Technology to reduce sludge and to recover metal(NEDO’s national project for research and development

Participating in NEDO’s national project for research and development, Aquatech has established a technology to recover useful metals from sludge containing heavy metals, which used to be dumped all of a lump, and at the same time to reduce substantially the volume of waste.

 Background of research and development

o far, waste water containing heavy metals is treated mostly by hydroxide precipitation method. A large part of metal hydroxide sludge containing nickel and copper etc. are dumped into reclaimed grounds without reused. Nowadays when we are facing with the problems of exhaustion and price hike of metal resources as well as increase of waste, such technology of recovering metal is sought that brings reduction of metal oxide sludge and energy conservation. We have tackled this assignment by use of gas sensor controlled sulfide method (NS process).

 Outcome of our research and development

・ Recovery of over 80% of useful metal from metal hydroxide sludge

・ Reduction of produced sludge by over 80%

・ Copper extracted from sludge sells to miners as copper sulfide. Nickel is recovered as metal nickel from nickel sulfide sludge by energy-saving method as described in the sketch below.