CN115650188A

CN115650188A - Method for preparing iron phosphate by using titanium dioxide byproduct ferrous sulfate

Info

Publication number: CN115650188A
Application number: CN202211092720.6A
Authority: CN
Inventors: 覃愿; 黎华挺; 蔡敏婷; 龙天成
Original assignee: Guangxi Jinmao Titanium Co ltd
Current assignee: Guangxi Jinmao Titanium Co ltd
Priority date: 2022-09-08
Filing date: 2022-09-08
Publication date: 2023-01-31

Abstract

The invention provides a method for preparing iron phosphate by using a titanium dioxide byproduct ferrous sulfate, belonging to the technical field of iron phosphate preparation, and the method comprises the steps of diluting 120g of ferrous sulfate to 1000mL, adding 150mL of sodium sulfide solution, stirring for reaction for 30 minutes, standing for 60 minutes, and filtering. Filtering the solution, slowly adding 200g/L phosphoric acid solution, adjusting pH to 1.5-2.0 with ammonia water, stirring for 30 min, standing for 60 min, and filtering. The pH of the filtrate is adjusted to 2.0-2.5 by ammonia water, 3g of sodium dodecyl benzene sulfonate is added, and hydrogen peroxide is gradually added dropwise under stirring until white precipitate appears. Stopping stirring, heating the solution to 60-80 ℃, standing for reaction for 60 minutes, filtering and washing. The filter cake was calcined at 600 ℃. Firstly, sodium sulfide solution is used for cleaning, some primary ions are cleaned, then phosphoric acid is used for cleaning, PO 43-can be decomposed and released under an acidic condition, deep purification is carried out, and a clean surface which can be read by sodium dodecyl benzene sulfonate is added later, so that the iron phosphate is cleaner and the purity of the prepared iron phosphate is higher.

Description

Method for preparing iron phosphate by using titanium dioxide byproduct ferrous sulfate

Technical Field

The invention relates to the technical field of iron phosphate preparation, in particular to a method for preparing iron phosphate by using a byproduct ferrous sulfate of titanium white.

Background

In recent years, lithium iron phosphate cathode materials have been used in various fields such as automobiles, energy storage, ships, and communication base stations due to their excellent safety performance. The lithium iron phosphate has the advantages of long cycle life, low cost, environmental friendliness, high safety performance and the like, and is the lithium ion battery anode material with the greatest market prospect at present.

Titanium dioxide, i.e. titanium dioxide, is an important inorganic pigment. The process for industrially preparing the titanium dioxide mainly comprises a sulfuric acid method and a chlorination method, wherein the main byproduct of the preparation of the titanium dioxide by the sulfuric acid method is ferrous sulfate which contains various metal impurities and hydrolytic titanium sulfate impurities with different hydrolysis degrees. Through impurity removal treatment, the method is used for preparing lithium iron phosphate serving as a lithium ion battery anode material, so that the problem of serious stockpiling of a byproduct ferrous sulfate is solved, and the development requirement of the battery industry can be met. The existing preparation method leads the latter product to contain other more other ions, so that the iron phosphate with higher purity and less other ions needs to be designed.

Disclosure of Invention

The invention aims to provide a method for preparing iron phosphate by using a titanium dioxide byproduct ferrous sulfate, which solves the technical problems in the background technology.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for preparing iron phosphate by using a titanium dioxide byproduct ferrous sulfate comprises the following steps:

step 1: diluting ferrous sulfate as a byproduct in the preparation of titanium dioxide, adding a sodium sulfide solution, stirring and filtering;

and 2, step: filtering the solution, adding a phosphoric acid solution, adding ammonia water to adjust the pH value, and then stirring and filtering;

and step 3: adding ammonia water into the filtrate, adding sodium dodecyl benzene sulfonate, stirring, and adding hydrogen peroxide until white precipitate appears;

and 4, step 4: stopping stirring and heating the solution to 60-80 ℃, standing for reaction for 60 minutes, filtering and washing to obtain a filter cake;

and 5: drying the filter cake to obtain a filter cake with 20-25% of residual water, and calcining the filter cake at 600 ℃.

Further, the specific process of step 1 is: diluting 120g ferrous sulfate to 1000mL, adding 150mL sodium sulfide solution, stirring for reaction for 30 min, standing for 60 min, and filtering.

Further, the sodium sulfide solution was diluted to 150mL for 7.5g of sodium sulfide.

Further, the specific process of step 2 is: adding 200g/L phosphoric acid solution, adjusting pH to 1.5-2.0 with ammonia water, stirring for 30 min, standing for 60 min, and filtering.

Further, the phosphoric acid solution was diluted to 250mL for 46.5g of 85% phosphoric acid.

Further, the specific process of step 3 is: adjusting pH of the filtrate to 2.0-2.5 with ammonia water, adding 3g sodium dodecyl benzene sulfonate, gradually adding dropwise under stirring, and stirring for 48-52 min until white precipitate appears.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

according to the invention, firstly, a sodium sulfide solution is used for cleaning, some primary ions are cleaned, then, phosphoric acid is used for cleaning, PO 43-can be decomposed and released under an acidic condition, deep purification is realized, and then, the surface can be cleaned by adding sodium dodecyl benzene sulfonate, so that the iron phosphate is cleaner and the purity of the prepared iron phosphate is higher.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to preferred embodiments. It should be noted, however, that the numerous details set forth in the description are merely for the purpose of providing the reader with a thorough understanding of one or more aspects of the present invention, which may be practiced without these specific details.

