Dry Grinding System for Tailings Dewatering
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Solution Overview
Problem
Wet-grinding methods in minerals processing lead to filter media blinding, increased water consumption, and unstable tailings ponds due to fines being processed in flotation circuits, compromising efficiency and geostability.
Innovation Solution
Implementing a dry grinding process using a vertical roller mill or HPGR followed by dry classification to separate fines, allowing them to bypass downstream flotation and dewatering processes, and combining the dry fines with dewatered tailings to reduce moisture content and improve geostability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet-grinding methods are used in minerals processing, then ore can be ground to fine sizes, but filter media blinding occurs and water consumption increases
Solution Approach 1:
The patent extracts the harmful wet fines (particles smaller than 20 microns) from the grinding circuit before they can cause filter media blinding. A classification device separates fines from coarser particles, and the fines are routed through a separate pathway that bypasses the flotation circuit and dewatering filters, thereby eliminating the blinding problem while maintaining efficient ore processing
Solution Approach 2:
The patent replaces the traditional wet-grinding mechanical system with a dry-grinding system. Instead of using wet grinding mills that produce slurry requiring filtration, the system uses dry grinding followed by air classification, substituting mechanical filtration with pneumatic separation to avoid filter media blinding
2Productivity
If wet-grinding methods are used in minerals processing, then ore can be processed through flotation circuits, but water consumption increases
Solution Approach 1:
The patent extracts fine particles from the grinding circuit through classification and routes them through a separate pathway that bypasses water-intensive flotation and dewatering processes. This eliminates the need for large volumes of water while maintaining the ability to process ore effectively
Solution Approach 2:
The patent changes the physical state parameter of the grinding process from wet to dry. By operating the grinding circuit in dry condition and using air classification instead of water-based separation, the system dramatically reduces water consumption while maintaining processing productivity
3Productivity
If wet-grinding methods are used in minerals processing, then flotation circuits can operate, but tailings ponds become unstable
Solution Approach 1:
The patent extracts fine particles from the processing circuit before they reach the tailings pond. By classifying and separating fines during grinding and routing them through a separate pathway, the system prevents wet fines from being deposited in tailings ponds, thereby maintaining pond stability while preserving metal recovery capabilities
Solution Approach 2:
The patent applies preliminary action by removing harmful fine particles from the circuit before they can cause instability in tailings ponds. The classification and separate routing of fines occurs upstream in the processing flow, preventing the problem rather than treating it downstream
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
This approach reduces filter media blinding, decreases water usage, and enhances the stability of tailings ponds by minimizing the amount of wet fines, thereby improving flotation circuit performance and geostability.
Implementation Method 1
a dry grinding process, (such as a grinding process involving a vertical roller mill or an HPGR)
Implementation Method 2
The vertical roller mill 32 receives fluidizing air or gas 43 from a fan 42 to suspend fines and not coarse particles
Implementation Method 3
discharged from the vertical roller mill 32 and provided as feed to a baghouse filter 34
Implementation Method 4
combining the dry fines with dewatered tailings to reduce moisture content and improve geostability
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A minerals processing system (200, 300) comprising a flotation circuit (109) is characterized in that a dry grinding circuit precedes the flotation circuit (109). The dry grinding circuit may use a vertical roller mill (32) or roller grinder (302), and at least one dry air particle separation device (201, 304, 307) positioned between said vertical roller mill (32) or roller grinder (302) and the flotation circuit (109). The at least one dry air particle separation device (201, 304, 307) produces a dry fines stream (38) and a dry coarse stream (202). The coarse stream (202) is provided to the flotation circuit (109) to recover metal values, whereas the dry fines stream (38) circumvents the flotation circuit (109) and is combined with dewatered tailings (116) derived from material (110, 111) leaving the flotation circuit (109).