阅读说明：本技术 二段浸出萃余液结晶制备硫酸铝铵工艺 (Process for preparing aluminum ammonium sulfate by crystallization of two-stage leaching raffinate ) 是由 穆宇 高利坤 张裕书 张少翔 张新良 蒋朋 陈超 刘能云 于 2020-07-09 设计创作，主要内容包括：本发明公开了一种二段浸出萃余液结晶制备硫酸铝铵工艺,包括如下步骤：(1)向萃余液中加入硫酸铵进行铵铝反应,并结晶得到硫酸铝铵粗产品；(2)向硫酸铝铵粗产品加入溶解液进行溶解、过滤,并真空结晶得到较纯硫酸铝铵粗产品；(3)向较纯硫酸铝铵粗产品加入去离子水溶解,并冷冻结晶得到纯净硫酸铝铵产品。本发明首先通过铵铝反应得到硫酸铝铵粗产品；然后通过真空结晶过滤,得到纯度为在80％以上的硫酸铝铵粗产品；最后通过冷冻结晶过滤,得到99％左右的硫酸铝铵产品。因此,本发明有效地将二段浸出萃余液中的铝进行回收利用,并且将回收得到的硫酸铝铵粗产品进一步提纯,以满足工业使用的要求。(The invention discloses a process for preparing aluminum ammonium sulfate by crystallizing two-stage leaching raffinate, which comprises the following steps: (1) adding ammonium sulfate into the raffinate to perform ammonium-aluminum reaction, and crystallizing to obtain an aluminum-ammonium sulfate crude product; (2) adding a dissolving solution into the coarse product of the aluminum ammonium sulfate for dissolving and filtering, and performing vacuum crystallization to obtain a purer coarse product of the aluminum ammonium sulfate; (3) adding deionized water into the purer aluminum ammonium sulfate crude product for dissolving, and freezing and crystallizing to obtain a pure aluminum ammonium sulfate product. Firstly, obtaining an aluminum ammonium sulfate crude product through an ammonium-aluminum reaction; then, vacuum crystallization and filtration are carried out to obtain a crude product of aluminum ammonium sulfate with the purity of more than 80 percent; finally, the aluminum ammonium sulfate product with the concentration of about 99 percent is obtained by freezing, crystallizing and filtering. Therefore, the invention effectively recycles the aluminum in the second-stage leaching raffinate, and further purifies the recycled aluminum ammonium sulfate crude product so as to meet the requirements of industrial use.)

1. The process for preparing the ammonium aluminum sulfate by crystallizing the second-stage leaching raffinate is characterized by comprising the following steps of:

s1: adding ammonium sulfate into the raffinate to perform ammonium-aluminum reaction, and crystallizing to obtain an aluminum-ammonium sulfate crude product;

s2: adding a dissolving solution into the coarse product of the aluminum ammonium sulfate for dissolving and filtering, and performing vacuum crystallization to obtain a purer coarse product of the aluminum ammonium sulfate;

s3: adding deionized water into the purer aluminum ammonium sulfate crude product for dissolving, and freezing and crystallizing to obtain a pure aluminum ammonium sulfate product.

2. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 1, wherein the step S1 comprises the following sub-steps:

s11: heating raffinate, and adding ammonium sulfate according to a certain ammonium-aluminum molar ratio to react aluminum sulfate in the raffinate with the ammonium sulfate to generate aluminum ammonium sulfate;

s12: after the reaction, the feed liquid is added into a crystallizer to crystallize aluminum ammonium sulfate to obtain a crude product of the aluminum ammonium sulfate.

3. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 2, wherein the heating temperature in the step S11 is 60-120 ℃; the reaction time in the step S11 is 10-60 min; the molar ratio of ammonium to aluminum in the step S11 is 1:1-1: 5.

4. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 1, wherein the dissolving solution in the step S2 is pure water.

5. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 4, wherein the step S2 comprises the following sub-steps:

s21: adding pure water into the crude product of the aluminum ammonium sulfate for dissolving;

s22: filtering the pure water solution to remove undissolved impurities;

s23: vacuum crystallizing the filtered solution to obtain a purer coarse product of the ammonium aluminum sulfate;

s24: the purer aluminum ammonium sulfate crude product is washed by washing water.

6. The process for preparing aluminum ammonium sulfate by crystallization of two-stage leach raffinate according to claim 5, wherein the step S2 further comprises the following sub-steps:

s25: the washed filtrate is returned to step S21 for dissolution of the crude aluminum ammonium sulfate product.

7. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate as claimed in claim 5, wherein the vacuum degree in the step S23 is 2000-2600 Pa.

8. The process for preparing ammonium aluminum sulfate by two-stage leaching raffinate crystallization in claim 5, wherein the crystallization time in the step S23 is 30-90 min.

9. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 1, wherein the step S3 comprises the following sub-steps:

s31: adding deionized water into the purer coarse product of the aluminum ammonium sulfate for dissolving;

s32: freezing and crystallizing the deionized water solution to obtain a crystallization solution;

s33: filtering the crystallization solution to obtain a pure aluminum ammonium sulfate product and a filtrate;

s34: the filtrate is returned to step S24 and used as washing water.

10. The process for preparing ammonium aluminum sulfate by crystallization of two-stage leach raffinate according to claim 9, wherein the freezing and crystallizing temperature in the step S32 is-30-15 ℃; the freezing and crystallizing time in the step S32 is 30-90 min.

Technical Field

The invention belongs to the technical field of titanium ore recycling, and particularly relates to a process for preparing aluminum ammonium sulfate by crystallizing second-stage leaching raffinate.

Background

After the second-stage leaching solution is used for extracting titanium, the content of titanium and iron in the solution is low, and the preparation of aluminum ammonium sulfate with higher purity is facilitated. The prior art has added (NH) to the second leach raffinate₄)₂SO₄The ammonium aluminum reaction is carried out, and after the reaction, the feed liquid is added into a crystallizer to carry out aluminum ammonium sulfate crystallization, however, the aluminum ammonium sulfate crystals prepared in the way are crude aluminum ammonium sulfate products containing many impurities, so that a crystallization and purification process of aluminum ammonium sulfate needs to be researched.

Disclosure of Invention

The invention provides a process for preparing aluminum ammonium sulfate by crystallizing two-stage leaching raffinate, which aims to overcome the defects of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the process for preparing the ammonium aluminum sulfate by crystallizing the second-stage leaching raffinate comprises the following steps:

s1: adding ammonium sulfate into the raffinate to perform ammonium-aluminum reaction, and crystallizing to obtain an aluminum-ammonium sulfate crude product;

s2: adding a dissolving solution into the coarse product of the aluminum ammonium sulfate for dissolving and filtering, and performing vacuum crystallization to obtain a purer coarse product of the aluminum ammonium sulfate;

s3: adding deionized water into the purer aluminum ammonium sulfate crude product for dissolving, and freezing and crystallizing to obtain a pure aluminum ammonium sulfate product.

As a further description of the above technical solution: the step S1 includes the following sub-steps:

s11: heating raffinate, and adding ammonium sulfate according to a certain ammonium-aluminum molar ratio to react aluminum sulfate in the raffinate with the ammonium sulfate to generate aluminum ammonium sulfate;

s12: after the reaction, the feed liquid is added into a crystallizer to crystallize aluminum ammonium sulfate to obtain a crude product of the aluminum ammonium sulfate.

As a further description of the above technical solution: the heating temperature in the step S11 is 60-120 ℃; the reaction time in the step S11 is 10-60 min; the molar ratio of ammonium to aluminum in the step S11 is 1:1-1: 5.

As a further description of the above technical solution: the dissolving solution in step S2 is pure water.

As a further description of the above technical solution: the step S2 includes the following sub-steps:

s21: adding pure water into the crude product of the aluminum ammonium sulfate for dissolving;

s22: filtering the pure water solution to remove undissolved impurities;

s23: vacuum crystallizing the filtered solution to obtain a purer coarse product of the ammonium aluminum sulfate;

s24: the purer aluminum ammonium sulfate crude product is washed by washing water.

As a further description of the above technical solution: the step S2 further includes the following sub-steps:

s25: the washed filtrate is returned to step S21 for dissolution of the crude aluminum ammonium sulfate product.

As a further description of the above technical solution: the vacuum degree in the step S23 is 2000-2600 Pa.

As a further description of the above technical solution: the crystallization time in the step S23 is 30-90 min.

As a further description of the above technical solution: the step S3 includes the following sub-steps:

s31: adding deionized water into the purer coarse product of the aluminum ammonium sulfate for dissolving;

s32: freezing and crystallizing the deionized water solution to obtain a crystallization solution;

s33: filtering the crystallization solution to obtain a pure aluminum ammonium sulfate product and a filtrate;

s34: the filtrate is returned to step S24 and used as washing water.

