Recycling and resourceful treatment method of alkaline wastewater in tantalum-niobium hydrometallurgy

Abstract

The invention discloses a recycling and resourceful treatment method of alkaline wastewater in tantalum-niobium hydrometallurgy. The alkaline wastewater in tantalum-niobium hydrometallurgy is ammonia-introduced neutralization mother liquor and washing wastewater thereof. The method comprises the following steps: (1) recycling the washing wastewater; (2) precipitating a magnesium compound to removefluorine; and (3) concentrating and recovering ammonium sulfate. According to the method, industrial water in tantalum-niobium production is greatly reduced through three procedures of washing wastewater recycling, magnesium compound precipitation defluorination and ammonium sulfate concentration and recovery, two byproducts of magnesium fluoride and ammonium sulfate are produced while environmental pollution is solved, full recovery of valuable resources in the wastewater is achieved, and the method has the advantages of being simple in process, low easy to use. The method is suitable for industrial production.

Description

technical field [0001] The invention relates to a recycling and resource treatment method of alkaline wastewater in tantalum-niobium hydrometallurgy. Background technique [0002] The high fluorine, sulfate and ammonia nitrogen wastewater produced by tantalum and niobium smelting is the main threat to environmental pollution in this industry. These wastewaters are roughly divided into two categories, one is the acid-containing residual liquid in the front stage of the production process, accounting for about 5% of the wastewater from tantalum and niobium smelting; the other is the alkaline wastewater produced by the neutralization and washing of liquid ammonia in the latter stage of the process , accounting for about 95% of the total waste liquid. The water consumption in the latter part and the salt content in the waste water are astonishing. It takes about 150 tons of deionized water to produce 1 ton of niobium oxide, and at the same time produces a waste liquid containin...

AI Technical Summary

Problems solved by technology

The most conventional treatment method is to use lime treatment to solidify free fluoride ions in the form of calcium fluoride. The solid residue produced by this method cannot be recycled and requires a lot of site stacking and landfill

Although distillation of fluorine-containing waste liquid is an effective recovery method, as reported by Lai Lanping et al., various ammonia nitrogen wastewater produced by hydrometallurgy of tantalum and niobium is classified and treated according to the concentration of ammonia nitrogen, through distillation, condensation, crystallization, stripping, and zeolite The adsorbent is carried out by ion exchange method for comprehensive treatment (Lai Lanping, Wang Kui, etc.: Experimental research on ammonia nitrogen removal method in tantalum and niobium hydrometallurgy wastewater [J], Industrial Water Treatment: 2011, 31 (3): 53-56), but Distillation requires the use of corrosion-resistant materials. Not only is the equipment expensive, but distillation separation is often insufficient, so it is difficult to use in terms of equipment operating costs.

Other methods also include ion exchange resin adsorption as proposed in the domestic patent "A Method for Treating and Reusing Wastewater from Tantalum and Niobium Hydrometallurgy" (201410788647.5) and "Methods for preparing rare earth polishing powder and recovering ammonium salts from niobium and tantalum fluorine-containing wastewater" "(201510136808.7) proposed the use of rare earth precipitation to remove fluorine, etc., but these methods have many problems such as resin poisoning and aging, and rare earth is a key strategic resource in my country, resulting in poor practicability

Moreover, the above-mentioned methods all use the passive treatment process to produce wastewater. The total water consumption of the factory has not been reduced, and even some wastewater treatment methods themselves consume a large amount of deionized water, which is extremely detrimental to the environmental benefits of factory operations.

Images