Production system for removing heavy metals from wet-process phosphoric acid

Abstract

The utility model discloses a production system for removing heavy metals from wet-process phosphoric acid, which comprises an aging tank, the aging tank is communicated with a first microtube filter, a transfer tank, a reaction scrubber and a second microtube filter through pipelines, the reaction scrubber is communicated with a tail gas fan and an alkaline bath through pipelines, and the transfer tank is communicated with a second microtube filter through pipelines. And the multi-stage reaction scrubber is communicated with the hydrogen sulfide generator through a pipeline. Large-particle-size heavy metal materials in wet-process phosphoric acid are filtered in the microtube filter to remove most of lead-containing substances and a small part of arsenic-containing substances, so that the reaction process of removing heavy metals is reduced, the phosphoric acid materials are purified by a sodium-containing wet process, the material discharge is reduced, and the production cost is reduced. And moreover, the condition that sodium elements are introduced under the condition of removing heavy metals from wet-process phosphoric acid is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of decolorization, in particular to a production system for removing heavy metals from wet-process phosphoric acid. Background Art

[0002] With the continuous development of phosphoric acid and phosphates in the phosphorus chemical industry, the quality requirements for phosphoric acid are getting higher and higher. As thermal phosphoric acid production equipment is constantly replaced by wet phosphoric acid production equipment, industry professionals are constantly studying ways to remove various impurities in wet phosphoric acid. The existing technology generally focuses on the arsenic removal method in the process of removing heavy metals in wet phosphoric acid. In the process of arsenic removal, other heavy metals and hydrogen sulfide also react, resulting in excessive consumption of sodium sulfide. In addition, how to recover the sodium-containing effluent phosphoric acid is also a problem in the industry. Summary of the invention

[0003] The purpose of the utility model is to make up for the shortcomings of the prior art and provide a production system for removing heavy metals from wet-process phosphoric acid.

[0004] The technical solution of this utility model:

[0005] A production device for removing heavy metals from wet phosphoric acid comprises an aging device, wherein the aging device is connected to a first microtube filter, a transfer tank, a reaction scrubber and a second microtube filter through a pipeline, the reaction scrubber is connected to an exhaust gas fan and an alkali washing tank through a pipeline, and the reaction scrubber is connected to a hydrogen sulfide generator through a pipeline.

[0006] Preferably, the alkali washing tank is connected to the hydrogen sulfide generator through a pipeline.

[0007] Preferably, the alkali washing tank is provided with a sodium hydroxide addition port.

[0008] Preferably, the hydrogen sulfide generator is provided with a wet purified phosphoric acid inlet pipe, a sodium sulfide inlet and a discharge pipe.

[0009] Preferably, the aging device has aging and clarification functions, and is composed of an aging tank and a clarification tank, and the number of the two is ≥1.

[0010] Preferably, the number of the reaction scrubber and the number of the alkali washing tank are ≥1 respectively.

[0011] The utility model has the following beneficial effects:

[0012] 1. The utility model adopts the method of filtering the large-size particles of heavy metal materials in wet-process phosphoric acid in a micro-tube filter to remove most of the lead-containing substances and a small part of the arsenic-containing substances, thereby reducing the reaction process of removing heavy metals.

[0013] 2. The utility model recycles and utilizes the wet-process purified phosphoric acid material containing sodium, thereby reducing the material discharge and avoiding the situation where the sodium element is introduced under the condition of removing heavy metals from the wet-process phosphoric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] In the figure: aging device 1, first microtube filter 2, transfer tank 3, reaction scrubber 4, second microtube filter 5, tail gas fan 6, alkali washing tank 7, sodium hydroxide addition port 701, hydrogen sulfide generator 8, wet purified phosphoric acid inlet pipe 801, sodium sulfide feed port 802, and discharge pipe 803. DETAILED DESCRIPTION

[0016] The following will be combined with the specific embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] Example 1

[0018] A production device for removing heavy metals from wet phosphoric acid comprises an aging device 1, wherein the aging device 1 is connected to a first microtube filter 2, a transfer tank 3, a reaction scrubber 4 and a second microtube filter 5 through a pipeline, the reaction scrubber 4 is connected to an exhaust gas fan 6 and an alkali washing tank 7 through a pipeline, and the reaction scrubber 4 is connected to a hydrogen sulfide generator 8 through a pipeline.

