Treatment technology of waste water containing fluoride and ammonia nitrogen

Abstract

The invention provides a treatment technology of waste water containing fluoride and ammonia nitrogen. The technology is used for treating waste water containing fluoride and ammonia nitrogen in tantalum-niobium hydrometallurgy. The technology is characterized in that the relative volatility difference between ammonia and water is utilized; an ammonia-water separating technology in which high-efficiency distillastion is treated as the main technology core is carried out and combined with a pre-treatment technology to perform defluorination-calcium removing-strong dissolving and complexing-molecular distilling, so as to realize the removal of fluorine and ammonia; the drained water obtained after treatment reaches national primary emission standard; meanwhile, high-purity ammonia water with concentration being equal to or greater than 15% is recovered for production. According to the technology, the ammonia is recycled, so that the balance of payments of the treatment cost of the ammonia containing waste water can be achieved; the requirement on comprehensive utilization of the resource can be met; the technology brings a certain economic benefits.

Description

technical field [0001] The invention belongs to the field of waste resource treatment or metallurgy, and relates to a treatment method for fluorine-containing ammonia nitrogen wastewater from tantalum and niobium hydrometallurgy, in particular to a treatment method using defluorination-calcium removal-enhanced decomplexation-molecular distillation The combined process recovers ammonia from wastewater and makes the treated water meet the national first-level discharge standards. Background technique [0002] The fluorine ammonium nitrogen concentration in the wastewater discharged from tantalum niobium wet process, tungsten, and rare earth smelting enterprises is relatively high, and some wastewater contains NH 4 The concentration of Cl reaches above 10g / L, and the fluorine-containing ammonium nitrogen wastewater is also the main wastewater in the production process of tantalum and niobium hydrometallurgy. The discharge of high content of fluorine leads to a series of enviro...

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Problems solved by technology

The one-time investment of "ammonia distillation" is too large, the latent heat is not utilized, the energy consumption is high, and the power consumption of "blowing" is too large

[0005] 2. When the A / O method is continued, not only the investment is high, but also the floor area is large, and the requirements for the pretreated water are strict (such as NH3-N must be less than 300mg / L, fluorine must be less than 50mg / L, and the stripping or stripping method is more than 100mg / L. High-concentration ammonia nitrogen wastewater above 5000mg / L cannot meet this requirement at all, so it can only be diluted with doubled water)

[0006] 3. Although the investment and floor area of ​​the continuous chemical precipitation method are smaller than that of the A / O method, its consumption of chemicals is too large. The ratio of N:P:Mg is 1:1.1-1.2, and the cost of treating chemicals is too high , and it is impossible for the effluent to meet the national primary or secondary discharge standards

[0007] 4. The ammonia nitrogen treatment method is not comprehensive, the removal rate of ammonia nitrogen is only 50%-70%, the recovery of ammonia is not complete, and there is secondary pollution

[0008] 5. Ammonia cannot be recovered from waste water to achieve comprehensive utilization of resources

[0009] Water is a precious non-renewable resource, but the wastewater generated by some metal processing processes cannot be reused in the metal processing process because it contains high concentrations of ammonia and fluorine. The treatment technology that makes the treated water quality meet the national first-level discharge standard is of great significance

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