KR20130073500A - Sea water magnesia manufacturing method using sea water concentration - Google Patents

Sea water magnesia manufacturing method using sea water concentration

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Publication number
KR20130073500A
KR20130073500A KR1020110141377A KR20110141377A KR20130073500A KR 20130073500 A KR20130073500 A KR 20130073500A KR 1020110141377 A KR1020110141377 A KR 1020110141377A KR 20110141377 A KR20110141377 A KR 20110141377A KR 20130073500 A KR20130073500 A KR 20130073500A
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KR
South Korea
Prior art keywords
seawater
concentrated
magnesia
magnesium hydroxide
supernatant
Prior art date
Application number
KR1020110141377A
Other languages
Korean (ko)
Inventor
문정기
윤영기
곽명화
Original Assignee
재단법인 포항산업과학연구원
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 재단법인 포항산업과학연구원 filed Critical 재단법인 포항산업과학연구원
Priority to KR1020110141377A priority Critical patent/KR20130073500A/en
Publication of KR20130073500A publication Critical patent/KR20130073500A/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/02—Magnesia
    • C01F5/06—Magnesia by thermal decomposition of magnesium compounds
    • C01F5/08—Magnesia by thermal decomposition of magnesium compounds by calcining magnesium hydroxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/02—Settling tanks with single outlets for the separated liquid
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/14—Magnesium hydroxide
    • C01F5/22—Magnesium hydroxide from magnesium compounds with alkali hydroxides or alkaline- earth oxides or hydroxides

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

PURPOSE: A producing method of seawater magnesia using concentrated seawater is provided to produce seawater magnesia with high productivity and simple processes by using a solid-liquid separator and the concentrated seawater obtained from a seawater desalination process. CONSTITUTION: A producing method of seawater magnesia using concentrated seawater comprises the following steps: decarbonating the concentrated seawater obtained from a seawater desalination process; precipitating magnesium hydroxide by adding a precipitation agent to supernatant of the decarbonated concentrated seawater; separating and filtering magnesium hydroxide from the supernatant using a solid-liquid separator; and plasticizing the separated magnesium hydroxide. The seawater desalination process is a reverse osmotic pressure type seawater desalination process. The precipitation agent is one or more selected from Ca (OH)2 or NaOH. The producing method of seawater magnesia processes the supernatant without magnesium hydroxide with a nanofilter into concentrated water and processed water. [Reference numerals] (AA) Seawater; (BB) Pre/preprocess; (CC) Product water; (DD) Corrosiveness; (EE) Concentrate; (FF) Decarbonation; (GG) Precipitation; (HH,KK) Supernatant; (II) Ca (OH)_2 injection; (JJ) Separation (decanter); (LL) Processed water; (MM) Discharging; (NN) Plasticity

Description

Seawater magnesia manufacturing method using concentrated seawater {SEA WATER MAGNESIA MANUFACTURING METHOD USING SEA WATER CONCENTRATION}

The present invention relates to a seawater magnesia production method using concentrated seawater.

Oxide produced by extracting magnesium ions in seawater during the process of obtaining magnesia as a raw material of refractory is called seawater magnesia. As such, the process of obtaining magnesia using seawater removes ions that may cause the purity of seawater magnesia, such as bicarbonate ions and sulfate ions, and then sinters them to obtain seawater magnesia.

As shown in FIG. 2, in the conventional seawater magnesia manufacturing process, when seawater and hydrated lime are reacted, magnesium ions in seawater react with calcium hydroxide (Ca (OH) 2 ) of hydrated lime, resulting in magnesium hydroxide (Mg (OH)). 2 ) and precipitates as precipitates, and calcium ions in lime oil, calcium hydroxide, react with chlorine ions in seawater and are dissolved in supernatant after completion of the reaction in the form of calcium chloride (CaCl 2 ), so they are easily separated from magnesium hydroxide after filtration. The magnesium hydroxide is calcined to produce magnesium hydroxide.

