JPS6320782B2 - - Google Patents
Info
- Publication number
- JPS6320782B2 JPS6320782B2 JP57129653A JP12965382A JPS6320782B2 JP S6320782 B2 JPS6320782 B2 JP S6320782B2 JP 57129653 A JP57129653 A JP 57129653A JP 12965382 A JP12965382 A JP 12965382A JP S6320782 B2 JPS6320782 B2 JP S6320782B2
- Authority
- JP
- Japan
- Prior art keywords
- quicklime
- calcium hydroxide
- impurities
- emulsification
- emulsion
- 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
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 123
- 239000000292 calcium oxide Substances 0.000 claims description 63
- 235000012255 calcium oxide Nutrition 0.000 claims description 63
- 239000000920 calcium hydroxide Substances 0.000 claims description 55
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 54
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 54
- 238000004945 emulsification Methods 0.000 claims description 28
- 239000000839 emulsion Substances 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 235000019738 Limestone Nutrition 0.000 claims description 10
- 239000006028 limestone Substances 0.000 claims description 10
- 239000000571 coke Substances 0.000 claims description 5
- 230000001804 emulsifying effect Effects 0.000 claims description 5
- 239000000295 fuel oil Substances 0.000 claims description 5
- 230000000887 hydrating effect Effects 0.000 claims description 4
- 239000010742 number 1 fuel oil Substances 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 235000011116 calcium hydroxide Nutrition 0.000 description 49
- 239000012535 impurity Substances 0.000 description 24
- 238000000034 method Methods 0.000 description 21
- 239000013078 crystal Substances 0.000 description 12
- 239000002245 particle Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 230000036571 hydration Effects 0.000 description 7
- 238000006703 hydration reaction Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 239000011362 coarse particle Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229940043430 calcium compound Drugs 0.000 description 2
