阅读说明：本技术 一种回收烧结制酸废液中硫酸铵的方法 (Method for recovering ammonium sulfate in sintering acid-making waste liquid ) 是由 袁浩杰 熊斌 黄婕 金浩 梁利生 李良华 朱彤 于 2020-06-30 设计创作，主要内容包括：本发明公开了一种回收烧结制酸废液中硫酸铵的方法,具体是从烧结制酸废液中分离得到烧结硫酸铵母液,再将烧结硫酸铵母液和煤气精制硫酸铵母液以一定的流量比混合,得到混合硫酸铵母液,结晶干燥制得硫酸铵,本发明可以实现对烧结制酸废液进行再利用,不仅可以回收其中的硫酸铵成分,生产出高质量的硫酸铵,可以用作工业化肥等,还降低了运输管道的腐蚀速率,减少了设备管道维护保养成本。本发明的方法简单易行,生产运行成本低,且不会产生新的废弃物,为烧结制酸废液的处理提供了新思路。(The invention discloses a method for recovering ammonium sulfate in sintering acid-making waste liquid, which is characterized in that sintering ammonium sulfate mother liquid is obtained by separating from the sintering acid-making waste liquid, then the sintering ammonium sulfate mother liquid and coal gas refined ammonium sulfate mother liquid are mixed according to a certain flow ratio to obtain mixed ammonium sulfate mother liquid, and ammonium sulfate is prepared by crystallization and drying. The method is simple and easy to implement, has low production and operation cost, does not generate new waste, and provides a new idea for treating the sintering acid-making waste liquid.)

1. A method for recovering ammonium sulfate in sintering acid-making waste liquid is characterized by comprising the following steps:

separating sintered ammonium sulfate mother liquor from the sintering acid making waste liquor to obtain sintered ammonium sulfate mother liquor, mixing the sintered ammonium sulfate mother liquor and coal gas refined ammonium sulfate mother liquor according to the flow ratio of 1: 5-10 to obtain mixed ammonium sulfate mother liquor, crystallizing and drying to obtain ammonium sulfate, wherein the sintering acid making waste liquor is waste liquor generated in the process of preparing sulfuric acid from sintering flue gas, and the coal gas refined ammonium sulfate mother liquor is obtained by absorbing ammonia gas in coal gas by using an acidic absorption liquid in the coal gas refining process.

2. The method of claim 1, wherein the flow ratio is 1:8 to 10.

3. The method according to claim 1 or 2, wherein the flow ratio is 1: 9.

4. The method as claimed in claim 1, wherein the step of separating the sintered ammonium sulfate mother liquor from the waste liquor of sintering acid production comprises the following steps: firstly, adjusting the pH value of the sintering acid-making waste liquid to 8-11, filtering, and absorbing by adopting an acidic absorption liquid to prepare a sintering ammonium sulfate mother liquid.

5. The method according to claim 4, wherein the pH of the sintering acid production waste liquid is adjusted to 8-9.

6. The method according to claim 4, wherein sodium hydroxide is added to the sintering acid production waste liquid to adjust the pH value.

7. The method of claim 1, wherein the acidic absorption liquid is sulfuric acid.

8. The method of claim 4, wherein the filtering is a two-stage filtering.

9. The method according to claim 8, wherein the filtering is performed by filtering the sintering acid production waste liquid through a multi-media filter and an activated carbon filter.

10. The method as claimed in claim 1, wherein the mixing method of the sintering ammonium sulfate mother liquor and the coal gas refined ammonium sulfate mother liquor is as follows: and pouring the sintered ammonium sulfate mother liquor into a coal fine discharging pit, controlling the flow rate through a self-sucking pump, and mixing the sintered ammonium sulfate mother liquor with the coal gas refined ammonium sulfate mother liquor discharged from the acid washing tower in a circulating tank to obtain mixed ammonium sulfate mother liquor.

Technical Field

The invention relates to the technical field of wastewater treatment, and particularly relates to a method for recovering ammonium sulfate in sintering acid-making waste liquid.

Background

The sintering unit of iron works produces a large amount of SO during the production of sintered ore₂、NO_XThe sintering flue gas with equal gas components is absorbed by currently adopting an active carbon adsorption method, and SO is resolved at high temperature₂And waiting for gas, so that the activated carbon is regenerated and recycled. At the same time, the SO resolved₂The gas is used for producing sulfuric acid through the processes of impurity removal, catalytic oxidation and the like, a large amount of acid-containing sintering acid-making waste liquid is generated in the acid-making process, and the current acid-making waste liquid is usually sent to a steelmaking working section for slag flushing or directly discharged after reaching the standard through waste water treatment. But because the sintering acid-making waste liquid contains a large amount of NH₄ ⁺And the ammonia nitrogen content is too high, so that the microorganism in the wastewater treatment system is poisoned by ammonia, the microorganism is decomposed, the quality of effluent exceeds the standard, the wastewater treatment pressure is increased, and meanwhile, Cl in the waste liquid^-The content is high, the corrosion rate of the transportation pipeline can be accelerated, and the maintenance cost of the equipment pipeline is increased. For example, Chinese patent CN102631830A discloses a method for reducing the waste water amount in the acid making process by smelting flue gas, in particular to a method for spraying ammonia and SO in the flue gas into a flue₃The generated ammonium sulfate exists in the form of particles such as aerosol and is easy to recover, so that the content of the strong acid gas in the flue is reduced, but Cl is contained in the treated waste liquid^-The content is still high and the corrosion of the transport pipeline is still severe.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming NH in the prior sintering acid-making waste liquid₄ ⁺And Cl^-The method for recovering ammonium sulfate from the sintering acid-making waste liquid comprises the steps of separating the sintering ammonium sulfate mother liquid from the sintering acid-making waste liquid, mixing the sintering ammonium sulfate mother liquid with coal gas refined ammonium sulfate mother liquid according to a certain proportion, recovering to obtain ammonium sulfate, and reducing Cl of the mixed liquid^-Concentration, and reduces the corrosion to the equipment pipeline.

