A feeding device and method for improving the acidolysis rate of sulfuric acid process for producing titanium dioxide

Abstract

The present invention discloses a feeding device for improving the acidolysis rate of the process of producing titanium dioxide by sulfuric acid method, comprising a reactor, a base, a reactor cover, a feeding port, a feeding pipe I and a feeding pipe II; the reactor is vertical; the base is arranged at the bottom of the reactor; the reactor cover is arranged at the top of the reactor; the feeding port is arranged at the middle position of the top of the reactor cover; the feeding pipe I is vertically inserted into the feeding port, and the lower end extends into the reactor; the feeding pipe II is arranged on the left side of the feeding pipe I, the pipe body is parallel to the feeding pipe I, and its lower end is bent toward the feeding pipe I, so that the materials in the feeding pipes I and II are intersected and mixed. The present invention also discloses a feeding method for improving the acidolysis rate of the process of producing titanium dioxide by sulfuric acid method. The present invention can solve the problem in the prior art that the waste acid and the acid-ore mixture are not sufficiently and evenly contacted, resulting in inconsistent main reaction concentrations of the acid-ore mixture, resulting in low acidolysis rate, and seriously affecting the economic benefits of the enterprise.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfuric acid process titanium dioxide production, and particularly relates to a feeding device and a method for improving the acidolysis rate in the sulfuric acid process of titanium dioxide production. Background Art

[0002] The scientific name of titanium dioxide is titanium dioxide. It has high pigment performance indicators such as whiteness and hiding power. It is widely used in paint, ink, plastic, rubber, papermaking, chemical fiber and other industries. Its industrial production methods mainly include sulfuric acid method and chlorination method.

[0003] In the production of titanium dioxide by sulfuric acid method, the acidolysis rate of the acidolysis reaction is an extremely important process technology indicator and economic value indicator. The acidolysis rate has a great impact on the economic benefits of the enterprise. There are two types of acidolysis reactions in the production of titanium dioxide by sulfuric acid method: intermittent acidolysis and continuous acidolysis. The main reaction of intermittent acidolysis is completed within a few minutes, and a large amount of acid gas is produced within a few minutes, which is difficult to completely absorb and treat. The continuous acidolysis reaction is an uninterrupted reaction, and the acid gas is evenly and continuously produced and can be completely absorbed and treated, solving the environmental protection problem.

[0004] The acidolysis reaction in the continuous acidolysis production process uses concentrated sulfuric acid of more than 98% and crushed ilmenite powder to premix into an acid-ore mixture according to the process ratio, and then the amount of waste acid with a concentration of 20% that triggers the reaction of the acid-ore mixture is measured strictly according to the process requirements. The waste acid and the acid-ore mixture continuously enter the high-temperature reactor. The more fully and evenly the waste acid and the acid-ore mixture are in contact, the more the acid-ore mixture reacts, which is more conducive to the improvement of the acidolysis rate. Therefore, the feeding method of the continuous acidolysis process reactor has a greater impact on the acidolysis rate.

[0005] In the traditional continuous acid hydrolysis process, the waste acid and the acid-ore mixture are fed into the reactor separately and stirred and mixed in the reactor. The waste acid and the acid-ore mixture are not in sufficient contact. When the waste acid and the acid-ore mixture are then encountered by the rotating stirring paddle in the reactor, the waste acid and the acid-ore mixture that are not in sufficient contact will be broken up and separated, resulting in inconsistent main reaction concentrations of the acid-ore mixture and low acid hydrolysis rate. Summary of the invention

[0006] In view of the above problems, the present invention provides a feeding device for improving the acidolysis rate in the process of producing titanium dioxide by sulfuric acid method, which can solve the problem in the prior art that the waste acid and the acid-ore mixture are not in sufficient and uniform contact, resulting in inconsistent main reaction concentration of the acid-ore mixture, causing low acidolysis rate and seriously affecting the economic benefits of the enterprise.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A feeding device for improving the acid hydrolysis rate of a sulfuric acid method titanium dioxide production process comprises a reactor, a base, a reactor cover, a feed port, a feed pipe I and a feed pipe II; the reactor is vertical; the base is arranged at the bottom of the reactor; the reactor cover is arranged at the top of the reactor; the feed port is arranged at the middle position of the top of the reactor cover; the feed pipe I is vertically inserted into the feed port, and the lower end extends into the reactor; the feed pipe II is arranged on the left side of the feed pipe I, the tube body is parallel to the feed pipe I, and the lower end thereof is bent toward the feed pipe I, so that the materials in the feed pipes I and II intersect and mix.