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229930014626 natural product Natural products 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- -1 quicklime hydrates Chemical class 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- RXCMFQDTWCCLBL-UHFFFAOYSA-N 4-amino-3-hydroxynaphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(N)=C(O)C=C(S(O)(=O)=O)C2=C1 RXCMFQDTWCCLBL-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- DGEZNRSVGBDHLK-UHFFFAOYSA-N [1,10]phenanthroline Chemical compound C1=CN=C2C3=NC=CC=C3C=CC2=C1 DGEZNRSVGBDHLK-UHFFFAOYSA-N 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000003321 atomic absorption spectrophotometry Methods 0.000 description 1
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 235000013373 food additive Nutrition 0.000 description 1
- 239000002778 food additive Substances 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- MCJGNVYPOGVAJF-UHFFFAOYSA-N quinolin-8-ol Chemical compound C1=CN=C2C(O)=CC=CC2=C1 MCJGNVYPOGVAJF-UHFFFAOYSA-N 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Description
本発明は、生石灰から高品位水酸化カルシウム
を製造する方法、詳しくは、生石灰を乳化率30〜
80％で乳化した後、固形分を分級して乳化物を得
る生石灰から高品位水酸化カルシウムを製造する
方法に関するものである。
水酸化カルシウムは強アルカリであり、中和
剤，排水処理剤として上下水道，公害防止用に、
又、漂白剤の製造原料、更には土壌の改質剤，建
設用材料，砂糖の精製，食品添加剤等、巾広い分
野に大量に消費されている化合物である。
一般に水酸化カルシウムは、石灰石をコーク
ス，石炭又は重油を使つて焼成し生石灰とし、こ
の生石灰を水で消化して水酸化カルシウムとする
方法で製造されている。
この方法は、水酸化カルシウムを安価にしかも
大量に製造することができるが、原料として石灰
石という天然物を直接用いるため、石灰石に由来
する不純物の種類およびその量は多く、燃料であ
るコークス，石炭，重油に由来する不純物も加わ
り、一般の化学品に比べてその純度は極めて低
い。そのため、使用分野は高純度を必要としない
粗野な分野か、不純物の除去工程を設けた分野に
限られている。
水酸化カルシウムに含まれる不純物としては、
CO2（即ちCaCO3），SiO2，Al2O3，Fe2O3，
MgO，SO4（CaSO4又はCaSO3）等があり、これ
らは総計で１〜5wt％もある。又、微量金属とし
て、Cr，Mn，Cu，Pb等があり、これらは10〜
1000ppm程含まれる。但し、その量および比率
は、石灰石の産地，コークス，石炭，重油の種類
によつて大巾に異なる。
又、石灰石は国内において数少ない自給天然資
源の一つであるが、石灰石の採掘が進むにつれて
その純度は低下する傾向にある。
以上のことから、水酸化カルシウムの高品位化
は極めて重要であり、高品位化することにより、
その需要は増大し、用途は拡大することになる。
従来より、水酸化カルシウムの高品位化には、
生石灰を篩にかけ、細粒を除いた後、水和させ
て、高品位の水酸化カルシウム得る方法がある。
これは燃料の燃えかす，砂，不純物の多い細粒生
石灰の除去が主目的である。しかしながら、該方
法による高品位化の効果は薄く、除去効果のある
不純物も、SiO2，Al2O3，SO4程度に限られてい
る。又、生石灰の表面をけずり取つた後、水和さ
せる方法がある。該方法は生石灰表面に付着した
燃料の燃えかすを除去するのが目的である。しか
しながら、生石灰の塊が不定形であることから、
その操作は極めて困難であり、大量生産できない
ばかりか、全表面をけずり取ることはできず、更
には生石灰内部の不純物を除くことは到底できな
い。又、生石灰を水和し、ほぼ完全に乳化して得
られる石灰乳を液体サイクロン又は湿式篩で処理
して、細粒部の水酸化カルシウムを得る方法があ
る。該方法は粗粒の砂分等を除くのが主目的であ
る。しかしながら、その効果は、SiO2，Al2O3の
除去程度に限られるばかりか、除去効果は小さ
い。
