WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
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
1.- This Chapter does not cover : (a) Slag or similar industrial waste prepared as macadam (heading 25.17); (b) Natural magnesium carbonate (magnesite), whether or not calcined (heading 25.19); (c) Sludges from the storage tanks of petroleum oils, consisting mainly of such oils (heading 27.10); (d) Basic slag of Chapter 31; (e) Slag wool, rock wool or similar mineral wools (heading 68.06); (f) Waste or scrap of precious metal or of metal clad with precious metal; other waste or scrap containing precious metal or precious metal compounds, of a kind used principally for the recovery of precious metal (heading 71.12 or 85.49); or (g) Copper, nickel or cobalt mattes produced by any process of smelting (Section XV). 2.- For the purposes of headings 26.01 to 26.17, the term “ores” means minerals of mineralogical species actually used in the metallurgical industry for the extraction of mercury, of the metals of heading 28.44 or of the metals of Section XIV or XV, even if they are intended for non-metallurgical purposes. Headings 26.01 to 26.17 do not, however, include minerals which have been submitted to processes not normal to the metallurgical industry. 3.- Heading 26.20 applies only to : (a) Slag, ash and residues of a kind used in industry either for the extraction of metals or as a basis for the manufacture of chemical compounds of metals, excluding ash and residues from the incineration of municipal waste (heading 26.21); and (b) Slag, ash and residues containing arsenic, whether or not containing metals, of a kind used either for the extraction of arsenic or metals or for the manufacture of their chemical compounds. Subheading Notes. 1.- For the purposes of subheading 2620.21, “leaded gasoline sludges and leaded anti-knock compound sludges” mean sludges obtained from storage tanks of leaded gasoline and leaded anti-knock compounds (for example, tetraethyl lead), and consisting essentially of lead, lead compounds and iron oxide. 2.- Slag, ash and residues containing arsenic, mercury, thallium or their mixtures, of a kind used for the extraction of arsenic or those metals or for the manufacture of their chemical compounds, are to be classified in subheading 2620.60.