[0009] Furthermore, the tube bodies of the feeding tube I and the feeding tube II are fixedly connected.

[0010] Furthermore, it also includes stirring paddles I and II, which are arranged horizontally side by side in the base, and the stirring paddles I and II are externally connected to a power device, and rotate under the drive of the power device, and the rotation directions are opposite.

[0011] Furthermore, the outlet at the lower end of the feeding pipe II is connected to the body of the feeding pipe I, so that the materials are intersected and mixed in the feeding pipe II.

[0012] Furthermore, the bending angle of the lower end of the feeding pipe II is 45°.

[0013] Furthermore, the feeding pipe I includes a feeding pipe, a connecting pipe, a mixing pipe, and an arc-shaped piece; the feeding pipe is arranged at the top; the upper end of the connecting pipe is sleeved on the bottom of the feeding pipe; the mixing pipe is semi-cylindrical, connected to the lower end of the right half of the feeding pipe, and the opening faces left; the arc-shaped piece is respectively connected to the lower ends of the front and rear sides of the left half of the feeding pipe, and is respectively connected to the mixing pipe, and a circular arc outlet is formed below the arc-shaped piece.

[0014] Furthermore, the bending angle of the lower end of the feeding pipe II is 65°, and the materials meet and mix below the arc outlet.

[0015] Furthermore, the outlet of the feeding pipe II is located 5 to 10 mm above the arc outlet of the feeding pipe I.

[0016] Furthermore, the lower end of the feed pipe is an oblique opening, which opens to the right with an inclination angle of 45°.

[0017] Furthermore, the length of the mixing tube is twice the distance between the lowest point of the lower end of the feed tube and the lower end of the connecting tube.

[0018] Furthermore, the feeding pipe I and the feeding pipe II are both made of heat-resistant and corrosion-resistant 904 stainless steel chrome-plated material.

[0019] The present invention also provides a feeding method for improving the acidolysis rate in the process of producing titanium dioxide by the sulfuric acid method. The above-mentioned feeding device is applied, and the acid-ore mixture enters from the feeding pipe I and flows out through the feeding pipe and the connecting pipe; at the same time, the waste acid is triggered to enter from the feeding pipe II, fully contact and mix with the acid-ore mixture below the arc outlet, and then they are concentrated together and flow into the reactor.

[0020] The present invention has the following beneficial effects:

[0021] (1) With the parallel pipe feeding method of the present invention, the waste acid and the acid-ore mixture can be fully and evenly contacted and then fall together into the high-temperature reactor. Even if the waste acid encounters the rotating stirring blades in the reactor, the main reaction concentration of the acid-ore mixture is consistent, thereby improving the acid hydrolysis rate.

[0022] (2) As a further optimized technical solution of the present invention, the feed pipe I is a combination of a feed pipe, a connecting pipe, a mixing pipe, and an arc-shaped sheet, so that a semi-open intersection is formed between the two streams of material, thereby preventing the solid phase from accumulating at the outlet of the feed pipe II and clogging the pipe mouth to affect normal production.

[0023] (3) Since the feeding method of the present invention ensures that the main reaction concentration of the acid-ore mixture reaches a consistent level for reaction, the acid hydrolysis rate is ultimately increased by about 1.5 percentage points, which can save a total of RMB 3.9024 million in industrial sulfuric acid and ilmenite costs each year, with considerable economic benefits.

[0024] (4) Since the present invention adopts a continuous acid hydrolysis reaction instead of an intermittent acid hydrolysis reaction, the continuous acid hydrolysis reaction is an uninterrupted reaction, and the acid gas is evenly generated and can be completely absorbed and treated, thus solving the environmental protection problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of Comparative Example 1 of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of Comparative Example 2 of the present invention;

[0029] The numbers and names in the figure are as follows:

[0030] 1-reactor; 2-base; 3-reactor cover; 4-feeding port; 5-feeding pipe I; 6-feeding pipe II; 7-stirring paddle I; 8-stirring paddle II;

[0031] 51 -feeding pipe; 52 -connecting pipe; 53 -mixing pipe; 54 -arc sheet. DETAILED DESCRIPTION

[0032] In order to facilitate a better understanding of the present invention, the following examples are used to illustrate the present invention. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention.