以上のことから鑑み、本発明者らは原料の不純
物の種類，含量の変動に左右されず、高品位でし
かも簡単なプロセスで経済的に水酸化カルシウム
を製造できる方法を確立すべく鋭意検討した結
果、生石灰の乳化をある範囲の乳化率で行ない、
固形分を分級により分離すれば高品位の水酸化カ
ルシウムが製造できることを見い出し本発明を完
成させた。
すなわち、本発明は生石灰を水和させて水酸化
カルシウムを製造する方法において、生石灰を乳
化率30〜80％の範囲で乳化した後、固形分を分級
して乳化物を得ることを特徴とする生石灰から高
品位水酸化カルシウムを製造する方法を提供する
ものである。
本発明を更に詳細に説明する。
本発明は生石灰を乳化率30〜80％の範囲で乳化
した後、固形分を分級して乳化物を得ることを必
須の要件とする。
本発明者らは、生石灰から高品位の水酸化カル
シウムを製造する方法を見い出すべく、生石灰の
水和および乳化に関して詳細に検討した。その結
果、三つの興味ある事実を発見した。
すなわち、生石灰の水和は非常に速く、短時間
のうちに完了する。しかしながら、乳化、すなわ
ち、数ミクロン程度の結晶および該結晶が数個か
ら十数個集合した水酸化カルシウムのスラリーに
なるには時間を要し、又、乳化は必ずしも水和生
石灰の表面からではなく、ある特定の部分から始
まり、最後には完全な乳化状態になる。又、完全
に乳化するまでの状態は、元の生石灰の形が均等
に細分化されていくのではなく、ある段階まで細
分化が進んだ時点、具体的には例えば、通常の塊
状生石灰の乳化では数ミリメートルから十数ミリ
メートルまでは細分化と乳化が同時に進み、それ
以後は乳化物が徐々に増え、それにつれて未乳化
物が漸次縮少していくのである。更に、乳化物の
不純物含量を乳化率で追つてみると、強い相関性
があり、乳化率が60％までは乳化物系中の不純物
が非常に少なく、70％から徐々に増え、80％を越
えると急激に増加することがわかつた。
これらのことについて本発明者らは、詳しくは
わからないが、次のように推察している。
すなわち、生石灰の水和は従来から言われてい
るように、極めて速く、水と反応して水酸化カル
シウムになる。しかし、水酸化カルシウムの結晶
化，結晶成長には時間を要し、数ミクロンに成長
した時点で母体である水和生石灰から単結晶及び
集合晶として離れ、水溶液中に懸濁、つまり乳化
する。又、生石灰の水和はその表面から進むが、
原料である生石灰が天然物であり、均質でないこ
とから水酸化カルシウムの結晶化は、ある特定の
結晶化容易な部分から進み、反応熱，結晶化及び
結晶成長による膨張で生石灰は細分化し、安定し
た時点で細分化は終わる。
更に、生石灰中の不純物のほとんどはカルシウ
ム化合物を形成し、不純物が水酸化カルシウムの
結晶化及び結晶成長を抑制すること、不純物のカ
ルシウム化合物の結晶化及び結晶成長や遅いこと
から、不純物の多い部分の乳化が遅延されること
によると考えている。
以上の説明からも明らかなように、生石灰の乳
化が不完全な状態で分級して、未乳化物を除くこ
とにより高品位の水酸化カルシウムが得られたの
である。
尚、本発明でいう乳化率とは、生石灰中の酸化
カルシウムを水酸化カルシウムに換算した値に対
する乳化物中の水酸化カルシウムの割合、すなわ
ち、水和生石灰から離れ水溶液中に懸濁した数ミ
クロン程度の結晶及び該結晶が数個から十数個集
合した水酸化カルシウム結晶の割合である。又、
該結晶は実質的に48メツシユの標準篩を通過し、
未乳化物は通過しないので乳化率の測定は48メツ
シユの標準篩を用いて行なつた。
本発明では、生石灰の乳化率を80％以下にする
ことが必須である。乳化率を80％より大きくする
と不純物も乳化し、乳化した水酸化カルシウムと
分離できなくなる。乳化率70％以下にすると、乳
化物に含まれる不純物量は更に少なくなるので望
ましい。乳化率60％以下では不純物量は極めて少
なくなり更に望ましい。乳化率60％より小さくし
ても更により以上の効果は見られない。又、乳化
率30％より小さくすると、乳化物の分級による分
離が困難となるばかりか、水酸化カルシウムの収
率の低下が大きくなるので好ましくない。乳化率
が40％以上になると乳化物の分級がより容易にな
るので望ましい。したがつて、本発明の乳化率の
範囲は30〜80％，望ましくは30〜70％，更に望ま
しくは40〜60％である。
又、生石灰の水和は水だけでなく、塩化カルシ
ウムや塩化ナトリウム等の塩水溶液を用いること
もできる。又、乳化装置としては、タンク式でも
キルン式でも、又、スクリユーミキサー式でもよ
い。又、回分式でも連続式でもよい。
乳化率は加える水の量，温度，時間，生石灰粒
径，撹拌等によつて調節できるが、乳化時間で調
節する方法が容易であり好ましい。
乳化物中の水酸化カルシウム濃度は、生石灰の
粒径，酸化カルシウムの結晶粒径，生石灰の密
度，生石灰に含まれる不純物の種類，量，更には
水和条件、例えば、温度，塩濃度によつて異なる
が、10〜40wt％とすることが適当であり、これ
は容易に実施できる。本発明法では、水を含まな
