JPH0360774B2 - - Google Patents
Info
- Publication number
- JPH0360774B2 JPH0360774B2 JP62184584A JP18458487A JPH0360774B2 JP H0360774 B2 JPH0360774 B2 JP H0360774B2 JP 62184584 A JP62184584 A JP 62184584A JP 18458487 A JP18458487 A JP 18458487A JP H0360774 B2 JPH0360774 B2 JP H0360774B2
- Authority
- JP
- Japan
- Prior art keywords
- magnesium hydroxide
- slurry
- seawater
- light
- fired
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
Links
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 32
- 239000000347 magnesium hydroxide Substances 0.000 claims description 31
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 16
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000001095 magnesium carbonate Substances 0.000 claims description 7
- 235000014380 magnesium carbonate Nutrition 0.000 claims description 7
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 7
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 7
- 230000002194 synthesizing effect Effects 0.000 claims description 6
- 238000001354 calcination Methods 0.000 claims description 2
- 239000002002 slurry Substances 0.000 description 23
- 239000013535 sea water Substances 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 13
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 7
- 238000006477 desulfuration reaction Methods 0.000 description 6
- 230000023556 desulfurization Effects 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 229910001629 magnesium chloride Inorganic materials 0.000 description 6
- 238000006386 neutralization reaction Methods 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- 239000011777 magnesium Substances 0.000 description 5
- 125000004430 oxygen atom Chemical group O* 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000003513 alkali Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 230000003009 desulfurizing effect Effects 0.000 description 4
- 229910052839 forsterite Inorganic materials 0.000 description 4
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- 235000012245 magnesium oxide Nutrition 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 125000004429 atom Chemical group 0.000 description 3
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- 235000011121 sodium hydroxide Nutrition 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 description 2
- 235000010261 calcium sulphite Nutrition 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000008235 industrial water Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 229910019440 Mg(OH) Inorganic materials 0.000 description 1
- 206010067482 No adverse event Diseases 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910004283 SiO 4 Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000006114 decarboxylation reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- 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
