Advantage of the new sulfide method

So far,the sludge containing metal produced by ghydroxide precipitation methodh was quite difficult to reclaim at refiner as mineral resource. Because traditional method for treatment of wastewater containing heavy metal, the sludge has high water content, low metal content and much miscellaneous salts. So we have developed new sulfide method (NS process), which controls feeding of sulfidizing agent by gas sensor. In this page, you find the advantage of new sulfide method compared with conventional method.

Merit of new sulfide method

We have developed new sulfide method (NS process), which controls feeding of sulfidizing agent by gas sensor.B

  • Possible to recover and recycle metals from waste water with metal.
  • High level treatment of waste water with heavy metal is possible (to the level that almost no residual metal is detected).
  • Reduction of sludge after treatment (not necessary to feed iron ion or aluminum ion, volume of sludge generated is about one third of conventional method)
  • Removal of elements obstructing treatment of waste water with heavy metal (chelating agentAammonia etc.)
  • Separate recovery of miscellaneous metals (in case there are plural metals in waste water, it is possible to separately recover various different metals at low cost by changing pH.)
  • Applicable to feeding system of sulfidizing agent for wet refining
  • Possible to reuse hydrogen sulfideEwaste of sulfide as medical agent

Comparison between new sulfide method and hydroxide precipitation method

Hydroxide precipitation method New sulfide method (NS process)
Reaction formula
  • Easy control of reaction
  • High safety, scarce offensive smell
  • Reduction of sludge produced
  • High level treatment is possible.
  • Small influence of chelating agent
  • Possible to separate recover of different metals
  • Easy recycling
  • High water content of sludge
  • Influence of chelating agent
  • Inclusion of impurities
  • Generation of H2S gas
  • Becoming colloidal by wrong feeding of sulfidizing agent
Treatment of sludge In most case, dumped into reclaimed ground
Polluting environmentEwaste of resources. Mineral resource is not recycled efficiently.

Possible to recycle

Outline of the new sulfide method