い水酸化カルシウムも得られる。すなわち、生石
灰に加える水の量を抑えて、乳化率（水和生石灰
から離れた数ミクロン程度の水酸化カルシウム結
晶の割合）が前述の範囲になつた時点で篩で処理
することにより、粉末状の水酸化カルシウムを得
る。
尚、本発明で用いる生石灰は、塊状生石灰、具
体的には石灰石をコークス，石炭又は重油で焼成
して得られた塊状生石灰が不純物の除去に対して
効果的であることから望ましい。又、塊状生石灰
の平均粒径は10〜100mmが不純物の除去効果，操
作面から好ましい。
又、生石灰を目開き10mm以上の篩で処理して得
られる粗粒部の生石灰を用いる場合、水酸化カル
シウムの高品位は更に進むので望ましい。
目開き20mm以上の篩で処理すると更に望まし
い。
次に乳化物と未乳化物の分級による分離につい
て説明する。
前述したように、未乳化物は均等に細分化され
ず、かなり大きい粗粒で存在しており、乳化物と
の粒径差が非常に大きいため、その分級は極めて
容易であり、従来法である生石灰をほぼ完全に乳
化して分級する方法と比べてはるかに容易であ
る。このことも本発明の大きな特徴である。
分級は液体サイクロン，篩，ハージング向流分
級器等、通常の分級器で容易に実施できる。
分級分離を行なう時の水酸化カルシウムの粒径
は、生石灰の粒径，乳化率等によつて多少異なる
が、未乳化物が粗粒であり、乳化物が微細である
ことから、2000ミクロン以下なら分級分離は容易
に実施できる。更に粒径が300ミクロン以下の場
合、乳化物と未乳化物を実質的に分離できるので
望ましく、100ミクロン以下なら更に望ましい。
尚、分級操作を行なう粒径を更に小さくしても水
酸化カルシウムの高品位化はそれ程進まず、反面
分級操作はやや難しくなり、乳化した水酸化カル
シウムの収率が低下する。
こうして高品位の水酸化カルシウムが得られる
が、これを過、更に乾燥して水酸化カルシウム
の粉末にしても良い。又、分級で得られた不純物
の多い未乳化物は更に乳化させて、低品位の水酸
化カルシウムとし、排水処理，土壌の改質等の粗
野な分野に用いることができる。
尚、本発明の予期しなかつた特徴として、次の
二点が挙げられる。
１得られる水酸化カルシウムは活性であり、反
応性に富む。２得られる水酸化カルシウムの溶解
速度が大きい。これらは水酸化カルシウムの純度
が高いことによるものと思われる。
次に本発明の特徴を列記する。
(1) 不純物の多い生石灰から、高品位の水酸化カ
ルシウムが得られる。
(2) 操作が簡単であり、経済的である。
(3) 得られる水酸化カルシウムは活性であり反応
性に富む。
(4) 得られる水酸化カルシウムの溶解速度が大き
い。
(5) 副生する粗悪な水酸化カルシウムも有効に使
える。
次に本発明の実施例を示すが、本発明はこれら
に限定されるものではない。又、実施例及び比較
例で示す部及び％は全て重量に基づくものであ
る。
尚、分析方法は下記の方法によつた。
CO2 小西式無水炭酸装置を用いた容量法（JIS
Ｒ 9011）
SiO2 過塩素酸法による沈殿をアルカリ溶融し
た後、１―アミノ―２―ナフトール―４―ス
ルホン酸による比色定量法（分光光度計使
用）
Al2O3 アンモニア水中和による沈殿をアルカリ
溶融した後、オキシンによる比色定量（分光
光度計使用）
Fe2O3 オルソフエナントロリン比色定量（分光
光度計使用）
MgO 原子吸光光度度法。
SO4 BaSO4生成による比濁法（分光光度計使
用）。
Cr，Mn，Ni フレームレス式原子吸光法。
実施例１〜４、比較例１〜２
30〜60mmの石灰石をコークスで焼成して得られ
た96％生石灰100部に水330部を加えて混合し水和
させ、乳化時間を変え、生成物を抜き出し、直ち
に48メツシユの標準篩で分級し、乳化物を得、不
純物の濃度を測定した。この結果を表１に示す。
実施例 ５
実施例１の生石灰を目開き127mmの篩で処理し
て得た粗粒部の97％生石灰100部に水330部を加え
て水和させ、10分後に48メツシユの標準篩で分級
し乳化物を得た。該乳化物の品質を表１に示す。
実施例 ６
実施例５の方法において、目開き25.4mmの篩で
処理する以外全て同様に操作したところ表１に示
す結果を得た。
実施例 ７
実施例６の方法において、9.2メツシユ（目開
き2000μ）の標準篩で分級する以外全て同様に操
作し、表１に示す結果を得た。
実施例 ８
実施例６の方法において、9.2メツシユ及び200
メツシユ（目開き74μ）の標準篩で分級する以外
成て同様に操作し、表１に示す結果を得た。
比較例 ３
実施例６の方法において、水和時間10時間にし
て完全に乳化させる以外は全て同様に操作し、表
１に示す結果を得た。
比較例 ４
比較例３で得られた乳化物を200メツシユの標
準篩で処理し、表１に示す結果を得た。
The present invention relates to a method for producing high-grade calcium hydroxide from quicklime.
