KR20130008895A - Apparatus for preparing magnesium hydroxide from bitterns - Google Patents

Abstract

PURPOSE: A manufacturing device of magnesium hydroxide from bittern is provided to economically manufacture magnesium hydroxide with high purity. CONSTITUTION: A manufacturing device of magnesium hydroxide from bittern comprises a waste feeding unit, an alkali feeding unit, a reaction aid feeding unit, a reactant diluting unit(104), a stirring reaction unit(110), and a control unit. The waste feeding unit supplies bittern. The alkali feeding unit supplies alkali material. The reaction aid feeding unit supplies magnesium hydroxide seed. The reactant diluting unit attenuates the bittern into diluted solution. The stirring reaction unit mixes the diluted bittern with the diluted alkali material to form magnesium hydroxide particles and agitates the mixed solution to grow magnesium hydroxide particles. [Reference numerals] (10) Control unit; (401) Temperature regulator; (A1,A2) Water or seawater; (B1,B2) Bittern; (CC) Magnesium hydroxide seed; (DD) Wastewater

Description

Apparatus for producing magnesium hydroxide from juices {APPARATUS FOR PREPARING MAGNESIUM HYDROXIDE FROM BITTERNS}

The present invention relates to a device for producing magnesium hydroxide from the juice, an apparatus for producing magnesium hydroxide from the bitter juice (Bitterns) which is a by-product generated in the decontamination plant, the magnesium hydroxide prepared according to the present invention is a by-product generated in the decontamination plant In spite of the low manufacturing cost, it is possible to manufacture magnesium hydroxide with dispersibility and high purity, and it is possible to manufacture magnesium hydroxide with higher purity than magnesium hydroxide manufactured from minerals. It can be used as a flame retardant, which is an additive of, and can be used as a part material of semiconductor process when it is converted to magnesium oxide through a sintering process. have.

In general, magnesium hydroxide is used as a raw material of magnesia, which is a basic refractory material, and recently, as a flame retardant which is added to rubber and plastics and does not burn well, it is increasing. In addition, as the IT industry develops, the use of high-purity magnesium oxide as a semiconductor process component material is increasing. As such, in order to use magnesium hydroxide as a flame retardant, not only high purity but also dispersibility must be excellent.

Magnesium hydroxide production methods include a method of using brucite or natural magnesite, a method of using seawater or brine, and a method of using magnesium chloride. Among the above methods, the method of using brucite or natural magnesite has a problem in that magnesium hydroxide of high purity cannot be obtained by purifying brucite or calcining and hydrating the natural magnesite.

In addition, the method of using seawater or brine among the above manufacturing method can produce magnesium hydroxide by reacting seawater or brine with alkali and obtain high-purity magnesium hydroxide, but the particles produced are present as fine particles and aggregated in a circular shape. There is a problem that is difficult to distribute.

Representative prior art for producing magnesium hydroxide is to prepare a high-purity magnesium hydroxide of MgO 99.3% or more by using B ₂ O ₃ adsorption resin, but such magnesium hydroxide is formed by the reaction of magnesium ions extracted from seawater with lime oil and cohesiveness It cannot be used for additives requiring dispersion (Japanese Patent Laid-Open No. 5-238725). In addition, magnesium hydroxide is prepared by hydrothermal treatment of magnesium chloride and alkali and magnesium oxide, and thus, high purity and high dispersibility of magnesium hydroxide can be produced, but there is a problem in that the manufacturing cost is too high and there is no economic efficiency (Japanese Laid-Open Patent Publication). 2000-233924). In Korea, there is a method of preparing magnesium hydroxide by appropriately treating magnesia prepared from seawater using magnesia manufactured from seawater as a raw material, but there is a problem that the manufacturing process has to go through multiple steps. .

In addition, the prior art uses a fine powder produced as a by-product during the process of manufacturing magnesium hydroxide using natural minerals such as brucite or natural magnesite, or magnesia from seawater to produce magnesium hydroxide, There is a problem that the manufacturing cost is relatively high.

Japanese Patent Laid-Open No. 5-238725 Japanese Laid-Open Patent Publication No. 2000-233924 Republic of Korea Patent No. 10-0649114

The present invention was derived to solve the above-mentioned problems of the prior art, and an object thereof is to provide an apparatus for producing magnesium hydroxide simply and economically from high juice which is wastewater discharged from the decontamination process.

In addition, another object of the present invention is to adjust the sodium hydroxide, which is an alkali substance (NaOH, Ca (OH) ₂ , NH ₄ OH, etc.) to an appropriate molar ratio with respect to magnesium ions contained in the juice and also to adjust the magnesium hydroxide produced during the manufacturing process By using as a seed, it is possible to provide an apparatus for producing magnesium hydroxide having low production cost and high purity by shortening the recovery amount and production time of magnesium hydroxide and increasing the stirring speed.

The present invention as a means for solving the above problems, a waste supply for supplying juice; An alkali supply unit for supplying an alkaline substance; A reaction aid supply for supplying magnesium hydroxide seed; A reactant dilution unit for diluting the juice by mixing the diluent with the juice supplied from the waste supply unit; The diluted juice is supplied from the reactant dilution unit, an alkali substance is supplied from the alkali supply unit, mixed to form magnesium hydroxide particles, and the mixed mixture is stirred to grow magnesium hydroxide particles, and magnesium hydroxide seeds are added from the reaction assistant supply unit. A stirring reaction section which adds and ripens magnesium hydroxide; And a control unit for automatically adjusting the system by controlling the units. It provides a magnesium hydroxide manufacturing apparatus comprising a.

