MANUFACTURING PROCESS OFPROCELAIN TILESNISHANT SINHA
WHAT IS A PROCELAIN TILES?▪ Ceramic tiles with a water absorption rate of less than 0.5% .▪ Used to cover floors and walls.
OVERALL MANUFACTURING PROCESS▪ Preparation of raw materials.▪ Pressing and drying.▪ Firing process with or without glaze.▪ Additional refinements.▪ Packaging process.
Raw Material Supply Mixing Extrusion Pre-CureCoating Racking and DereckingCuringDepalletingPost-cure Coating& DryingInspectionYard Stacking Loading & DispatchCollecting& Packing
RAW MATERIALS▪ Sand▪ White clay▪ Talc▪ Feldspar▪ Calcite▪ Dolomite
MIXING▪ All the Raw Materials are crushed in an uniform size.▪ Sometimes, water is added and the ingredients are wet milled orground in a ball mill.▪ Excess water is removed using filter pressing followed by spraydrying.
EXTRUSION▪ The dry powder ismechanically placed intomoulds of the required size.▪ The body of the tile ispressed to that size in ahydraulic press.▪ The pressure applied rangesfrom 3,500 to 7,200 tons
DRYING▪ The moisture content in thebody is reduced to therequired levels by placing thetiles in dryers.▪ Here heat is applied byconvection from hot gasesapplied to the surface of thetiles.
RACKING AND DERACKING▪ Temporary storage furtherprocess.▪ Helps in removing excessmoisture, if present.▪ Also helps in the products toget stable.
GLAZING▪ Unglazed, extruded tiles are firedafter the drying stage.▪ Ceramic tiles have a single or multiplecoats of glaze applied.▪ The glaze adds protection texture andenhances chemical resistance.▪ Silica is the prime component ofglaze.
FIRING▪ Most important part of theprocess because it willdetermine:– Mechanical strength– Dimensional– Stability– Chemical resistance– Ease of maintenance– Fire resistance.▪ Fired at temperatures ofaround 1220 Celsius inapproximately 40 minuteprocess.
BYPRODUCTS▪ A variety of pollutants are generated during the various manufacturing steps, such as:– Fluorine– Lead compounds.▪ Lead compounds have been significantly reduced with the recent development of no-lead orlow-lead glazes.▪ Fluorine emissions can be controlled with scrubbers, devices that basically spray the gases withwater to remove harmful pollutants.▪ The tile industry is also developing processes to recycle wastewater and sludge produced duringmilling, glazing, and spray-drying.
QUALITY CONTROL▪ Most tile manufacturers now use statistical process control (SPC) for each step of themanufacturing process.▪ Statistical process control consists of charts that are used to monitor variousprocessing parameters, such as :– particle size– milling time– drying temperature and time– compaction pressure– dimensions after pressing– Density– firing temperature and time▪ These charts identify problems with equipment, out of spec conditions, and help toimprove yields before the final product is finished.▪ Work closely with their raw material suppliers to ensure that specifications are metbefore the material is used.