Other

26.21 - Other slag and ash, including seaweed ash (kelp); ash and residues from the incineration of municipal waste. 2621.10 2621.90 - Ash and residues from the incineration of municipal waste - Other This heading covers slag and ash not falling in heading 26.18,26.19 or 26.20, derived £tom the workin of ores or from metallurgical rocesses, as well as those derived from any other materif or process. Although many of g e products are used as fertilisers they are classified here and not in Chapter 3 1 (except in the case of basic slag). The products covered include : (1) Ash and clinker of mineral ori 'n produced primarily fiom burning coal, lignite, peat or oil in utility boilers. Its princip uses are as a raw material for cement manufacture, as a supplement to cement m concrete, in mine backfill, as a mineral filler in plastics and paints, as a lightweight aggregate in building bbck manufacture and in civil engineering stmctures such as embankments, highway ramps and bridge abutments. It includes : f (a) Fly ash - finel divided particles entrained in furnace flue gases and removed from the gas stream by ag or electrostatic filters; g (b) Bottom ash - more coarse ash removed by settlement from the gas stream immediately after leaving the furnace; (c) Boiler slag - coarse residues removed fiom the bottom of the furnace; (d) Fluidised bed combustor ash (FBC-ash) - inorganic residues from burning coal or oil in a fluidised bed of limestone or of dolomite. (2) Kelp and other vegetable ash. Kel covered by this heading is material r d u c e d by inc~neratingcertain types of seawee2 In its raw state it is a heavy, rough, blac sh material but, when refined, it is a dull white powder. It is mainly used for extracting iodine or in the glass industry. This group also includes rice husk ash, composed almost entirely of silica, and used primarily for the manufacture of sound-insulating bricks or other sound-insulating products. (3) Bone ash obtained fiom the calcination of bones in the open air. Apart from its use for soil improvement, this product is also used for coating ingot moulds in copper smelting. The heading excludes animal black, obtained from the calcination of bones m a closed vessel (heading 38.02). (4) Crude potassium salts obtained in the sugar industry fiom residues of beet molasses by incineration, washing, etc. (5) Ash and residues resultin from the incineration of municipal waste (see Note 4 to Chapter 38). Such ash an residues are fre uently a mixture of clinker and some toxic metals (e.g., lead) and generally used for t e construction of temporary roadways on landfill sites as a substitute for aggre ates. Metal content of this type of ash and residues does not warrant the recovery of meta s or metal compounds. % TI f