Preferably, the filter unit for separating the precipitate by pressure filtration of the mixed solution reacted in the stirring reaction unit to obtain magnesium hydroxide; And further comprising:

Preferably, the drying unit for washing and drying the magnesium hydroxide of the precipitate obtained from the filtration unit; And a grinding and storage unit for grinding and storing magnesium hydroxide washed and dried in the drying unit.

Preferably, a firing unit for firing magnesium hydroxide pulverized in the grinding and storage unit to produce magnesium oxide; And further comprising:

Preferably, the wastewater circulation unit for reusing the supernatant separated from the filtration unit as dilution water; And further comprising:

Preferably, the reactant dilution unit comprises a reactant dilution tank, and receives the diluent consisting of water or seawater from the diluent supply unit to dilute the juice, and when diluted, water or seawater in a ratio of 1: 1 to 1:20 relative to the juice It is characterized by dilution by addition.

Preferably, the alkali supply unit includes an alkali material storage tank, and the alkali solution supplied from the alkaline material storage tank is sodium hydroxide (NaOH).

Preferably, the stirring reaction unit comprises a stirring reactor, the molar ratio (Mg: Na molar ratio) of the juice and the sodium hydroxide in accordance with the measurement of the pH meter of the stirring reactor when mixing the juice and alkali material in the stirring reactor It is characterized in that the mixture is adjusted to 1: 1 to 1: 5.

Preferably, when mixing the juice and alkali material in the stirred reactor, the reaction temperature is adjusted to 20 ℃ to 80 ℃ by the temperature controller of the stirring reactor, the mixing speed is 50 rpm to 100 rpm by the stirring motor of the stirring reactor It is characterized in that the stirring within 10 minutes.

Preferably, the alkali supply unit comprises an alkali storage tank, wherein the alkaline solution supplied from the alkali storage tank is sodium carbonate (Ca (OH) ₂ ) or ammonium hydroxide (NH ₄ OH).

Preferably, the stirring reaction unit comprises a stirring reactor, when stirring the mixed liquid of juice and alkaline material, the reaction temperature is adjusted to 20 ℃ to 80 ℃ by the temperature controller of the stirring reactor, the stirring speed of the stirring motor of the stirring reactor It is characterized in that it is stirred for 10 to 150 minutes at 50 rpm to 500 rpm.

Preferably, the reaction aid supply unit comprises a seed supply tank, the seed supplied from the seed supply tank comprises magnesium hydroxide, 2.5% by weight of magnesium hydroxide compared to the magnesium concentration contained in the mixture of the juice and alkaline material when the seed is added It is characterized by the addition of from 15 to 15% by mass.

Preferably, the stirring reaction unit comprises a stirring reactor, the reaction temperature is adjusted to 20 ℃ to 80 ℃ by the temperature controller of the stirring reactor when the magnesium hydroxide is aged, the stirring speed is 100 rpm to by a stirring motor of the stirring reactor It is characterized in that the stirring for 10 minutes to 150 minutes at 500 rpm.

Preferably, the magnesium hydroxide is produced by firing magnesium hydroxide at 300 ° C to 1000 ° C during firing in the firing unit.

Preferably, the reaction unit further comprises a double jacketed reactor, a heater and a pump for temperature control in the stirred reactor, the double jacketed reactor to circulate oil or steam from the bottom to the top through the heater and the pump of the stirred reactor It is characterized by adjusting the internal temperature.

According to the present invention, it is possible to effectively recycle magnesium, which is a useful metal contained in the high juice, which is a liquid waste, in a decontamination plant, and to produce magnesium hydroxide having high purity and excellent dispersibility.

In addition, the filtration time is shortened and the recovery rate is excellent in the manufacturing process of magnesium hydroxide, there is an effect that the manufacturing process is simple and economically can be produced magnesium hydroxide.

In addition, since the purity and the manufacturing process is simpler than magnesium hydroxide produced from natural minerals, there is an effect that it is possible to recover magnesium, as well as magnesium hydroxide, by recovering magnesium, which is a useful metal from infinite marine resources.

1 is a schematic view showing a magnesium hydroxide production apparatus according to the present invention.
Figure 2 is a view for explaining a stirred reactor in the magnesium hydroxide production apparatus of the present invention.
Figure 3 is a graph of the result of measuring the effect of the filtration time according to the precipitation time in accordance with embodiments of the present invention.
4 is a view showing a state of the supernatant after filtration according to the precipitation time according to embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides an apparatus for producing magnesium hydroxide from Bitterns, a byproduct of the decontamination process.

The magnesium hydroxide manufacturing apparatus according to the present invention forms magnesium hydroxide particles by mixing magnesium, which is a useful metal contained in the high juice which is a large amount of liquid waste generated in a decontamination plant, with an alkaline substance, and proceeds with stirring to grow the formed magnesium hydroxide particles. The seeds are mixed to increase magnesium hydroxide recovery and filtration rate, and the mixture is aged and crystallized.

