Iodine Extraction from Natural Brine Solutions

Historically, iodine has been recovered on a commercial scale from seaweed. In this classical approach the seaweed is dried and burned, ash is leached using water and the remainder is dosed with sulfuric acid before being vaporized and sublimed to isolate the desired element. 

Production from brines began in 1854 and to this day remains prevalent. Due to low concentrations of the desired element, large quantities of brine typically must be processed to operate economically. Highly unfavorable process conditions have led to the use of inorganic chemical substances to treat the brine. These inorganic agents include aluminum sulfate, ferric chloride, and poly-aluminum chloride. Inorganic chemical treatment is highly effective in treating brine; however, substantial volumes of sludge that are generated can lead to serious health problems for consumers.

“Standing on the shoulders of giants”

–  Isaac Newton (1675)

Conventional methods use energy intensive techniques with energy demands an order of magnitude greater than modern techniques. These methods including thermally driven and chemical driven desalination processes treat the brine using strategies that are detrimental to the environment. Evaporative techniques require significant amounts of energy and chemical methods produce considerable amounts of harmful waste through the addition of dangerous chemicals.

The proposed design intends to present a robust set of technologies that can be utilized in an array of applications that extends beyond iodine recovery. The use of highly selective proprietary materials allows for potential investors to tailor solutions to their specific application. Tuning the behavior of the process has been implemented into our design to accommodate a diverse range of applications. These tunable selections include the active layer properties of the nanofiltration membranes, selective properties of the sorbent material and oxidation agent chosen for the process. 

Our design does not reinvent the wheel but instead applies the existing body of knowledge found in academic literature and couples them with the latest technologies. Supported by previous pilot operations we aim to achieve the highest degree of productivity, and effectiveness in our practical solution. We believe that through the use advanced materials and the proposed techniques we can achieve extraordinary results concerning environmental appeal. These benefits are comparable to existing processes with respect to the energy demands, greenhouse gas emissions and quantities of produced chemical waste.

Global iodine demand is rapidly growing; from USD$ 853M in 2020 to a projected USD$ 1.1B in 2027. Current processing technologies are unsuitable for expansion as they are environmentally damaging and require immense raw materials and infrastructure for their operation. The chemical mining and processing industry needs an innovative solution to extract iodine. Our solution is a low-energy, low-chemical, iodine extraction process that produces a high purity iodine product. 

Heat and material balances were performed for each unit operation and compared across literature and pilot operation results for similar conditions. The selection of the relevant equipment and sizing was completed in accordance with multiple engineering design textbooks, which provide standard practice and operation specification selection guidelines for each individual unit process. Comparison using multiple methods of validation ensured that the trajectory of the solution was constrained to within tolerable thresholds to permit economical operation. Process simulations using python and matlab were used to solve systems of differential equations relevant to the underlying process.

Machine learning and deep neural networks were used in what is known as a physics informed neural network. Using this method the solution vector space of physically realizable conditions can be quantified and deviation from plausable states can be evaluated with a loss function. For visual intuition below is the solution to the laplace equation in cylindrical coordinates.

Closed form solutions of various equations were evaluated, which would allow for future data collection endeavors to tailor predictive modelling to conditions imposed by the underlying physics. Attached below is a closed form solution to the modified bessel functions of the first kind.

On a technical basis, our design solution is based on various considerations identified from academic papers with appropriate fundamental equations, we created models for each unit to accurately simulate our process outputs and operating conditions. The specific operating conditions enabled us to source equipment and utilities to create a financial model that justify the financial profitability. Finally, through an optimization process, we were able to reach a base case NPV of $ 2.9M.