CERAMIC PRODUCTS
Chapter Notes.
1.-This Chapter applies only to ceramic products which have been fired after shaping. Headings No. 69.04 to 69.14 apply only to such products other than those classifiable in headings Nos. 69.01 to 69.03.
2.-This Chapter does not cover :
(a) Products of heading No. 28.44;
(b) Articles of heading No. 68.04;
(c) Articles of CHAPTER 71 (for example imitation jewellery);
(d) Cermets of heading No. 81.13;
(e) Articles of CHAPTER 82;
(f) Electrical insulators (heading No. 85.46) or fittings of insulating material of heading No. 85.47;
(g) Artificial teeth (heading No. 90.21);
(h) Articles of CHAPTER 91 (for example clocks and clock cases);
(ij) Articles of CHAPTER 94 (for example furniture lamps and lighting fittings prefabricated buildings);
(k) Articles of CHAPTER 95 (for example toys games and sports requisites);
(l) Articles of heading No. 96.06 (for example buttons) or of heading No. 96.14 (for example smoking pipes); or
(m) Articles of CHAPTER 97 (for example works of art).
GENERAL
The term " ceramic products " applies to products obtained :
(A) By firing inorganic non-metallic materials which have been prepared and shaped previously at in general room temperature. Raw materials comprise inter alia clays siliceous materials materials with a high melting point such as oxides carbides nitrides graphite or other carbon and in some cases binders such as refractory clays or phosphates.
(B) From rock (e.g. steatite) fired after shaping.
The manufacturing process of the ceramic products referred to in paragraph (A) above (whatever their constituent material) comprises the following main stages :
(i) Preparation of the paste (or body).
In some cases (e.g. manufacture of sintered alumina articles) the constituent material is used directly in powder form with the addition of a small amount of lubricant. In most cases however it is first made into a paste. This involves measuring and mixing the various constituents and where necessary milling sieving filter-pressing kneading maturing and de-airing. Some refractory products are also made from a blend of graded aggregate and fines along with a small amount of liquid binder which may be aqueous (e.g. tar resin materials phosphoric acid lignin liquor).
(ii) Shaping.
The prepared powder or paste is then shaped as nearly as possible to the desired form.
This is done by extrusion (through an extrusion die) pressing moulding casting or hand-shaping followed in some cases by some degree of machining.
(iii)Drying the resulting articles.
(iv) Firing.
In this operation the " green ware " is heated to a temperature generally ranging from 800 to 1 800 øC or higher according to the nature of the product. After firing the grains are closely bound together as a result of diffusion chemical transformation or partial fusion.
(v) Finishing.
The finishing processes depend on the intended use of the ceramic product.
Sometimes machine finishing to a high degree of precision is necessary. Finishing may also include marking metallising or impregnation.
Ceramic products are also very often coloured (either in the body or superficially) decorated or glazed by using as appropriate specially prepared colours or opacifiers vitrifiable enamels or glazes slips lustres etc.
Firing after shaping is the essential distinction between the goods of this Chapter and the mineral or stone articles classified in CHAPTER 68 which are generally not fired and the glass articles of CHAPTER 70 in which the vitrifiable compound has undergone complete fusion.
According to the composition and the firing process adopted the following products are obtained :
I. Goods of siliceous fossil meals or of similar siliceous earths and refractory goods of sub-Chapter I (headings 69.01 to 69.03).
II. Other ceramic products consisting essentially of common pottery stoneware earthenware porcelain or china etc. constituting sub-Chapter II (headings 69.04 to 69.14).
This Chapter excludes :
(a)Broken pottery (heading 25.30).
(b)Products of heading 28.44.
(c)Blocks plates bars and similar semi-manufactures of graphite or of other carbon or metallo-graphitic or other grades used e.g. for cutting into electrical brushes (heading 38.01) (see corresponding Explanatory Note).
(d)Unmounted cut elements of piezo-electric ceramic materials e.g. of barium titanate or of lead zirconate titanate
(heading 38.24).
(e)Articles of heading 68.04.
(f)Glass-ceramic products (CHAPTER 70).
(g)Sintered mixtures of base metal powders and heterogeneous intimate base metal mixtures obtained by melting
(Section XV).
(h)Cermets of heading 81.13.
(ij)Plates sticks tips and the like for tools unmounted of cermets (heading 82.09) and other articles of CHAPTER 82.
2 HEADINGS
SUB-CHAPTER I - GOODS OF SILICEOUS FOSSIL MEALS OR OF SIMILAR SILICEOUS EARTHS AND REFRACTORY GOODS