Study On Boiling Chlorination Process Of High Titanium Slag

The 85#high titanium slag produced by Panzhihua Iron and Steel,in which TiO2 reaches a high content up to 85%,plays a significant role in titanium raw material resources.With the increasing demand for titanium products in recent years,Panzhihua Iron and Steel devotes to studying large chlorination process of titanium white technology used high titanium slag as raw material.Among them,how to manufacture the coarse titanium tetrachloride by boiling and chloridizing the high titanium slag is the foundation of the whole technology.In this paper,we use 85#high titanium slag as the research object,and choose cold ash fluidizing and hot boiling chlorination as small scale approach,have mainly carried on three aspects of system research,include the theory of thermodynamics calculation,cold fluidization experiment and test in hot boiling chlorination.The results were obtained as followed:First of all,the standard gibbs free energy of direct chlorination reaction and add carbon chlorination reaction of the main titanium oxide and oxide of impurities in high titanium slag are calculated,and the results show that:in the temperature range from 750 to 1150 ?,the direct chlorination of high titanium slag can react directly with low valent titanium oxide and oxide impurities of FeO,MnO,CaO and MgO,and the main components TiO2 in high titanium slag cannot react in direct chlorination process.While in the temperature range from 750 to 1150 ?,all components can react in theory on the reaction of carbochlorination of high titanium slag,and the order of the reaction is CaO>MnO>FeO(turn into FeCl2)>MgO ?Fe2O3>FeO(turn into FeCl3)>TiO2>Al2O3>Si02.Second,the results of cold fluidization tests in high titanium slag show that the superficial gas velocity range in which the high titanium slag can fluidize are 0.2 m/s?0.5 m/s,within the scope of the gas velocity,the elutriation amount of high titanium slag is relatively stable,and the final elutriation rate of high titanium slag with different quality is basically the same.When the superficial gas velocity is up to 0.4?0.5 m/s,the dead zone of high titanium slag in bed almost disappears and achieves full fluidization,however,the high gas velocity will lead high particles elutriation rate,thereby causing loss to the raw material,therefor,with comprehensive consideration,proper superficial gas velocity in the cold fluidized process is 0.4 m/s.When the mass ratio of high titanium slag and petroleum coke is about 3:1,fluidization effect is better,they can be mixed uniformly in a very short period of time,and there is no delamination when the fluidization get started.The results of enlarged phi 260 mm chlorination furnace simulation with heikki Barracuda simulation software show that when the superficial gas velocity is 0.4 m/s,the mixed fluidized state of high titanium slag and petroleum coke in chlorination furnace,the temperature distribution effect and the distribution of the phase are better than the results when the superficial gas velocity is 0.8 m/s.Finally,based on thermodynamics,through the study of direct chlorination and carbochlorination process of high titanium slag under hot conditions,the results show that in the direct chlorination of high titanium slag,only low valent titanium oxide(TiO&Ti2O3),FeO and MnO react and generate the corresponding chloride;while in the carbochlorination process,all components in high titanium slag will react,which has proved the necessity of adding reducing agents(petroleum coke)in boiling chlorination process of the high titanium slag.With single factor experiment,suitable boiling chlorination conditions for PanGang to produce 85#high titanium slag are obtained.When the reaction temperature is 950 ?,superficial gas velocity is 0.4 m/s,chlorine concentration is 63%,the particle size of high titanium slag is 60?100 mesh,particle size of petroleum coke is 10?30 mesh,C/O ratio is 100:35 and the reaction time is 40 min,the chlorination rate of high titanium slag can reach 91%;In addition,most of the magnesium chloride generated in chlorination process can be removed out of the reactor by evaporation and airflow,thereby having little effect on the chlorination process.However,most of the calcium chloride will stay in the fluidized bed,causing particle agglomeration in the furnace and affecting the chloride process.With the above results in consideration,it is concluded that:under cold condition,when high titanium slag and petroleum coke is mixed in a mass ratio of about 3:1,they can fluidize and mix uniformly,and the fluidization effect is better when the superficial gas velocity is 0.4 m/s.In addition,suitable boiling chlorination conditions for PanGang to produce 85#high titanium slag are as follows:the reaction temperature is 950 ?,superficial gas velocity is 0.4 m/s,chlorine concentration is 63%,the particle size of high titanium slag is 60?100 mesh,particle size of petroleum coke is 10?30 mesh,C/O ratio is 100:35 and the reaction time is 40 min,under the condition the chlorination rate can reach 91%.