To this end, the magnesium hydroxide manufacturing apparatus according to the present invention includes a waste supply unit for supplying a large amount of liquid juice generated in a decontamination plant, an alkali supply unit for supplying an alkaline substance, a reaction aid supply unit for supplying magnesium hydroxide seed, and a juice And a stirring reaction section for aging and crystallizing the mixed solution through the seed added with the alkaline substance, and a filtration section for separating the precipitate by pressure filtration of the reacted mixed solution to obtain magnesium hydroxide.

The magnesium hydroxide manufacturing apparatus includes a drying unit for washing and drying the precipitated magnesium hydroxide, a crushing and storing unit for crushing and storing the washed and dried magnesium hydroxide, and calcining the crushed magnesium hydroxide to produce magnesium oxide. It is configured to further include a firing unit for generating a.

In addition, the magnesium hydroxide manufacturing apparatus further comprises a diluent supply unit for supplying a diluent for diluting the supplied juice, and a reactant dilution unit for diluting the juice by mixing the juice supplied from the waste supply and the diluent supplied from the diluent supply. do.

In addition, the magnesium hydroxide manufacturing apparatus further includes a wastewater circulation unit for reusing the supernatant separated from the filtration unit as dilution water.

And such a magnesium hydroxide manufacturing apparatus includes a control unit for automatically adjusting the system by controlling the respective parts.

First, the waste supply unit is configured to include a juice transfer tank 101 for receiving the juice generated from the outside (Bitterns) and a juice storage tank 102 for receiving and storing the juice from the juice transfer tank 101.

Here, the juice may be a byproduct of the decontamination process.

The juice transferred from the juice transfer tank 101 to the juice storage tank 102 is transferred to the juice storage tank 102 through a flow screw 301 which is a transfer pipe at the bottom of the juice transfer tank 101.

Here, the juice storage tank 102 is equipped with a weight measurement load cell 202 for measuring the amount of the internal juice, the measurement value of the weight of the juice weight measurement load cell 202 is transmitted to the control unit 10 for automatic control It will be used as a measure.

That is, when the amount of the juice supplied from the juice transfer tank 101 is supplied to the upper limit, the flow type screw (in the control unit 10) is reported by the measurement value of the juice weighing load cell 202 mounted on the juice storage tank 102. 301 is controlled to stop the automatic supply, and when the amount of juice in the juice storage tank 102 is lower than the lower limit, the flow control screw 301, which is a conveying pipe by the control unit 10 operates the juice juice storage tank 102 ).

Meanwhile, the alkaline material supply unit includes an alkaline material storage tank 105.

The alkaline material storage tank 105 is supplied with an alkali material (NaOH, etc.) from the outside and when the amount of the alkali material is the lower limit, the whole process is performed by the controller 10 according to the measurement report of the alkali weighing load cell 205. Will stop.

The alkali material is transferred from the lower portion of the alkali material storage tank 105 to the stirring reactor 110 through the flow screw 305.

The alkali substance used in the present invention is not particularly limited, but sodium hydroxide (NaOH) is preferred.

Meanwhile, the reaction aid supply unit 106 includes a seed supply tank 106.

The seed supply tank 106 receives a seed to be added to the reaction from the outside, and when the amount of seeds is a lower limit, the whole process is performed by the controller 10 according to the measurement report of the seed weight measurement load cell 206. To be controlled.

Here, the seed supplied through the seed supply tank 106 is preferably magnesium hydroxide, and the magnesium hydroxide seed used serves as a template for determining the form of the finally produced synthetic magnesium hydroxide. The amount of magnesium hydroxide seed used at this time is 2.5 to 15% by weight.

The seed is transferred from the bottom of the seed feed tank 106 to the stirred reactor 110 through a flow screw 306.

The seed used in the present invention is preferably magnesium hydroxide.

On the other hand, the juice supplied from the waste supply may be diluted with water or sea water and used for the reaction. To this end, a diluent supply for supplying water or seawater and a reactant dilution for diluting the juice from the waste supply using water or seawater supplied from such a diluent supply.

Here, the high juice contains a high concentration of various ions (Na, K, Ca, etc.), so the magnesium hydroxide particles are hindered when mixed with an alkaline substance, so the water must be diluted with water or sea water. The recovery of magnesium hydroxide increases only when it is reacted with alkaline solution.

The diluent supply unit includes a diluent storage tank 103 to supply water or seawater stored in the diluent storage tank 103 as a diluent, and the reactant dilution unit receiving the diluent includes the reactant dilution tank 104. The juice supplied from the storage tank 102 is mixed with the diluent to dilute the juice.

The amount of diluent (water or seawater) used in this dilution process may be 1 to 20 times (ie, the juice is diluted with water or seawater at a dilution ratio of 1: 1 to 1:20), preferably 10 times better The higher the dilution ratio of the actual juice, the higher the magnesium hydroxide recovery rate, but when the high juice dilution ratio is high, there is a problem that many process drainages used as diluents occur. great.

The reactant dilution tank 104 receives the juice and the diluent from the juice storage tank 102 and the diluent storage tank 103 to make diluted juice, and flows the screw 304 at the bottom of the reactant dilution tank 104. The diluted juice is transferred to the stirred reactor 110 through. At this time, the amount of the diluted juice supplied from the reactant dilution tank 104 is the reactant dilution tank 104 by the control unit 10 according to the weight of the reactants measured by the reactant load cell 207 of the stirring reactor 110. The floating screw 304 is controlled to be automatically controlled.

