Study On Recovery And Utilization Of Iron In Red Mud

Red mud is a waste generated during the production of alumina,which contains a large amount of iron and makes its appearance red.At present,the main method of processing red mud is the storage method,which not only seriously pollutes the surrounding environment,but also is a huge waste of valuable metals in red mud.At present,the methods of comprehensive utilization of red mud have been used as a building material matrix,as an environmentally friendly material adsorbent,etc.,can not be very good recycling of valuable metals in red mud.In recent years,hydrometallurgical treatment of red mud has been able to recycle valuable metals in red mud,which is the hotspot of red mud treatment.A single-factor condition optimization experiment was conducted on the acid leaching reaction of red mud,and the optimal conditions were determined as leaching temperature 70?,leaching time 3 h,and solid-liquid ratio 1:5.Under this process condition,the leaching rate of waste acid to red mud can reach 45%.Orthogonal experiments determine the degree of influence of time,temperature and solid-liquid ratio on leaching rate.The priority of the three is:leaching time>leaching temperature>solid-liquid ratio.The leaching process is enlarged by 10 times and 30times.The experimental results show that regardless of the 10 times or 30 times magnification,the leaching rate is between 44%and 47%,and the leaching effect is the same as when it is not amplified.It is determined that the countercurrent stage is 6stages,and the leaching reaches equilibrium when the water is discharged for 9rounds,and the leaching rate is more than 95%when balanced.Wash the leaching residue obtained in the leaching process.The single-factor condition optimization experiment determined that the best process conditions for leaching residue washing were:washing temperature 50?,pickling time 2.5 h,pickling once,washing twice.Under optimal conditions,the filter residue was washed in 3 levels of cross-flow,with 5 rounds.The experimental results show that in continuous operation,the cross-flow washing improves the whiteness of the filter residue significantly and the process is stable.The MgO neutralization method was used to convert the iron in its leaching solution into ferric hydroxide.Exploratory experiments on the preparation of ferric hydroxide by MgO neutralization method confirmed that under the same preparation conditions,the yield of ferric hydroxide in the ventilated group was much higher than that in the unvented group.A single factor optimization experiment was conducted to determine the best experimental conditions for the preparation of ferric hydroxide by this method:reaction temperature 60?,reaction time 2 h,MgO dosage 40 g/L,and aeration rate 20 L/min.The MgSO₄in the iron removal mother liquor is recovered by the evaporation concentration method,and the purity of the MgSO₄obtained after recrystallization is above 95%,and the yield can reach 81.3%.The kinetic study on the red acid leaching of waste acid and the crystallization of magnesium sulfate provides a theoretical basis for industrialization.It is determined that every 1,000 tons of red mud treatment will make a profit of 1.71 million yuan.And conduct a SWOT analysis to briefly explain the advantages and disadvantages of the process and the opportunities and challenges it faces.