A multistage process scheme for extracting valuable minerals from desalination reject brine while simultaneously sequestering CO₂ has been proposed. As a part of the proposed scheme, simultaneous removal of calcium ions and CO₂ uptake of a magnesium free reject brine was investigated in an inert particle spouted bed reactor (IPSBR) by reacting CO₂ with reject brine in presence of NaOH. Response surface methodology was applied to optimize the effect of NaOH dosage, gas flowrate and salinity on the reaction with the target of maximizing calcium removal and CO₂ uptake. A second order regression model was generated for both target responses. The predicted responses for both targets were in good agreement with the obtained experimental response. Based on a multivariate optimization, the optimum conditions for NaOH, flowrate and salinity for simultaneous calcium removal and CO₂ uptake were found to be 5 g/L, 2 L/min and 75 g/L, respectively. Under these conditions, 100% removal of Ca²⁺ ions from the brine could be achieved with a CO₂ uptake of 5.4 g/L. Moreover, the solid products obtained under the optimum conditions were characterized confirming the formation of high purity calcium carbonates. Based on optimized conditions, the proposed multistage process scheme promises to produce highly pure Mg(OH)₂ and CaCO₃, while sequestering 5400 tons of CO₂ for every million tons of brine treated. The scheme can be further improved by incorporating an electrolysis unit to produce HCl along with NaOH that can be recirculated to eliminate the need for any external addition of NaOH, thus, creating a sustainable process for reject brine management and CO₂ sequestration.

已经提出了一种用于从脱盐废液中提取有价值矿物质同时隔离CO ₂的多阶段工艺方案。作为所提出方案的一部分，在惰性颗粒喷射床反应器 (IPSBR) 中，通过在 NaOH 存在下_{使 CO 2与废盐水反应，研究了同时去除钙离子和吸收不含镁的废盐水的 CO 2 。}应用响应面法优化 NaOH 用量、气体流量和盐度对反应的影响，以最大限度地去除钙和 CO _2为目标摄取。为两个目标响应生成了二阶回归模型。两个目标的预测响应与获得的实验响应非常一致。基于多变量优化，发现同时去除钙和吸收 CO ₂的 NaOH、流速和盐度的最佳条件分别为 5 g/L、2 L/min 和 75 g/L。在这些条件下，可以实现从盐水中 100% 去除 Ca ^{2+离子，CO} ₂吸收率为 5.4 g/L。此外，对在最佳条件下获得的固体产物进行了表征，证实了高纯度碳酸钙的形成。基于优化的条件，所提出的多级工艺方案有望生产高纯度 Mg(OH) ₂和 CaCO _{3 ，同时}每处理 100 万吨盐水可隔离 5400 吨 CO _{2 。}该方案可以通过结合电解装置来进一步改进，以生产 HCl 和可再循环的 NaOH，从而消除对任何外部添加 NaOH 的需要，从而为废盐水管理和 CO ₂封存创造可持续的过程。