The present invention relates to a method for producing high-grade calcium hydroxide from quicklime, which is emulsified at 80% and then classified to obtain an emulsion. Calcium hydroxide is a strong alkali and is used as a neutralizing agent and wastewater treatment agent for water supply, sewage, and pollution prevention.
It is also a compound that is consumed in large quantities in a wide range of fields, including raw materials for the production of bleach, soil conditioners, construction materials, sugar refining, and food additives. Generally, calcium hydroxide is produced by burning limestone with coke, coal, or heavy oil to produce quicklime, and then digesting this quicklime with water to produce calcium hydroxide. This method can produce calcium hydroxide cheaply and in large quantities, but because it directly uses a natural product called limestone as a raw material, there are many types and amounts of impurities derived from limestone, and there are many types and amounts of impurities derived from limestone. , Impurities derived from heavy oil are also added, and its purity is extremely low compared to general chemicals. Therefore, the field of use is limited to crude fields that do not require high purity or to fields that require a step to remove impurities. Impurities contained in calcium hydroxide include:
CO 2 (i.e. CaCO 3 ), SiO 2 , Al 2 O 3 , Fe 2 O 3 ,
There are MgO, SO 4 (CaSO 4 or CaSO 3 ), etc., and the total amount of these is 1 to 5 wt%. In addition, there are trace metals such as Cr, Mn, Cu, Pb, etc.
Contains about 1000ppm. However, the amount and ratio vary widely depending on the production area of limestone, the type of coke, coal, and heavy oil. In addition, limestone is one of the few self-sufficient natural resources in Japan, but as limestone mining progresses, its purity tends to decline. From the above, it is extremely important to improve the quality of calcium hydroxide, and by improving the quality of calcium hydroxide,
Its demand will increase and its uses will expand. Traditionally, to improve the quality of calcium hydroxide,
There is a method of obtaining high-grade calcium hydroxide by sieving quicklime to remove fine particles and then hydrating it.
The main purpose of this is to remove fuel embers, sand, and fine quicklime containing many impurities. However, the effect of improving the quality by this method is weak, and the impurities that can be removed are limited to about SiO 2 , Al 2 O 3 , and SO 4 . Another method is to scrape off the surface of quicklime and then hydrate it. The purpose of this method is to remove fuel residue adhering to the surface of quicklime. However, since the lump of quicklime is irregular in shape,
This operation is extremely difficult, and not only cannot it be mass-produced, but it is also impossible to scrape off the entire surface, and furthermore, it is impossible to remove the impurities inside the quicklime. There is also a method of hydrating quicklime and almost completely emulsifying it to obtain milk of lime, which is then treated with a liquid cyclone or a wet sieve to obtain calcium hydroxide in the form of fine particles. The main purpose of this method is to remove coarse particles such as sand. However, the effect is not only limited to the removal of SiO 2 and Al 2 O 3 but also the removal effect is small. In view of the above, the inventors of the present invention have conducted extensive studies to establish a method for economically producing calcium hydroxide in a simple and high-quality manner, regardless of the type and content of impurities in the raw materials. As a result, quicklime is emulsified within a certain range of emulsification rate,
They discovered that high-grade calcium hydroxide could be produced by separating the solid content by classification, and completed the present invention. That is, the present invention is a method for producing calcium hydroxide by hydrating quicklime, which is characterized by emulsifying quicklime to an emulsification rate of 30 to 80% and then classifying the solid content to obtain an emulsion. The present invention provides a method for producing high-grade calcium hydroxide from quicklime. The present invention will be explained in more detail. The essential requirement of the present invention is to emulsify quicklime to an emulsification rate of 30 to 80% and then classify the solid content to obtain an emulsion. The present inventors conducted detailed studies on hydration and emulsification of quicklime in order to find a method for producing high-grade calcium hydroxide from quicklime. As a result, we discovered three interesting facts. That is, the hydration of quicklime is very fast and is completed within a short period of time. However, it takes time to emulsify, that is, to form a slurry of calcium hydroxide containing crystals of several microns and a few to a dozen or more of these crystals, and emulsification does not necessarily occur from the surface of hydrated lime; It starts from a specific part and ends up in a complete emulsion. In addition, the state until complete emulsification is not that the original form of quicklime is evenly divided into small pieces, but when the subdivision has progressed to a certain stage, specifically, for example, when normal lump quicklime is