Hydrothermal Preparation And Adsorption Properties Of Special Morphology Basic Nickel Carbonate And Nickel Oxide

The iron content in laterite nickel ore is relatively high,and it often enters the leaching solution in the form of iron ions during the leaching process,which greatly increases the burden of subsequent purification work and production costs.How to effectively reduce the concentration of iron ions in the leaching solution is particularly important.In this paper,laterite nickel ore is used as the raw material,and the two-stage roasting-water leaching method is adopted to reduce the concentration of iron ions in the leaching solution.The nickel gap in my country has been expanding year by year.While improving the utilization rate of nickel resources,it is necessary to increase the added value of nickel.In this paper,the nickel sulfate solution obtained by purification of the laterite nickel ore leaching solution is used as the raw material,and urea is used as the precipitating agent.The porous network and hollow spherical basic nickel carbonate are synthesized by the hydrothermal method,and the preparation conditions are optimized.The porous network and hollow spherical basic nickel carbonate are used as adsorbents to adsorb the organic pollutants Congo red and Methyl blue,and their adsorption performance is investigated.Porous mesh and hollow spherical nickel carbonate were used as precursors to prepare porous mesh and hollow spherical nickel oxide,and their adsorption properties were investigated.It realizes the extraction of elements from minerals and the preparation of high-performance materials,which greatly increases the added value of the product.The research got the following results:(1)Under the conditions of roasting at 475℃ for 2 h in the first stage and roasting at 650℃ for 2 h in the second stage,the extraction rates of nickel,magnesium,aluminum,iron and chromium are 94.94%,98.87%,48.55%,6.46%and 8.91%,respectively.After the second stage of roasting,the extraction rate of nickel remained basically unchanged,the extraction rate of magnesium was improved,and the extraction rate of iron was reduced from 88.7%to 6.46%,which greatly reduced the iron content in the leaching solution and reduced the burden of purification of subsequent leachate.(2)The suitable conditions for preparing porous mesh basic nickel carbonate are:the ratio of nickel sulfate to urea is 1:0.5,the hydrothermal temperature is 120℃ the hydrothermal time is 12 h,and the nickel ion concentration is 0.10 mol·L-1.The porous network basic nickel carbonate was used as the precursor,and the porous network nickel oxide was obtained by Calcined at 400℃ for 2 h.Reticular basic nickel carbonate and nickel oxide were used as adsorbents to adsorb organic pollutants Congo red and Methyl blue,and their theoretical adsorption capacities were 540.54,729.93 and 574.71,1017.41 mol·L-1,respectively.The adsorption process is in accordance with the Freundlich isotherm adsorption model,indicating that it is multi-layer adsorption.The adsorption kinetics are in accordance with the quasi-second-order kinetic model,indicating that the adsorption method is chemical adsorption.(3)Suitable conditions for preparing hollow spherical basic nickel carbonate are:the ratio of nickel sulfate to urea is 1:4.5,the hydrothermal temperature is 120℃ the hydrothermal time is 12 h,and the nickel ion concentration is 0.20 mol·L-1.The hollow spherical basic nickel carbonate was used as the precursor and calcined at 400℃ for 2 h to obtain the hollow spherical nickel oxide.Using spherical basic nickel carbonate and nickel oxide as adsorbents to adsorb organic pollutants Congo red and Methyl blue,their theoretical adsorption capacities are 555.56,1112.63 and 367.65,406.50 mo1·L-1,respectively.The adsorption process is in accordance with the Freundlich isotherm adsorption model,indicating that it is multi-layer adsorption.The adsorption kinetics are in accordance with the quasi-second-order kinetic model,indicating that the adsorption method is chemical adsorption.