Preparation method and device for efficiently preparing magnesium hydroxide

Abstract

The present invention relates to a device for efficiently preparing magnesium hydroxide, comprising a material mixing tank, a coordinated pressure control unit I, a reactor, a coordinated pressure control unit II, a condenser, a three-way valve, a material storage tank, a coordinated pressure control unit III and a steam generator. A outlet of the material mixing tank is connected with one end of the coordinated pressure control unit I by a pump; the other end of the coordinated pressure control unit I is connected with an inlet of the reactor; the outlet of the reactor is connected with one end of the coordinated pressure control unit II; the other end of the coordinated pressure control unit II is connected with one end of the condenser; the other end of the condenser is connected with a first port of the three-way valve; a second port of the three-way valve is connected with a material inlet of the material mixing tank; a third port of the three-way valve is connected with the material storage tank; a steam inlet of the reactor is connected with one end of the coordinated pressure control unit III; and the other end of the coordinated pressure control unit III is connected with the steam generator.

Claims

1. A preparation method for magnesium hydroxide in a reaction apparatus, the reaction apparatus comprises a mixing tank, a coordinated pressure control unit I, a pump, a reactor, a coordinated pressure control unit II, a condenser, a three-way valve, a storage tank, a coordinated pressure control unit III, and a steam generator, wherein an outlet of the mixing tank is connected to the pump, the pump is connected to a first end of the coordinated pressure control unit I, a second end of the coordinated pressure control unit I is connected to an inlet of the reactor, an outlet of the reactor is connected to a first end of the coordinated pressure control unit II, a second end of the coordinated pressure control unit II is connected to an inlet of the condenser, an outlet of the condenser is connected to a first port of the three-way valve, a second port of the three-way valve is connected to an inlet of the mixing tank, a third port of the three-way valve is connected to the storage tank, a steam inlet of the reactor is connected to a first end of the coordinated pressure control unit III, and a second end of the coordinated pressure control unit III is connected to the steam generator, the method comprising: (1) mixing magnesium oxide and water in the mixing tank to obtain a magnesium oxide slurry, wherein the magnesium oxide accounts for 5-15% of a total weight of the slurry; (2) transferring the magnesium oxide slurry to the reactor using the pump, generating steam in the steam generator, and introducing the steam into the reactor and heating the reactor to 90-150° C., controlling the pressure of the coordinated pressure control unit I at 0.2-0.5 MPa, and the coordinated pressure control unit II at 0.2-0.5 MPa, and the pressure of the coordinated pressure control unit III at 0.2-0.5 MPa, and feeding a fluid from the outlet of the reactor to the inlet of the mixing tank, passing successively the coordinated control unit II, the condenser, and the three-port valve so as to circulate the fluid between the reactor and the mixing tank; and (3) circulating the fluid for 10-35 minutes, and directing the fluid to the storage tank.

2. The preparation method according to claim 1, wherein the magnesium oxide accounts for 15% of the total weight of the slurry.

3. The preparation method according to claim 1, wherein the pressure of the coordinated pressure control unit I is 0.3-0.5 MPa.

4. The preparation method according to claim 1, wherein the pressure of the coordinated pressure control unit II is 0.3-0.5 MPa.

5. The preparation method according to claim 1, wherein the pressure of the coordinated pressure control unit III is 0.3-0.5 MPa.

6. The preparation method according to claim 1, wherein the reactor is heated to 120-150° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention has one drawing,

(2) FIG. 1 is a structural schematic diagram of the device for efficiently preparing magnesium hydroxide;

(3) Wherein, 1. mixing tank, 11. outlet of the mixing tank, 12. inlet of the mixing tank, 2. coordinated pressure control unit I, 3. reactor, 31. inlet of the reactor, 32. outlet of the reactor, 33. steam inlet of the reactor, 4. coordinated pressure control unit II, 5. the condenser, 6. three-way valve, 61. first port of the three-way valve, 62. second port of the three-way valve, 63. third port of the three-way valve, 7. storage tank, 8. coordinated pressure control unit III, 9. steam generator 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(4) The following nonrestrictive embodiments can be provided for that ordinary person skilled in the art to understand the present invention more comprehensively rather than limiting the present invention in any way.

