Preparation Of Nanometer Iron Oxide From Waste Acid Pickling Solution

Acid as a cleaning agent in metallurgy,machinery and metal products processing industry has been widely used.When the concentration of acid in the acid solution decreases to a certain extent,its cleaning effect will be significantly reduced and become waste acid s-olution（or pickling waste liquid）.Acid washing waste liquor is highly acidic and contains a large number of metal ions,which is classified as hazardous waste for management.Nanomet-er iron oxide has good light fastness,magnetism,and has good absorption and shielding effect to ultraviolet ray,can be widely used in flash paint,printing ink,plastics,leather,paint,auto-mobile,electron,high magnetic recording materials,catalyst and biomedical engineering,etc.,different shape,size of iron oxide nanomaterials due to the special effect of nano shows uniq-ue advantages.Therefore,it is of great significance to pay attention to the synthesis,cha-racte rization and properties of nanometer iron oxide particles.In this study,nano-iron oxide pig-ment was prepared from waste acid of hydrochloric acid pickling.This article can be mainly divided into three parts,first of all,the first part is the determi-nation of the component content in pickling waste liquor,according to the test can determine waste liquid containing a large number of ferrous chloride（FeCl2）,concentration at about 6%,also contains a small amount of ferric chloride（FeCl₃）,concentration was 1%,and the main composition of the residual acid（HCl）,and its concentration is as high as 15%above.In the second part,the preparation of ferrous chloride and the removal of impurities from the solution are introduced.After several groups of tests,it can be determined that every 100g of pickling waste liquid reacts with at least 35g of scrap iron oxide scale to produce ferrous chloride solution with a mass concentration of about 24%.It was diluted and put into permanganate.Flocculation and precipitation were used to remove impurities.Finally,metal ion impurities such as Mn²⁺and Cr³⁺were successfully removed,and ferrous chloride solute-on with a purity of more than 99.8%was obtained;In the third part,nanometer iron oxide was prepared from ferrous chloride by ultrasonic-precipitation method.First,the single-factor test was used to investigate the influence of test conditions,such as the concentration of FeCl2,the concentration of precipitant（NH3·H2O）,the dosage of dispersant（PVP）,the calcination temp-erature and the ultrasonic time,on the particle size of the product.According to 5 factors 4 le-vels of orthogonal test table for the experiment of 16 groups of preparation of nanometer iron oxide,and the sample by using XRD and field emission scanning electron microscopy（sem）characterizing the two methods,finally able to get best effect condition,namely in FeCl2concentration for 18 g/L,NH3·H2O concentration was 5%,the amount of 2g PVP,calcinat-ion temperature 800℃,30 min,ultrasonic time can get quality and particles uniformly disper-sed spherical alpha Fe₂O₃ particles is about 30 nm;The fourth part for the application of nano-meter iron oxide pigment research and performance comparis-on,according to the test can g-et nano composite coating iron oxide pigment preparation,its 4H pencil hardness can be achieved,soaking in acid and alkali,0.01 mol/L 3 days above will appear fade and imagine such as craze,comprehensive comparison nanometer iron oxide pigment than ordinary orga-nic pigment is more outstanding performance.