Low-Matte Nickel Converter Slag Metal Recovery via Roasting and Leaching
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Solution Overview
Problem
The traditional pyrometallurgical process for extracting valuable metals from low nickel matte converter slags results in significant resource wastage and environmental pollution due to high energy consumption, complex parameters, and substantial losses of cobalt and other valuable elements during the conversion to high nickel matte.
Innovation Solution
A method involving roasting with quicklime to remove silica, followed by magnetic separation, acid leaching to produce iron oxide red, and oxidative pressure acid leaching with hydrogen sulfide gas to separate and recover nickel, cobalt, and copper from the slags, optimizing the utilization of components in the converter slags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low nickel matte is melted by blowing into high nickel matte to remove iron and sulfur, then the composition meets processing requirements, but converter temperature must reach 1200-1300°C and time takes 8-10 hours causing high energy consumption
Solution Approach 1:
The patent applies preliminary action by removing silica through roasting with quicklime before the melting by blowing process. This preliminary removal of silica prevents it from consuming energy during the high-temperature melting process and reduces the overall energy requirement of 1200-1300°C, while still achieving the required composition quality in the final product.
2Loss of substance
If converter slag is sent to electric cleaning furnace for repeated smelting to enrich valuable metals, then cobalt and other valuable metals are recovered, but cobalt loss reaches about 50% and causes repeated material circulation and serious environmental pollution
Solution Approach 1:
The patent extracts valuable metals directly from converter slag through a one-step leaching process using sulfuric acid and hydrogen peroxide, bypassing the repeated smelting cycle entirely. This extraction approach recovers cobalt, nickel, and copper with high efficiency (cobalt loss reduced from 50% to minimal levels) without generating the environmental pollution associated with repeated electric furnace operations and material circulation.
Solution Approach 2:
Instead of repeatedly processing and circulating materials through electric cleaning furnaces, the patent discards the conventional multi-step approach and recovers valuable metals in a single leaching operation. The converter slag is directly leached to extract cobalt, nickel, and copper, eliminating the need for repeated smelting and reducing both material circulation and environmental impact.
3Loss of substance
If converter slag is reduction smelted or reduction sulfide smelted to obtain cobalt matte or cobalt alloy, then valuable metals are recovered, but the process has complex parameters, high reaction temperature, and high energy consumption
Solution Approach 1:
The patent replaces complex mechanical and thermal processing systems (reduction smelting, reduction sulfide smelting) with a chemical leaching system. Instead of using high-temperature reduction processes with complex parameter control, the invention uses sulfuric acid and hydrogen peroxide leaching, which operates under simpler, more controllable conditions while achieving the same valuable metal recovery objective with reduced energy consumption and process complexity.
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 method effectively recovers valuable metals with high recovery rates (up to 99.7% for nickel and cobalt) while reducing energy consumption and environmental impact by converting waste slags into valuable products, such as nickel and cobalt sulfates, and copper sulfide.
Implementation Method 1
S1: mixing the low nickel matte converter slag with quicklime, then roasting to obtain a roasted material
Implementation Method 2
S2: performing a grinding and a magnetic separation to the roasted material to obtain a silicate and an iron-rich slag
Implementation Method 3
S4: mixing the filter residue with an acid solution to perform an oxidative pressure acid leaching
Implementation Method 4
S4: mixing the filter residue with an acid solution to perform an oxidative pressure acid leaching
Implementation Method 5
S5: introducing a hydrogen sulfide gas into the leaching solution, adjusting pH, then performing a solid-liquid separation to obtain a copper sulfide precipitate and a nickel-cobalt-containing filtrate
Data Source
AI summary
Disclosed in the present invention is a method for extracting valuable metal from low-matte nickel converter slag. The method comprises: mixing low-matte nickel converter slag and quicklime then calcinating, obtaining a calcinated material; grinding and magnetically separating the calcinated material, obtaining silicate and iron-rich slag; adding a strong alkali solution to the iron-rich slag to perform leaching processing, and performing solid-liquid separation, obtaining a filtrate and a residue; mixing the residue with an acid solution, performing oxygen pressure acid leaching, and performing solid-liquid separation, obtaining a leachate and iron oxide; introducing hydrogen sulfide gas into the leachate, adjusting the pH, and performing solid-liquid separation, obtaining a copper sulfide precipitate and a nickel-cobalt-containing filtrate. In the present invention, first, removing silicon dioxide is removed by means of calcination to prepare silicate, then iron oxide is prepared by means of acid leaching, and finally metal separation is performed on the leachate, causing various components of the converter slag to be effectively utilized. The process flow of the present invention is short and effectively utilizes each component of the low-matte nickel converter slag, waste is turned into valuable material, and the loss of valuable metal elements is reduced.