- C01F5/16—Magnesium hydroxide by treating magnesia, e.g. calcined dolomite, with water or solutions of salts not containing magnesium
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Description
［産業上の利用分野］
本発明は活性水酸化マグネシウムの合成方法に
関し、さらに詳しくは、低粘度であるために高濃
度スラリーにすることができて運搬や貯蔵を容易
に行なうことができ、中和剤や脱硫剤として好適
な活性水酸化マグネシウムの合成方法に関する。
［従来の技術と発明が解決しようとする課題］
近年、排煙の脱流や排水の中和を行なうことに
よる環境汚染の防止に多大な努力が払われてい
る。
排気脱硫や排水の中和には、従来から、水酸化
マグネシウムが使用されている。
この水酸化マグネシウムは、従来海水中の塩化
マグネシウムを原料にして製造されている。
すなわち、海水中にはマグネシウムとして塩化
マグネシウムが存在するので、下式により水酸化
マグネシウムを製造することができる。
MgCl2＋Ca（OH）2→Mg（OH）2＋CaCl2
しかしながら、海水中にはマグネシウムは
1200ppm程度しか存在しない。この海水から得ら
れる塩化マグネシウムを原料とする水酸化マグネ
シウムの合成方法は、脱炭酸、上記式の反応、沈
降、洗浄、濃縮等の各工程を必要として製造工程
が複雑であり、また、濃縮して得られた30％前後
のスラリーの粘度が極めて高くて輸送に困難を生
じるという問題点を有している。したがつて、海
水を原料にして得られる水酸化マグネシウム（以
下、海水マグを略称する。）はコストの高いもの
になつている。
また、前記合成方法により得られる海水マグに
は不純物として水酸化カルシウムが含まれている
ので、海水マグを例えば脱硫剤として使用する
と、脱硫塔内に、亜硫酸カルシウムの堆積を生じ
て、脱硫塔の運転を頻繁に停止して脱硫塔内の清
掃を行なわねばならないという欠点が、海水マグ
にある。
一方、脱硫剤や中和剤として高活性の水酸化マ
グネシウムの合成方法として、天然産のマグネサ
イト（MgCO3）を焼成して得られる軽焼マグネ
シア（以下、軽焼マグと略称する。）を消和する
方法がある。
しかしながら、軽焼マグは、水に対する溶解性
がきわめて低く、それゆえに消和速度が遅いと言
う欠点がある。その上に消和の結果として得られ
る水酸化マグネシウムは、酸に対する反応速度が
遅いと言う欠点がある。
なお、このような軽焼マグの欠点は、次の理由
に由来すると推定される。すなわち、天然産のマ
グネサイトを800℃程度で焼成することにより得
られる酸化マグネシウムは、ペリクレース
（Periclase）型の結晶構造（Mg原子が６個の酸
素原子に囲まれた最密充填構造）を有するからで
ある。
本発明の目的は、一般に水に対して溶解困難で
消和速度が遅いとされている軽焼マグから、海水
から生産されている海水マグよりも酸に対する反
応性の高い水酸化マグネシウムを、簡単な製造工
程により製造することのできる方法を提供するこ
とにある。
［前記課題を解決するための手段］
前記目的を達成するための本発明は、天然産マ
グネサイトを焼成して得られる微粉砕された軽焼
マグと水とを、その液性をPH11以上にするととも
に85℃以上に加熱しながら消和させることを特徴
とする活性水酸化マグネシウムの合成方法であ
る。
マグネサイトの焼成は、一般に550℃〜1500℃
の範囲で行なわれるが、本法には650℃〜1300℃、
好ましくは800℃〜1200℃で焼成されたものがよ
い。この温度を超えたり越えたり、未満であつた
りすると、水酸化マグネシウムの活性度が劣る。
焼成の結果、ペリクレース型の軽焼マグが得ら
れる。マグネサイト中には、不純物としてヒレブ
ランダイト（Hillebrandite，2CaO・SiO2・
H2O）とフオルステライト（Forsterite，
Mg2SiO4）とが通常含まれている。前記焼成を
すると、このヒレブランダイトはラルナイト
（Larnite，2CaO・SiO2）に変化し、一方、
Forsteriteはそのまま残る。その結果、軽焼マグ
中にはLarniteとForsteriteとが不純物として残
存しているが、これらの不純物は、本発明の方法
によつて得られた活性水酸化マグネシウムを脱硫
剤や中和剤に使用する場合、何等の悪影響を及ぼ
すものではない。たとえば、本発明の活性水酸化
マグネシウムを排煙脱硫に使用するとき、不純物
であるカルシウム成分はLarniteの形態であるか
ら、脱硫塔内では亜硫酸カルシウムが形成され
ず、脱硫塔内に残存しても容易に洗浄除去するこ
とができる。
前記軽焼マグと水とを反応させるに当たり、軽
焼マグは微粉砕しておくことが望ましい。消和を
円滑に進行させるためである。
この軽焼マグの粒度としては１〜75μｍ、好ま
しくは１〜30μｍのものがよい。30μｍを超える
と消和が遅くなる。
消和に際し、水と軽焼マグとの混合割合は、
H2O／MgOとして表わすなら、3.5〜9.0mol比、
好ましくは5.0〜6.0mol比とする方がよい。
本発明における消和に際し、その液性はPH11以
上、好ましくは12以上である。PHが11以上である
と、後述する反応温度を特定温度に調整すること
によつて、消和系における軽焼マグのペリクレー
ス型構造が開裂する。すなわち、Mg原子を囲ん
でいる６個の酸素原子の内４〜５個の酸素原子が
水酸基に置き換わり、１〜２個の酸素原子がフリ
ーラジカル状の活性原子になる。このフリーラジ
カル状の酸素原子を有する構造に変化するので、
高活性水酸化マグネシウムが得られるものと推定
される。
本発明の方法において、消和に際する液性とし
てPHが11未満であると、高活性水酸化マグネシウ
ムの生成率が低下し、沈降性の大きい不活性水酸
化マグネシウムが生成する。
消和における液性のPHを前記の値にするために
は、アルカリ剤例えば苛性ソーダまたは水酸化カ
リウムなど強アルカリを反応系に添加するのが好
ましい。
混合する強アルカリの使用量は、水の量にもよ
つて一概に決定することはできないが、水に対す
るアルカリ量をH2O／alkaliとして表わすなら、
