C
SECTION C — CHEMISTRY; METALLURGY
 C

Note(s)

  1. In section C, the definitions of groups of chemical elements are as follows:

    Alkali metals: Li, Na, K, Rb, Cs, Fr

    Alkaline earth metals: Ca, Sr, Ba, Ra

    Lanthanides: elements with atomic numbers 57 to 71 inclusive

    Rare earths: Sc, Y, Lanthanides

    Actinides: elements with atomic numbers 89 to 103 inclusive

    Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W

    Halogens: F, Cl, Br, I, At

    Noble gases: He, Ne, Ar, Kr, Xe, Rn

    Platinum group: Os, Ir, Pt, Ru, Rh, Pd

    Noble metals: Ag, Au, Platinum group

    Light metals: alkali metals, alkaline earth metals, Be, Al, Mg

    Heavy metals: metals other than light metals

    Iron group: Fe, Co, Ni

    Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens

    Metals: elements other than non-metals

    Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards

  2. Section C covers :
    1. pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation;
    2. applied chemistry, which covers compositions containing the above compounds, such as: glass, ceramics, fertilisers, plastics compositions, paints, products of the petroleum industry. It also covers certain compositions on account of their having particular properties rendering them suitable for certain purposes, as in the case of explosives, dyestuffs, adhesives, lubricants, and detergents;
    3. certain marginal industries, such as the manufacture of coke and of solid or gaseous fuels, the production and refining of oils, fats and waxes, the fermentation industry (e.g., brewing and wine-making), the sugar industry;
    4. certain operations or treatments, which are either purely mechanical, e.g., the mechanical treatment of leather and skins, or partly mechanical, e.g., the treatment of water or the prevention of corrosion in general;
    5. metallurgy, ferrous or non-ferrous alloys.
  3. In all sections of the IPC, in the absence of an indication to the contrary, the Periodic System of chemical elements referred to is the one with 8 groups as represented in the table below. For example, group C07F 3/00 "Compounds containing elements of the 2nd Group of the Periodic System" refers to the elements of columns IIa and IIb. [2009.01]

    1. In the case of operations, treatments, products or articles having both a chemical and a non-chemical part or aspect, the general rule is that the chemical part or aspect is covered by section C.
    2. In some of these cases, the chemical part or aspect brings with it a non-chemical one, even though purely mechanical, because this latter aspect either is essential to the operation or treatment or constitutes an important element thereof. It has seemed, in fact, more logical not to dissociate the different parts or aspects of a coherent whole. This is the case for applied chemistry and for the industries, operations and treatments mentioned in Notes (1)(c), (d) and (e). For example, furnaces peculiar to the manufacture of glass are covered by class C03 and not by class F27.
    3. There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example:
    4. In still other cases, the pure chemical aspect is covered by section C and the applied chemical aspect by another section, such as A, B or F, e.g., the use of a substance or composition for:
    5. When the chemical and mechanical aspects are so closely interlocked that a neat and simple division is not possible, or when certain mechanical processes follow as a natural or logical continuation of a chemical treatment, section C may cover, in addition to the chemical aspect, a part only of the mechanical aspect, e.g., after-treatment of artificial stone, covered by class C04. In this latter case, a note or a reference is usually given to make the position clear, even if sometimes the division is rather arbitrary.
  
METALLURGY
 C21
METALLURGY OF IRON
 C21B
MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B 1/00; electric heating H05B)
 C21B

Note(s)

  1. This subclass covers:
    • the production of iron or steel from source materials, e.g. the production of pig-iron;
    • apparatus specially adapted therefor, e.g. blast furnaces, air heaters (furnaces in general F27).
  2. Processes using enzymes or micro-organisms in order to:
    1. liberate, separate or purify a pre-existing compound or composition, or to
    2. treat textiles or clean solid surfaces of materials
    are further classified in subclass C12S.  [5]
 C21B
Subclass index
MAKING PIG-IRON
In blast furnaces 5/00, 7/00, 9/00
Other processes 11/00
General features 3/00
MAKING IRON 13/00, 15/00
MAKING LIQUID STEEL BY DIRECT PROCESSES 13/00
P:40 C21B 3/00
General features in the manufacture of pig-iron (mixers for pig-iron C21C 1/06)
 C21B 3/02
·  by applying additives, e.g. fluxing agents
 C21B 3/04
·  Recovery of by-products, e.g. slag
 C21B 3/06
·  ·  Treatment of liquid slag (slag wool C03B; slag stones C04B)
 C21B 3/08
·  ·  ·  Cooling slag
 C21B 3/10
·  ·  ·  Slag pots; Slag cars
P:10 C21B 5/00
Making pig-iron in the blast furnace
 C21B 5/02
·  Making special pig-iron, e.g. by applying additives, e.g. oxides of other metals
 C21B 5/04
·  Making slag of special composition
 C21B 5/06
·  using top gas in the blast furnace process (in coke ovens C10B)
P:50 C21B 7/00
Blast furnaces (lifts associated with blast furnaces B66B 9/06)
 C21B 7/02
·  Internal forms
 C21B 7/04
·  with special refractories (refractory materials C04B)
 C21B 7/06
·  ·  Linings for furnaces
 C21B 7/08
·  Top armourings
 C21B 7/10
·  Cooling; Devices therefor
 C21B 7/12
·  Opening or sealing the tap holes
 C21B 7/14
·  Discharging devices, e.g. for slag
 C21B 7/16
·  Tuyères
 C21B 7/18
·  Bell-and-hopper arrangements
 C21B 7/20
·  ·  with appliances for distributing the burden
 C21B 7/22
·  Dust arresters
 C21B 7/24
·  Test rods or other checking devices
P:60 C21B 9/00
Stoves for heating the blast in blast furnaces
 C21B 9/02
·  Brick hot-blast stoves
 C21B 9/04
·  ·  with combustion shaft
 C21B 9/06
·  ·  Linings
 C21B 9/08
·  Iron hot-blast stoves
 C21B 9/10
·  Other details, e.g. blast mains
 C21B 9/12
·  ·  Hot-blast valves or slides for blast furnaces (valves in general F16K)
 C21B 9/14
·  Preheating the combustion air
 C21B 9/16
·  Cooling or drying the hot-blast
P:20 C21B 11/00
Making pig-iron other than in blast furnaces
 C21B 11/02
·  in low shaft furnaces
 C21B 11/06
·  in rotary kilns
 C21B 11/08
·  in hearth-type furnaces
 C21B 11/10
·  in electric furnaces
P:0 C21B 13/00
Making spongy iron or liquid steel, by direct processes
 C21B 13/02
·  in shaft furnaces
 C21B 13/04
·  in retorts
 C21B 13/06
·  in multi-storied furnaces
 C21B 13/08
·  in rotary furnaces
 C21B 13/10
·  in hearth-type furnaces
 C21B 13/12
·  in electric furnaces
 C21B 13/14
·  Multi-stage processes
P:30 C21B 15/00
Other processes for the manufacture of iron from iron compounds (general methods of reducing to metal C22B 5/00; by electrolysis C25C 1/06)
 C21B 15/02
·  Metallothermic processes, e.g. thermit reduction
 C21B 15/04
·  from iron carbonyl