[0033] Example 1

[0034] A feeding device for improving the acid decomposition rate of the process of producing titanium dioxide by sulfuric acid method, such as Figure 1 As shown, it includes a reactor 1, a base 2, a reactor cover 3, a feed port 4, a feeding pipe I5, and a feeding pipe II6; the reactor 1 is vertical; the base 2 is arranged at the bottom of the reactor 1; the reactor cover 3 is arranged at the top of the reactor 1; the feeding port 4 is arranged at the middle position of the top of the reactor cover 3; the feeding pipe I5 is vertically inserted into the feeding port 4, and the lower end extends into the reactor 1; the feeding pipe II6 is arranged on the left side of the feeding pipe I5, the tube body is parallel to the feeding pipe I5, and its lower end is bent toward the feeding pipe I5, so that the materials in the feeding pipes I5 and II6 intersect and mix.

[0035] It also includes stirring paddles I7 and II8, which are arranged horizontally side by side in the base 2. The stirring paddles I7 and II8 are externally connected to a power device and rotate under the drive of the power device in opposite directions.

[0036] The outlet at the lower end of the feeding pipe II 6 is connected to the body of the feeding pipe I 5 .

[0037] The bending angle of the lower end of the feeding pipe II6 is 45°.

[0038] Feed pipe Ⅰ5 and feed pipe Ⅱ6 are both made of heat-resistant and corrosion-resistant 904 stainless steel chrome-plated material.

[0039] Feed pipe Ⅰ5 diameter is

[0040] The method of using this embodiment is:

[0041] The waste acid and acid ore mixture are fed into the reactor in parallel. Figure 1 As shown, the acid-ore mixture enters from the feeding pipe Ⅰ5, and at the same time, the waste acid enters from the feeding pipe Ⅱ6. The waste acid and the acid-ore mixture are fully and evenly contacted in the feeding pipe Ⅰ5 before falling into the reaction kettle 1.

[0042] Example 2

[0043] A feeding device for improving the acid decomposition rate of the process of producing titanium dioxide by sulfuric acid method, such as Figure 2As shown, it includes a reactor 1, a base 2, a reactor cover 3, a feed port 4, a feeding pipe I5, and a feeding pipe II6; the reactor 1 is vertical; the base 2 is arranged at the bottom of the reactor 1; the reactor cover 3 is arranged at the top of the reactor 1; the feeding port 4 is arranged in the middle position of the top of the reactor cover 3; the feeding pipe I5 is vertically inserted into the feeding port 4, and the lower end extends into the reactor 1; the feeding pipe II6 is arranged on the left side of the feeding pipe I5, the tube body is parallel to the feeding pipe I5, and its lower end is bent to the right.

[0044] It also includes stirring paddles I7 and II8, which are arranged horizontally side by side in the base 2. The stirring paddles I7 and II8 are externally connected to a power device and rotate under the drive of the power device in opposite directions.

[0045] The feeding pipe I5 includes a feeding pipe 51, a connecting pipe 52, a mixing pipe 53, and an arc-shaped piece 54; the feeding pipe 51 is arranged at the top; the upper end of the connecting pipe 52 is sleeved on the bottom of the feeding pipe 51; the mixing pipe 53 is semi-cylindrical, connected to the lower end of the right half of the feeding pipe 51, and the opening faces left; the arc-shaped piece 54 is respectively connected to the lower ends of the front and rear sides of the left half of the feeding pipe 51, and is respectively connected to the mixing pipe 53, and a circular arc outlet is formed below the arc-shaped piece 54.

[0046] The bending angle of the lower end of the feeding pipe II6 is 65°.

[0047] The outlet of the feeding pipe II 6 is located 5 to 10 mm above the outlet of the feeding pipe I 5 .

[0048] The lower end of the feed pipe 51 is an oblique opening, which opens to the right with an inclination angle of 45°.

[0049] The length of the mixing tube 53 is twice the distance between the lowest point of the lower end of the feeding tube 51 and the lower end of the connecting tube 52 .

[0050] Feed pipe Ⅰ5 and feed pipe Ⅱ6 are both made of heat-resistant and corrosion-resistant 904 stainless steel chrome-plated material.

[0051] The diameter of the feed pipe 5 is The diameters of the connecting pipe 52 and the mixing pipe 53 are The feed pipe 5 is welded inside the connecting pipe 52 .

[0052] A feeding method for improving the acidolysis rate in the process of producing titanium dioxide by sulfuric acid method, using the above-mentioned feeding device, the acid-ore mixture enters from the feeding pipe I5, flows out to the right side of the connecting pipe 52 through the feeding pipe 51, and flows down along the right side wall of the connecting pipe 52; at the same time, the waste acid is caused to enter from the feeding pipe II6, and is in a horizontal inclination angle of 65°, and is fully contacted and mixed with the acid-ore mixture below the positive arc outlet, and then is concentrated together and flows into the reactor 1.

