Research progress and outlook of refractory materials for high-salt organic liquid waste incinerators

High-salt, organic waste liquids are characterized as having high COD value, complex composition, strong acidity or alkalinity, high salinity, and poor biodegradability, resulting in them contributing to environmental pollution. High-temperature incineration technology to treat high-concentration organic waste liquid has obvious advantages of thorough treatment, reduced effluents, and near-universal applicability to the many types of complex organic substances. Additionally, it is an effective way to dispose of high-salt, liquid chemical waste. Due to the complex composition and the high salt content of high-salt organic liquid waste, the high-temperature slag causes serious erosion to the refractory material of the incinerator during use. Damaged incinerator refractory linings are significant safety hazards and can cause major economic losses. It is crucial to study and understand the corrosion resistance of refractory materials very well. This paper introduces the main types of refractory materials suitable for high-salt organic waste liquid incinerators, the main types of incinerators and their applications, and finally, describes the mechanism of erosion of the refractory materials in detail. Based on the characteristics of the incineration process of phenol and acetone coproduction organic liquid waste, a method was proposed for the in situ anticorrosion treatment of high-salt organic liquid waste using traditional corundum–mullite refractory materials. The slag enters the refractory material through pores on the interface and reacts strongly with the refractory material surface at 1000–1300 ℃ to produce a low-melting, liquid phase product. The thermal stress of the product is different from that of the original refractory material. If it falls off and is damaged, the service life of the refractory material is extremely short, and the replacement cycle is only 3 months. The addition of Cr₂O₃ powder to the waste liquid is eventually deposited at the interface of the refractory material after the liquid waste is incinerated and forms an antierosion, refractory, solid solution layer. The corrosion-resistant layer on the surface of the refractory brick rarely reacts with the molten slag to form a low melting point phase. The protective layer can effectively slow down the penetration and erosion of the refractory materials by the slag. The preliminary test run results show that adding 5% Cr₂O₃ to the liquid waste can prolong the service life of corundum–mullite refractory bricks to several days. This study demonstrated that the in situ strengthening method to improve the corrosion resistance of conventional refractory materials is economical and efficient and shows good prospects of popularization and application.