Process Water Silica Removal by Flocculation and Cleaning Flotation
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Solution Overview
Problem
The formation of gels and colloids due to soluble and colloidal Si-compounds in aqueous streams of minerals processing plants leads to loss of valuable metals, reduced recovery and quality of final products, and operational issues such as thickening and filtration problems, which are exacerbated in closed-loop systems.
Innovation Solution
A method involving the addition of coagulants, flocculants, and/or flotation chemicals to aqueous streams to form flocs, followed by cleaning flotation using gas bubbles of specific diameters to separate Si-compounds as an overflow, and recirculating the underflow for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coagulants and flocculants are added to form flocs, then Si-compounds can be separated, but the process complexity increases
Solution Approach 1:
Coagulants and flocculants are introduced as intermediary substances to facilitate the aggregation of Si-compounds into removable flocs, enabling effective separation while managing process complexity through controlled chemical addition
Solution Approach 2:
The process utilizes parameter changes in the aqueous stream (pH adjustment, chemical concentration) to optimize floc formation and separation efficiency, allowing adaptable control of the treatment process
2Reliability
If cleaning flotation is used to separate Si-compounds, then turbidity is reduced, but energy consumption increases
Solution Approach 1:
The cleaning flotation process employs pneumatic principles by introducing gas bubbles to attach to and lift Si-containing flocs to the surface, achieving turbidity reduction through gas-liquid interaction rather than high-energy mechanical means
Solution Approach 2:
The process utilizes phase transition of gas to bubbles and their subsequent rise through the liquid phase, leveraging buoyancy and phase behavior to separate Si-compounds with relatively low energy input
3Manufacturing precision
If gas bubbles with specific diameter are used, then separation efficiency improves, but equipment complexity increases
Solution Approach 1:
The patent specifies controlling gas bubble diameter within a particular range to optimize separation efficiency, using parameter control of bubble size rather than complex equipment design to achieve precise separation
Solution Approach 2:
The process dynamically adjusts bubble characteristics and flow conditions to maintain optimal separation performance, allowing the system to adapt to varying feed conditions while managing equipment complexity
4Loss of substance
If process water is recirculated, then water consumption is reduced, but Si and Fe complexes accumulate
Solution Approach 1:
The process selectively removes Si and Fe complexes from recirculating water through flotation separation, discarding the harmful complexes while recovering and recirculating the cleaned water, thus preventing accumulation
Solution Approach 2:
The system implements a feedback mechanism where treated water quality is monitored and the flotation process is adjusted to maintain effective removal of Si and Fe complexes, preventing their accumulation in recirculating streams
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
Reduces turbidity by 50-99% and achieves Si-removal rates of 55-90%, enabling the reuse of treated process water without negatively impacting the process outcomes and addressing issues caused by Si and Fe complexes.
Implementation Method 1
adding coagulant(s) and/or flocculant(s) to the aqueous stream in order to facilitate formation of flocs comprising at least some of the Si-compounds
Implementation Method 2
adding coagulant(s) and/or flocculant(s) to the aqueous stream in order to facilitate formation of flocs comprising at least some of the Si-compounds
Implementation Method 3
subjecting the treated aqueous stream to cleaning flotation in order to separate at least some of the Si-compounds as a cleaning flotation overflow
Data Source
AI summary
A method for removing soluble and/or colloidal Si-compounds from an aqueous stream of a minerals processing plant is provided. The method includes adding coagulant(s) and/or flocculant(s) and/or flotation chemical(s) to the aqueous stream in order to facilitate formation of flocs comprising at least some of the Si-compounds, and in order to form a treated aqueous stream, subjecting the treated aqueous stream to cleaning flotation in order to separate at least some of the Si-compounds as a cleaning flotation overflow, and removing the cleaning flotation overflow. The cleaning flotation comprises gas bubbles, at least 90% of the gas bubbles having a diameter of from 0.2 to 250 μm.