The above purpose of the invention is realized by the following technical scheme:

a method for recovering ammonium sulfate in sintering acid-making waste liquid comprises the following steps:

separating sintered ammonium sulfate mother liquor from the sintering acid making waste liquor to obtain sintered ammonium sulfate mother liquor, mixing the sintered ammonium sulfate mother liquor and coal gas refined ammonium sulfate mother liquor according to the flow ratio of 1: 5-10 to obtain mixed ammonium sulfate mother liquor, crystallizing and drying to obtain ammonium sulfate, wherein the sintering acid making waste liquor is waste liquor generated in the process of preparing sulfuric acid from sintering flue gas, and the coal gas refined ammonium sulfate mother liquor is obtained by absorbing ammonia gas in coal gas by using an acidic absorption liquid in the coal gas refining process.

The invention firstly separates the mother liquor of sintering ammonium sulfate from the waste liquor of sintering acid making, and then directly mixes the mother liquor of sintering ammonium sulfate with the mother liquor of coal gas refined ammonium sulfate according to a certain proportion, because the components in the mother liquor of coal gas refined ammonium sulfate are similar to those in the mother liquor of sintering ammonium sulfate, but Cl is contained in the mother liquor of coal gas refined ammonium sulfate^-The concentration is much lower than that of the sintered ammonium sulfate mother liquor, so that NH is mixed₄ ⁺The content is increased, ammonium sulfate can be recovered by crystallization, and Cl^-The concentration is reduced, and the corrosion speed of the system is reduced.

Specifically, the coal gas refined ammonium sulfate mother liquor is obtained by spraying sulfuric acid in an acid washing tower in a coal gas refining system to absorb ammonia gas in coal gas.

Preferably, the flow ratio is 1: 8-10.

More preferably, the flow ratio is 1: 9.

Preferably, the method for separating the sintered ammonium sulfate mother liquor from the waste liquor of sintering acid production comprises the following steps: firstly, adjusting the pH value of the sintering acid-making waste liquid to 8-11, filtering, and absorbing by adopting an acidic absorption liquid to prepare a sintering ammonium sulfate mother liquid.

Preferably, the pH value of the sintering acid-making waste liquid is adjusted to 8-9.

Preferably, sodium hydroxide is added into the sintering acid-making waste liquid to adjust the pH value.

Preferably, the absorption liquid is sulfuric acid.

Preferably, the filtration is a two-stage filtration.

Preferably, the filtration is to filter the sintering acid making waste liquid through a multi-media filter and an activated carbon filter. The turbidity of the filtered water is further reduced, and most organic matters and residual heavy metals in the waste liquid are removed.

Preferably, the mixing method of the sintered ammonium sulfate mother liquor and the coal gas refined ammonium sulfate mother liquor comprises the following steps: and pouring the sintered ammonium sulfate mother liquor into a coal fine discharging pit, controlling the flow rate through a self-sucking pump, and mixing the sintered ammonium sulfate mother liquor with the coal gas refined ammonium sulfate mother liquor discharged from the acid washing tower in a circulating tank to obtain mixed ammonium sulfate mother liquor.

The method provided by the invention is adopted to finally crystallize and dry to prepare ammonium sulfate, ammonium sulfate in the sintering acid-making waste liquid is recovered, and the residual acid gas condensate water enters the recovery system provided by the invention again to supplement water for a system for circularly preparing ammonium sulfate, so that the soft water consumption can be saved, and the method provided by the invention can realize the full recovery of the sintering ammonium sulfate mother liquor.

Compared with the prior art, the invention has the beneficial effects that:

the method directly mixes the two solutions of the sintering ammonium sulfate mother liquor and the coal gas refined ammonium sulfate mother liquor according to a certain proportion, can realize the recycling of the sintering acid-making waste liquor, can recover the ammonium sulfate component in the sintering acid-making waste liquor, can produce high-quality ammonium sulfate, can be used as industrial fertilizer and the like, also reduces the corrosion to a conveying pipeline, and reduces the maintenance cost of the equipment pipeline. The method is simple and easy to implement, has low production and operation cost, does not generate new waste, and provides a new idea for treating the sintering acid-making waste liquid.

Drawings

Fig. 1 is a flow chart of the process for recovering ammonium sulfate from waste liquid from sintering acid production in example 1.

FIG. 2 is a flow chart of the process of separating the mother liquor of ammonium sulfate in acid production by sintering from the waste liquor in acid production by sintering.

FIG. 3 shows Na at different flow ratios⁺、Cl^-And (5) a variation trend graph.

FIG. 4 shows NH at different flow ratios₄ ⁺、SO₄ ^2-And (5) a variation trend graph.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.