Session: 12, Room:
One of the most commonly used methods of recycling of spent zinc-carbon (alkaline) batteries is hydrometallurgical leaching with sulfuric acid. The technology is highly efficient and enables the recovery of the majority of deposited metals. Unfortunately, it also generates highly acidic wastewaters containing significant amounts of sulfates and metal ions, which have typically been considered off-balance material.
The aim of the study was to develop
a biotechnology for the recovery of metals (in the form of sulfides), based on the activity of sulfate-reducing bacteria (SRB). SRB reduce sulfates to sulfides, which bind with metal ions to produce an insoluble precipitate. To maximize the efficiency of metal sulfide biorecovery by SRB, the acidic wastewaters were pretreated with sodium hydroxide and then with biogenic ammonia (produced by urea-degrading bacteria) to reach pH 5.0. Further alkalinity was generated during organic compound decomposition carried out by SRB in cultures containing appropriately diluted, pretreated leachates.
As a result of the proposed biotechnology, metal ions and sulfates, were almost completely removed from the leachate. This way new raw materials: metal sulfides and treated (industrial-quality) water with circumneutral pH were produced.
Thu, 09/05/2019 - 13:48 to 13:51
Flash presentation in Solid waste management