On the other hand, the stirred reaction unit is supplied with the diluted juice from the reactant dilution unit and the alkaline substance is supplied from the alkali supply unit and mixed to form magnesium hydroxide particles, the mixed liquid mixture is stirred to grow magnesium hydroxide particles, the reaction aid The magnesium hydroxide is added from the supply to mature the magnesium hydroxide, and includes a stirring reactor 110, a stirring motor 113, a pH meter 403, and a temperature controller 401.

The stirring reactor 110 mixes and matures the juice supplied from the reactant dilution tank 104 with the alkali material supplied from the alkaline material storage tank 105 and the magnesium hydroxide seed supplied from the seed supply tank 106. .

Referring to FIG. 2, the stirring reactor 110 is described in more detail. The stirring reactor 110 has a lower portion configured as a double jacket reactor 110a, and the double jacket reactor 110a is a temperature controller 401. Steam is circulated from the bottom to the top through the pump 402 to adjust the internal temperature of the stirred reactor 110 to a temperature of 100 ℃ or less, preferably 20 ℃ to 80 ℃. In this case, the internal fluid of the double jacket reactor 110a may be configured by changing steam, and the shape of the double jacket reactor 110a may be changed to meet the purpose.

In addition, the stirred reactor 110 is preferably a closed structure in a structure that is well mixed with the juice and alkaline materials.

When the reactant is filled in the stirred reactor 110 from the reactant dilution tank 104, the alkali material is automatically supplied from the alkaline material storage tank 105 through the flowable screw 305 and also from the seed supply tank 106. Magnesium hydroxide seed is automatically fed through 306, and during this process the stirring motor 113 is operated to completely mix the reactants, magnesium hydroxide seed and alkali material. Here water or seawater is mixed for the reaction. At this time, the speed of the stirring motor 113 is 50 to 400rpm, preferably 10 to 150 minutes stirring at 50 to 100 rpm.

In such a stirred reactor 110, the magnesium hydroxide is synthesized through aging and crystallization to produce synthetic magnesium hydroxide.

Here, the pH meter 403 for measuring pH according to the molar ratio of Mg and Na is installed in the upper, lower and middle portions of the stirred reactor 110, respectively, according to the measured value of the pH meter 403 The controller 10 controls the supply amount of the juice and alkali material to the stirred reactor 110. At this time, the pH of the reactant through the pH meter 403 installed in the upper, lower and middle portions of the reactor 110 is operated to be within the range of 12 (± 1).

The amount of diluted juice and alkali material that is stirred in the stirring reactor 110 is controlled in a molar ratio, and the supply amount of alkali material can be adjusted according to the degree of inclusion of Mg by MgCl ₂ , which is the basic chemical composition of the juice. The juice used in the present invention occupies Na 29399 mg / L, K 34018 mg / L, Mg 35337 mg / L, and Ca 11907 mg / L according to ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer) analysis.

The alkali substance used in the present invention is not particularly limited, but preferably includes an OH- component, and sodium hydroxide (NaOH), sodium carbonate (Ca (OH) ₂ ), ammonium hydroxide (NH ₄ OH), and the like are particularly preferable. Do. In addition, the alkaline substance is preferably used in the present invention in a liquid state, but the alkaline substance may be used in a powder state.

In the present invention, the molar ratio of the diluted juice and alkali material is automatically adjusted from 1: 1 to 1: 5 through the reactant dilution unit and the alkali supply unit load cells 204 and 205 (ie, alkali to concentration of magnesium contained in the juice). Material is supplied with an alkali material in a ratio of 1: 1 to 1: 5 moles), and preferably, magnesium hydroxide having high performance can be prepared when the molar ratio of the juice (Mg) to the alkali material (NaOH) is 1: 3. there was.

In addition, to increase the magnesium hydroxide recovery rate and filtration rate, magnesium hydroxide is added to 0.25% by mass to 5% by mass relative to the magnesium concentration to promote the growth of magnesium hydroxide during seed mixing to grow the nuclei of magnesium hydroxide in the fine particles, At this time, the stirring speed is preferably stirred for 10 to 150 minutes at 50 to 500 rpm.

Next, the mixture in which the stirring proceeds in the stirring reactor 110 is filtered through a filtration unit, and the precipitate generated in the filtration process is washed and dried in the drying unit and pulverized into fine powder through the crushing and storage unit.

The filtration unit includes a filter press 111 and separates the precipitate through filtration in the filter press 111 and discharges it through the filter press screw 308. Here, the wastewater generated in the filtration process is transferred to the wastewater circulation.

And the drying unit includes a dryer 107, the dryer 107 is from 90 ℃ to 100 ℃, preferably 100 ℃ to improve the strength of the magnesium hydroxide precipitate discharged through the filter press screw 308 At least 60 minutes at a drying temperature of at least drying.

The mill and reservoir include a mill 108 and a reactant storage tank 109. Since the mixture melted at a high temperature through the dryer 107 is discharged in the form of fine powder and agglomerates, the grinder 108 grinds it into fine powder. The mixture ground into fine powder is fed to the reactant storage tank 109 through a flow screw 310 which is a transfer tube at the bottom of the mill 108. At this time, the reactant storage tank 109 is equipped with the reactant weighing load cell 211, and stops the operation of the flow type screw 310 by the controller 10 when the upper limit is reached according to the reactant weight supplied.

The firing unit includes a calcination machine 112. The calciner 112 receives magnesium hydroxide from the reactant storage tank 109 to perform heat treatment, and the heat treatment is performed at a temperature of 300 ° C. to 1000 ° C., thereby producing magnesium oxide.

