This article delves into the exploration of novel techniques for the recovery of manganese from waste zinc-manganese batteries. It introduces a new method that employs oxalic acid as a reducing agent to break down the manganese compounds in these batteries, facilitating the recycling of manganese. This innovative approach not only mitigates environmental pollution caused by discarded batteries but also promotes resource utilization, with a manganese recovery rate exceeding 96%.
China is a leading producer, consumer, and exporter of disposable zinc-manganese batteries. In 2001, the country's production of disposable batteries hit 17.5 billion, with consumption around 8 billion, 70% of which were zinc-manganese batteries. According to metal powder suppliers, the production of 1 billion manganese batteries consumes significant amounts of zinc metal, MnO2, copper block, zinc chloride, carbon rods, and ammonium chloride.
If China could achieve a 50% recovery rate from its battery consumption, it could recycle substantial amounts of zinc metal, manganese, copper, carbon rods, and ammonium chloride annually. However, without proper recycling and processing, these valuable industrial raw materials remain unrecovered, and the discarded batteries contribute to heavy metal contamination of soil and groundwater.
Data indicates that a single No. 1 battery can render a square meter of soil permanently unusable, while a button battery can contaminate 600 tons of water, equivalent to a lifetime's water consumption. Therefore, the recycling of waste batteries holds immense practical significance. As China's economy develops and societal awareness of environmental protection grows, research into waste battery recycling methods has increased.
Waste zinc-manganese batteries consist of various components, including zinc, manganese powder, acetylene black, ammonium chloride, electrically paste, asphalt, plastics, copper cap, steel, paper, and MnOOH. Manganese powder constitutes approximately 65% of waste batteries, highlighting the importance of effective and efficient manganese treatment in the battery recycling process.
One method involves cutting and sorting waste zinc-manganese batteries to obtain a mixture of manganese black powder. This mixture is then fired in a tubular furnace, stirred with hot sulfuric acid, treated with sodium hypochlorite, and then filtered, washed, and dried to obtain MnO2. However, this process yields a low-purity product and introduces new ions, potentially causing secondary environmental pollution.
Another method involves cutting and sorting the waste batteries, watering, filtering, and roasting the obtained black manganese powder mixture. This mixture is then leached, filtered, dried, and reacted with potassium chlorate and potassium hydroxide in a molten state to produce potassium permanganate. Although this process is less complicated, it requires further processing to obtain relatively pure potassium permanganate.
This paper introduces a new method that uses oxalic acid as a reducing agent to reduce manganese compounds in battery materials. This innovative approach allows for the recycling of manganese from waste batteries and the production of high-purity manganese sulfate. This method not only reduces environmental pollution but also promotes resource utilization, with a manganese recovery rate exceeding 96%.
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