Chemical

Ihobe Eusko Jaurlaritza

VALOMPLUS

RECOVERY OF MANGANESE SLUDGE TO ACTIVATE SECONDARY USES

AUTLAN is the second European producer of electrolytic manganese dioxide (MnO2 or EMD), a compound necessary for the manufacture of commercial and industrial batteries, whereby it has highly efficient facilities that enable high purity MnO2 to be obtained, which generates waste of varied composition and in the form of sludge that usually accumulates in landfills and may amount to more than 12,500 tonnes each year.

Results from previous projects showed that the waste could not be used without prior treatment. VALOMPLUS aims to use this knowledge on the waste generated in the preceding project to define the final application for the waste, enabling circular economy principles to be followed and waste recovery to be improved.

AUTLAN has led VALOMPLUS and has relied on the collaboration of OVIEDO UNIVERSITY for its implementation.

AUTLAN
OBJECTIVES
  • Develop procedures to recover the waste sludge generated in the electrolytic manganese dioxide production process, for which no recovery option currently exists worldwide.
  • Reduce the amount of waste sludge generated that needs to be landfilled.
  • Transform or adapt this waste so that it can be converted into one or more of the raw materials in the production process of AUTLAN or other companies.
RESULTS
  • 8% saving in the consumption of raw materials through a new way of reusing waste in the EMD production process developed in collaboration with OVIEDO UNIVERSITY, although it does involve the generation of new waste.
  • Identification of particle separation by cyclones as the most suitable separation method among those studied (magnetic separation, filters, etc.).
  • Difficulties in recovery and the need for large quantities of water and energy for the removal of sulphur contained in the waste 
CONCLUSIONS
  • A recovery methodology has been developed that involves the generation of two new types of waste. The implementation of the method developed therefore requires recovery pathways for the two new types of waste.
  • This method requires a substantial increase (about 200 %) in sulphuric acid consumption.
  • The resulting electrolyte cannot be used by AUTLAN EMD or other companies due to impurities. Its purification is being studied.

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