Meanwhile, the wastewater circulation unit includes a circulation tank 114, and receives and stores wastewater generated in the filtration process of the filter press 111, and the wastewater thus stored is supplied to the reactant dilution tank 104 to be reused as a diluent. Can be. Such wastewater may also be reintroduced into the stirred reactor 110. In this way, the waste water can be reused, so that environmental pollution can be reduced, and the manufacturing cost can be reduced. Since such waste water is dissolved in sodium ions, the amount of sodium ion source can be determined in consideration of the amount thereof.

The following examples provide specific experimental examples for confirming the effects of the present invention, which are intended only to illustrate the present invention and confirm the effects thereof, and are not intended to limit or limit the scope of the present invention. Reveal.

The physical and chemical properties of magnesium hydroxide prepared from the juice were measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer), XRD (X-ray Diffraction), Scanning Electron Microscope (SEM) and the like.

In order to examine the proper molar ratio (Mg: Na molar ratio) for preparing magnesium hydroxide from the juice, the reaction conditions were fixed at a dilution ratio of 1:10, agitation time 120 minutes, and a stirring rate of 300 rpm. Magnesium hydroxide was prepared by changing the ratio.

20 ml of the juice is added to the reactor, and the dilution ratio is adjusted to 10 times with distilled water to make a reactant. The diluted juice is turned well with a stirrer and mixed well and the initial pH is measured. A total of 20 ml of 1 M, 2 M, 3 M, and 5 M NaOH solutions prepared therein, each 5 ml per minute, is added and stirred at 300 rpm for 120 minutes. After the reaction, the pH was measured, placed in a pressure filter, and the supernatant and the precipitate were separated.

At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried for 100 to 12 hours to obtain magnesium hydroxide.

Table 1 below shows the pH change and magnesium hydroxide recovery according to the Mg: Na molar ratio.

As shown in Table 1, it can be seen that as the Mg: Na molar ratio increases, the recovery of magnesium hydroxide approaches the theoretical recovery. In particular, when the Mg: Na molar ratio was low, the pH was lower than 9.34 compared to the high recovery condition. As reported in the literature, the pH of Mg ions and NaOH, which is a precipitant, was smoothly reacted to produce magnesium hydroxide particles of 12 or more. Coincided with

In addition, when the Mg: Na molar ratio is 1: 1, Mg ions and OH ⁻ ions contained in the juice are predicted to interfere with binding to magnesium hydroxide by other impurities, and the production of the produced magnesium hydroxide particles is different. The dry weight of Mg (OH) ₂ recovered by filtration was estimated to be three times lower than the theoretical weight.

However, it can be seen that as the molar ratio increases, the pH is maintained at 12 to 13 and recovers more than 80% of the expected weight. This is consistent with the report that Mg ions contained in the juice are precipitated with magnesium hydroxide between pH 12-13 and affect the particles of magnesium hydroxide produced during precipitation.

However, the excess Mg: Na molar ratio increases the cost of recovering magnesium hydroxide, which affects the economics. Therefore, the future process parameters are fixed by fixing the Mg: Na molar ratio to 1: 3.

Table 1 below shows the pH change and magnesium hydroxide recovery according to the Mg: Na molar ratio.

Experimental conditions After precipitation
Solution volume (ml) pH Actual dry weight (g) before after Mg: Na = 1: 1 220 8.10 9.34 0.634 Mg: Na = 1: 2 220 8.10 11.99 1.314 Mg: Na = 1: 3 220 8.10 12.78 1.446 Mg: Na = 1: 5 220 8.10 13.12 1.712

Next, to determine the effect of the dilution ratio of the juice, the Mg: Na molar ratio was fixed at 1: 3, and then the agitation time was 120 minutes for the dilution ratio (1, 2, 5, 10, 20). The stirring speed was fixed at 300 rpm, and magnesium hydroxide was prepared by changing the molar ratio of NaOH, which is an alkaline substance, and magnesium hydroxide recovery and pH effects were measured.

20 ml of juice is added to the reactor and dilution with distilled or sea water is adjusted to 1, 2, 5, 10, 20 times to prepare a diluted juice juice. The diluted juice is turned well with a stirrer and mixed well and the initial pH is measured.

As shown in Example 1, after fixing the optimal Mg: Na molar ratio of 1: 3, a total of 20 ml of 5 mL / min of NaOH solution, which is an alkaline substance, was added and stirred at a speed of 300 rpm for 120 minutes. After the reaction, the pH was measured, placed in a pressure filter, and the supernatant and the precipitate were separated.

At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried at 100 ° C. for about 12 hours to obtain magnesium hydroxide.

Table 2 below shows the pH change and magnesium hydroxide recovery according to the dilution ratio of the juice.

As shown in Table 2, when NaOH as a precipitant was supplied to the juice solution, the recovery rate of magnesium hydroxide was very low. When excess Mg ions were present in the juice, NaOH was dissolved in the high concentration solution when NaOH was added. Due to the influence on solubility, the number of collisions with Mg ions was low, and thus the reaction rate was reduced, indicating that magnesium hydroxide was lowered.

Therefore, the higher the dilution rate of the juice, the higher the magnesium hydroxide recovery rate, but when the high juice dilution ratio is high, there is a problem that a lot of process drainage used as the dilution water occurs. It can be seen that this is excellent.

