1 Classify according to purpose.

(1) Interior wall brick: Glazing refined pottery product with water absorption less than 21 percent applies to decorate interior wall. Its main characteristics are high glossiness in glaze, rich decorative means and higher overall quality and dimension precision.

(2) Exterior wall brick: Ceramic brick with water absorption less than 10 percent applies to decorate exterior wall. According to different outside air temperature, brick spread with different water absorption is chosen. In cold area, brick with water absorption less than 3 percent should be chosen, multiple glazes of exterior wall should be semi dull (sub-light) or lightless and the brick with small water absorption should not be glazed.

(3) Floor tile: It is the ceramic brick applying to spread and stick floor. It owns main characteristics of large rigidity of working face, wear resistance, thicker body, high mechanical strength and good fouling resistance.

2. Classify according to material quality.

(1) Ceramic tile: Water absorption is less than 0.5 percent, light permeability is superior, its
section is exquisite and shows conchiform.

(2) Semi-ceramic tile: Water absorption is between 0.5 percent and 10 percent. It involves vitrified tile, fine stoneware tile and stoneware tile. Its light permeability is bad but mechanical strength is high, thermal stability is good and chemical resistance is excellent. Its section shows stone form.

(3) Fine earthenware tile: Its water absorption is larger and commonly is between 10 percent and 21 percent, sintering degree of base is low, base is lighttight, mechanical strength is lower and surface is coarse.

3. Classify according to forming methods.

(1) Dry press method (powder method): Make pug into the powder lot with water content less than 6 percent, and then make the powder lot within the die into sheet tile through press.

(2) Stiff mud method (extrusion method, wet pressing method and rolling method, etc): Make pug into mud pie with water content about 20 percent, and then press the plastic mud pie into sheet tile with different pressurization modes such as extrusion and rolling, etc.

(3) Slip casting method: Make pug into slip-casting material which then takes shape with plaster cast. Owing to the efficiency of such forming method is low, is mainly applies to produce special-shaped product with little parts.

When testing product performance, testing standard usually is chosen according to materials and forming methods. For example, when testing ceramic tile, the standard should be that for the ceramic tile which is molded with powder method and has water absorption less than 0.5 percent.