Example 1:

step 1: diluting the ferrous sulfate as the by-product of titanium dioxide preparation, adding sodium sulfide solution, stirring and filtering. To dilute 120g of ferrous sulfate to 1000mL, 150mL of sodium sulfide solution was added, the reaction was stirred for 30 minutes, allowed to stand for 60 minutes, and filtered. The sodium sulfide solution was diluted to 150mL for 7.5g of sodium sulfide.

Step 2: and (3) filtering the solution, adding a phosphoric acid solution, adding ammonia water to adjust the pH, and stirring and filtering. Specifically, 200g/L phosphoric acid solution is added, the pH value is adjusted to 1.5 by ammonia water, the mixture is stirred for 30 minutes, kept stand for 60 minutes and filtered. The phosphoric acid solution was diluted to 250mL with 46.5g of 85% phosphoric acid.

And step 3: and adding ammonia water into the filtrate, then adding sodium dodecyl benzene sulfonate, stirring, and adding hydrogen peroxide until white precipitate appears. And (3) adjusting the pH of the filtrate to 2.0 by using ammonia water, adding 3g of sodium dodecyl benzene sulfonate, gradually dropwise adding the sodium dodecyl benzene sulfonate under stirring, and stopping adding hydrogen peroxide until white precipitate appears after stirring for 48 minutes.

And 4, step 4: stopping stirring, heating the solution to 600 ℃, standing for reaction for 60 minutes, filtering and washing to obtain a filter cake.

And 5: the filter cake was dried to leave a filter cake of 20% moisture and the filter cake was calcined at 600 ℃.

Example 2:

a method for preparing iron phosphate by using ferrous sulfate as a titanium dioxide byproduct comprises the following steps:

Step 2: and (3) filtering the solution, adding a phosphoric acid solution, adding ammonia water to adjust the pH, and stirring and filtering. Adding 200g/L phosphoric acid solution, adjusting pH to 2.0 with ammonia water, stirring for 30 min, standing for 60 min, and filtering. The phosphoric acid solution was diluted to 250mL with 46.5g of 85% phosphoric acid.

And step 3: and adding ammonia water into the filtrate, then adding sodium dodecyl benzene sulfonate, stirring, and adding hydrogen peroxide until white precipitate appears. The pH of the filtrate is adjusted to 2.5 by ammonia water, 3g of sodium dodecyl benzene sulfonate is added, the sodium dodecyl benzene sulfonate is gradually added dropwise under stirring, the adding time under stirring is 52 minutes, and the hydrogen peroxide stops until white precipitate appears.

And 4, step 4: stopping stirring, heating the solution to 80 ℃, standing for reaction for 60 minutes, filtering and washing to obtain a filter cake.

And 5: the filter cake was dried to leave a 25% moisture filter cake and the filter cake was calcined at 600 ℃.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims

1. A method for preparing iron phosphate by using ferrous sulfate as a titanium dioxide byproduct is characterized by comprising the following steps: the method comprises the following steps:

step 1: diluting ferrous sulfate as a byproduct for preparing titanium dioxide, and then adding a sodium sulfide solution, stirring and filtering;

step 2: filtering the solution, adding a phosphoric acid solution, adding ammonia water to adjust the pH value, and then stirring and filtering;

and 3, step 3: adding ammonia water into the filtrate, adding sodium dodecyl benzene sulfonate, stirring, and adding hydrogen peroxide until white precipitate appears;

and 5: drying the filter cake to obtain a filter cake with 20-25% of water, and calcining the filter cake at 600 ℃.

2. The method for preparing iron phosphate by using the by-product ferrous sulfate of titanium white as claimed in claim 1, wherein the method comprises the following steps: the specific process of the step 1 is as follows: diluting 120g of ferrous sulfate to 1000mL, adding 150mL of sodium sulfide solution, stirring for reaction for 30 minutes, standing for 60 minutes, and filtering.

3. The method for preparing iron phosphate by using the by-product ferrous sulfate of titanium white as claimed in claim 2, wherein the method comprises the following steps: the sodium sulfide solution was diluted to 150mL for 7.5g of sodium sulfide.

4. The method for preparing iron phosphate by using ferrous sulfate as a byproduct of titanium dioxide according to claim 1, which is characterized in that: the specific process of the step 2 is as follows: adding 200g/L phosphoric acid solution, adjusting pH to 1.5-2.0 with ammonia water, stirring for 30 min, standing for 60 min, and filtering.

5. The method for preparing iron phosphate by using the ferrous sulfate as the byproduct of titanium dioxide according to claim 4, wherein the method comprises the following steps: the phosphoric acid solution was diluted to 250mL with 46.5g of 85% phosphoric acid.

6. The method for preparing iron phosphate by using ferrous sulfate as a byproduct of titanium dioxide according to claim 1, which is characterized in that: the specific process of the step 3 is as follows: adjusting pH of the filtrate to 2.0-2.5 with ammonia water, adding 3g of sodium dodecyl benzene sulfonate, gradually dropwise adding while stirring, and stirring for 48-52 minutes until white precipitate appears.