Embodiment 1

(5) A device for efficiently preparing magnesium hydroxide, comprises a mixing tank 1, a coordinated pressure control unit I 2, a reactor 3, a coordinated pressure control unit II 4, a condenser 5, a three-way valve 6, a storage tank 7, a coordinated pressure control unit III 8, and a steam generator 9, wherein an outlet 11 of the mixing tank is connected with one end of the coordinated pressure control unit I 2 through a pressure pump; the other end of the coordinated pressure control unit I 2 is connected with an inlet 31 of the reactor; an outlet 32 of the reactor is connected with one end of the coordinated pressure control unit II 4; the other end of the coordinated pressure control unit II 4 is connected with one end of the condenser 5; the other end of the condenser 5 is connected with a first port 61 of the three-way valve; a second port 62 of the three-way valve is connected with an inlet 12 of the mixing tank; a third port 63 of the three-way valve is connected with the storage tank 7; a steam inlet 33 of the reactor is connected with one end of the coordinated pressure control unit III 8; the other end of the coordinated pressure control unit III 8 is connected with the steam generator 9; and the coordinated pressure control unit is composed of a pressure sensor and an electromagnetic valve.

(6) A preparation method for efficiently preparing magnesium hydroxide, comprises the following steps:

(7) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 5% of the total weight;

(8) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, and heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.2-0.3 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.2-0.3 MPa, and the pressure of the coordinated pressure control unit III 8 to be 0.2-0.3 MPa, raising the reaction temperature to 90-120° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 1.95 L/min; and

(9) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(10) The test result of Embodiment 1 is showed in Table 1:

(11) TABLE-US-00001 TABLE 1 Hydration ratio of Embodiment 1 Reaction Time (min) 10 15 20 25 30 35 Hydration 57.8 59.2 54.3 58.4 56.5 59.1 Ratio (%)

Embodiment 2

(12) The difference with Embodiment 1 lies in that:

(13) a preparation method for efficiently preparing magnesium hydroxide, comprises the following steps:

(14) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 5% of the total weight;

(15) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, and heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.3-0.5 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.3-0.5 MPa, and the pressure of the coordinated pressure control unit III 8 to be 0.3-0.5 MPa, raising the reaction temperature to 120-150° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 1.55 L/min; and

(16) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(17) The test result of Embodiment 2 is showed in Table 2:

(18) TABLE-US-00002 TABLE 2 Hydration ratio of Embodiment 2 Reaction Time (min) 10 15 20 25 30 35 Hydration 55.8 57.4 53.9 58.2 56.3 59.4 Ratio (%)

Embodiment 3

(19) The difference with Embodiment 1 lies in that:

(20) A preparation method for efficiently preparing magnesium hydroxide, comprises the following steps:

(21) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 10% of the total weight;

(22) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, and heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.2-0.3 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.2-0.3 MPa, and the pressure of the coordinated pressure control unit III 8 to be 0.2-0.3 MPa, raising the reaction temperature to be 90-120° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 1.2 L/min; and

(23) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(24) The test result of Embodiment 3 is showed in Table 3:

(25) TABLE-US-00003 TABLE 3 Hydration ratio of Embodiment 3 Reaction Time (min) 10 15 20 25 30 35 Hydration 82.5 83.1 81.7 83.9 82.0 83.4 Ratio (%)

Embodiment 4

(26) The difference with Embodiment 1 lies in that:

(27) A preparation method for efficiently preparing magnesium hydroxide, comprises the following steps:

(28) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 10% of the total weight;

(29) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.3-0.5 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.3-0.5 MPa, and the pressure of the coordinated pressure control unit III 8 to be 0.3-0.5 MPa, raising the reaction temperature to be 120-150° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 2.9 L/min; and

(30) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(31) The test result of Embodiment 4 is showed in Table 4:

