WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
25.23 - Portland cement, aluminous cement, slag cement, supersulphate cement and similar hydraulic cements, whether or not coloured or in the form of clinkers (+). 2523.10 - Cement clinkers - Portland cement : - - White cement, whether or not artificially coloured 2523.29 - - Other 2523.30 - Aluminous cement 2523.90 - Other hydraulic cements 2523.21 Portland cement is obtained by firing limestone containin in its natural state, or mixed artificially with, a suitable proportion of clay. Other materi s such as silica, alumina or iron bearing substances may also be added. As a result of the firing process, semi-finished roducts known as clinkers are obtained. These clinkers are subsequently ground to roduce !ortland cement, which may incorporate additives and accelerators to modify its hy aulic properties. The princi a1 types of Portland cement are normal Portland cement, moderate Portland cement and white ortland cement. d 6: The heading also covers aluminous cement, slag cement, supersulphate cement (ground blast furnace slag mixed with an accelerator and calcined gypsum), pozzolana cement, Roman cement, etc., and mixtures of the above-mentioned cements. The cements of this heading may be coloured. This heading does not include certain roducts sometimes known under the name of cement, such as, Keene's cement or English cement (a umed plaster gypsum) (heading 25.20), and pozzolana earth, santorin earth and similar substances, sometimes called natural cements (heading 25.30). P The heading also excludes : (a) Finely ound blast furnace sla which requires the addition of a small uantity of accelerator at the time oPmaking u (heading 2 1 9 ) ; the ground slag mixed with an acce erator, ready for use, does, however, fall in &s heading. P (b) Dental cements and bone reconstruction cements (heading 30.06). (c) Cements of heading 32.14. (d) Refractory cements and mortars, based on chamotte or dinas earths, etc. (heading 38.16). (e) Non-refractory mortars and concretes (heading 38.24).
Subheading Explanatory Note. Subheadings 2523.21 and 2523.29 For the purposes of subheadings 2523.21 and 2523.29, " Portland cement " means cement obtained by grinding Portland clinker with the possible addition of a small quantity of calcium sulphate. It is to be noted : - - that Portland clinker is a product of subheading 2523.10 consisting mostly of calcium silicates which is obtained by heatin to artial fusion a redetermined and homogeneous mixture of materials principally oontainingBme 7 ~ a O and ) silica t)Sio2) with a smaller proportion of alumina (AlrO$ and Iron oxide (Fe203)and; that the term " calcium sulphate " covers sulphate products appropriate toethe rut% !$unm a sum and its derivatives and anhydrite and other calcium of cements.
1.- Except where their context or Note 4 to this Chapter otherwise requires, the headings of this Chapter cover only products which are in the crude state or which have been washed (even with chemical substances eliminating the impurities without changing the structure of the product), crushed, ground, powdered, levigated, sifted, screened, concentrated by flotation, magnetic separation or other mechanical or physical processes (except crystallisation), but not products which have been roasted, calcined, obtained by mixing or subjected to processing beyond that mentioned in each heading. The products of this Chapter may contain an added anti-dusting agent, provided that such addition does not render the product particularly suitable for specific use rather than for general use. 2.- This Chapter does not cover : (a) Sublimed sulphur, precipitated sulphur or colloidal sulphur (heading 28.02); (b) Earth colours containing 70 % or more by weight of combined iron evaluated as Fe O 2 3 (heading 28.21); (c) Medicaments or other products of Chapter 30; (d) Perfumery, cosmetic or toilet preparations (Chapter 33); (e) Dolomite ramming mix (heading 38.16); (f) Setts, curbstones or flagstones (heading 68.01); mosaic cubes or the like (heading 68.02); roofing, facing or damp course slates (heading 68.03); (g) Precious or semi-precious stones (heading 71.02 or 71.03); (h) Cultured crystals (other than optical elements) weighing not less than 2.5 g each, of sodium chloride or of magnesium oxide, of heading 38.24; optical elements of sodium chloride or of magnesium oxide (heading 90.01); (ij) Billiard chalks (heading 95.04); or (k) Writing or drawing chalks or tailors' chalks (heading 96.09). 3.- Any products classifiable in heading 25.17 and any other heading of the Chapter are to be classified in heading 25.17. 4.- Heading 25.30 applies, inter alia, to : vermiculite, perlite and chlorites, unexpanded; earth colours, whether or not calcined or mixed together; natural micaceous iron oxides; meerschaum (whether or not in polished pieces); amber; agglomerated meerschaum and agglomerated amber, in plates, rods, sticks or similar forms, not worked after moulding; jet; strontianite (whether or not calcined), other than strontium oxide; broken pieces of pottery, brick or concrete.