About 2.2 ton of waste copper slag is generated for every tonne of copper produced which is currently being dumped near the plant site. CSIR-NML developed a very unique process by which the slag is converted to two commercial products such as ferric/ferrous sulfate and silica powder.
About 5 kL of ~35% ferric sulfate solution and ~300 kg SiO2 powder for every tone of slag treated. Ferric sulfate is an important ingredient for arsenic removal from the toxic waste stream of copper industries and silica produced from the process is useful for phosphoric acid plants. Implementation of the process will not only take care of environmental norms but also will make the industry independent of the availability of chemicals for the critical operation of treating effluents.
National Metallurgical Laboratory (NML)
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