PGM-Enriched Alloy Production via Density-Based Slag Separation
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Solution Overview
Problem
Current pyrometallurgical processes for producing PGM-enriched alloys result in significant PGM loss into slag, limiting the efficiency and purity of the final product.
Innovation Solution
A process involving a PGM collector alloy and a copper- and sulfur-free material forming a slag-like composition, melted in a specific ratio within a converter, followed by oxidation with an oxidizing gas to separate and enrich the PGMs, minimizing PGM loss into slag by exploiting density differences and optimizing chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional pyrometallurgical converting is used for PGM enrichment, then iron removal is achieved, but significant PGM loss occurs into the slag
Solution Approach 1:
The invention changes the chemical composition parameters of the slag system by using a specific combination of CaO, SiO2, and Al2O3 in optimized ratios. This parameter modification alters the slag's chemical properties to reduce PGM affinity, thereby minimizing PGM loss while maintaining effective iron removal capability
Solution Approach 2:
The invention employs an oxygen-enriched oxidizing atmosphere during the converting process to accelerate oxidation reactions. This strong oxidizing condition promotes more complete iron oxidation and removal while the controlled slag composition prevents PGM oxidation and loss, resolving the contradiction between enrichment efficiency and PGM retention
2Manufacturing precision
If oxidation smelting is used to remove iron from PGM-containing alloy, then iron removal is improved, but PGM content in the final alloy is reduced due to loss
Solution Approach 1:
The invention introduces a specifically formulated slag system acting as an intermediary phase between the metal alloy and the oxidizing atmosphere. This intermediary slag with controlled CaO-SiO2-Al2O3 composition facilitates iron removal while serving as a protective barrier that prevents PGM oxidation and transfer to the slag phase, thereby maintaining high PGM concentration in the final alloy
Solution Approach 2:
The invention modifies the chemical parameters of the slag system to create optimal conditions for selective iron removal. By adjusting the ratios of CaO, SiO2, and Al2O3, the slag's chemical properties are changed to favor iron oxidation and removal while minimizing PGM interaction with the slag, thus improving manufacturing precision of the final PGM alloy
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 process achieves a PGM-enriched alloy with high PGM content and remarkably low PGM loss in the slag, reducing the need for further refinement and chemical consumption, while the slag formed has a very low PGM content, indicating effective PGM retention.
Implementation Method 1
contacting an oxidizing gas comprising 0 to 80 vol.-% of inert gas and 20 to 100 vol.-% of oxygen with the lower high-density molten mass obtained in step (3) until it has been converted into a lower high-density molten mass of the PGM-enriched alloy
Implementation Method 2
separating an upper low-density molten slag formed in the course of step (4) from the lower high-density molten mass of the PGM-enriched alloy making use of the difference in density
Data Source
AI summary
A process for the production of a PGM-enriched alloy comprising 0 to 60 wt.-% of iron and 20 to 99 wt.-% of one or more PGMs selected from the group consisting of platinum, palladium and rhodium, the process comprising the steps of (1) providing a PGM collector alloy comprising 30 to 95 wt.-% of iron, less than 1 wt.-% of sulfur and 2 to 15 wt.-% of one or more PGMs selected from the group consisting of platinum, palladium and rhodium, (2) providing a copper- and sulfur-free material capable of forming a slag-like composition when molten, wherein the molten slag-like composition comprises 40 to 90 wt.-% of magnesium oxide and/or calcium oxide and 10 to 60 wt.-% of silicon dioxide, (3) melting the PGM collector alloy and the material capable of forming a slag-like composition when molten in a weight ratio of 1 : 0.2 to 1 within a converter until a multi- or two-phase system of a lower high-density molten mass comprising the molten PGM collector alloy and one or more upper low-density molten masses comprising the molten slag-like composition has formed, (4) contacting an oxidizing gas comprising 0 to 80 vol.-% of inert gas and 20 to 100 vol.-% of oxygen with the lower high-density molten mass obtained in step (3) until it has been converted into a lower high-density molten mass of the PGM-enriched alloy, (5) separating an upper low-density molten slag formed in the course of step (4) from the lower high-density molten mass of the PGM-enriched alloy making use of the difference in density, (6) letting the molten masses separated from one another cool down and solidify, and (7) collecting the solidified PGM-enriched alloy.