Conference presentation

Ion Exchange Membrane Electrolysis for Acid Regeneration and Selective Metal Recovery in Mineral Processing

Robert Karas, Rowow LLC. 39th Annual Regional Mining and Phosphate Conference (FLSME), Chemical Processing session, Thursday, October 15, 2026, Plant City, Florida.

Download the slides (PDF, 3.5 MB)Email info@rowow.net

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Slide 1 of 19. Title slide: Ion Exchange Membrane Electrolysis for Acid Regeneration and Selective Metal Recovery

Slide 2 of 19. Same chemistry, used two different ways: ion exchange resin and ion exchange membrane

Slide 3 of 19. Membranes let electricity choose which ions move: no membrane, two membranes and three membranes

Slide 4 of 19. Every step in a phosphate plant moves ions, and all of chemistry comes down to atoms and their electrons

Slide 5 of 19. In a membrane electrolysis cell, making acid, separating and neutralizing happen in one cell

Slide 6 of 19. Industry already runs membranes at large scale

Slide 7 of 19. Price and handling keep membranes out of mining

Slide 8 of 19. Our membrane: water softener resin and PVC cement

Slide 9 of 19. We published the recipe so anyone can make the membrane under our pending open source charter

Slide 10 of 19. Membrane data: the characterization paper

Slide 11 of 19. Cutting cost across the whole cell, not only the membrane

Slide 12 of 19. Florida's phosphate waste still holds a lot of value

Slide 14 of 19. Regenerated electrolyzed acid now beats burning sulfur

Slide 15 of 19. The closed loop in the continuous mining unit

Slide 16 of 19. Metals leave the cell as a deposit at the cathode

Slide 17 of 19. The mixed concentrate can be split by voltage, pH, membrane or solvent

Slide 19 of 19. Thank you. Questions? Shown over a faded concept model of the trailer pilot plant

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About the talk

Ion exchange membranes let electricity move and sort the ions that reagents move today, and they already run at industrial scale in chlor-alkali, electrodialysis and acid recovery. Their price has kept them out of mining: commercial cation exchange membranes retail at about 230 dollars per square foot, and in one published model of a membrane plant on acidic mine water the membranes were a third of capital cost.

The talk describes S.E.M Technology, a closed-loop process built on membrane-divided electrolysis. Dilute hydrochloric acid and a chlorine-based oxidizer are regenerated from brine and electricity at the anode while dissolved metals plate out as powder at the cathode, so the leach solution is reused rather than bought again. The enabling component is an ion exchange membrane cast from water softener resin in a PVC cement binder, under one dollar per square foot at 160 microns in our cost model, with the recipe published as open hardware and replicated by independent builders.

It then turns to Florida phosphate: the value left in clay and phosphogypsum, the 2026 sulfur price, and a literature-based comparison of regenerated acid against burned sulfur.

What the slides cover

Resin and membranes, and how a membrane cell makes acid, separates ions and neutralizes in one box
Why price and handling keep membranes out of mining
Our membrane, why it is open source, and the characterization data now being measured
Phosphate waste, the sulfur problem, and the energy and cost of regenerated acid
The closed loop already running, options for selective separation of metals, and what comes next

How to read the numbers

The energy and cost comparison on page 14 uses published figures, not our own runs.
Totals on page 12 are our arithmetic from the sources listed on that slide, rounded, and are estimates.
Every slide lists its sources at the bottom.

Follow up

The membrane recipe and build files are on GitHub. Test runs on your own material and on-site units are described on the Solutions page, and cells and membranes are in the shop. The recording of the talk is on YouTube, with more videos on our channel. Questions: info@rowow.net.