Ash-water Classifier Segmentation for Metal Recovery
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Solution Overview
Problem
Current methods for processing ash from waste incineration plants are inefficient in optimizing value creation and metal recovery, as they often require costly disposal of pollutant-contaminated fractions and do not effectively utilize non-ferrous metals across all grain sizes.
Innovation Solution
A three-stage classification process within the good fraction of the ash-water mixture, where only the coarse fraction is processed for metals, while the middle and fine fractions are separated and managed to reduce pollutant contamination and optimize economic operation, without the use of a hydrocyclone upstream of the classifying device, and with additional steps for dewatering and post-cleaning to enhance metal extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the good fraction is classified into only two fractions (coarse and fine) as in prior art, then the process is simpler, but metal recovery efficiency is suboptimal because non-ferrous metals are not present in economically usable form in every particle size
Solution Approach 1:
The good fraction is segmented into three distinct particle size fractions (coarse, medium, and fine) based on the distribution of non-ferrous metals across different grain sizes. This segmentation allows each fraction to be processed differently, optimizing metal recovery by focusing resources on the coarse and medium fractions where economically usable metals are present, while eliminating unnecessary processing of the fine fraction.
2Productivity
If all fractions are subjected to metal processing as in prior art, then comprehensive metal recovery is attempted, but economic costs increase due to processing fractions with low metal content
Solution Approach 1:
Different processing approaches are applied to different fractions based on their specific characteristics. The coarse and medium fractions are subjected to metal processing where non-ferrous metals are present in economically usable forms, while the fine fraction is excluded from metal processing due to the absence of economically viable metal content, thereby optimizing resource allocation and reducing unnecessary processing costs.
3Productivity
If the middle fraction is used for metal processing as in prior art, then more material is processed for potential metal recovery, but efficiency decreases because the middle fraction contains only a few non-ferrous metals
Solution Approach 1:
Instead of processing all fractions equally, the invention applies metal processing only to the extent necessary - specifically to the coarse and medium fractions where non-ferrous metals are present in economically usable forms. This partial action approach avoids the inefficiency of processing the fine fraction which contains negligible metal content, thereby optimizing the ratio of material processed to metal recovered.
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 significantly increases the efficiency of metal recovery by focusing on the coarse fraction for processing, reduces pollutant contamination, and minimizes economic costs by avoiding unnecessary metal processing steps, while maintaining environmental compliance and reducing foam formation issues.
Implementation Method 1
The processing of municipal solid waste incineration ash takes place using a wet classification process. For this, the ash is mixed with liquid.
Implementation Method 2
after sieving of a coarse fraction, is fed as a feed stream to a classification stage comprising an upflow classifier and an upstream hydrocyclone. Fine particles are separated in the hydrocyclone.
Data Source
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AI summary
The invention relates to a method and an installation for treating ash from waste incinerators, comprising a classifier device (5) for classifying an ash-water mixture, in three stages, into a course fraction (8), a medium fraction (9) with a smaller grain size of no more than 1.2 mm, and a fine fraction (10) with an even smaller grain size of no more than 0.4 mm. Only the course fraction (8) is fed to a treatment of the metal contained in said course fraction.