emulsified. Then, fragmentation and emulsification proceed simultaneously from a few millimeters to more than ten millimeters, and after that, the emulsified matter gradually increases, and the unemulsified matter gradually shrinks accordingly. Furthermore, when we track the impurity content of the emulsion with the emulsification rate, there is a strong correlation; impurities in the emulsion system are very small until the emulsification rate reaches 60%, gradually increase from 70%, and reach 80%. It was found that the value increases rapidly when exceeded. Although the present inventors do not know the details of these matters, they speculate as follows. That is, as has been conventionally said, quicklime hydrates extremely quickly and reacts with water to form calcium hydroxide. However, it takes time for calcium hydroxide to crystallize and grow, and when it grows to several microns, it separates from the parent hydrated quicklime as single crystals and aggregated crystals, and is suspended, or emulsified, in an aqueous solution. Also, hydration of quicklime proceeds from its surface,
Since the raw material quicklime is a natural product and is not homogeneous, the crystallization of calcium hydroxide proceeds from a certain part that is easy to crystallize, and due to the heat of reaction, crystallization, and expansion due to crystal growth, the quicklime is fragmented and stabilized. At that point, the subdivision ends. Furthermore, most of the impurities in quicklime form calcium compounds, and impurities suppress the crystallization and crystal growth of calcium hydroxide, and the crystallization and crystal growth of impurity calcium compounds is slow and slow, so the parts with a lot of impurities This is thought to be due to the delay in emulsification of As is clear from the above explanation, high-grade calcium hydroxide was obtained by classifying quicklime in an incompletely emulsified state and removing unemulsified matter. The emulsification rate in the present invention refers to the ratio of calcium hydroxide in the emulsion to the value obtained by converting calcium oxide in the quicklime to calcium hydroxide, that is, the ratio of several microns of calcium hydroxide separated from the hydrated quicklime and suspended in the aqueous solution. This is the ratio of calcium hydroxide crystals that are composed of several to ten or more crystals. or,
the crystals pass substantially through a 48 mesh standard sieve;
Since unemulsified matter did not pass through, the emulsification rate was measured using a 48-mesh standard sieve. In the present invention, it is essential that the emulsification rate of quicklime be 80% or less. When the emulsification rate is greater than 80%, impurities are also emulsified and cannot be separated from emulsified calcium hydroxide. An emulsification rate of 70% or less is desirable because the amount of impurities contained in the emulsion is further reduced. An emulsification rate of 60% or less is more desirable since the amount of impurities is extremely small. Even if the emulsification rate is lower than 60%, no further effect is observed. On the other hand, if the emulsification rate is less than 30%, it is not preferable because it becomes difficult to separate the emulsion by classification and the yield of calcium hydroxide is greatly reduced. It is desirable that the emulsification rate is 40% or more because it makes classification of the emulsion easier. Therefore, the range of the emulsification rate of the present invention is 30 to 80%, preferably 30 to 70%, and more preferably 40 to 60%. Furthermore, for hydration of quicklime, not only water but also an aqueous salt solution such as calcium chloride or sodium chloride can be used. Further, the emulsifying device may be of a tank type, a kiln type, or a screw mixer type. Moreover, a batch type or a continuous type may be used. The emulsification rate can be adjusted by adjusting the amount of water added, temperature, time, quicklime particle size, stirring, etc., but the method of adjusting by emulsification time is easy and preferred. The concentration of calcium hydroxide in the emulsion depends on the particle size of quicklime, the crystal grain size of calcium oxide, the density of quicklime, the type and amount of impurities contained in quicklime, and the hydration conditions such as temperature and salt concentration. Although the amount varies, it is appropriate to set the content to 10 to 40 wt%, and this can be easily achieved. The method of the invention also yields water-free calcium hydroxide. In other words, by reducing the amount of water added to the quicklime and treating it with a sieve when the emulsification rate (the proportion of calcium hydroxide crystals several microns apart from the hydrated quicklime) reaches the above range, powdery of calcium hydroxide is obtained. The quicklime used in the present invention is preferably lump quicklime, specifically lump quicklime obtained by burning limestone with coke, coal, or heavy oil because it is effective in removing impurities. Further, the average particle size of the lump quicklime is preferably 10 to 100 mm from the viewpoint of impurity removal effect and operation. Further, when using coarse-grained quicklime obtained by processing quicklime through a sieve with