Study On The Preparation And Coating Properties Of Titanium Oxide/Kaolin Composite

Titanium dioxide is a high quality white pigment,which is widely used in plastics,coatings,inks,cosmetics and other industries.At present,the original titanium ore resources are in short supply.Besides,the production of titanium dioxide energy consumption is high,and the by-products produced in the process will harm the environment.As pigment,titanium dioxide is used only on the particle surface,and its core form,which accounts for 30%-60% of the total amount,is not fully utilized.Therefore,through the study of titanium dioxide composite pigment,reducing the amount of titanium dioxide pigment has good social and economic benefits.The coal measure kaolin in China has the advantages of large reserves,high whiteness,high brightness,stable chemical properties,and easy dispersion in water,etc.It is suitable for preparing kaolin/titanium oxide composite material as coating as the core of nucleated titanium dioxide.In this paper,the properties of kaolin/titanium oxide composite prepared by mechanical method,wet method,hydrothermal method,chemical deposition method and sol-gel method were investigated.The hydrothermal method and chemical deposition method were studied systematically.The main research contents are as follows:(1)Kaolin/titanium oxide composites were prepared by mechanical method,wet method,hydrothermal method,chemical deposition method and sol-gel method.The mechanical and wet methods used rutile titanium dioxide and kaolin as raw materials,and the chemical deposition and hydrothermal methods used titanium sulfate and kaolin as raw materials,while the sol-gel method used tetrabutyl titanate and kaolin as raw materials.The phase and chemical composition of kaolin/titanium oxide composites were analyzed by means of X-ray diffraction(XRD)and X-ray fluorescence spectroscopy(XRF).The morphology of the composite was observed by scanning electron microscope(SEM).The results show that the coating amount of the composite prepared by mechanical method and wet method is less.The distribution of the composite prepared by sol-gel method is not uniform on the surface of kaolin,while the coating amount of the composite prepared by hydrothermal method and chemical deposition method is more and the distribution of the titanium oxide is uniform on the surface of kaolin.(2)Using titanium sulfate and kaolin as raw materials,kaolin/titanium oxide composites were prepared by hydrothermal method.The effects of titanium oxide content,hydrothermal temperature,urea addition and calcination temperature on the properties of composites were investigated.Kaolin/titanium oxide composites were prepared with titanium tetrachloride and kaolin as raw materials.The structure of the composite was characterized by means of X-ray diffraction(XRD),physical adsorption(BET)and Fourier transform attenuated total reflection infrared spectrometer(ATR-FTIR).Coating properties of composites were determined by whiteness meter and reflectance meter,and oil absorption value of composites was determined according to GB-T 5211.15-2014.The results show that when titanium sulfate is used as raw material,when the mass ratio of titanium oxide to kaolin is 1/10,the hydrothermal temperature is 120?,the molar ratio of 1/2 urea to titanium sulfate is 0.8,and the calcination temperature is 800 ?,the maximum whiteness of the composite material reaches 92.3,the maximum oil absorption value is 148 g/100 g,and the covering rate is 87.99%.When titanium tetrachloride was used as raw material,chemical deposition method was adopted.When the mass ratio of titanium oxide to kaolin was 1/10,ammonia water was used as precipitant,and the hydrolyzed p H was 2.5,the whiteness of the composite reached 91.0,the oil absorption value reached 129 g/100 g,and the coverage rate was 80.58%.