Jacketed Rotary Converter for PGM Converting Process
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Solution Overview
Problem
Conventional converting processes for platinum group metal (PGM) collector alloys are inefficient due to slow melting rates, high oxygen addition rates, and refractory lining corrosion, leading to significant PGM losses in the slag.
Innovation Solution
The process involves reducing the amount of added flux materials, partially pre-oxidizing the collector alloy, recycling converter slag, and using a refractory protectant to inhibit corrosion and extend refractory life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high levels of added flux materials (SiO2, MgO/CaO) are used to form low melting slag, then impurity removal is improved and PGM content in alloy is enhanced, but slag volume increases and PGM losses in slag rise
Solution Approach 1:
The patent changes the chemical composition parameters of the slag-forming materials, specifically using fluxes with lower SiO2 content (40-70 wt%) and higher MgO/CaO content (10-30 wt% or 40-90 wt%), along with controlled additions of Al2O3 (0-20 wt%) and other oxides. This parameter optimization allows effective impurity removal while minimizing PGM partitioning into the slag phase, thereby reducing PGM losses.
2Productivity
If high oxygen injection rates are used to accelerate converting, then processing rate is improved, but refractory lining corrosion increases and converter lifespan decreases
Solution Approach 1:
The patent introduces refractory protectant materials (such as chromite, magnesia, or alumina-based compounds) as intermediaries between the molten alloy and the refractory lining. These protectants form a protective barrier layer that reduces direct contact between the aggressive molten material and the refractory, thereby reducing corrosion and extending converter lifespan even at high oxygen injection rates.
Solution Approach 2:
The patent employs consumable refractory protectant layers that are deliberately designed to be replaced periodically. These protectants sacrificially consume themselves to protect the main refractory lining, providing a cost-effective solution to maintain converter reliability during high-productivity operations.
3Manufacturing precision
If conventional converting process is used, then PGM enrichment is achieved, but melting time is long (10 hours) and processing efficiency is low
Solution Approach 1:
The patent applies preliminary pre-oxidation to the collector alloy before the main converting process. By partially oxidizing the alloy in advance, the subsequent converting operation proceeds more rapidly as less oxidation time is needed during the main process, thereby significantly reducing total processing time while still achieving the required PGM enrichment levels.
Solution Approach 2:
The patent optimizes multiple process parameters including oxygen injection rate, temperature control, and flux composition to accelerate the converting kinetics. By carefully controlling these parameters, the process achieves rapid PGM enrichment in a fraction of the conventional time, transforming a 10-hour process into a much shorter 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
This approach reduces the volume of converter slag, shortens alloy melting time, increases converting capacity, and minimizes PGM losses while improving the reliability and durability of converter components.
Implementation Method 1
injecting oxygen-containing gas into the alloy pool to convert iron from the collector alloy to iron oxide and enrich PGM in the alloy pool
Implementation Method 2
a heat transfer jacket for the pot adjacent the refractory lining; and a coolant system to circulate a heat transfer medium through the jacket to remove heat from the alloy pool
Data Source
AI summary
PGM converting process and jacketed rotary converter. The process can include low- or no-flux converting; partial pre-oxidation of PGM collector alloy; using a refractory protectant in the converter; magnetic separation of slag; recycling part of the slag to the converter; smelting catalyst material in a primary furnace to produce the collector alloy; and/or smelting the converter slag in a secondary furnace with slag from the primary furnace. The converter can include an inclined converter pot mounted for rotation; a refractory lining; an opening in a top of the pot to introduce converter feed; a lance for injecting oxygen-containing gas into the alloy pool; a heat transfer jacket adjacent the refractory lining; and a coolant system to circulate a heat transfer medium through the jacket to remove heat from the alloy pool in thermal communication with the refractory lining.