However, magnesium ions in seawater also react to remove ions that may cause a decrease in purity of seawater magnesia such as bicarbonate ions and sulfate ions in seawater, and it is difficult to secure a large amount of seawater magnesia.

One aspect of the present invention is to provide a method of producing seawater magnesia having high productivity and a simple process.

One aspect of the present invention is a method for producing seawater magnesia, the step of decarbonizing the concentrated seawater generated in the seawater desalination process of treating the seawater, and by adding a precipitant to the supernatant of the concentrated seawater subjected to the decarbonation process Precipitating magnesium hydroxide, separating magnesium hydroxide from the supernatant on which magnesium hydroxide is precipitated by a solid-liquid separator, and filtering the supernatant from which magnesium hydroxide is separated with concentrated water and treated water with a nanofilter, and separating as described above. It provides a seawater magnesia manufacturing method using concentrated seawater comprising the step of firing the magnesium hydroxide.

In addition, the solution of the above-mentioned problems does not list all the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

According to the present invention, by using the concentrated seawater generated in the seawater desalination process, and using a solid-liquid separator, there is an effect that can be produced by the high productivity and simple process seawater magnesia.

In addition, according to the present invention, the nanofilter concentrated water can be supplied to freshwater to control the pH of the freshwater.

1 is a flow chart showing a seawater magnesia recovery process according to the present invention.
2 is a flowchart showing a seawater magnesia recovery process according to a conventional method.
FIG. 3 is a graph showing Mg, Ca, and B behaviors when seawater magnesia is recovered using general seawater and (b) seawater magnesia is recovered using concentrated seawater.

The present inventors conducted research to reduce the production cost and improve the productivity of seawater magnesia. As a result, by using concentrated seawater generated in the seawater desalination process, a large amount of seawater magnesia can be produced, and by using a solid-liquid separator, magnesium hydroxide It was possible to improve the precipitation process, and by filtering the supernatant of the solid-liquid separator with a nanofilter to supply concentrated water to fresh water, it was confirmed that the corrosiveness of fresh water can be improved and the present invention was reached.

Hereinafter, a seawater magnesia manufacturing method using concentrated seawater, which is an aspect of the present invention, will be described in detail with reference to FIG. 1.

The concentrated seawater used in the present invention is concentrated seawater discharged from a conventional seawater desalination process. As shown in Fig. 3, the concentrated seawater has a high content of ions including magnesium, so that a large amount of seawater magnesia can be obtained with a small amount of concentrated seawater. At this time, it is preferable to use concentrated seawater separated from fresh water in the seawater desalination plant.

More preferably, the seawater desalination plant uses concentrated seawater separated from freshwater through a seawater reverse osmosis (SWRO) process.

The concentrated seawater prepared as described above is subjected to a decarbonation process to improve the purity of magnesia. In order to perform the decarbonation process, the present invention uses an additive having a hydroxide ion group such as Ca (OH) 2 and NaOH.

When an additive having a hydroxide ion group is added to concentrated seawater for manufacturing seawater magnesia, bicarbonate ions such as HCO 3-react with the additive to form a precipitate. For example, when Ca (OH) 2 is added as an additive, bicarbonate ions such as HCO 3- react to form CaCO 3 precipitates. In this case, some of the magnesium may be precipitated together, but since the ions such as bicarbonate ions react and precipitate first, the effect of magnesium purity is less affected.

In addition, the precipitant per 1 l of concentrated seawater is preferably contained 10 to 15%, the stirring time of the decarbonation process is preferably 5 to 15 minutes.

Then, magnesium hydroxide is precipitated by adding an additive to the supernatant which has undergone the decarbonation process in which the precipitates such as CaCO 3 are removed. As the precipitant, an additive having a hydroxide ion group is used, and a preferred additive is at least one of Ca (OH) 2 and NaOH.

