 7
Municipal Solid Waste Processing; Materials Recovery Facilities................................................169
7.1 Introduction ...........................................................................................................................169
7.2 The Materials Recovery Facility...........................................................................................169
7.2.1 Unit Operations .........................................................................................................171
7.2.2 Weigh station.............................................................................................................172
7.2.3 Receiving Area ..........................................................................................................172
7.2.4 Storage Area ..............................................................................................................172
7.2.5 Mobile Equipment in the MRF .................................................................................175
7.2.6 Fixed Equipment in the MRF....................................................................................175
7.2.7 Conveyors..................................................................................................................175
7.2.8 Scales.........................................................................................................................178
7.3 Materials Recovery at MRF Unit Operations .......................................................................178
7.4 Materials Separation and Processing at the MRF.................................................................180
7.4.1 Hand-Sorting .............................................................................................................180
7.4.2 Screening ...................................................................................................................181
7.4.2.1 Trommel Screens........................................................................................182
7.4.2.2 Disk Screens...............................................................................................186
7.4.2.3 Vibrating Screens .......................................................................................186
7.4.3 Size Reduction...........................................................................................................187
7.4.3.1 Densifiers....................................................................................................187
7.4.3.2 Compactors.................................................................................................187
7.4.3.3 Baler ...........................................................................................................188
7.4.3.4 Shredders....................................................................................................189
7.4.3.5 Hammermills..............................................................................................190
7.4.3.6 Horizontal-Shaft Hammermills..................................................................190
7.4.3.7 Vertical-Shaft Hammermills.......................................................................191
7.4.3.8 Flail Mill.....................................................................................................193