Chifeng Yuntong Pioneers Domestic High-Salinity Wastewater Recycling and Reuse Process

Recently, Chifeng Yuntong Copper Industry Co., Ltd. broke through the bottleneck in the recycling and utilization of high-salinity wastewater and successfully passed the review by an expert panel consisting of seven experts from Changsha Engineering & Research Institute for Nonferrous Metallurgy Co., Ltd. The experts unanimously agreed that the comprehensive treatment project of waste heat and exhaust steam reuse coupled with zero-discharge of high-salinity wastewater at Chifeng Yuntong Copper Industry Co., Ltd. features advanced technology and is the first of its kind in China.

As early as the beginning of 2021, the Party Committee of Chifeng Yuntong Copper Industry Co., Ltd. actively responded to the national environmental protection requirements, and made early arrangements for the treatment of high-salinity wastewater. It entrusted the research task of high-salinity wastewater disposal from the tertiary water of acid production and the concentrated chemical water produced from urban reclaimed water to the Power Plant of Chifeng Yuntong Copper Industry Co., Ltd. The Power Plant took swift action and embarked on the journey of exploring the recycling and utilization of high-salinity wastewater.

The Party branch of the Power Plant of Chifeng Yuntong Copper Industry Co., Ltd. leveraged its political and organizational functions, and assembled a capable project team by selecting professional technical personnel. Party members in the branch were bold in their assumptions, diligent in their research and experiments. The project team built experimental equipment in-house and conducted a series of process experiments. Throughout the practical process, the team continuously identified, analyzed, and resolved challenges. Through trial and error, they accurately determined the heat source for the recycling and utilization process, providing a clear direction for the project's experiments.

To further optimize the process, after screening information from multiple sources, Chifeng Yuntong Copper Industry Co., Ltd. ultimately reached a cooperation agreement with China ENFI Engineering Corporation. Leveraging its patented LTE low-temperature thermal concentration technology, the company conducted experiments on the low-temperature evaporation and concentration stage of high-salinity wastewater. The experimental results were remarkable, achieving a target water production rate of 90%, with an average conductivity of the produced water of only 66.18 μs/cm. The produced water can be directly used as makeup water for circulating water, among other applications. The project team focused on investigating the corrosion conditions on the surface of coupons made of different materials during the wastewater concentration process, identifying the core materials, and providing a crucial basis for equipment material selection.

Building on the previous work, the project team explored and implemented an innovative low-temperature evaporation and concentration coupled with an air omnipotent tower to revolutionize the low-temperature evaporation crystallization and salt separation process. This successfully produced qualified sodium sulphate anhydrous (meeting the Class II qualified product standard of GB/T 6009-2014, "Industrial Anhydrous Sodium Sulphate") and sodium chloride (meeting the solar salt standard for industrial salt in GB/T 5462-2015, "Industrial Salt"). This innovation not only significantly reduced equipment energy consumption and operating costs but also opened up a new path for high-salinity wastewater treatment.

The project team continued to focus on ion control and the optimization of the operating cycle, precisely controlling the content of calcium ions, fluoride ions, chloride ions, and other ions in high-salinity wastewater, and gradually clarifying the influence of ion changes on scaling and the issue of titanium tube corrosion. Through unremitting efforts, the maximum operating cycle of the equipment successfully reached 45 days, significantly enhancing the operational stability of the equipment and providing strong support for improving wastewater treatment efficiency and cost control.

After four years of experimental exploration, refinement, and validation, a significant breakthrough has been achieved in the comprehensive treatment process for high-salinity wastewater. A low-temperature evaporation and concentration process for high-salinity wastewater, featuring a short process flow, low energy consumption, long life, low cost, controllable ions, high adaptability to the water quality of high-salinity and high-calcium wastewater from smelting, and controllable equipment investment and comprehensive costs, has been developed. This process also includes a salt separation step, laying a solid foundation for the green development of enterprises and the efficient treatment of wastewater. Currently, multiple links in the high-salinity wastewater recycling and utilization process have been successfully connected, meeting the conditions for the transformation of high-salinity wastewater treatment achievements.

Next, Chifeng Yuntong will actively promote the transformation of scientific and technological achievements related to the "low-temperature evaporation and concentration of high-salinity wastewater + collaborative air omnipotent tower low-temperature evaporation crystallization and salt separation process" in accordance with the requirements of the Chifeng Municipal Ecological Environment Bureau for discharged wastewater. It will fully implement industrial projects, practice environmental protection responsibilities with concrete actions, and contribute to the continuous improvement of the regional ecological environment.