Next, the magnesium hydroxide is separated from the supernatant of magnesium hydroxide precipitated by a solid-liquid separator, and the supernatant from which magnesium hydroxide is separated is filtered through a nanofilter into concentrated water and treated water.

The precipitated magnesium hydroxide is, for example, dispersed in the form of a slurry having a particle diameter of 0.3 ~ 5㎛ and an average particle diameter of 2 ~ 5㎛. Therefore, when using a sedimentation basin to separate the magnesium hydroxide as in the prior art there is a problem that the precipitation is not easy, the size of the sedimentation tank is enlarged. Therefore, in the present invention, separation of magnesium hydroxide can be facilitated by using a solid-liquid separator.

On the other hand, concentrated seawater and freshwater are produced in the seawater desalination treatment process, in which the produced freshwater contains little ions and has a low pH and is therefore limited in use because of high corrosiveness. In one embodiment of the present invention, by supplying the concentrated water obtained by filtering the supernatant from which the magnesium hydroxide is separated by a nano-filter to fresh water, the pH of the fresh water can be controlled to improve the corrosiveness.

The concentrated water obtained by filtration with the nanofilter contains divalent ions such as Ca or Mg, and when the nanofilter concentrated water is supplied to freshwater, the pH of the freshwater may be increased. The treated water treated in the nanofilter is discharged.

Next, the magnesium hydroxide separated as above is calcined to prepare seawater magnesium.

Claims (5)

In the seawater magnesia manufacturing method,
Decarbonizing concentrated seawater generated in a seawater desalination process of treating seawater to produce fresh water;
Precipitating magnesium hydroxide by adding a precipitant to the supernatant of the concentrated seawater having undergone the decarbonation process;
Separating and filtering the magnesium hydroxide by a solid-liquid separator from the supernatant in which the magnesium hydroxide is precipitated as described above; And
Seawater magnesia production method using concentrated seawater comprising the step of firing the separated magnesium hydroxide as described above.
The method of claim 1,
Seawater magnesia production method using concentrated seawater, characterized in that the seawater desalination process is a reverse osmosis-type seawater desalination process.
The method of claim 1,
The precipitant is Ca (OH) 2 , NaOH seawater magnesia characterized in that using at least one of.
The method of claim 1,
Seawater magnesia manufacturing method characterized in that it further comprises the step of filtering the supernatant from which the magnesium hydroxide is separated with concentrated water and treated water with a nano-filter.
5. The method of claim 4,
The nanofilter concentrated water is a seawater magnesia production method characterized in that it is supplied to the fresh water.
KR1020110141377A 2011-12-23 2011-12-23 Sea water magnesia manufacturing method using sea water concentration KR20130073500A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020110141377A KR20130073500A (en) 2011-12-23 2011-12-23 Sea water magnesia manufacturing method using sea water concentration

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020110141377A KR20130073500A (en) 2011-12-23 2011-12-23 Sea water magnesia manufacturing method using sea water concentration

Publications (1)

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KR20130073500A true KR20130073500A (en) 2013-07-03

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2534235A (en) * 2014-12-12 2016-07-20 Taiwan Carbon Nanotube Tech Corp Method for fabricating metal electrode from seawater and generating electric power with metal electrode
WO2024128654A1 (en) * 2022-12-13 2024-06-20 포스코홀딩스 주식회사 Method of removing magnesium in brine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2534235A (en) * 2014-12-12 2016-07-20 Taiwan Carbon Nanotube Tech Corp Method for fabricating metal electrode from seawater and generating electric power with metal electrode
CN105990561A (en) * 2014-12-12 2016-10-05 台湾奈米碳管股份有限公司 Method for producing electric energy from seawater by producing metal electrodes
GB2534235B (en) * 2014-12-12 2018-06-06 Taiwan Carbon Nanotube Tech Corporation Method for fabricating metal electrode from seawater and generating electric power with metal electrode
WO2024128654A1 (en) * 2022-12-13 2024-06-20 포스코홀딩스 주식회사 Method of removing magnesium in brine

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