(32) TABLE-US-00004 TABLE 4 Hydration ratio of Embodiment 4 Reaction Time (min) 10 15 20 25 30 35 Hydration 83.7 82.6 84.7 83.4 84.9 82.1 Ratio (%)

Embodiment 5

(33) The difference with Embodiment 1 lies in that:

(34) a preparation method for efficiently preparing magnesium hydroxide, comprises the following steps:

(35) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 15% of the total weight;

(36) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.2-0.3 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.2-0.3 MPa and the pressure of the coordinated pressure control unit III 8 to be 0.2-0.3 MPa, raising the reaction temperature to be 90-120° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 3.1 L/min; and

(37) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(38) The test result of Embodiment 5 is showed in Table 5:

(39) TABLE-US-00005 TABLE 5 Hydration ratio of Embodiment 5 Reaction Time (min) 10 15 20 25 30 35 Hydration 91.4 93.6 92.3 92.8 91.5 92.4 Ratio (%)

Embodiment 6

(40) The difference with Embodiment 1 lies in that:

(41) a preparation method for efficiently preparing magnesium hydroxide comprises the following steps:

(42) (1) adding magnesium oxide and water to the mixing tank 1 and mixing uniformly to obtain magnesium oxide slurry, wherein the magnesium oxide accounts for 15% of the total weight;

(43) (2) adding the magnesium oxide slurry to the reactor 3 through the pump, starting the steam generator 9, introducing steam to the reactor 3, heating the reactor 3, controlling the pressure of the coordinated pressure control unit I 2 to be 0.3-0.5 MPa, the pressure of the coordinated pressure control unit II 4 to be 0.3-0.5 MPa and the pressure of the coordinated pressure control unit III 8 to be 0.3-0.5 MPa, raising the reaction temperature to be 120-150° C., returning liquid in reaction to the mixing tank 1 through the second port 62 of the three-way valve, and then returning it to the reactor 3 from the mixing tank 1 to form a circulation loop, wherein the circulation flow is 2.75 L/min; and

(44) (3) circulating for 35 min, then closing the second port 62 of the three-way valve, opening the third port 63 of the three-way valve, and adding liquid obtained after reaction to the storage tank 7.

(45) The test result of Embodiment 6 is showed in Table 6:

(46) TABLE-US-00006 TABLE 6 Hydration ratio of Embodiment 6 Reaction Time (min) 10 15 20 25 30 35 Hydration 90.1 92.5 95.4 93.7 93.5 95.1 Ratio (%)

(47) Test Conclusions:

(48) (1) by the adoption of the method for preparing magnesium hydroxide in the present invention, the reaction conversion ratio at 10 min tends to be stable, and the reaction conversion ratio after 10 min less changes with time; and

(49) (2) when the percentage concentration by mass of magnesium oxide is 10-15%, the reaction conversion ratio at 10 min reaches 80-90%.

(50) Contrast Test 1

(51) A jar test is adopted in contrast to the test of the present invention;

(52) The test conditions of Contrast test 1 is showed in Table 7.

(53) TABLE-US-00007 TABLE 7 Test conditions of Contrast test 1 Percentage Concentration by Reaction Mass of Magnesium Oxide Temperature Stirring Rate Contrast test 1 10% 90° C. 900 r/min
The test results of Contrast test 1 is showed in Table 8.

(54) TABLE-US-00008 TABLE 8 Test Results of Contrast test 1 Reaction Time (min) 10 20 30 40 50 60 90 120 Hydration 47.1 52.0 56.7 65.1 66.0 70.0 72.8 77.7 Ratio (%)

(55) Conclusion: when the hydration time of a jar test is 120 min, the reaction conversion ratio of magnesium oxide is only 77.7%; according to the preparation method disclosed by the present invention, under the same reaction temperature, over 80% reaction conversation ratio can be obtained after 10 min reaction, and therefore, compared with the traditional method, the present invention has the remarkable advantages of quickly and efficiently; and meanwhile, the reaction ratio is shortened, so that the occupied area of the device disclosed by the present invention is greatly reduced compared with that of a traditional device.