Method and device for recovering ammonia nitrogen from oxidative dehydration catalyst preparation wastewater

Abstract

The invention relates to a method and a device for recovering ammonia nitrogen from oxidative dehydration catalyst preparation wastewater. The method comprises the following steps: high-concentration wastewater produced in oxidative dehydration catalyst preparation is treated with gaseous carbon dioxide, such that zinc ions form a precipitate, zinc ammonia complex ion-form ammonia nitrogen is converted into ammonium ion ammonia nitrogen, and metal ion impurities are removed; the precipitate is dissolved with nitric acid, and the solution is used as a catalyst preparation raw material; when the weight concentration of the original ammonium nitrate ammonia nitrogen of the high-concentration wastewater and the newly formed ammonium ion ammonia nitrogen reaches 2-6%, alkali is added, such that ammonium salt is converted into ammonia water; with a distillation method, ammonia water is recovered from the top of a distillation tower; the ammonia water with mass concentration higher than 10% is recycled in the catalyst preparation process; in the wastewater obtained at the bottom of the distillation tower, the ammonia nitrogen content is no higher than 50mg / L, and the mass concentration of sodium nitrate is higher than 5%, such that recycling is convenient. With the method provided by the invention, zinc ions can be precipitated, and ammonia nitrogen existing in a form of zinc ammonia complex ion can be converted into ammonium ion ammonia nitrogen. Therefore, a problem of incomplete precipitation caused by that zinc ion precipitation is influenced by zinc ammonia complex ion balance when sodium carbonate is adopted as a precipitation agent is solved.

Description

Technical field [0001] The invention relates to a method for treating ammonia nitrogen wastewater and a method for converting ammonia nitrogen into ammonia water for recovery. Background technique [0002] The fluidized bed oxidative dehydrogenation of butene produces butadiene using a zinc ferrite catalyst, and the fluidized bed oxidative dehydrogenation catalyst uses a co-precipitation process, such as Chinese patents CN1072110 and CN1184705. Co-precipitation uses ammonia as the precipitant to precipitate the corresponding metal from the nitrate solution, and prepare the catalyst through the processes of aging, washing, drying, and roasting. The washing process produces a large amount of wastewater containing ammonium nitrate. Since ammonia water and zinc ions form zinc-ammonia complex ions, when ammonia water is used as a precipitant, while zinc hydroxide is precipitated, part of the zinc ions are dissolved in the wastewater in the form of zinc-ammonia complex ions. The trea...

AI Technical Summary

Problems solved by technology

[0012] Existing techniques do not involve the use of CO 2 Process for treating high-ammonia-nitrogen wastewater containing zinc-ammonia complex ions as a precipitant, and then recovering ammonia water

Images