400〜2500mol比、好ましくは700〜800mol比と
する方がよい。
消和における反応温度は、85℃以上、好ましく
は95℃以上である。反応温度が85℃以上である
と、軽焼マグのペリクレース型構造の開裂が容易
に行なわれる。逆に反応温度が85℃未満である
と、消和の進行が遅くなる。
消和時間は、通常２〜３時間で十分である。
消和の終了後、反応生成液を冷却すると、高活
性水酸化マグネシウム含有のスラリー液が得られ
る。
このスラリーをそのまま製品として使用するこ
とができる。
本発明の方法によると、高活性水酸化マグネシ
ウムを高濃度で含有し、しかも低粘度のスラリー
が得られる。
［発明の効果］
本発明の方法によると、
(イ) 従来から消和が困難とされていた軽焼マグか
ら高活性水酸化マグネシウムを製造することが
できる。
(ロ) 高活性水酸化マグネシウムは45％の高濃度で
も製造することができて、しかも低粘度である
ため貯蔵や輸送に便利である。
(ハ) 海水中の塩化マグネシウムを原料にしないの
で、塩素含有量が殆ど０である活性水酸化マグ
ネシウムを製造することができ、したがつて、
この高活性水酸化マグネシウムを使用する場
合、機器の腐食を招くと言う問題がない。
(ニ) 簡単な製造工程により高活性水酸化マグネシ
ウムを製造することができる、
等の数々の優れた効果を奏する。
［実施例］
（実施例 １）
鉄製の攪拌機付きの、容積15m3である反応槽中
に工水10m3を張り込み、攪拌しながら工水中の苛
性ソーダ30Kgを添加し、これを十分に溶解した。
反応槽内の液のPHは12.5であつた。天然産マグネ
サイトを焼成して得た平均粒度５〜30ｍμの軽焼
マグ4000Kgをさらに添加して十分に混合攪拌し
た。その後攪拌しながらスチームにて混合液を加
熱し100℃に達した時点で加熱を停止した。軽焼
マグの添加後、３時間かけて消和を行なつた。消
和中、系内を攪拌し続けた。
反応終了後、反応槽内を冷却して、スラリーを
得た。
このスラリーに関するデータを第１表に示し
た。なお、市販の海水マグに関するデータも合せ
て第１表に示した。
第１表において、粘度は、Ｂ型粘度計（No.２ロ
ータを使用）を用いて液温約20℃で測定した値で
ある。粒度分布は、溶媒として水を使用し、液温
34〜35℃に調整して、セデイグラフにより測定し
た。
また、含有される高活性水酸化マグネシウムが
0.208モルになるようにスラリーを秤取り、この
スラリーと２規定硫酸200c.c.（0.2モル）とを混合
し、混合液のPHが６になるまでの時間を測定し
た。なお、中和反応時の液温は45〜50℃であつ
た。
混合液のPHの時間に対する変化を第２表に示し
た。なお、市販の海水マグの中和反応性をも合せ
て第２表に示した。
第１表に示されるように、本発明で製造された
高活性水酸化マグネシウムは、スラリー中に32.5
％も含有されていながら、そのスラリーの粘度は
360と極めて低く流動性に富む。これに対して、
海水中の塩化マグネシウムを原料にして製造され
た市販の海水マグは、海水マグの含有量がこの実
施例で得られたスラリーにおけるのとほぼ同程度
にありながら、海水マグのスラリーの粘度は異常
に高い。したがつて、本発明の方法により得られ
た高活性水酸化マグネシウム含有のスラリーは、
貯蔵性および輸送性に優れている。また、本発明
の方法により得られた水酸化マグネシウムは海水
マグよりもはるかに短い時間の内に硫酸を中和す
ることができたことがわかる。
（比較例 １）
消和反応時の反応温度を50℃にした以外は前記
実施例１と同様に実施して水酸化マグネシウム含
有のスラリーを得た。
このスラリーの特性と前記実施例１におけるス
ラリーとの比較を第３表にて行なつた。
得られたスラリーを用いて前記実施例１と同様
にして中和反応を行なつた。結果を第４表に示し
た。
（比較例 ２）
苛性ソーダを使用しないことのほかは前記実施
例１と同様に実施した。
得られたスラリーの特性と前記実施例１におけ
るスラリーとの比較を第３表にて行なつた。
得られたスラリーを用いて前記実施例１と同様
にして中和反応を行なつた。結果を第４表に示し
た。
（比較例 ３）
軽焼マグの代りに、海水中の塩化マグネシウム
から得られた水酸化マグネシウムを焼成して製造
された市販の軽焼マグを使用した以外は前記実施
例１と同様にして実施した。
得られたスラリーの特性と前記実施例１におけ
るスラリーとの比較を第３表にて行なつた。
得られたスラリーを用いて前記実施例１と同様
にして中和反応を行なつた。結果を第４表に示し
た。
[Industrial Application Field] The present invention relates to a method for synthesizing active magnesium hydroxide, and more specifically, it has a low viscosity, so it can be made into a highly concentrated slurry, and can be easily transported and stored. The present invention relates to a method for synthesizing active magnesium hydroxide suitable as an additive or a desulfurizing agent. [Prior art and problems to be solved by the invention] In recent years, great efforts have been made to prevent environmental pollution by draining flue gas and neutralizing wastewater. Magnesium hydroxide has traditionally been used for exhaust gas desulfurization and wastewater neutralization. This magnesium hydroxide has conventionally been produced using magnesium chloride in seawater as a raw material. That is, since magnesium chloride exists as magnesium in seawater, magnesium hydroxide can be produced by the following formula. MgCl 2 +Ca(OH) 2 →Mg(OH) 2 +CaCl 2However , there is no magnesium in seawater.
