Process and device for dealkalizing red mud and recovering aluminum oxide by using waste flue gas and waste heat of cement plant
A waste flue gas and cement plant technology, which is applied in the preparation of alkali metal aluminate/alumina/hydroxide, cement production, aluminum compounds, etc., can solve the problems of not considering recycling, reduce fuel costs, increase heat Value, the effect of efficient recycling
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Embodiment 1
[0047] A process for recovering alumina while using waste flue gas and waste heat from a cement plant to dealkalize red mud is carried out according to the following steps:
[0048] 1. Mix red mud and water in the acid reaction tank 1 at a ratio of 2.5:1, add sulfuric acid, adjust the pH value to 2.5, stir and react for 6 hours, and the reaction temperature is 70°C.
[0049] 2. Send the reaction slurry into the alkali reaction tank 2, add sodium hydroxide solution, adjust the pH value to 9, stir and react for 2 hours, and the reaction temperature is 70°C.
[0050] 3. Mix the slurry in step 2 with calcium carbide slag in the carbide slag reaction tank 3, press CaO 电石渣 / Na 2 o 赤泥 =3.5; heat the slurry in carbide slag reaction tank 3 to 80°C, stir for 360min at a stirring speed of 200r / min; let stand for 5min.
[0051] 4. After the reaction is completed, the solid-liquid separator 4 is used for separation to produce a primary filter residue and a primary filtrate.
[0052] 5....
Embodiment 2
[0064] A process for recovering alumina while using waste flue gas and waste heat from a cement plant to dealkalize red mud is characterized in that it is carried out in the following steps:
[0065] 1. Mix red mud and water in the acid reaction tank 1 at a ratio of 4:1, add sulfuric acid, adjust the pH value to 4, stir and react for 3 hours, and the reaction temperature is 85°C.
[0066] 2. Send the reaction slurry into the alkali reaction tank 2, add sodium hydroxide solution, adjust the pH value to 11, stir and react for 2 hours, and the reaction temperature is 85°C.
[0067] 3. Mix the slurry in step 2 with calcium carbide slag in the carbide slag reaction tank 3, press CaO 电石渣 / Na 2 o 赤泥 =4.0; heat the slurry in carbide slag reaction tank 3 to 95°C, stir for 60 minutes at a stirring speed of 500 r / min; let stand for 10 minutes.
[0068] 4. After the reaction is completed, the solid-liquid separator 4 is used for separation to produce a primary filter residue and a prim...
Embodiment 3
[0079] The alkali content of dealkalized red mud is low, which can avoid the blockage caused by the adhesion of alkali compounds to the preheater cone during the clinker sintering process, and can also avoid the reaction between alkali and clinker to form alkali minerals and solid solutions , to avoid local expansion due to the heat release of the alkali-aggregate reaction, deformation and cracking of structures, etc. This example examines the properties of the cement clinker prepared from the dealkalized red mud prepared in Examples 1 and 2.
[0080] Red mud configuration cement ingredients:
[0081] raw material name limestone sandstone powder sandstone waste Iron ore sludge dry red mud Raw material Ingredients ratio 80.00 6.00 4.00 3.00 7.00 100
[0082] Red mud configuration cement batching rate value setting:
[0083] KH=0.87; SM=2.07; IM=1.58
[0084] Cement clinker preparation process:
[0085] Put the prepared raw meal into the ...
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