Table 2 below shows the pH change and magnesium hydroxide recovery according to the dilution ratio of the juice.

Experimental conditions After precipitation
Solution volume (ml) pH real
Dry weight (g) before after Bittern crude 200 6.20 12.92 8.178 Bittern diluted 2times 120 7.32 12.98 4.028 Bittern diluted 5times 120 8.04 12.96 2.19 Bittern diluted 10times 220 8.10 12.78 1.446 Bittern diluted 20times 420 8.66 12.59 0.388

Next, in order to determine the effect of the stirring time, as shown in Examples 1 and 2, the dilution ratio of the juice having the optimum performance was 10 times, the stirring speed was 300 rpm, and the Mg: Na molar ratio was 1: 3. After fixation, the magnesium hydroxide recovery and pH influence were measured according to the stirring time.

20 ml of the juice is added to the reactor and the dilution ratio is adjusted to 10 times with distilled or sea water as shown in Example 2 to make the juice dilution reactant. The diluted juice is turned well with a stirrer and mixed well and the initial pH is measured. As shown in Example 1, after fixing the optimal Mg: Na molar ratio 1: 3, a total of 20ml of NaOH solution, 5 ml per minute, was added, respectively, and fixed at 30, 60, 90, 120, and 150 minutes at 300 rpm. Stir. After the reaction, the pH was measured, placed in a pressure filter, and the supernatant and the precipitate were separated.

At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried at 100 ° C. for about 12 hours to obtain magnesium hydroxide.

Table 3 below shows the pH change and magnesium hydroxide recovery according to the stirring time.

As shown in Table 3, the magnesium hydroxide recovery was reduced from 0.886 g to 0.660 g until the stirring time was 90 minutes. Mg ions and OH ^- ions were physically combined up to 90 minutes when the precipitant was added to the magnesium hydroxide floc (nucleus). Although the formation temporarily increases, it is believed that the amount of magnesium hydroxide recovered decreases because the floc does not grow with the stirring time. After 90 minutes, the recovery rate increases because the magnesium hydroxide filtered as the floc grows increases.

Therefore, in the case of the stirring time, 120 minutes is a condition that can form a Mg (OH) ₂ floc separable by filtration, so a stirring time of at least 120 minutes or more is required during the process operation.

Table 3 below shows the pH change and magnesium hydroxide recovery according to the stirring time.

Experimental conditions After precipitation
Solution volume (ml) pH real
Dry weight (g) before after Bittern 30min Reaction 220 8.10 12.70 0.886 Bittern 60min Reaction 220 8.10 12.74 0.720 Bittern 90min Reaction 220 8.10 12.69 0.660 Bittern 120min Reaction 220 8.10 12.78 1.446 Bittern 150min Reaction 220 8.10 12.83 1.484

Next, to determine the effect of stirring speed, the dilution ratio of the high juice, which is the optimum condition shown in Examples 1 to 3, was fixed 10 times, the Mg: Na molar ratio of 1: 3, and the stirring time was 120 minutes, followed by the recovery of magnesium hydroxide. pH influence was measured.

First, 20 ml of juice is added to the reactor, and dilution ratio is adjusted to 10 times with distilled or sea water as shown in Example 2 to make a juice dilution reactant. The diluted juice is turned well with a stirrer and mixed well and the initial pH is measured. As shown in Example 1, after fixing the optimal Mg: Na molar ratio of 1: 3, a total of 20 ml of 5 mL / min of NaOH solution, which is an alkaline substance, was added. The stirring speed was 50 rpm, 100 rpm, 200 rpm, 300 rpm, 400 Experiment by adjusting to rpm, stirring by fixing the stirring time to 120 minutes as shown in Example 3. At this time, the pH was measured after the reaction, and put into a pressure filter to separate the supernatant and the precipitate.

At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried at 100 ° C. for about 12 hours to obtain magnesium hydroxide.

Table 4 below shows the pH change and magnesium hydroxide recovery according to the stirring speed.

As shown in Table 4, as the stirring speed was increased, nucleation was increased, and the recovery rate of magnesium hydroxide was increased, and when the stirring speed was 400 rpm, magnesium hydroxide recovery and recovery were 1.839 g (theoretical recovery amount: 1.878 g) and 97.9. It was%. Therefore, as a result of experimenting on the effect of the stirring speed on the particles, a high stirring speed of 300 rpm or higher was applied to the NaOH introduced into the precipitant to be highly dispersed in the high juice of high density and viscosity and to promote the nuclear growth and to react with magnesium hydroxide. Know what you need.

Table 4 below shows the pH change and magnesium hydroxide recovery according to the stirring speed.

Experimental conditions After precipitation
Solution volume (ml) pH real
Dry weight (g) before after 50 rpm 220 8.10 12.72 1.059 100 rpm 220 8.10 12.73 1.268 200 rpm 220 8.10 12.79 1.435 300 rpm 220 8.10 12.78 1.446 400 rpm 220 8.10 12.76 1.839

Next, to determine the effect according to the reaction temperature, the dilution ratio of the juice, which is the optimum condition shown in Examples 1 to 4, was 10 times, the stirring speed was 300 rpm, and the Mg: Na molar ratio was fixed at 1: 3 and the stirring time was 120 minutes. Magnesium hydroxide recovery amount and filtration time were measured.