As a further description of the above technical solution: the freezing and crystallizing temperature in the step S32 is-30-15 ℃; the freezing and crystallizing time in the step S32 is 30-90 min.

The invention has the following beneficial effects:

firstly, obtaining an aluminum ammonium sulfate crude product through an ammonium-aluminum reaction; then, vacuum crystallization and filtration are carried out to obtain a crude product of aluminum ammonium sulfate with the purity of more than 80 percent; finally, the aluminum ammonium sulfate product with the concentration of about 99 percent is obtained by freezing, crystallizing and filtering. Therefore, the invention effectively recycles the aluminum in the second-stage leaching raffinate, and further purifies the recycled aluminum ammonium sulfate crude product so as to meet the requirements of industrial use.

Drawings

FIG. 1 is a flow chart of a process for preparing ammonium aluminum sulfate by two-stage leaching raffinate crystallization.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in figure 1, the process for preparing the ammonium aluminum sulfate by the crystallization of the two-stage leaching raffinate comprises the following steps:

(1) adding ammonium sulfate into the raffinate to perform ammonium-aluminum reaction, and crystallizing to obtain an aluminum-ammonium sulfate crude product;

(2) adding a dissolving solution into the coarse product of the aluminum ammonium sulfate for dissolving and filtering, and performing vacuum crystallization to obtain a purer coarse product of the aluminum ammonium sulfate;

(3) adding deionized water into the purer aluminum ammonium sulfate crude product for dissolving, and freezing and crystallizing to obtain a pure aluminum ammonium sulfate product.

Firstly, obtaining an aluminum ammonium sulfate crude product through an ammonium-aluminum reaction; then, vacuum crystallization and filtration are carried out to obtain a crude product of aluminum ammonium sulfate with the purity of more than 80 percent; finally, the aluminum ammonium sulfate product with the concentration of about 99 percent is obtained by freezing, crystallizing and filtering. Therefore, the invention effectively recycles the aluminum in the second-stage leaching raffinate, and further purifies the recycled aluminum ammonium sulfate crude product so as to meet the requirements of industrial use.

In this embodiment, the step (1) includes the following sub-steps:

(11) heating raffinate, and adding ammonium sulfate according to a certain ammonium-aluminum molar ratio to react aluminum sulfate in the raffinate with the ammonium sulfate to generate aluminum ammonium sulfate;

(12) after the reaction, the feed liquid is added into a crystallizer for aluminum ammonium sulfate crystallization, and then the crude product of the aluminum ammonium sulfate and the crystallization tail liquid are obtained by filtration.

In the present embodiment, the heating temperature in step (11) is 60-120 ℃, preferably, the heating temperature in step (11) is 80 ℃; the reaction time in the step (11) is 10-60min, and preferably, the reaction time in the step (11) is 30 min; the molar ratio of ammonium to aluminum in the step (11) is 1:1-1:5, and preferably, the molar ratio of ammonium to aluminum in the step (11) is 1: 3.

In this embodiment, the dissolving solution in the step (2) is pure water.

In this embodiment, the step (2) includes the following sub-steps:

(21) adding pure water into the crude product of the aluminum ammonium sulfate for dissolving;

(22) filtering the pure water solution to remove undissolved impurities;

(23) carrying out vacuum crystallization and filtration on the filtered solution to obtain a purer coarse product of the ammonium aluminum sulfate;

(24) the purer aluminum ammonium sulfate crude product is washed by washing water.

(25) And (5) returning the washed filtrate to the step (21) for dissolving the crude product of the aluminum ammonium sulfate.

In the present embodiment, the vacuum degree in the step (23) is 2000-2600Pa, preferably, the vacuum degree in the step (23) is 2400 Pa; the crystallization time in the step (23) is 30-90min, and preferably, the crystallization time in the step (23) is 60 min.

In this embodiment, the step (3) includes the following sub-steps:

(31) adding deionized water into the purer coarse product of the aluminum ammonium sulfate for dissolving;

(32) freezing and crystallizing the deionized water solution to obtain a crystallization solution;

(33) filtering the crystallization solution to obtain a pure aluminum ammonium sulfate product and a filtrate;

(34) the filtrate is returned to step (24) for use as wash water.

In this embodiment, the freezing crystallization temperature in the step (32) is-30-15 ℃; the freezing and crystallizing time in the step (32) is 30-90min, and preferably, the freezing and crystallizing time in the step (32) is 60 min.