Silicon-Containing Polymer Flocculation for Bauxite Solid Removal
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Solution Overview
Problem
Efficient removal of suspended solids, particularly calcium silicates, calcium aluminosilicates, and calcium titanates, from bauxite ore processing streams in alumina production remains a challenge, as existing methods are inadequate for achieving high purity and rapid separation in Bayer and Sinter processes.
Innovation Solution
The use of silicon-containing polymers as flocculants, either alone or in combination with conventional flocculants, effectively flocculates suspended solids in bauxite ore processing streams, enhancing the separation of calcium silicates, calcium aluminosilicates, and calcium titanates, thereby reducing the need for filtration and improving alumina product purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional flocculants (starch, flour, polyacrylate salt polymer, acrylate salt/acrylamide copolymer, hydroxamated polymers) are used to separate finer solid particles from green liquor in the mud settler, then suspended solids are removed from the process stream, but the separation efficiency is insufficient and filtration is still required to achieve low enough suspended solid levels
Solution Approach 1:
The invention changes the chemical parameter of the flocculant by using silicon-containing polymers with specific functional groups (silane, siloxane, or silicone groups) instead of conventional flocculants. This parameter change enables the flocculant to effectively interact with and remove suspended solids including calcium silicates, calcium aluminosilicates, and calcium titanates, achieving complete separation without requiring subsequent filtration
Solution Approach 2:
The invention employs composite flocculant compositions that may combine silicon-containing polymers with other polymers or flocculating agents. This composite approach leverages the specific affinity of silicon-containing groups for metal silicate and titanate particles while maintaining the bulk flocculation capabilities, resulting in superior suspended solids removal that eliminates the need for filtration
2Speed
If the clarification process is made more efficient to achieve faster separation of suspended solids, then the overall process efficiency improves, but existing flocculants cannot achieve both rapid settling and high purity separation simultaneously
Solution Approach 1:
The invention changes the chemical composition parameter of the flocculant to silicon-containing polymers, which create larger and denser floc structures that settle more rapidly. The silicon-containing functional groups specifically bind to suspended solids particles, accelerating the aggregation process and increasing settling speed while simultaneously achieving high separation clarity that eliminates the need for filtration
3Manufacturing precision
If additional processing steps are added to remove suspended solids to very low levels, then alumina product purity is improved, but the process complexity and cost increase
Solution Approach 1:
The invention extracts the filtration step from the process by using silicon-containing polymer flocculants that are so effective at removing suspended solids that they achieve the required purity level through settling alone. The silicon-containing groups specifically target and remove calcium silicates, calcium aluminosilicates, and calcium titanates, eliminating the need for the separate filtration operation and reducing overall process complexity
Solution Approach 2:
The invention makes the flocculation action continuous and sufficient by using silicon-containing polymers that maintain effective suspended solids removal throughout the settling process. The continuous agitation and settling process, enhanced by the silicon-containing flocculant, achieves complete separation without requiring the discontinuous additional filtration step, thereby maintaining continuous productive operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The silicon-containing polymers significantly improve the flocculation and separation of suspended solids, leading to reduced suspended solid content in process streams and enhanced clarity and purity of the alumina product, outperforming state-of-the-art methods by facilitating faster settling rates and improved clarity.
Implementation Method 1
contacting the streams with silicon-containing polymers... effectively flocculates suspended solids in bauxite ore processing streams, enhancing the separation of calcium silicates, calcium aluminosilicates, and calcium titanates
Data Source
AI summary
The suspended solids content of a process stream in a process for digesting bauxite ore to produce alumina is reduced by contacting the stream with silicon- containing polymers.