First, 20 ml of high juice is added to a temperature control reactor, and the dilution ratio is adjusted to 10 times with distilled or seawater to prepare a high juice dilution reactant. The diluted juice is mixed well by turning with a stirrer and the initial pH is measured. 3 ml of NaOH solution is added to 20 ml of 5 ml / min each, and stirred according to the reaction temperature conditions (40 ° C., 50 ° C., 70 ° C. and 80 ° C.). Stir for 120 minutes at a speed of 300 rpm.

At this time, the pH was measured after the reaction, and put into a pressure filter to separate the supernatant and the precipitate. At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried at 100 ° C. for about 12 hours to obtain magnesium hydroxide.

Table 5 below shows the filtration time and magnesium hydroxide recovery according to the reaction temperature conditions.

As shown in Table 5, it can be seen that the magnesium hydroxide dry weight increases with increasing precipitation reaction temperature, and the filtration time is also shortened. The particle size decreases with increasing precipitation temperature, and the sedimentation rate gradually increases with increasing temperature, which follows Myers's theory of crystal growth. It is consistent with what is reported.

In addition, the filtration time of the precipitate according to the precipitation reaction temperature was found to be further shortened as the reaction temperature increases. This means that as the precipitation reaction temperature increases, the surface of the magnesium hydroxide particles produced by decreasing the flocculation effect of the precipitate during filtration changes in a direction favorable for filtration.

Table 5 below shows the filtration time and magnesium hydroxide recovery according to the reaction temperature conditions.

Experimental conditions After precipitation
Solution volume (ml) pH real
Dry weight (g) Filtration time (min) before after Room temperature 220 8.1 12.78 1.446 180-240 40 220 8.4 12.59 1.438 35 50 220 8.4 12.59 1.428 35 70 220 8.4 12.61 1.647 25 80 220 8.4 12.53 1.788 30

Next, the effect of magnesium hydroxide seed addition to increase the particle growth and filtration efficiency of magnesium hydroxide was measured.

In general, the magnesium hydroxide obtained in the precipitation process is very fine particles that can cause many problems in the filtration process. In order to prevent such a problem and increase the efficiency of the filtration process, a magnesium hydroxide precipitate is prepared in advance, and the suspension is added to the juice to carry out seed addition to promote the growth of magnesium hydroxide particles.

First, 20 ml of the juice is added to the reactor, and the dilution ratio is adjusted to 10 times with distilled water to make a reactant. The diluted juice is turned well with a stirrer and mixed well and the initial pH is measured. 20 ml of 3 M NaOH solution prepared therein were added 5 ml / min each, and the mixture was stirred at 300 rpm for 120 minutes. In particular, in order to increase the particle size of magnesium hydroxide, magnesium hydroxide seed was added at the initial stage of stirring (2.5% by mass, 5% by mass, 15% by mass, 20% by mass) to react for 120 minutes, and then pH was measured. In a pressure filter, the supernatant and sediment are separated.

At this time, the precipitate separated as a solid may be manufactured with magnesium hydroxide, and filtered and washed with water or seawater to remove unreacted alkaline solution and impurities, thereby improving the purity of magnesium hydroxide. In general, the precipitate remaining in the filter paper was put in a drier and dried at 100 ° C. for about 12 hours to obtain magnesium hydroxide.

Table 6 below shows the filtration time and the magnesium hydroxide recovery amount according to the amount of magnesium hydroxide added.

As shown in Table 6, the dry weight of magnesium hydroxide was greatly increased, and the filtration time was also significantly shortened. Particularly, when magnesium hydroxide fine particles were added as a result of adding 5% by mass of seeds, the amount of recovered magnesium hydroxide was about 10% higher when added as a solid than when the solution was added as a solution. It can be seen that it is greatly shortened.

It can be seen that magnesium hydroxide fine particles are added to facilitate the filtration operation together with the promotion of particle generation from the nucleation of the added solution.

Therefore, the addition of magnesium hydroxide seed during the batch and continuous process plays a decisive role in the recovery and filtration time of magnesium hydroxide, which is an important issue that must be considered in the process design to produce magnesium hydroxide in the future with increased production and low cost. .

Table 6 below shows the filtration time and the magnesium hydroxide recovery amount according to the amount of seed addition of magnesium hydroxide.

Experimental conditions Solution volume after precipitation (ml) pH Estimated Mg (OH) ₂ Weight (g) real
Dry weight (g) (%) Filtration time
(minute) before after 2.5% 0.5ml
(Insert into solution) 220 9.27 13 1.925 2.18 (113.25) 7 0.045 g
(Injected with a solid sample) 220 8.82 13.10 1.923 2.15 (111.80) 8 5% 1ml 220 9.56 13.02 1.972 1.96 (99.39) 8 0.09g 220 9.09 13.07 1.968 2.17 (110.26) 8 10% 2ml 220 9.65 13.05 2.066 2.07 (100.26) 7.5 0.18 g 220 9.5 13 2.058 2.33 (113.22) 8 15% 3 ml 220 9.75 13.13 2.160 2.27 (105.09) 8

On the other hand, Figure 3 shows the result of measuring the effect of the filtration time according to the precipitation time by leaving the precipitation solution for a long time 120 minutes after the stirring time according to the embodiments of the present invention shown in the graph. In addition, Figure 4 shows the state of the supernatant after filtration according to the precipitation time according to the embodiments of the present invention described above. Through this, it can be seen that the longer the settling time, the more favorable the preparation of magnesium hydroxide. As a result, the shorter the precipitation time, the larger the particles of magnesium hydroxide formed to shorten the filtration time during filtration, and the longer the precipitation time, the lower the recovery rate of magnesium hydroxide because the formed magnesium hydroxide is decomposed into fine particles.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

