Open Call for Solutions: Treatment and Beneficiation of High Silica

Solution Submission Deadline: 5  Mar/2024 (call opens February 20, 2024)

Opportunity Overview

A major Middle Eastern mining company seeks innovative solutions to address a critical challenge related to high silica content in bauxite, which leads to excessive consumption of caustic soda during the Bayer Process.


Our alumina refinery operations use high-temperature caustic soda, to extract valuable components from bauxite using the Bayer process. Although, this is a crucial process for refining bauxite, a rise in silica in the bauxite has led to significant economic and environmental concerns, increasing operational costs, including managing Red Mud with its high soda content.  

Although, this challenge is particularly associated with low-grade bauxite, the variable impurity levels in our bauxite feed compound the cost and environmental issues.

The Problem

The bauxite received by the refinery contains high silica content, resulting in significant caustic soda consumption to mitigate the silica’s effects. This increases the operation costs substantially.

Our refinery uses about 5 million tonnes of bauxite annually.

The Solution
A desilication process is usually used to treat low-grade, high-silica bauxite before the Bayer process. However, operational restrictions prevent us from implementing this approach. We are now seeking suitable proven solutions to decrease the silica content in the bauxite feed and reduce operational costs and environmental impacts linked to caustic soda consumption.The goals of the projects are:Optimize the silica content in the bauxite feed to reduce the caustic soda consumption to counteract the increased silica content.Minimize changes in the mineral composition caused by the pre-treatment to prevent challenges arising in the downstream process related to a possible increase in the contents of other impurities.Acceptable integration of the suggested solution/process with the existing infrastructure.Reduce environmental impact resulting from increased alkalinity in the Red Mud.

Additional Comments

Silica consumes corresponding amount of caustic through Bayer sodalite formation. During the sodalite formation, lots of impurities (sulphate, chloride, carbonate etc.) also get removed. Generally, this impurity removal capability is denoted by DSP factor in bauxite. 

Because of the current impurity removal capacity, Refinery liquor is very pure, causticity (measure of carbonate in Bayer liquor) varies between 94 to 96%. Because of this high causticity, refinery could reach 88 gpl yield in spite of using predominantly boehmitic bauxite (almost 2/3rd of extractable alumina in bauxite is boehmitic). This yield with high boehmitic bauxite is a benchmark.

Sodalite also removes the cations, present in traces in bauxite – like beryllium, lithium etc. There is other control mechanism of these metals, and they are important for metal purity.

While caustic reduction through silica beneficiation is an excellent idea, it should not be seen in isolation with liquor causticity, yield, trace metal control etc. So such initiative / study should be all-encompassing, as described.

The Request for Solutions Process

Phase1: Submission Period
Suppliers are invited to submit their short-form solution to the challenge by March 5, 2025 for evaluation by CEMI and the mining organization.  A shortlisting process takes place, and successful companies are invited to participate in phase 2.

Phase 2 : Shortlisted suppliers will be invited to a technical briefing, where each supplier can gain more information about the challenge.

Following the technical briefing, suppliers will pitch their solution directly to the mining organization online. This provides the opportunity to ‘sell’ the solution, gain feedback from operational teams and field questions about the solution.

Phase 3: Following the Pitch Session, a final shortlisting of suppliers takes place. The remaining suppliers are invited to submit a formal technical and economic proposal to solve the challenge.

Phase 4:  Winner AnnouncedThe mining organization will select the best fit solution/s for the challenge and the supplier will work directly with them to trial the technology and implement the solution.

Request for Solutions Process

Open a Call for Solutions20 Feb 2024
Solution Submission Deadline5 Mar
Solutions shortlist10 Mar
Technical Briefing- shortlist11 Mar- 14 Mar
Pitch Sessions24 Mar- 26 Mar
Final selection28 Mar
Final Proposal Deadline28 Mar- 5 Apr

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