[0053] Comparative Example 1

[0054] Two streams of materials enter the high temperature reactor 1 in parallel, such as Figure 3 As shown, the acid-ore mixture enters from the feeding pipe Ⅰ5, and the waste acid enters from the feeding pipe Ⅱ6 at the same time, and they fall directly into the reaction kettle 1 respectively.

[0055] Comparative Example 2

[0056] The waste acid and acid ore mixture is fed into the reactor by jacketing, such as Figure 4 As shown, the acid-ore mixture enters from the feeding pipe Ⅰ5, and the waste acid is simultaneously caused to enter from the feeding pipe Ⅱ6, the acid-ore mixture flows through the center of the pipe, and the waste acid flows through the jacket into the reactor 1.

[0057] Comparative test

[0058] 1. Determination method:

[0059] ①Take about 200g of the solid phase product of the acid hydrolysis reaction, grind it evenly, weigh about 10g of the sample, put it into a 300mL beaker, add 100mL of 5% dilute sulfuric acid into the beaker, stir evenly for two minutes, and put it into a 65℃ oven for one hour. Then take it out and filter it into a 200mL volumetric flask, wash the filter residue with warm 5% dilute sulfuric acid until the filtrate is no longer colored when detected with 3% H2O2.

[0060] ② Transfer all the filter residue and filter paper into a 30mL porcelain crucible, heat it on an electric furnace to ashing, then place it in a 750℃ muffle furnace and burn it for 60 minutes. Take it out and cool it, then add 7g of potassium pyrosulfate and place it in a 700-750℃ muffle furnace and burn it until it is transparent. Take it out, cool it, and immerse it in a 300mL beaker with 80mL of 10% dilute sulfuric acid. Slowly heat it on an electric furnace until the melt is completely dissolved, then wash out the crucible, transfer all the solution into a 300mL conical flask, add 25mL of concentrated hydrochloric acid, aluminum sheet 2g, install the reduction rack, heat with low heat for reduction, remove the heat source when the reaction is intense, continue heating when the reaction slows down, increase the heat after the reaction is over until large bubbles appear to remove the hydrogen in the solution, and when the solution is clear, the reduction is over, then pass carbon dioxide gas, cool to room temperature with running water under the protection of carbon dioxide, and titrate with 0.1mol / L ammonium ferric sulfate standard solution. When it is almost colorless, add 5mL of 10% ammonium thiocyanate indicator, and continue titrating until light brown yellow is the end point. The consumption number is recorded as V2 mL.

[0061] ③ Dilute the filtrate to the mark with 5% dilute sulfuric acid, shake well, take 20mL of the filtrate and put it into a 300mL conical flask, add 80mL of 10% dilute sulfuric acid, 25mL of concentrated hydrochloric acid, and 2g of aluminum flakes, and perform the following procedures according to the above filter residue operation. The final endpoint consumption is recorded as V1 mL.

[0062] 2. Calculation of acid hydrolysis rate:

[0063]

[0064] Where: V1---Consumption of titanium dioxide in filtrate, mL

[0065] V2---Residual titanium dioxide consumption, mL

[0066] 3. Uniform judgment:

[0067] Whether it is uniform is judged based on whether the temperature, color and acid hydrolysis rate of the discharge material at both ends of the reactor (end A and end B) are consistent. If the temperature, color and acid hydrolysis rate of the discharge material at both ends of the reactor (end A and end B) are inconsistent, it can be judged as uneven.

[0068] 4. Pipe blocking judgment:

[0069] If the current of the feed pump is abnormal or decreases, it can be determined that the pipe is blocked.

[0070] 5. Experimental results: as shown in the following table.

[0071] Group Acid hydrolysis rate / % Is the concentration uniform? Is the pipe blocked? Example 1 98.02 Uniform Easy to block the pipe Example 2 98.19 Uniform No blocking of pipes Comparative Example 1 96.69 Uneven No blocking of pipes Comparative Example 2 97.1 Relatively uniform No blocking of pipes

[0072] The results show that in the feeding methods of Examples 1 and 2 of the present invention, the waste acid and the acid-ore mixture can achieve full and uniform contact before falling into the reactor. Even if it encounters the stirring blade rotating in the reactor, the main reaction concentration of the acid-ore mixture is consistent. However, the outlet of the feed pipe of the feeding method of Example 1 is prone to solid phase accumulation and blockage of the pipe mouth. The feeding often needs to be stopped in the middle of production to clean up the solid phase, affecting normal production; Example 2 solves the problem of the acid-ore mixture blocking the pipe mouth at the same time.

