Study On Corrosion Resistance Mechanism Of Refractories Used In Chemical High Salt Organic Waste Liquid Incinerator

High temperature incineration treatment of high concentration organic waste liquor has obvious advantages in thoroughness of treatment,reduction of effluent and adaptability to various complex organic compounds.It is an effective way to solve high salt chemical waste liquor.The composition of high-salt waste liquid is complex,and the slag will seriously erode the refractory material of incinerator under high temperature,and the damage of refractory lining will cause safety accidents and economic losses.It is of great significance to understand the damage mechanism of refractory lining of incinerator and improve the anti-erosion ability of refractory lining.This paper presents a method to improve the erosion resistance of corundum-mullite refractories by in-situ strengthening.The effect of Cr₂O₃/Zr O₂ on the phase transformation,interface morphology evolution and pore distribution of corundum mullite refractory was studied,and the in-situ erosion resistance mechanism was revealed.The main research results of this paper are as follows:（1）The corrosion mechanism of industrial incinerator slag on corundum-mullite refractories was studied.The study of phase transition showed that the main phase of slag sodium sulfate reacted with silica and alumina in refractories to form nephelite and albite.With the increase of temperature,the erosion of refractories by slag increases.After erosion,the porosity of refractory brick decreases to 0.0222 m L/g,mainly because the original pores of mullite phase are filled by molten slag and new meeting,leading to the decrease of porosity.Na and Si elements are mainly distributed in mullite phase,and the penetration depth is up to 35 mm.The penetration position of slag is mainly in Mullite phase,and the intrusion of bulk corundum phase is less.（2）The method of adding Cr₂O₃/Zr O₂ to corundum-mullite refractory was proposed.Thermodynamic study showed that Na₂SO₄ could significantly reduce the softening property of corundum-mullite refractory,and high temperature significantly accelerated the erosion process.Compared with Al₂O₃-Si O₂-Na₂SO₄ system,the formation temperature of pure liquid zone exceeds 1600℃after adding Cr₂O₃/Zr O₂in Al₂O₃-Si O₂-Na₂SO₄ system,and the liquid area decreases significantly,indicating that Cr₂O₃/Zr O₂ can effectively prevent slag erosion.The experimental results show that when chromium oxide powder is added to the slag,a 3 mm thick aluminum-chromium solid solution dense layer with high melting point is formed on the surface of the refractory material at high temperature,which is closely bonded with the original refractory brick,and the pore size of the refractory brick decreases from 19952.5 nm to 7166.1 nm.It can effectively slow down the infiltration erosion of molten slag.Zirconium silicate with high melting point was obtained by adding zirconium oxide.However,zirconium silicate has poor bonding property with the original refractory,which can easily fall off from the surface of refractory and cannot protect the refractory.（3）According to the anti-erosion mechanism,Cr₂O₃ in-situ strengthening corundum-mullite refractory technology was proposed.Cr₂O₃ powder was directly added into the waste liquid and entered into the incinerator through a nozzle.During the combustion process,Cr₂O₃ was deposited on the refractory interface.In order to slow down the further erosion of slag,a high melting point（Al,Cr）₂O₃ solid solution is formed on the lining surface of waste liquid incinerator under working conditions.