| Synthetic rutile is a high quality raw material for preparation of four titanium tetrachloride by chlorination.However,the research on the complete process of preparing high quality synthetic rutile is still lacking in China,even if we have the largest reserves of titanium resources in the world,we can not get rid of the dependence on imported minerals.So it is necessary to develop a kind of production technology which is suitable for the preparation of high quality synthetic rutile.Hydrochloric acid leaching of ilmenite concentrate can effectively remove iron impurities,obtaining high quality artificial rutile.In order to improve the process and solve the problem in the treatment of hydrochloric acid leaching of ilmenite concentrate filtrate(waste acid),recycling use of resources,this paper will study on a method of comprehensive recovery of waste acid.After comparing many kinds of hydrochloric acid recovery methods that Ruthner spray roasting method can not only fully recovering hydrochloric acid,but also can recycle the iron,which can not only solve the problem of emissions,but also realize the recycling of resources.Based on the laboratory conditions and requirements,combined with numerical simulation method design a suitable laboratory scale spray roasting device,for small and medium enterprises according to the need to establish their own spray roasting device provides a reference.In the ilmenite concentrate leached by hydrochloric acid method,the concentration of waste acid obtained by one-stage pressure technology was about 12% with 44g/L iron ion concentration,while the concentration of waste acid obtained by two-stage pressure technology was about 8% with 75g/L iron ion concentration.In order to improve the hydrochloric acid concentration recycled by spray roasting,the waste acid shall be pre-concentrated before the roasting.Aiming at the waste acids obtained by two leaching technologies,this paper conducted distillation on waste acid directly or with calcium chloride.The results indicated that the concentration of cold hydrochloric acid obtained by direct distillation was rather low,which can not be used for continuous treatment with acid.However,the added calcium chloride can improve the concentration of cold hydrochloric acid obviously.Add 1mol/L calcium chloride into 12% waste acid,the recovered 19.6% cold hydrochloric acid can be used to leach the ilmenite concentrate.For 8% waste acid,with the adding calcium chloride,the new acid concentration recovered by distillation get increased.However,it can not meet the new acid quality requirements.In order to design a set of small spray roasting equipment,this paper adopted CED software FLUENT and applied various physical models to conduct numerous simulation on flow field,temperature field,component distribution and pressure etc in the roasting reactors with different structures based on the finite volume method.The simulation results showed that the electric furnace heating is rather reasonable for the experimental waste acid roasting reactor.Meanwhile,this paper conducted numerous simulation on the main chemical reactions occurred at the time of waste acid roasting in the reactor.The results indicated that the spray roasting experiment on the waste acid can be conducted smoothly at the time when the temperature of electric furnace set up as 800?.The temperature in main chemical creation region was 640? to 740?.In order to verify the feasibility of using spray roasting method to dispose the waste acid and test the reliability of numerical simulation results,this paper formulated a set of spray roasting reactor.When the temperature of electric furnace was 800 ?,the technical parameters such as the spray flow can be adjusted to obtain 19.9% hydrochloric acid maximally,which can meet the new acid concentration requirements for further ilmenite concentrate leaching.Wash,filter and dry off the by-products to obtain iron oxide powder,of which TFe was 65% that can be used as iron-making material or processed into coating materials. |
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