[0073] In Comparative Example 1, the waste acid and the acid-ore mixture are not in sufficient contact. When the material falls into the reactor, it encounters the rotating stirring blades in the reactor, which will break up and separate the waste acid and the acid-ore mixture that are not in sufficient contact, resulting in inconsistent main reaction concentrations of the acid-ore mixture and a low acidolysis rate.

[0074] Although Comparative Example 2 solves the problem of pipe blockage, the waste acid passes through the jacket and contacts the acid-ore mixture in a circular manner. The contact effect between the waste acid and the acid-ore mixture is better than that in Comparative Example 1, but the contact between the waste acid and the acid-ore mixture is still not sufficient. In the process of falling into the reactor, the material encounters the rotating stirring blades in the reactor, which will break up and separate the waste acid and the acid-ore mixture, or the main reaction concentration of the acid-ore mixture cannot be consistent, affecting the acidolysis rate.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A feeding device for improving the acidolysis rate of titanium dioxide production in the sulfuric acid process, characterized in that: The invention comprises a reaction kettle (1), a base (2), a kettle cover (3), a feed port (4), a feed pipe I (5), and a feed pipe II (6); the reaction kettle (1) is vertical; the base (2) is arranged at the bottom of the reaction kettle (1); the kettle cover (3) is arranged at the top of the reaction kettle (1); the feed port (4) is arranged at the middle position of the top of the kettle cover (3); the feed pipe I (5) is vertically inserted into the feed port (4), and the lower end thereof extends into the reaction kettle (1); the feed pipe II (6) is arranged on the left side of the feed pipe I (5), the tube body is parallel to the feed pipe I (5), and the lower end thereof is bent toward the feed pipe I (5), so that the materials in the feed pipe I (5) and the feed pipe II (6) are intersected and mixed; The feeding pipe I (5) comprises a feeding pipe (51), a connecting pipe (52), a mixing pipe (53), and an arc-shaped sheet (54); the feeding pipe (51) is arranged at the top; the upper end of the connecting pipe (52) is sleeved on the bottom of the feeding pipe (51); the mixing pipe (53) is semi-cylindrical, connected to the lower end of the right half of the feeding pipe (51), and the opening faces left; the arc-shaped sheet (54) is respectively connected to the lower ends of the front and rear sides of the left half of the mixing pipe (53), and a circular arc outlet is formed below the arc-shaped sheet (54); The outlet of the feeding pipe II (6) is located 5 to 10 mm above the outlet of the feeding pipe I (5).

2. The feeding device for improving the acidolysis rate of the sulfuric acid process for producing titanium dioxide according to claim 1, characterized in that: It also includes a stirring paddle I (7) and a stirring paddle II (8), wherein the stirring paddle I (7) and the stirring paddle II (8) are arranged side by side horizontally in the base (2) and rotate in opposite directions.

3. The feeding device for improving the acidolysis rate of the sulfuric acid process for producing titanium dioxide according to claim 1 or 2, characterized in that: The lower end outlet of the feeding pipe II (6) is connected to the body of the feeding pipe I (5).

4. The feeding device for improving the acidolysis rate of the sulfuric acid process for producing titanium dioxide according to claim 3, characterized in that: The bending angle of the lower end of the feeding pipe II (6) is 45°.

5. The feeding device for improving the acidolysis rate of the sulfuric acid process for producing titanium dioxide according to claim 1, characterized in that: The bending angle of the lower end of the feeding pipe II (6) is 65°.

6. The feeding device for improving the acidolysis rate of the process of producing titanium dioxide by sulfuric acid method according to claim 1, characterized in that: The lower end of the feed pipe (51) is an oblique opening, which opens to the right with an inclination angle of 45°.

7. The feeding device for improving the acidolysis rate of the process of producing titanium dioxide by sulfuric acid method according to claim 1, characterized in that: The length of the mixing tube (53) is twice the distance between the lowest point of the lower end of the feed tube (51) and the lower end of the connecting tube (52).

8. A feeding method for improving the acidolysis rate of titanium dioxide production in a sulfuric acid process, using a feeding device as described in any one of claims 1 to 7, characterized in that: The acid-ore mixture enters from the feed pipe I (5), flows out through the feed pipe (51) and the connecting pipe (52); at the same time, the waste acid enters from the feed pipe II (6), contacts and mixes with the acid-ore mixture below the arc outlet, and then gathers together and flows into the reactor (1).

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