The European Waste Catalogue (EWC) [or Verordnung ueber das Europaeische Abfallverzeichnis (AVV)] classifies used honing and grinding tools with the code 12 01 21 or 12 01 20, if they contain hazardous materials [BGBI01]. The main category 12 includes waste of material removal processes and physical and chemical surface alteration. The waste generator has to determine toxicity and physical characteristics to identify the waste correctly and dispose in compliance with the applicable federal, state, and local regulations [UNIT12a]. For example, metal bonds for diamonds are often considered hazardous waste and have to be disposed accordingly [MCCL10b]. Coated abrasives can produce a huge amount of waste.
In 2010, Germany disposed 7400 t of honing and grinding tools with hazardous materials and 13,600 t of other honing and grinding tools [DEST10]. 200 t of the honing and grinding tools with hazardous materials were combusted and 5700 t got chemical-physical treatment; 1000 t of the honing and grinding tools without hazardous materials went to landfill, 200 t to combustion and 7100 to chemical-physical treatment [DEST10].
The intrinsic energy of materials can be turned into heat through combustion. Heat recovery efficiency is at best 50 % and the efficiency to generate electricity
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Table 4.4 Material data on combustion (*estimated values) [GRAN10]
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from recovered heat at best 35 % [ASHB09, p. 68]. Material for combustion has to be separated from non-combustible material, and the combustion process needs careful control so that the emissions are not toxic [ASHB09, p. 67 f.]. Table 4.4 shows heat and CO2 of combusting epoxy and phenol, which are resin bond ingredients.