Only about 1200ppm exists. The method for synthesizing magnesium hydroxide using magnesium chloride obtained from seawater as a raw material requires a complex manufacturing process, requiring steps such as decarboxylation, reaction of the above formula, sedimentation, washing, and concentration. The problem is that the viscosity of the slurry obtained by this method is extremely high at around 30%, making it difficult to transport. Therefore, magnesium hydroxide (hereinafter abbreviated as seawater mag) obtained from seawater has become expensive. Furthermore, since the seawater mag obtained by the above synthesis method contains calcium hydroxide as an impurity, if seawater mag is used as a desulfurizing agent, for example, calcium sulfite will accumulate in the desulfurization tower. Seawater mugs have the disadvantage that operation must be stopped frequently to clean the inside of the desulfurization tower. On the other hand, as a method for synthesizing magnesium hydroxide, which is highly active as a desulfurizing agent and a neutralizing agent, light-fired magnesia (hereinafter abbreviated as light-fired mag), which is obtained by firing naturally produced magnesite (MgCO 3 ), is used. There is a way to reconcile it. However, light-fired mugs have a drawback that their solubility in water is extremely low, and therefore their dissipation rate is slow. Moreover, the magnesium hydroxide obtained as a result of slaking has the disadvantage of a slow reaction rate with acids. The drawbacks of such light fired mugs are presumed to be due to the following reasons. In other words, magnesium oxide, which is obtained by firing naturally occurring magnesite at around 800°C, has a periclase crystal structure (a close-packed structure in which Mg atoms are surrounded by six oxygen atoms). It is from. The purpose of the present invention is to easily replace magnesium hydroxide, which is more reactive to acids than seawater mags produced from seawater, from light-fired mags, which are generally considered to be difficult to dissolve in water and slow to dissipate. The object of the present invention is to provide a method that can be manufactured using a manufacturing process. [Means for solving the above-mentioned problems] The present invention for achieving the above-mentioned objects uses finely ground light-fired mag obtained by firing naturally produced magnesite and water to a pH of 11 or higher. This is a method for synthesizing active magnesium hydroxide, which is characterized in that it is slaked while heating at 85°C or higher. Magnesite is generally fired at 550°C to 1500°C.
