Abstract:

A large number of oilfield water which is rich in inorganic salt resources is produced in the process of oil extrac-tion,in addition to a large amount of sodium,potassium and magnesium plasma,oilfield water is also enriched with a variety of trace elements such as lithium and rubidium.Recovery of lithium in oilfield water not only avoids environmental pollution,but also has great significance for maximizing the utilization of resources and sustainable development.The primary oilfield water was obtained from oilfield water by evaporation,organic phase removal,freezing and mirabilite brine mixing process to remove calcium.Secondly,raw oilfield water was obtained by further removed calcium and magnesium through chemical method and adsorption method respectively from primary oilfield water.Finally,battery-level lithium carbonate was prepared by raw oilfield water reacted with sodium carbonate solution.The experimental results showed that both chemical and adsorp-tion methods could remove calcium and magnesium ions from oilfield water,the purity of lithium carbonate was over 99.7% prepared by raw oilfield water and soda solution,the content of impurity met the requirement of battery-level lithium carbonate.It has successfully realized the recovery and utilization of lithium resources in oilfield water.

Key words: oilfield water, battery grade Li₂CO₃, Na₂CO₃