Comprehensive Utilization Of Laterite Nickel Ore Smelting Nickel-iron Slag

Lateritic nickel ore smelting Nickel-iron slags are a type of solid waste generated during the ferronickel smelting process.As the demand for nickel increases worldwide,the discharge of Nickel-iron slags has dramatically increased.Since the Industrial Revolution,environmental issues have become increasingly prominent.In particular,over-emissions of greenhouse gases such as CO2 have caused global warming.Therefore,how to effectively reduce carbon emissions has become an environmental issue of increasing concern.Under the current technological conditions,Carbon Capture and Storage(CCS)is considered as a viable solution to the problem of excessive CO2 emissions,and the key to this technology lies in the cheap,efficient and energy-saving adsorbent Research and development,4A zeolite molecular sieve has a strong adsorption capacity for CO2,but also has a high selective CO2/N2 adsorption,which is an ideal adsorbent for separating CO2 in flue gas.In this paper,we use Nickel-iron slag as raw material,impregnated with sodium hydroxide solution to extract its silicon element.In this process,the synthesis process was explored by single factor experiment.The optimum experimental conditions were as follows:the stirring intensity was 1000r·min-1,the concentration of NaOH solution was 60%,the liquid-solid ratio was 6:1 and the reaction time was 90min,the reaction temperature was 220?.In this condition,the silica extraction rate reached 76.72%.Subsequently,the extracted silicon was used as the raw material for the synthesis of 4A zeolite molecular sieve,NaAlO2 was added as aluminum source,and the cheap and efficient 4A zeolite molecular sieve was successfully prepared by hydrothermal synthesis.During the synthesis of 4A zeolite,different n(SiO2/Al2O3),n(H2O/Na2O),hydrothermal synthesis time and hydrothermal synthesis temperature on zeolite 4A zeolite were studied.The results showed that the optimum synthesis conditions were as follows:Silica to alumina ratio n(SiO2/Al2O3)=0.5,water to sodium ratio n(H2O/Na2O)=60,hydrothermal synthesis time t=8h,hydrothermal synthesis temperature T=100?.Based on a large number of experiments to explore the synthesis of zeolite 4A zeolite.The structure and properties of 4A zeolites synthesized under optimal conditions were characterized by XRD,TG,FT-IR,SEM and BET.It is very important to reserch the adsorption properties of 4A zeolite.Therefore,the thermo gravity analyzer was used to study the adsorption properties of the zeolite 4A on CO2 and N2.The results showed that the adsorption capacity of zeolite 4A at 30?,60? and 90?,The saturated adsorption capacity for CO2 was 3.57mmol/g,1.50mmol/g and 0.84mmo/g,respectively.The saturated adsorption capacity of N2 at 30? was 2.76mmol/g,The balance of CO2 adsorption capacity of 7.73%.At last,the adsorption kinetics of CO2 on 4A zeolite molecular sieve was studied by data fitting method.The adsorption process is more consistent with the model of the rate of the Bangham.The adsorption of CO2 on 4A zeolite is mainly due to its pore function,is a physical adsorption.