However, this method includes temperatures ranging from 650℃ to 1300℃,
Preferably, it is fired at 800°C to 1200°C. If the temperature exceeds, exceeds, or falls below this temperature, the activity of magnesium hydroxide will be poor. As a result of firing, a periclase-type light fired mug is obtained. Magnesite contains impurities such as hillebrandite (2CaO・SiO2・
H 2 O) and forsterite (Forsterite,
Mg 2 SiO 4 ). When the calcination is performed, this hillebrandite changes to Larnite (2CaO・SiO 2 ), and on the other hand,
Forsterite remains. As a result, Larnite and Forsterite remain as impurities in the light fired mug, but these impurities can be removed by using activated magnesium hydroxide obtained by the method of the present invention as a desulfurizing agent or neutralizing agent. If you do so, there will be no adverse effects. For example, when the active magnesium hydroxide of the present invention is used for flue gas desulfurization, the impurity calcium component is in the form of Larnite, so calcium sulfite is not formed in the desulfurization tower and even if it remains in the desulfurization tower. Can be easily washed and removed. Before reacting the light baked mug with water, it is desirable that the light baked mug be finely pulverized. This is to facilitate reconciliation. The grain size of this light fired mug is preferably 1 to 75 μm, preferably 1 to 30 μm. If it exceeds 30 μm, dissipation will be slow. When slaked, the mixing ratio of water and light fired mug is as follows:
If expressed as H 2 O/MgO, the mol ratio is 3.5 to 9.0,
Preferably, the mol ratio is 5.0 to 6.0. When slaked in the present invention, the pH is 11 or higher, preferably 12 or higher. When the pH is 11 or higher, the periclase structure of the light fired mag in the slaked system is cleaved by adjusting the reaction temperature to a specific temperature, which will be described later. That is, 4 to 5 oxygen atoms out of 6 oxygen atoms surrounding the Mg atom are replaced with hydroxyl groups, and 1 to 2 oxygen atoms become active atoms in the form of free radicals. Because it changes to a structure with this free radical-like oxygen atom,
It is estimated that highly active magnesium hydroxide can be obtained. In the method of the present invention, if the liquid pH at the time of slaking is less than 11, the production rate of highly active magnesium hydroxide will decrease, and inactive magnesium hydroxide with high sedimentation properties will be produced. In order to bring the pH of the liquid to the above value during slaking, it is preferable to add an alkaline agent, such as a strong alkali such as caustic soda or potassium hydroxide, to the reaction system. The amount of strong alkali to be mixed cannot be determined unconditionally depending on the amount of water, but if the amount of alkali to water is expressed as H 2 O/alkali,
It is better to set the ratio to be 400 to 2500 mol, preferably 700 to 800 mol. The reaction temperature in slaked is 85°C or higher, preferably 95°C or higher. When the reaction temperature is 85° C. or higher, the periclase structure of the light fired mug is easily cleaved. Conversely, if the reaction temperature is less than 85°C, the progress of slaking will be slow. Generally, 2 to 3 hours is sufficient for the slaked time. When the reaction product liquid is cooled after completion of slaking, a slurry liquid containing highly active magnesium hydroxide is obtained. This slurry can be used as a product as it is. According to the method of the present invention, a slurry containing highly active magnesium hydroxide at a high concentration and having a low viscosity can be obtained. [Effects of the Invention] According to the method of the present invention: (a) Highly active magnesium hydroxide can be produced from light fired mag, which has been considered difficult to slake. (b) Highly active magnesium hydroxide can be produced even at a high concentration of 45%, and its low viscosity makes it convenient for storage and transportation. (c) Since magnesium chloride in seawater is not used as a raw material, active magnesium hydroxide with almost zero chlorine content can be produced, and therefore,
When using this highly active magnesium hydroxide, there is no problem of corrosion of equipment. (d) Highly active magnesium hydroxide can be produced through a simple production process, and many other excellent effects are achieved. [Example] (Example 1) 10 m 3 of industrial water was poured into a reaction tank with a volume of 15 m 3 equipped with an iron stirrer, and 30 kg of caustic soda in the industrial water was added while stirring, and this was sufficiently dissolved.
The pH of the liquid in the reaction tank was 12.5. 4000 kg of light fired mag with an average particle size of 5 to 30 mμ obtained by firing naturally produced magnesite was further added and thoroughly mixed and stirred. Thereafter, the mixed solution was heated with steam while stirring, and heating was stopped when the temperature reached 100°C. After the addition of the light burnt mug, the mixture was slaked for 3 hours. The inside of the system was continuously stirred during the quenching. After the reaction was completed, the inside of the reaction tank was cooled to obtain a slurry. Data regarding this slurry are shown in Table 1. Additionally, data regarding commercially available seawater mugs are also shown in Table 1. In Table 1, the viscosity is a value measured using a B-type viscometer (using No. 2 rotor) at a liquid temperature of about 20°C. Particle size distribution is determined by using water as a solvent and adjusting the liquid temperature.
