Method for reclaiming ferric oxide from coal ash and coal gangue

Abstract

The invention discloses a method of recovering an iron oxide from a fly ash and a gangue. The method adopts the process of grinding and roasting the fly ash and the gangue, the process of immersing and carbon dioxide decomposing the alumina, the process of acidizing and separating the silica and the process of obtaining iron oxide by the method of hydroxide precipitation. The purity of the iron oxide made by the method is high and the extraction rate of the iron oxide in the fly ash and the gangue can reach to 86 percent. The whole process is carried out under the pressure condition, so the method has low requirements to the equipment. The method solves the problems of land occupation and environment pollution caused by residue stacking after alumina extraction, also solves the problems of large amount of residue and low added value of the residue. The whole process realizes recycling of resources and can not cause new pollution to the surrounding environment.

Description

technical field

[0001] The invention belongs to the technical field of solid waste recovery and utilization, and in particular relates to a method for recovering iron oxide from fly ash and coal gangue. Background technique

[0002] Coal-based solid waste includes fly ash and coal gangue, which come from the mining, processing and utilization of coal. Coal gangue is a rock associated with coal, which is removed during coal mining and coal washing. Fly ash is coal combustion waste, which is the solid waste residue discharged from coal-fired power plants. At present, the total stockpile of coal-based solid waste in my country has exceeded 2 billion tons, and it is still increasing at a rate of about 100 million tons per year, which not only occupies a large amount of land resources, but also seriously pollutes the environment.

[0003] In the near future, comprehensive utilization of fly ash and coal gangue must be implemented, and the goal of zero discharge of waste must be...

Examples

Embodiment 1

[0034] 1. Grind the fly ash and make the particle diameter less than 200 mesh, preferably between 200-400 mesh. The ground fly ash was mixed with Na 2 CO 3 Mix and stir according to the ratio of fly ash: sodium carbonate=1:1;

[0035] 2. Calcining the mixture formed in the previous step at a temperature of 800° C. for 50 minutes.

[0036] 3. Add appropriate amount of water to the sintered product, sintered product: water = 1:50. After leaching at 60°C for 2 hours, it was filtered.

[0037] 4, feed CO into the concentrated filtrate gained in step 3 2 , filtered after carbon separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture.

[0038] 5. Add industrial hydrochloric acid to the filter residue obtained in steps 3 and 4, the solid-to-liquid ratio is 1:5, and react for 50 minutes at a temperature of 60°C. Filter after the reaction, the resulting filter residue is silica gel, and the filtrate is AlCl 3 with FeCl 3 mixture.

[0039] 6. AlCl obtained in step 5 ...

Embodiment 2

[0044] 1. Grind the gangue to make the particle diameter 240 mesh. The coal gangue after grinding is mixed with Na2CO3 by coal gangue: sodium carbonate=1: 3 ratio mixing, stirring;

[0045] 2. Calcining the mixture formed in the previous step at a temperature of 900° C. for 25 minutes.

[0046] 3. Add an appropriate amount of water to the sintered product, the Na in it 2 SiO 3 and NaAlO 2 is dissolved in water. Sintered product: water = 1:85. After leaching for 1 hour at a temperature of 80°C, filter.

[0047] 4, feed the CO obtained in step 2 into the concentrated filtrate gained in step 3 2 , filtered after carbon separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture.

[0048] 5. Add industrial hydrochloric acid to the filter residue obtained in steps 3 and 4, the solid-to-liquid ratio is 1:5, and react for 400 minutes at a temperature of 70°C. Filter after the reaction, the resulting filter residue is silica gel, and the filtrate is AlCl 3 with FeCl 3...

technical field

[0001] The invention belongs to the technical field of solid waste recovery and utilization, and in particular relates to a method for recovering iron oxide from fly ash and coal gangue. Background technique

[0002] Coal-based solid waste includes fly ash and coal gangue, which come from the mining, processing and utilization of coal. Coal gangue is a rock associated with coal, which is removed during coal mining and coal washing. Fly ash is coal combustion waste, which is the solid waste residue discharged from coal-fired power plants. At present, the total stockpile of coal-based solid waste in my country has exceeded 2 billion tons, and it is still increasing at a rate of about 100 million tons per year, which not only occupies a large amount of land resources, but also seriously pollutes the environment.

[0003] In the near future, comprehensive utilization of fly ash and coal gangue must be implemented, and the goal of zero discharge of waste must be...

Examples

Embodiment 1

[0034] 1. Grind the fly ash and make the particle diameter less than 200 mesh, preferably between 200-400 mesh. The ground fly ash was mixed with Na 2 CO 3 Mix and stir according to the ratio of fly ash: sodium carbonate=1:1;

[0035] 2. Calcining the mixture formed in the previous step at a temperature of 800° C. for 50 minutes.

[0036] 3. Add appropriate amount of water to the sintered product, sintered product: water = 1:50. After leaching at 60°C for 2 hours, it was filtered.

[0037] 4, feed CO into the concentrated filtrate gained in step 3 2 , filtered after carbon separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture.

[0038] 5. Add industrial hydrochloric acid to the filter residue obtained in steps 3 and 4, the solid-to-liquid ratio is 1:5, and react for 50 minutes at a temperature of 60°C. Filter after the reaction, the resulting filter residue is silica gel, and the filtrate is AlCl 3 with FeCl 3 mixture.

[0039] 6. AlCl obtained in step 5 ...

Embodiment 2

[0044] 1. Grind the gangue to make the particle diameter 240 mesh. The coal gangue after grinding is mixed with Na2CO3 by coal gangue: sodium carbonate=1: 3 ratio mixing, stirring;

[0045] 2. Calcining the mixture formed in the previous step at a temperature of 900° C. for 25 minutes.

[0046] 3. Add an appropriate amount of water to the sintered product, the Na in it 2 SiO 3 and NaAlO 2 is dissolved in water. Sintered product: water = 1:85. After leaching for 1 hour at a temperature of 80°C, filter.

[0047] 4, feed the CO obtained in step 2 into the concentrated filtrate gained in step 3 2 , filtered after carbon separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture.

[0048] 5. Add industrial hydrochloric acid to the filter residue obtained in steps 3 and 4, the solid-to-liquid ratio is 1:5, and react for 400 minutes at a temperature of 70°C. Filter after the reaction, the resulting filter residue is silica gel, and the filtrate is AlCl 3 with FeCl 3...