101: juice juice transfer tank 102: juice juice storage tank
103: diluent storage tank 104: reactant dilution tank
105: alkaline material storage tank 106: seed supply tank
107: dryer 108: grinder
109: reactant storage tank 110: stirred reactor
111 filter press 112

Claims (15)

A waste supply unit for supplying juice;
An alkali supply unit for supplying an alkaline substance;
A reaction aid supply for supplying magnesium hydroxide seed;
A reactant dilution unit for diluting the juice by mixing the diluent with the juice supplied from the waste supply unit;
The diluted juice is supplied from the reactant dilution unit, an alkali substance is supplied from the alkali supply unit, mixed to form magnesium hydroxide particles, and the mixed mixture is stirred to grow magnesium hydroxide particles, and magnesium hydroxide seeds are added from the reaction assistant supply unit. A stirring reaction section which adds and ripens magnesium hydroxide; And
A control unit for automatically adjusting the system by controlling the units; Magnesium hydroxide production apparatus comprising a.
The method of claim 1,
A filtering unit for separating the precipitate by pressure filtration of the mixed solution reacted in the stirring reaction unit to obtain magnesium hydroxide; Magnesium hydroxide production apparatus further comprising a.
The method of claim 2,
A drying unit for washing and drying the magnesium hydroxide of the precipitate obtained from the filtration unit; And
Magnesium hydroxide manufacturing apparatus further comprises a; crushing and storage unit for crushing and storing the magnesium hydroxide washed and dried in the drying unit.
The method of claim 3,
A firing unit for firing magnesium hydroxide pulverized in the pulverizing and storing unit to produce magnesium oxide; Magnesium hydroxide production apparatus further comprising a.
The method of claim 2,
A wastewater circulation unit for reusing the supernatant separated from the filtration unit with dilution water; Magnesium hydroxide production apparatus further comprising a.
The method of claim 1,
The reactant dilution unit comprises a reactant dilution tank, and receives a diluent consisting of water or seawater from the diluent supply unit to dilute the juice;
Magnesium hydroxide production apparatus characterized in that the dilution by adding water or seawater in a ratio of 1: 1 to 1:20 relative to the juice.
The method of claim 1,
The alkali supply unit includes an alkali material storage tank, wherein the alkali solution supplied from the alkali material storage tank is sodium hydroxide (NaOH) production apparatus.
8. The method of claim 7,
The stirring reaction unit includes a stirring reactor, wherein the molar ratio (Mg: Na molar ratio) of the juice and the sodium hydroxide is 1: 1 to 1 according to the measured value of the pH meter of the stirring reactor when mixing the juice and alkali material in the stirring reactor. Magnesium hydroxide production apparatus characterized in that the mixture is adjusted to 1: 5.
The method of claim 8,
When mixing the juice and alkali material in the stirring reactor, the reaction temperature is controlled from 20 ° C. to 80 ° C. by the temperature controller of the stirring reactor, and the mixing speed is within 10 minutes at 50 rpm to 100 rpm by the stirring motor of the stirring reactor. Magnesium hydroxide production apparatus, characterized in that the stirring.
The method of claim 1,
The alkali supply unit includes an alkali material storage tank, wherein the alkaline solution supplied from the alkaline material storage tank is sodium carbonate (Ca (OH) ₂ ) or ammonium hydroxide (NH ₄ OH).
8. The method of claim 7,
The stirring reaction unit includes a stirring reactor, and when stirring the mixed liquid of the juice and alkali material, the reaction temperature is adjusted to 20 ℃ to 80 ℃ by the temperature controller of the stirring reactor, the stirring speed is 50 rpm by the stirring motor of the stirring reactor Magnesium hydroxide production apparatus characterized in that the stirring for 10 minutes to 150 minutes at 500 rpm.
The method of claim 1,
The reaction aid supply unit includes a seed supply tank, and the seed supplied from the seed supply tank includes magnesium hydroxide, and when the seed is added, 2.5% by mass to 15% by mass of magnesium hydroxide relative to the magnesium concentration contained in the mixture of the juice and the alkaline substance. An apparatus for producing magnesium hydroxide, which is added in%.
8. The method of claim 7,
The stirring reaction unit includes a stirring reactor, the reaction temperature is adjusted to 20 ℃ to 80 ℃ by the temperature controller of the magnesium hydroxide during aging of magnesium hydroxide, the stirring speed is 10 at 100 rpm to 500 rpm by the stirring motor of the stirring reactor Magnesium hydroxide production apparatus, characterized in that the stirring for minutes to 150 minutes.
5. The method of claim 4,
Magnesium hydroxide production apparatus characterized in that the magnesium hydroxide is produced by firing at 300 ℃ to 1000 ℃ when firing in the firing unit.
The method of claim 1,
The reaction unit further comprises a double jacketed reactor, a heater and a pump for temperature control in the stirred reactor,
The double jacket reactor is magnesium hydroxide manufacturing apparatus characterized in that for controlling the internal temperature of the stirring reactor by circulating oil or steam from the bottom to the top through a heater and a pump.

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