Modification Of Pyrolysis Carbon Black From Waste Tires By Pottassium Ferrate And Application In Rubber Compoudings

The amount of waste tires belonging to solid waste is large.Pyrolysis technology is the most effective,environmentally friendly and economical way to treat waste tires,and it can achieve 100%recycling of materials and energy.Pyrolysis carbon black is one of the most important products of pyrolysis of waste tires.How to realize the efficient reuse of pyrolysis carbon black is a crucial step in the entire recycling process.Compared with commercial carbon black,pyrolysis carbon black has large particle size,low structure,no surface activity,and high ash content.The current modification methods are low in efficiency and cause serious environmental pollution.This project intends to first study and analyze the basic properties of pyrolysis carbon black,using potassium ferrate to have strong oxidizing properties in alkaline environments,and develop low liquid-to-solid ratio conditions Pyrolysis carbon black deep impurity removal-modification reaction system;adjust the reaction temperature,reaction time and reagent ratio and other factors to optimize the reaction system.The reaction system treatment can remove the impurities of pyrolysis carbon black inorganic S,Zn,Ca,etc.,simultaneously improve the structure degree,reduce the particle size,and improve the surface activity.The above-mentioned modification and upgrading technology can improve the performance of pyrolysis carbon black in all directions,and has the characteristics of high efficiency and low pollution.Finally,the modified pyrolysis carbon black is applied to natural rubber,which provides an effective way for the high value and cascade utilization of waste tire pyrolysis carbon black.The main research contents of this paper are as follows:(1)A more comprehensive characterization of the basic properties of waste tire pyrolysis carbon black provided by Qingdao Double Star Tire Group Co.,Ltd.With the help of comprehensive analysis methods such as XPS,FT-IR,EDS,TEM,etc.,the difference between pyrolysis carbon black and industrial carbon black is analyzed.The inorganic ash on the surface of pyrolysis carbon black is mainly O,Zn,S,Si,Ca,and its content is as much as 20%,while the ash content of industrial carbon black is less than0.5%.Among them,zinc is in the form of Zn O and Zn S,silicon is in the form of elemental Si and Si O₂,and calcium is in the form of Ca CO₃.The iodine absorption value of pyrolysis carbon black is 60 g kg^-1,which is between N330 and N550.The oil absorption value of pyrolysis carbon black is 100 ml·100g^-1,which is lower than N330 and N550.The p H value of pyrolysis carbon black is 6.5,and the functional groups on its surface are acidic,mainly including hydroxyl,carboxyl and ester groups.(2)Use potassium ferrate alkaline reaction system to remove impurities and improve pyrolysis carbon black.The effect of reaction time,reaction temperature and reagent ratio on the impurity removal effect of pyrolysis carbon black was systematically studied.Using analysis methods such as particle size analyzer,TEM,RAMAN,XRD,etc.,it is concluded that the particle size of pyrolysis carbon black after modification is reduced,and the content of inorganic ash is reduced from 16%to 1.74%at most.The content of carboxyl,ester,and hydroxyl functional groups increased by 1.42%.The DBP oil absorption value of pyrolysis carbon black was tested by manual method,and the results showed that the modified pyrolysis carbon black increased from 62 ml/100g to 110ml/100g at the highest,and the structure degree was significantly improved.An optimal experimental condition was initially obtained:reaction temperature 70 ?,reaction time 3 h,CBP:K₂FeO₄=1:1.(3)The modified pyrolysis carbon black of potassium ferrate alkaline reaction system was applied to natural rubber,and the vulcanization,mechanical,hardness,abrasion,dynamic mechanical properties of the rubber compound and vulcanizate were tested.The results show that:compared with unmodified pyrolysis carbon black/NR vulcanizate,the scorch time of modified pyrolysis carbon black/NR vulcanizate is reduced,the vulcanization rate is accelerated,and the difference between the highest torque and the lowest torque(M_H-M_L)An increase of 40%,the tensile strength increased from 18 MPa to25 MPa,and the tensile strength increased from 38 KN/m to 38 KN/m.At the same time,the hardness and abrasion performance were improved.The modified pyrolysis carbon black/NR vulcanizate has improved wet skid resistance and low rolling resistance.It was finally confirmed that the best experimental conditions for the modified pyrolysis carbon black of potassium ferrate alkaline reaction system:reaction temperature 70 ?,reaction time 3 h,CBP:K₂FeO₄=1:1.