[0019] Preferably, the alkaline washing tank 7 is connected to the hydrogen sulfide generator 8 through a pipeline.

[0020] Preferably, the alkaline washing tank 7 is provided with a sodium hydroxide addition port 701 .

[0021] Preferably, the hydrogen sulfide generator 8 is provided with a wet purified phosphoric acid inlet pipe 801 , a sodium sulfide inlet 802 and a discharge pipe 803 .

[0022] Preferably, the aging device 1 has an aging and clarification function, and is composed of an aging tank and a clarification tank, and the number of the aging tank and the clarification tank is ≥ 1.

[0023] Preferably, the reactive scrubber 4 and the alkaline washing tank 7 are provided in plurality.

[0024] (1) The wet-process phosphoric acid with a P2O5 concentration of 48% is fully aged and clarified in the aging tank 1, and then filtered using the first microtube filter 2 with a precision diameter of 50 nm. After filtration, the wet-process phosphoric acid is transported to the transfer tank for storage.

[0025] (2) The wet-process phosphoric acid produced in step (1) is then transferred to the multi-stage scrubber in step 5;

[0026] (3) mixing 55% wet-process purified phosphoric acid and sodium sulfide in a hydrogen sulfide generator to react and produce hydrogen sulfide gas, which is pumped into a multi-stage scrubber through an exhaust blower; wherein the molar ratio of the amount of sodium sulfide added to the arsenic content in the wet-process phosphoric acid with a concentration of 66% stored in the transfer tank in step (1) is 1.1:1;

[0027] (4) The reaction solution in step (3) is a wet-process purified sodium phosphate solution which is transported out for recycling;

[0028] (5) The wet-process phosphoric acid in step (2) and the hydrogen sulfide produced in step (3) are reversely contacted in a multi-stage scrubber to cause a reaction and a washing process. After the wet-process phosphoric acid and hydrogen sulfide undergo a multi-stage reaction to remove heavy metals, the wet-process phosphoric acid is filtered through a second micro-tube filter 5 with a precision diameter of 100 nm to obtain a heavy metal-free wet-process phosphoric acid product. After the hydrogen sulfide is washed in multiple stages with the wet-process phosphoric acid, it is transported to the alkali washing tower through the tail gas fan;

[0029] (6) The hydrogen sulfide that is not completely washed in step (5) is washed with sodium hydroxide in an alkaline washing tower and then discharged in a qualified manner;

[0030] (7) In step (5), the alkaline washing liquid is fed to a hydrogen sulfide generator, and the hydrogen sulfide in the alkaline washing liquid reacts and overflows and is recycled.

[0031] The method of Example 1 was used for application, and the conditions and results are shown in Table 1.

[0032] Table 1

[0033]

[0034] The above are only relatively preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A production system for removing heavy metals from wet phosphoric acid, comprising an aging device (1), characterized in that: The aging device (1) is connected to the first micro-tube filter (2), the transfer tank (3), the reaction scrubber (4) and the second micro-tube filter (5) through a pipeline; the reaction scrubber (4) is connected to the exhaust gas fan (6) and the alkali washing tank (7) through a pipeline; and the reaction scrubber (4) is connected to the hydrogen sulfide generator (8) through a pipeline.

2. The production system for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The alkaline washing tank (7) is connected to the hydrogen sulfide generator (8) through a pipeline.

3. The production system for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The alkali washing tank (7) is provided with a sodium hydroxide addition port (701).

4. The production system for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The hydrogen sulfide generator (8) is provided with a wet-process purified phosphoric acid inlet pipe (801), a sodium sulfide inlet (802) and a discharge pipe (803).

5. The production system for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The aging device (1) has an aging and clarification function and is composed of an aging tank and a clarification tank, the number of which is ≥1.

6. The production system for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The number of the reaction scrubber (4) and the number of the alkali washing tank (7) are ≥1 respectively.

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