Several Theory And Operation Optimization Challenges In The Development Of Modern Copper Flash Smelters

The research on several theory and operation optimizationchallenges in the development of modern copper flash smelters would bevery important for breaking through the technical difficulties of flashsmelting, increasing the copper recovery, upgrading the domesticsmelteries' profit and competition ability in the international market.A new flash smelting theory—Particle Pulsation Collision Modelwas presented with overall analysis on the reacting particles in the shaftof the flash smelter, with conclusions of the former research results, andwith the proving from micro-particle kinematics, dynamics, two-phasefluid dynamics, statistic analysis and conclusion. Both the particlesplitting and the collision occur in the process of suspend smelting, whichare the two-side of the union of conflict. The particle splitting is the resultof rapid oxidation of the concentrate; meanwhile it results in intensifyingthe particle pulsation, which is the main cause of the particle collision.The particle gathering makes the oxidation and desulfurization reactioncontinue, which is the main mechanism of the oxygen transfer betweensolid and liquid phases. The specific statements on the Particle PulsationCollision Model are as follows.(1) The particle splitting and collision co-exist at different height ofreacting shaft.(2) It is presented that the concentrate particle pulsation is the mainreason for particle collision and gathering with the analysis on pulsationand collision of the high intensive turbulent jet of particle group.(3) With the oxidation continuance, melted sulphide and SO₂bubbles are formed at the particle center. The out-surface of the particle isporous ferric oxide shell. The gas formation in melting core impels theparticle splitting and collision. The higher the oxygen concentration andthe particle temperature are, the intenser the process is.(4) Because of the difference of the sizes, components, surroundingoxygen concentration and temperature of the particles, particles'oxidation have much difference. The heat released from the oxidation melts the concentrate particles, and the desulfurizations of under-oxidizedparticles are not completed.(5) While dropping in the shaft, the over-oxidized particles collideeach other or with the under-oxidized particles and gather to becomebigger. At the same time, the over-oxidized particles are deoxidized bythe under-oxidized particles.With analyzing the reaction dynamics and thermodynamics, it isconfirmed that the process of suspend smelting is made up of concentratecombustion, over-oxidization, collision and reducing reaction,re-oxidization, slagging reaction and fuel combustion. The numericalsimulation model of the flash smelter is set up, whose rationality andreliability have been proved by direct, logic and indirect methods.In this dissertation, the form of copper loss in the slag had beentested and analyzed. The melted matter at the different heights was takenout, and the industry examination of settler's working condition wasperformed for the analysis of main reason of the scar formation. Therelationships between copper lose percentage (or copper in slag) andsmelting capacity, copper matte grade, the slag component (Fe/SiO₂),slag thickness and Fe₃O₄ content were worked out on the basis ofstatistics analysis on Jinlong copper flash smelter's data. The viewpointand technical scheme was presented, which the Fe₃O₄ content must becontrolled for reducing the copper loss.For controlling the Fe₃O₄ content and intensifying the flash smelting,Gradient Oxygen Distribution Smelting Method is presented, which is toset up obvious oxygen gradient in the system of shaft, settler and electricfurnace. This is performed by adding coke or coal from the top ofreaction shaft. This kind of gradient oxygen distribution would be helpfulfor reducing Fe₃O₄ content and intensifying smelting. The optimizedoperation of controlling Fe₃O₄ formation is obtained with the numericalsimulation of the copper flash smelter.At the end, the structure of super-intensified concentrate burner isstudied and designed conceptually. It's a kind of swirl nozzle, which canchange the flame shape and the reaction process with different swirlingnumber. With the super-intensified concentrate burner, the highest throughput will be 3～4 times as before. With a series of simulation test, itis proved that feeding the concentration with air and optimizing the mainoperation parameters would successfully realize the ideas and aim of thedesign for the burner.