The temperature was adjusted to 34 to 35°C and measured using a Sedigraph. In addition, the highly active magnesium hydroxide contained in
A slurry was weighed out so that the amount was 0.208 mol, and this slurry was mixed with 200 c.c. (0.2 mol) of 2N sulfuric acid, and the time until the pH of the mixture reached 6 was measured. Note that the liquid temperature during the neutralization reaction was 45 to 50°C. Table 2 shows the change in pH of the mixture over time. The neutralization reactivity of commercially available seawater mugs is also shown in Table 2. As shown in Table 1, the highly active magnesium hydroxide produced in the present invention contains 32.5%
%, but the viscosity of the slurry is
360, extremely low and highly liquid. On the contrary,
Although the content of commercially available seawater mugs manufactured using magnesium chloride in seawater as a raw material is approximately the same as that in the slurry obtained in this example, the viscosity of the slurry of seawater mugs is abnormal. expensive. Therefore, the highly active magnesium hydroxide-containing slurry obtained by the method of the present invention is
Excellent storage and transportability. It is also seen that the magnesium hydroxide obtained by the method of the present invention was able to neutralize sulfuric acid in a much shorter time than the seawater mug. (Comparative Example 1) A slurry containing magnesium hydroxide was obtained in the same manner as in Example 1 except that the reaction temperature during the slaked reaction was 50°C. Table 3 shows a comparison between the characteristics of this slurry and the slurry in Example 1. Using the obtained slurry, a neutralization reaction was carried out in the same manner as in Example 1 above. The results are shown in Table 4. (Comparative Example 2) The same procedure as in Example 1 was carried out except that caustic soda was not used. Table 3 shows a comparison between the properties of the obtained slurry and the slurry in Example 1. Using the obtained slurry, a neutralization reaction was carried out in the same manner as in Example 1 above. The results are shown in Table 4. (Comparative Example 3) Conducted in the same manner as in Example 1, except that instead of the light baked mug, a commercially available light baked mug produced by firing magnesium hydroxide obtained from magnesium chloride in seawater was used. did. Table 3 shows a comparison between the properties of the obtained slurry and the slurry in Example 1. Using the obtained slurry, a neutralization reaction was carried out in the same manner as in Example 1 above. The results are shown in Table 4.
【表】【table】
【表】
＊：単位は秒
[Table] *: Unit is seconds
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】
＊：単位は秒
前記実施例１と比較例１，２および３の結果を
比べると、特定の焼成マグネシアを特定の液性条
件および消和温度条件の下で消和することによつ
て初めて高活性水酸化マグネシウムを製造するこ
とのできることが解る。[Table] *: Unit is seconds Comparing the results of Example 1 and Comparative Examples 1, 2, and 3, it is found that slaked specific calcined magnesia under specific liquid conditions and slaked temperature conditions Only then did it become clear that highly active magnesium hydroxide could be produced.
Claims (1)
砕された軽焼マグネシアと水とを、その液性をPH
11以上にするとともに85℃以上に加熱しながら消
和させることを特徴とする活性水酸化マグネシウ
ムの合成方法。1. Finely ground light calcined magnesia obtained by calcining natural magnesite and water, and adjust the liquid property to PH.
