Study Of Dry Processed Powder For Porcelain Tiles

Dry pulverizing process technology is a major breakthrough and innovation in ceramic wall and floor tile industry,which is able to reduce investment,production cost,energy consumption and dust pollution most importantly.However,the dry pulverizing process technology is merely applied in the production of internal wall tiles.In this work,we intend to apply dry pulverizing process in the ceramic tile industry and obtain the same qualities as ceramic tiles prepared by traditional wet spraying methods.The raw materials from the main production areas?such as Foshan,Zibo,Gaoan?in our country were firstly collected in this study.The representative raw materials were sorted according to their chemical compositions and attrition properties.The main phases of representative raw materials were studied as well.The granulation powders were prepared by dry and wet pulverizing process respectively based on the mature formula of ceramic tiles,and the particle size distribution and microstructure of two kinds of powers were compared.The physical properties of the samples after firing were analyzed,mainly including the firing shrinkage,water absorption,density,thermal expansion coefficient and bending strength.Besides,XRF?X-ray fluorescence spectrometry?,XRD?X-ray diffraction analysis?,TG-DSC?thermogravimetric-differential thermal analysis?,SEM?scanning electron microscopy?and other characterization methods were selected to reveal the relationship between the chemical composition,phase composition,firing process,structure and properties of raw materials,and to explore the mechanism of dry pulverizing process.Finally,based on the original formula,high temperature fluxes were introduced to obtain the ceramic tile bodies with low water absorption,and the mechanism of increased density was further discussed.The major research achievements are as follows:?1?Chemical compositions of the collected raw materials were measured and the corresponding database was established.It is revealed that the grade of raw materials is overall low with a high Fe₂O₃ content,especially for feldspar raw materials.Most potassium feldspar raw materials have a K₂O content below<6 wt%.Additionally,taking stable quartz in grindability as a reference,grindability data of raw materials are systematically measured.Feldspar raw materials are also stable in grindability with an average index of 2.53,which are difficult to grind.Comparatively,grindability of clay raw materials are highly dependent on their places of origin.?2?Taking felspar from Xishui and Mengyin,albite,clay from Hebei,pyrauxite from Zhejiang,Datong and Hainan Clay as raw materials for the body formula,dry and wet methods were both employed to prepare samples.After sintering at 1200?,the particles prepared by dry milling exhibit a broad size distribution,a rough surface and a low mobility.Comparatively,the particles prepared by wet milling show a uniform size distribution and are solid.Therefore,the resultant sintered samples from dry method have high water absorption,low sintering shrinkage with a value of 1.53%,low rupture strength of 31.31 MPa and low expansion coefficient of 226.27×10^-7.Despite great differences in the physical properties,the sintered samples from the two methods have the same phases,mainly?-SiO₂ and mullite.It is revealed that the liquid content is increased at a high temperature and fast sintering condition,which promotes the formation of these phases.?3?For a better densification of sintered samples out of dry pulverizing process,fluxing agents with a weight ratio of 5 wt%and 10 wt%were added into the original formula Y and their influences on the properties of porcelain tiles were investigated.The results show that the fluxing agents promotes the formation of liquid phase,which benefits the viscous flow under the effect of surface tension,hole filling and densification of samples.The sintered samples with adding of 10 wt%show low water absorption of 0.07%,porosity of 0.25%,volume density of 2.54 g/cm³,flexural strength of 39.10 MPa,which fulfill the standard for porcelain tiles GB/T4100-2015.