Numerical Simulation Of Frozen Slag Inside Brickless Reaction Shaft Of Copper Flash Smelting Furnace

A brickless reaction shaft is a new type of shaft used in a flash smelting furnace. Unlike atraditional reaction shaft, there are no refractory bricks; steel nails are welded to the steel shellto prevent frozen slag from falling down. In addition, there are no water jackets buried in theshaft wall; cooling water is sprayed around the outer side of the steel shell. Good conditionsof the frozen slag inside a brickless reaction shaft are important for furnace life, heat loss aswell as production safety. Therefore, it’s significant to research the formation mechanism offrozen slag inside brickless reaction shaft of copper flash smelting furnace by means ofnumerical simulation from the view of theory and application.Based on the principle of heat transfer, a model of frozen slag in the brickless reactionshaft of a flash smelting furnace was established and applied to investigate the influence ofthe operational and structural parameters on the thickness of the frozen slag using COMSOLsimulation software. The main contents of this research are listed as follows:Based on the law of conservation of mass and the law of conservation of energy, modelsof material balance and heat balance were established to calculate the gas temperature insidethe brickless reaction shaft according to the material composition and technologic conditions.The calculated gas temperature was then added to the COMSOL Chemical ReactionEngineering module as a heat source.A thermo-fluid-solid three-field model of brickless reaction shaft was achieved byrealizing the heat transfer between smelting gas, frozen slag, steel shell and cooling waterbased on the heat transfer module and dynamic grid function of COMSOL. Using the model,the temperature field and the frozen slag inside brickless reaction shaft of a flash smelting furnacecan be displayed dynamically.The influence of melting temperature of frozen slag (MTFS), gas temperature (GT),material composition (MC), oxygen volume per ton concentrate (OVPTC), cooling watertemperature (CWT), and the structural parameters (steel shell thickness, steel nail length,steelnail thickness, and distance between nails) on the thickness of the frozen slag wasinvestigated. The results showed that:1. Frozen slag with a desired thickness and cooling water with strong flow are importantto prevent the brickless reaction shaft from eroding by high temperature in the inner chamber. 2. MTFS has a marked effect on the boundary of the frozen slag. A higher MTFS willincrease the thickness of the frozen slag.3. It is efficient for the formation of frozen slag to aviod ultra-high GT by providingconcentrate with reasonable composition and controlling OVPTC.4. The structural parameters of brickless reaction shaft have some effects on the thickness offrozen slag,especially, the distance between steel nails has a marked impact.Thus, mechanical andthermal factors should take precedence together when designing the steel nails of a bricklessreaction shaft.Results of this research will provide theoretical support for the industrial application andoperational optimization of brickless reaction shaft of flash smelting furnace.