A method for synthesizing active magnesium hydroxide, which is characterized in that it is made to be 11 or higher and slaked while being heated to 85°C or higher.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62184584A JPS6428214A (en) | 1987-07-23 | 1987-07-23 | Synthesis of active magnesium hydroxide |
| KR1019870015179A KR930003750B1 (en) | 1987-07-23 | 1987-12-29 | Synthesis method of active magnesium hydroxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62184584A JPS6428214A (en) | 1987-07-23 | 1987-07-23 | Synthesis of active magnesium hydroxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6428214A JPS6428214A (en) | 1989-01-30 |
| JPH0360774B2 true JPH0360774B2 (en) | 1991-09-17 |
Family
ID=16155766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62184584A Granted JPS6428214A (en) | 1987-07-23 | 1987-07-23 | Synthesis of active magnesium hydroxide |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS6428214A (en) |
| KR (1) | KR930003750B1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0599085A1 (en) * | 1992-10-29 | 1994-06-01 | Daicel Abosisangyo Co., Ltd. | Method for the production of active magnesium hydroxide |
| US9256158B2 (en) | 2010-06-11 | 2016-02-09 | Ricoh Company, Limited | Apparatus and method for preventing an information storage device from falling from a removable device |
| US10358364B2 (en) | 2013-10-24 | 2019-07-23 | Calix Ltd | Process and apparatus for manufacture of hydroxide slurry |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01294520A (en) * | 1988-01-13 | 1989-11-28 | Sankurei:Kk | Method for slaking naturally occurring light burned magnesia |
| JPH0363741U (en) * | 1989-10-26 | 1991-06-21 | ||
| JPH03151543A (en) * | 1989-11-08 | 1991-06-27 | Mazda Motor Corp | Idle revolution controller of engine |
| CN103115837B (en) * | 2013-01-05 | 2015-05-20 | 江苏苏博特新材料股份有限公司 | Method for testing content of magnesium oxide in magnesium oxide expanding agent |
-
1987
- 1987-07-23 JP JP62184584A patent/JPS6428214A/en active Granted
- 1987-12-29 KR KR1019870015179A patent/KR930003750B1/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0599085A1 (en) * | 1992-10-29 | 1994-06-01 | Daicel Abosisangyo Co., Ltd. | Method for the production of active magnesium hydroxide |
| US9256158B2 (en) | 2010-06-11 | 2016-02-09 | Ricoh Company, Limited | Apparatus and method for preventing an information storage device from falling from a removable device |
| US10358364B2 (en) | 2013-10-24 | 2019-07-23 | Calix Ltd | Process and apparatus for manufacture of hydroxide slurry |
| US10800683B2 (en) | 2013-10-24 | 2020-10-13 | Calix Ltd | Process for manufacture of hydroxide slurry |
| US11401183B2 (en) | 2013-10-24 | 2022-08-02 | Calix Ltd | Process for manufacture of hydroxide slurry |
Also Published As
| Publication number | Publication date |
|---|---|
| KR930003750B1 (en) | 1993-05-10 |
| KR890001876A (en) | 1989-04-06 |
| JPS6428214A (en) | 1989-01-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5705141A (en) | Calcium and/or magnesium hydroxide, and preparation and use thereof | |
| US1953201A (en) | Aluminum hydrate of low water content and process of producing the same | |
| CN104876253B (en) | The processing method of calcium in high-calcium fly ass | |
| JPH0360774B2 (en) | ||
| CN110563015B (en) | Preparation method of light calcium carbonate for food | |
| JPS63503535A (en) | How to produce zirconia | |
| JPS585174B2 (en) | Method for producing basic aluminum lactate | |
| JPS6335571B2 (en) | ||
| US2480901A (en) | Process for preparing fluxing materials | |
| US2132585A (en) | Purification of alkali metal hydroxides | |
| JP2614602B2 (en) | Continuous production method of platy dihydrate gypsum from sulfuric acid solution. | |
| JPH06191832A (en) | Preparation method of activated magnesium hydroxide | |
| US2716589A (en) | Process of re-forming magnesium bisulfite solution | |
| US2343151A (en) | Method of processing dolomite | |
| US2386389A (en) | Production of calcium and magnesium compounds from dolomite | |
| JP2000103617A (en) | Production of particulate barium carbonate | |
| JP7788482B2 (en) | Calcium carbonate manufacturing method | |
| JP7787924B2 (en) | Calcium carbonate manufacturing method | |
| KR20020004916A (en) | Manufacturing method of slaked lime | |
| Hoak et al. | Basicity factors of limestone and lime | |
| KR100404457B1 (en) | Method for manufacturing a magnesium hydroxide suspension for using as a counteragent | |
| JP2656443B2 (en) | Method for producing magnesium hydroxide | |
| US2257544A (en) | Calcium magnesium carbonate product and process of manufacture | |
| CN112142071A (en) | Sintering method seed precipitation mother liquor treatment method | |
| US2215966A (en) | Preparation of magnesium compounds |