【Frontiers of HaiChuan Chemical Technology】Internationally leading technology for the zero-waste utilization of brine resources

Thread Content

The \"new technology for the efficient utilization of brine based on waste recycling and zone control theory\", independently developed by Shandong Haihua Group Co., Ltd., passed the evaluation of scientific and technological achievements organized by the China Petroleum and Chemical Industry Federation last week. The appraisal committee, with Yao Jianian, an academician of the Chinese Academy of Sciences, serving as the chief judge, unanimously agreed that this achievement is highly innovative and has reached an internationally leading level, and thus approved it unanimously. 　　The evaluation committee stated that, based on waste recycling and zonal control theories, this innovative technology has achieved a number of breakthrough results. Firstly, the theories of domain-controlled and directional separation were proposed for the first time, and nanofiltration membrane technology capable of withstanding extreme operating conditions and enabling high-flux confined mass transfer was developed. This improved the yield of two-stage nanofiltration processes, reduced the amount of scale inhibitors used by 60%, extended the membrane’s lifespan by 150%, and increased the recovery rate of brine from 50% to 60%, thereby reducing the cost of saltwater purification by 75%. Secondly, a brine grading treatment technology based on domain control theory was developed; through the engineering application of two-stage confined mass transfer nanofiltration, efficient utilization of brines in complex salt systems is achieved. Thirdly, a pretreatment technology for bromine-extracted brine based on waste recycling was developed, which enables the efficient use of acidic brine after bromine extraction at low cost, while also facilitating the utilization of waste. Key technologies for air flotation to remove turbidity from brines with high salt content, high turbidity, and high viscosity were developed, and these were successfully applied for the first time in the purification of high-salt brines. 　　The Laizhou Bay area in the Bohai Sea, where Haihua Company is located, possesses abundant underground brine resources of a seawater-like nature; their concentration is 3 to 4 times that of seawater, and these resources serve as an important foundation for the development of the local sea salt and marine chemical industries. Since its commissioning, the Haihua Soda Ash Plant has been producing soda ash by converting seawater into crude salt; the costs associated with producing crude salt and refining it directly increase the manufacturing costs of soda ash. With the widespread use of nanofiltration membranes, it has become possible to use nanofiltration technology to refine underground brine for the production of soda ash. Aiming at this goal, Haihua has spent many years working diligently on this issue. Through pilot tests, scale-up trials, industrial testing, and further expansion of production, it has gradually overcome various industry challenges related to the separation of monovalent and divalent ions in complex brine systems. It has also developed theories for waste recycling and zone-based control. The sodium chloride solution extracted from brine is used directly in the production of soda ash, thereby enabling efficient utilization of sodium chloride in brine and reducing production costs. 　　It is reported that this technology transformation project has been included as a key project for the circular transformation of **-level parks. Currently, this technology has been successfully applied in a project aimed at the efficient recycling of 35,000 cubic meters of refined brine per day, thereby creating a new \"zero-waste\" system for brine utilization that supports the sustainable development of soda ash production. Between 2019 and 2024, it generated benefits worth over 340 million yuan, achieving a win-win situation in terms of environmental and economic outcomes. At the same time, this achievement also provides important technical approaches for brine purification in the two-alkali and salt production industries, lithium extraction from salt lake brines using membrane technology, as well as the reuse of concentrated seawater resources obtained through desalination.