DIN EN ISO 4349:2024-10

This document (EN ISO 4349:2024) has been prepared by Technical Committee ISO/TC 300 "Solid recovered materials, including solid recovered fuels" in collaboration with Technical Committee CEN/TC 343 "Solid recovered materials, including solid recovered fuels", the secretariat of which is held by SFS (Finland). This document specifies the determination of the share of material recovery in the case of energy recovery (that is, co-processing) of solid recovered fuels (SRFs), for example, in a cement kiln. This share, called the recycling index (R-index), is calculated on the basis of the ash content and the ash composition. When solid recovered fuels (SRFs) are co-processed mainly in the cement industry, simultaneous energy recovery and recycling of mineral components of waste material takes place because the ash is directly incorporated into the clinker. SRF co-processing therefore allows for the replacement of both mineral resources and fossil fuels. SRF ashes contain various chemical components that are crucial raw materials for cement manufacturers, fulfil specific tasks in cement clinker production or represent clinker phases giving the clinker its specific properties. For example, a major part of SRF ashes from mixed municipal and commercial waste consists of the four main chemical components that are required for cement clinker production: Al₂O₃, CaO, Fe₂O_{3 and SiO2 (see Annex A). Additionally, minor ash constituents include MgO and TiO<(Index)2}, both of which are present in or as clinker phases. K₂O and Na₂O are typical constituents of feldspars that are present in the clay used as a raw material for the process. SO₃, which is also present in SRF ash, or another sulfate carrier is needed in order to convert these alkali oxides into alkali sulfates, a clinker phase that alters the clinker’s chemical reactivity with water. The responsible German standardization committee is Working Committee NA 062-05-83 AA "Sekundärbrennstoffe" ("Recovered fuels" at DIN Standards Committee Materials Testing (NMP).