Pe Foam Tape,Heavy Duty Pe Foam Tape,High-Viscosity Pe Foam Tape,High Bonding Pe Foam Tape Shanghai Huike New Material Technology Co., Ltd. , https://www.shhuike.com
Treatment and Recycling of Waste Acid--Supply Manganese Sulfate or Manganese Carbonate
Manganese ore and soft coal is 100: (14 to 21) were pulverized and mixed. The coal here is used as a reducing agent, and its amount is 2 to 3 times more than the theoretical amount, in order to ensure the reduction during the roasting. If the coal is too small, the reduction will be lost in the later stage, and the generated MnO will be oxidized to MnO 2 , which will reduce the reduction rate. Then put it into the reverberatory furnace and then keep it at 850~900 °C for 1 h to obtain MnO. The reaction formula is as follows:
In a reducing atmosphere, the material is added to the waste acid by hydrating, and the leaching is performed. Since a part of the MnO 2 in the ore powder has not reacted, or has reacted to form MnO, a small amount of MnO is oxidized at a high temperature. Formed as MnO 2 . These MnO 2 are sufficient to oxidize Fe-SO 4 in the spent acid to Fe 2 (SO 4 ) 3 . If blue is detected by the red blood salt test solution, Fe 2+ still exists. At this time, it is necessary to add soft manganese ore powder to oxidize Fe 2+ to Fe 3+ . Then a small amount of Na 2 S was added, the heavy metal ions and sulfide ions, generating heavy metal sulfide precipitate. If the acidity is too large, add some manganese carbonate ore powder to neutralize, and finally add ammonia to adjust the pH to 5, so that Fe 3+ , Ti 4+ and Al 3+ are hydrolyzed to form a pair of hydroxide precipitates, which are mixed together in the slag. It is filtered and removed. The sulfuric acid in the spent acid and the new sulfuric acid produced by the hydrolysis together with MnO form manganese sulfate. Its relevant reaction formula is as follows:
MnO 2 +2FeSO 4 +2H 2 SO 4 ===MnSO 4 +Fe 2 (SO 4 ) 3 +2H 2 O
Fe 2 (SO 4 ) 3 +6H 2 O===2Fe(OH) 3 ↓+3H 2 SO 4
TiOSO 4 +3H 2 O===Ti(OH) 4 ↓+H 2 SO 4
Al 2 (SO 4 ) 3 +6H 2 O===2Al(OH) 3 ↓+3H 2 SO 4
H 2 SO 4 +MnO===MnSO 4 +H 2 O
The reaction liquid is heated to boiling, the aggregation of the colloidal particles is accelerated, and the precipitation is accelerated, and then the mixture is allowed to stand for a certain period of time, that is, separated by a plate and frame filter press, the residue is washed with water, the filter residue is discarded, and the washing liquid is incorporated into the waste acid tank. The filtrate is concentrated and cooled, that is, the manganese sulfate crystal is precipitated, and then separated by a centrifuge, the filtrate is returned to be concentrated, and the filter cake is dried and packaged, which is a finished manganese sulfate.
In order to produce manganese carbonate, the above manganese sulfate solution is directly added to a mixture of ammonium hydrogencarbonate and ammonia water without concentration, so that it forms a precipitate of manganese carbonate, and then filtered under reduced pressure, the mother liquid is discarded, and the manganese carbonate is washed several times to no SO. After 4 2- ion, it is dried and packaged at a temperature below 70 °C to obtain a finished manganese carbonate. Its reaction formula is as follows:
MnSO 4 +NH 4 HCO 3 +NH 3 ·H 2 O===MnCO 3 ↓+(NH 4 ) 2 SO 4 +H 2 O
The production process for producing manganese sulfate (or manganese carbonate) from waste acid is shown in the figure below.