Experimental study on the recycling of cesium formate mud based on capacitive deionization technology

Abstract:

As a natural weight-increasing mud， cesium formate mud can solve the problems of solid phase weighting agent sedimentation and sticking in a high-temperature and high-pressure environment， and shows a broad application prospect in deep drilling. However， in the recovery process of cesium formate mud， the separation of soluble interfering ions is difficult， which limits its recycling and cost control. In order to solve this problem， a treatment method based on capacitive deionization technology （CDI） is proposed to remove the interfering ions in the cesium formate mud， realize the recycling of the cesium formate mud and reduce the cost of use. The physical and chemical properties of cesium formate and its stability in a high-temperature and high-pressure environment were analyzed. The removal efficiency of different valence ions （Na⁺， Mg²⁺， Al³⁺） and the desorption and regeneration performance of the electrode were investigated by constructing an electrosorption experimental platform. The experimental results show that the removal rate of Na⁺ and Mg²⁺ by CDI can reach 85.2 % and 67.1 %， while the removal rate of Al³⁺ is less than 30 % under 1.0V. In the desorption experiment， the conductivity of Na⁺， Mg²⁺ and Al³⁺ solutions recovered from 2.47μS/cm to 66.2， 57.6， 32μS/cm， respectively， indicating that the electrode could be regenerated by desorption. The study reveals the influence of voltage， concentration and ion charge number on the removal rate， and confirms that CDI technology has certain potential for removing interfering ions in mud. This study provides a new idea for the green recycling of cesium formate mud.