an opening of 10 mm or more, it is desirable because the quality of calcium hydroxide is further improved. It is more preferable to use a sieve with an opening of 20 mm or more. Next, separation of emulsified and non-emulsified products by classification will be explained. As mentioned above, the unemulsified material is not evenly divided and exists as quite large coarse particles, and the difference in particle size from the emulsified material is very large, so it is extremely easy to classify it and cannot be classified using conventional methods. This method is much easier than the method of almost completely emulsifying and classifying quicklime. This is also a major feature of the present invention. Classification can be easily carried out using ordinary classifiers such as hydrocyclones, sieves, and Harding countercurrent classifiers. The particle size of calcium hydroxide during classification and separation varies somewhat depending on the particle size of quicklime, emulsification rate, etc., but since unemulsified material is coarse particles and emulsified material is fine, it is less than 2000 microns. Then classification separation can be carried out easily. Further, it is preferable that the particle size is 300 microns or less, since emulsified matter and non-emulsified material can be substantially separated, and particle size of 100 microns or less is even more desirable.
Incidentally, even if the particle size for performing the classification operation is further reduced, the quality of calcium hydroxide does not improve much, but on the other hand, the classification operation becomes somewhat difficult and the yield of emulsified calcium hydroxide decreases. In this way, high-grade calcium hydroxide is obtained, which may be filtered and further dried to form calcium hydroxide powder. In addition, the unemulsified material with many impurities obtained by classification is further emulsified to form low-grade calcium hydroxide, which can be used in crude fields such as wastewater treatment and soil improvement. Incidentally, the following two points can be mentioned as unexpected features of the present invention. 1 The calcium hydroxide obtained is active and highly reactive. 2. The dissolution rate of the resulting calcium hydroxide is high. This seems to be due to the high purity of calcium hydroxide. Next, the features of the present invention will be listed. (1) High-grade calcium hydroxide can be obtained from quicklime with many impurities. (2) It is easy to operate and economical. (3) The resulting calcium hydroxide is active and highly reactive. (4) The dissolution rate of the resulting calcium hydroxide is high. (5) Even the inferior calcium hydroxide produced as a by-product can be used effectively. Next, examples of the present invention will be shown, but the present invention is not limited thereto. Furthermore, all parts and percentages shown in Examples and Comparative Examples are based on weight. The analysis method was as follows. CO 2 Volumetric method using Konishi type anhydrous carbonation device (JIS
R 9011) After melting the precipitate by SiO 2 perchloric acid method with alkali, colorimetric determination method using 1-amino-2-naphthol-4-sulfonic acid (using a spectrophotometer) Al 2 O 3 Precipitate by hydration in ammonia water After alkali melting, colorimetric determination with oxine (using a spectrophotometer) Fe 2 O 3 orthophenanthroline colorimetric determination (using a spectrophotometer) MgO Atomic absorption spectrophotometry. Nephelometric method (using a spectrophotometer) using SO 4 BaSO 4 production. Cr, Mn, Ni frameless atomic absorption spectrometry. Examples 1 to 4, Comparative Examples 1 to 2 330 parts of water was added to 100 parts of 96% quicklime obtained by calcining 30-60 mm limestone with coke, mixed to hydrate, emulsification time was varied, and the product was extracted and immediately classified using a 48-mesh standard sieve to obtain an emulsion, and the concentration of impurities was measured. The results are shown in Table 1. Example 5 330 parts of water was added to 100 parts of coarse 97% quicklime obtained by processing the quicklime of Example 1 through a sieve with an opening of 127 mm to hydrate it, and after 10 minutes it was classified using a standard sieve with a mesh size of 48. An emulsion was obtained. The quality of the emulsion is shown in Table 1. Example 6 The same procedure as in Example 5 was repeated except for using a 25.4 mm sieve, and the results shown in Table 1 were obtained. Example 7 The same procedure as in Example 6 was carried out except that classification was carried out using a standard sieve of 9.2 mesh (mesh opening 2000 μm), and the results shown in Table 1 were obtained. Example 8 In the method of Example 6, 9.2 mesh and 200
The same procedure was performed except for classifying using a standard mesh sieve (mesh opening 74μ), and the results shown in Table 1 were obtained. Comparative Example 3 The procedure of Example 6 was repeated except that the hydration time was changed to 10 hours to achieve complete emulsification, and the results shown in Table 1 were obtained. Comparative Example 4 The emulsion obtained in Comparative Example 3 was processed through a 200-mesh standard sieve, and the results shown in Table 1 were obtained.
