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Silica Extraction Process

Sustainably Harvested Silica is a World First

Sustainably Harvested Silica is a World First

The Geo40 silica harvesting process not only produces natural colloidal silica from geothermal fluids, it also has major benefits for the geothermal power industry world-wide.

Geo40’s unique process works on the treatment of geothermal water from the steam separator in a geothermal power plant.



How The Process Works

Water leaving the plant is close to silica saturation. Geo40 receives the water and cools it to below the saturation point. During the cooling stage, the silica forms discrete colloidal silica particles that are around 1nm – 2nm in size.
These particles are then aged and filtered out using a continuous ultrafiltration (UF) and washing circuit to concentrate the silica from its incoming concentration to a 4wt% solution. This concentrate is then further processed, using conventional technology, into sustainably produced and cost competitive, high quality colloidal silica products.
Filtrate from the process is now low in silica and able to be used for further mineral extraction before being sent to cool the incoming geothermal water and be reheated and pumped to the reinjection wells at the edge of the geothermal field.
The hot filtrate water leaving the plant is low on silica and cannot cause further silica scaling in the pipework and reinjection wells, saving significant costs for the geothermal power generator.
Before it gets reinjected back into the field, the hot low silica geothermal water can now also be used for direct heating opportunities, or further power generation, improving the efficiency of the renewable power being generated.

What Comes Next?

The future: a geothermal ecosystem + the Geo40 process + partners

1. Hot geothermal water is pumped to the surface from the geothermal aquifer.

2. Hot geothermal water enters the power station. Geothermal operator generates electricity, from the steam, to sell into the grid.

3. Geothermal water flows on to the Geo40 plant. Silica is harvested, removing it from the water and allowing Geo40 to obtain silica and minerals to process into products.

4a. Geothermal water flows on to a partner plant, generating heat to sell to industrial heat customers, OR;

4b. Geothermal water flows on to a Climeon partner plant, generating an additional 10MW of electricity.

5. In the future, geothermal water flows onto another Geo40 plant, where lithium and caesium are harvested for Geo40 to sell.

6. Geothermal water flows on to a partner plant that enables carbon sequestration.

7. Geothermal water is reinjected back into the aquifer.

The future: more sustainable products

Geo40 is well advanced in technologies for removing the dissolved lithium in the geothermal water after the silica has been harvested. To date, near battery grade, sustainably produced and cost competitive, lithium carbonate has been produced from the lithium harvested.

If you’d like to know more about Geo40 and our products, please get in touch.