Bio Carbon: A Sustainable Reductant in Synthetic Rutile Production

Introduction

Synthetic rutile, a high-purity titanium dioxide product, is typically produced from ilmenite (FeTiO3) using the Becher process. Traditionally, coal serves as the reductant, but recent studies have tested bio carbon (biochar) as an alternative, demonstrating promising results that align with global sustainability goals.

The Becher Process and the Use of Bio Carbon

The Becher process, developed in Western Australia, involves reducing ilmenite with carbon-rich materials to remove iron oxides and increase TiO2 content to 88-95%. Traditionally, coal has been the reductant of choice, playing a dual role as both a fuel and a reducing agent. However, coal’s environmental drawbacks—such as high emissions of CO2, sulfur dioxide, and heavy metals—have prompted the exploration of renewable reductants like bio carbon.

Bio carbon, derived from biomass, has been tested in place of coal in the Becher process. The results show that bio carbon can match or exceed the performance of coal, producing synthetic rutile with TiO2 content between 93% and 95%. Pyrochar Pty Ltd is actively working with industry partners to conduct advanced and commercial-scale trials with its proprietary Biocharon (biochar), aiming to establish bio carbon as a mainstream alternative in synthetic rutile production.

Specifications of Bio Carbon for Use in Synthetic Rutile Production

Not all biochar can be used effectively in synthetic rutile production. To qualify as a reductant, bio carbon must meet strict parameters, including high fixed carbon content, low volatile matter, minimal ash content, controlled moisture levels, significant calorific value, and specific density requirements. These specifications ensure that the bio carbon provides sufficient reduction potential without introducing impurities that could affect the quality of the synthetic rutile.

1. Fixed Carbon: High fixed carbon is essential for efficient reduction of ilmenite.
2. Volatile Matter: Low volatile matter ensures stable performance during high-temperature processing.
3. Ash Content: Minimal ash reduces contamination in the final product.
4. Moisture: Controlled moisture levels are crucial to maintain energy efficiency and avoid process disruptions.
5. Density: Adequate density is necessary to ensure effective material handling and feed rates in the kiln process.
6. Calorific Value: A significant calorific value ensures that bio carbon provides enough heat energy to maintain process temperatures.

Activated Carbon as a Byproduct

An added advantage of using bio carbon is the production of activated carbon as a secondary byproduct. Activated carbon derived from biomass generally exhibits higher porosity and a greater surface area than coal-based activated carbon, resulting in a higher iodine number. This enhanced porosity makes bio-derived activated carbon more effective for applications in filtration, adsorption, and environmental remediation.

Conclusion

The use of bio carbon as a reductant in synthetic rutile production represents a significant step towards more sustainable metallurgical processes. Pyrochar Pty Ltd is at the forefront of this shift, collaborating with industry to validate bio carbon’s efficacy on a commercial scale. By meeting stringent quality standards and offering superior byproducts, bio carbon not only aligns with environmental objectives but also enhances the overall value proposition for synthetic rutile producers.