Matte ceramic tile and preparation method thereof

A method for preparing a matte ceramic tile, comprising the following steps:

• (1) preparing raw materials for a blank body:
• preparing the raw materials according to a predetermined ratio, feeding the raw materials directly into a three-stage continuous ball mill, adding water to obtain a mixture with a water content of 32 wt % to 35 wt %, and ball milling continuously for 2 to 5 hours to obtain a slurry;
• wherein the raw materials comprise waste from edging and polishing, desulfurization residue, waste porcelain powder, nepheline powder, sodium potassium powder, potassium feldspar powder, and a carbon-containing clay;
• (2) powder spray granulation:
• storing the slurry produced by the continuous ball mill in an underground slurry tank;
• transferring the slurry into a drying tower by a plunger pump after aging and homogenization for powder spray granulation;
• a powder obtained by powder spray granulation has a volumetric weight of 1.0 to 1.1 g/cm3 and a water content of 6.0 wt % to 6.5 wt %;
• (3) aging:
• conveying the powder obtained by powder spray granulation to a powder silo directly with a belt, aging the powder in the powder silo for more than 48 hours before pressing and molding;
• water content of the powder after aging is 5.0 wt % to 6.0 wt %;
• (4) pressing and molding of the blank body:
• transporting the powder after aging to a hopper provided at a top of a press;
• pushing the powder into a mold frame of the press by a grid distributor;
• applying pressure to the powder by the press to partially release gas trapped in voids of the powder, causing powder particles to shift and combine through internal frictional forces to take on a desired shape, forming a blank body;
• the shape of the blank body formed has a cross-section identical to that of a mold, and shapes of an upper surface and a lower surface of the blank body are determined by shapes of an upper press mold and a lower press mold in the mold frame;
• (5) drying:
• drying the blank body in a roller hearth furnace having 3 to 5 layers;
• a maximum drying temperature is 160° C. to 200°° C., drying time is 30 min to 60 min;
• strength of the blank body after drying is 1.2 Mpa to 1.8 Mpa, a water content of a dried blank body is <0.1 wt %;
• (6) polishing the blank body:
• polishing a surface of the blank body coming out from the roller hearth furnace by a blank body polishing machine;
• (7) spraying water:
• spraying water onto the upper surface of the blank body by a high-pressure water-spraying cabinet equipped with a spray gun;
• the spray gun has a nozzle size of 0.36 mm;
• water pressure during spraying is 12 bar to 18 bar, water is sprayed in an amount of 55 g/m2 to 100 g/m2;
• (8) glazing:
• glazing is performed using a linear glazing machine with the following process parameters:
• specific gravity of a glaze slurry:
• 1.45 to 1.80;
• time taken for a glaze slurry to flow out of a viscometer, determined according to Chinese national standard GB/T1723 Paint Viscosity Determination Method:
• 18 s to 30s;
• and
• a thickness of a glaze layer:
• 0.03 mm to 0.1 mm;
• (9) applying a decorative pattern:
• applying a decorative pattern to a glazed surface of the blank body via any one of screen printing, rubber roller printing, and inkjet printing;
• and
• (10) firing:
• transferring a decorated blank body from the previous step to a firing kiln for firing at a firing temperature of 1050° C. to 1170° C. and a firing time of 50 min to 80 min, wherein a firing time for a stage of between 1150° C. to 1170° C. is 6 min to 10 min,
• wherein the waste from edging and polishing is solid waste produced during cold working at a later stage of ceramic tile production, and
• wherein the waste porcelain powder is ceramic tile powder having a desirable particle size obtained after a series of crushing treatments on defective ceramic tiles.