【表】【table】
Claims (1)
する方法において、生石灰を乳化率30〜80％で乳
化した後、固形分を分級して水酸化カルシウムの
乳化物を得ることを特徴とする生石灰から高品位
水酸化カルシウムを製造する方法。 ２ 生石灰が石灰石をコークス，石炭又は重油で
焼成して得られた塊状生石灰である特許請求の範
囲第１項記載の生石灰から高品位水酸化カルシウ
ムを製造する方法。 ３ 生石灰が生石灰を目開き10mm以上の篩で処理
して得られる粗粒部の生石灰である特許請求の範
囲第１項又は第２項記載の生石灰から高品位水酸
化カルシウムを製造する方法。 ４ 生石灰の乳化率を30〜70％にする特許請求の
範囲第１項から第３項のいずれか記載の生石灰か
ら高品位水酸化カルシウムを製造する方法。[Claims] 1. A method for producing calcium hydroxide by hydrating quicklime, which involves emulsifying quicklime at an emulsification rate of 30 to 80% and then classifying the solid content to obtain an emulsion of calcium hydroxide. A method for producing high-grade calcium hydroxide from quicklime, characterized by: 2. The method for producing high-grade calcium hydroxide from quicklime according to claim 1, wherein the quicklime is lump quicklime obtained by burning limestone with coke, coal, or heavy oil. 3. A method for producing high-grade calcium hydroxide from quicklime according to claim 1 or 2, wherein the quicklime is coarse-grained quicklime obtained by processing quicklime through a sieve with an opening of 10 mm or more. 4. A method for producing high-grade calcium hydroxide from quicklime according to any one of claims 1 to 3, wherein the emulsification rate of quicklime is 30 to 70%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12965382A JPS5921521A (en) | 1982-07-27 | 1982-07-27 | Manufacture of calcium hydroxide of high grade from quick lime |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12965382A JPS5921521A (en) | 1982-07-27 | 1982-07-27 | Manufacture of calcium hydroxide of high grade from quick lime |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5921521A JPS5921521A (en) | 1984-02-03 |
| JPS6320782B2 true JPS6320782B2 (en) | 1988-04-30 |
Family
ID=15014828
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12965382A Granted JPS5921521A (en) | 1982-07-27 | 1982-07-27 | Manufacture of calcium hydroxide of high grade from quick lime |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5921521A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020044434A (en) * | 2000-12-06 | 2002-06-15 | 이구택 | The method of producing quick lime to use limestone sludge |
| JP4513277B2 (en) * | 2003-05-23 | 2010-07-28 | 東レ株式会社 | Method for producing slaked lime slurry |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5070299A (en) * | 1973-10-26 | 1975-06-11 | ||
| JPS50161493A (en) * | 1974-06-20 | 1975-12-27 |
-
1982
- 1982-07-27 JP JP12965382A patent/JPS5921521A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5070299A (en) * | 1973-10-26 | 1975-06-11 | ||
| JPS50161493A (en) * | 1974-06-20 | 1975-12-27 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5921521A (en) | 1984-02-03 |
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