JPH0489400A - Production of acicular gypsum crystal - Google Patents
Production of acicular gypsum crystalInfo
- Publication number
- JPH0489400A JPH0489400A JP20357090A JP20357090A JPH0489400A JP H0489400 A JPH0489400 A JP H0489400A JP 20357090 A JP20357090 A JP 20357090A JP 20357090 A JP20357090 A JP 20357090A JP H0489400 A JPH0489400 A JP H0489400A
- Authority
- JP
- Japan
- Prior art keywords
- gypsum
- crystal slurry
- crystals
- milk
- lime
- 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.)
- Pending
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 97
- 239000010440 gypsum Substances 0.000 title claims abstract description 97
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 97
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000002002 slurry Substances 0.000 claims abstract description 41
- 235000011116 calcium hydroxide Nutrition 0.000 claims abstract description 19
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 19
- 238000010521 absorption reaction Methods 0.000 claims description 18
- 230000003647 oxidation Effects 0.000 claims description 11
- 238000007254 oxidation reaction Methods 0.000 claims description 11
- 230000018044 dehydration Effects 0.000 claims description 4
- 238000006297 dehydration reaction Methods 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 19
- 239000002245 particle Substances 0.000 description 16
- 239000007788 liquid Substances 0.000 description 13
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- 239000008267 milk Substances 0.000 description 3
- 210000004080 milk Anatomy 0.000 description 3
- 235000013336 milk Nutrition 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、針状石膏結晶の製造方法に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing acicular gypsum crystals.
［従来の技術］
従来の針状石膏結晶の製造方法は、次のように行われる
。まず、石灰乳にＳＯ２ガスを吸収させる。次いて、Ｓ
Ｏ２ガス吸収後の石灰乳を酸化させて石膏結晶スラリー
を得る。得られた石膏結晶スラリーを濃縮した後、脱水
して針状石膏結晶を得る。[Prior Art] A conventional method for producing acicular gypsum crystals is carried out as follows. First, milk of lime is made to absorb SO2 gas. Next, S
After absorbing O2 gas, milk of lime is oxidized to obtain gypsum crystal slurry. After concentrating the obtained gypsum crystal slurry, it is dehydrated to obtain acicular gypsum crystals.
従来の方法により得られた針状石膏結晶′は、１０〜２
０μｍの粒径を有する。The acicular gypsum crystals obtained by the conventional method have 10 to 2
It has a particle size of 0 μm.
［発明が解決しようとする課題］
しかしながら、１０〜２０μｍの粒径を有する石膏結晶
は、粒径が小さく不均一であるので、商品価値が低い。[Problems to be Solved by the Invention] However, gypsum crystals having a particle size of 10 to 20 μm have a low commercial value because the particle size is small and non-uniform.
このため、２０μｍ以上の比較的大きい粒径を有する石
膏結晶を製造する方法の開発が進められている。従来、
比較的大きい粒径を有する石膏結晶を効率よく製造する
方法は存在しなかった。For this reason, the development of a method for producing gypsum crystals having a relatively large particle size of 20 μm or more is underway. Conventionally,
There has been no method to efficiently produce gypsum crystals with relatively large particle sizes.
本発明はかかる点に鑑みてなされたものであり、比較的
大きい粒径を有する石膏結晶を効率よく得ることができ
る針状石膏結晶の製造方法を提供することを目的とする
。The present invention has been made in view of this point, and an object of the present invention is to provide a method for producing acicular gypsum crystals that can efficiently obtain gypsum crystals having a relatively large particle size.
［課題を解決するための手段］
本発明は、石灰乳にＳＯ２ガスを吸収させるＳＯ２ガス
吸収工程と、前記ＳＯ２ガス吸収後の石灰乳を酸化させ
て石膏結晶スラリーを得る酸化工程と、該石膏結晶スラ
リーを濃縮する濃縮工程と、濃縮後の石膏結晶スラリー
を脱水する脱水工程とを具偏する針状石膏結晶の製造方
法において、ＳＯ２ガス吸収下程で発生する石膏結晶の
１倍〜５倍量の該石膏結晶を含んた量の石膏結晶スラリ
を前記ＳＯ２ガス吸収工程に連続的に帰還させるように
したことを特徴とする針状石膏結晶の製造方法である。[Means for Solving the Problems] The present invention includes an SO2 gas absorption step in which milk of lime absorbs SO2 gas, an oxidation step in which a gypsum crystal slurry is obtained by oxidizing the milk of lime after absorbing the SO2 gas, and In a method for producing acicular gypsum crystals that includes a concentration step of concentrating a crystal slurry and a dehydration step of dehydrating the gypsum crystal slurry after concentration, the amount of gypsum crystals generated in the lower stage of SO2 gas absorption is 1 to 5 times This method of producing acicular gypsum crystals is characterized in that a gypsum crystal slurry in an amount containing the gypsum crystals is continuously returned to the SO2 gas absorption step.
［作用］
本発明の針状石膏結晶の製造方法によれば、ＳＯ２ガス
吸収工程で発生する石膏結晶の１倍〜５倍量の石膏結晶
を含む量の石膏結晶スラリーをＳＯ２ガス吸収工程に帰
還させて針状石膏結晶を製造する。このため、石膏結晶
スラリー中の石膏結晶は、酸化工程においてさらに成長
する。この結果、比較的大きい粒径を有する針状石膏結
晶か得られる。[Function] According to the method for producing acicular gypsum crystals of the present invention, gypsum crystal slurry in an amount containing 1 to 5 times the amount of gypsum crystals generated in the SO2 gas absorption process is returned to the SO2 gas absorption process. to produce acicular gypsum crystals. Therefore, the gypsum crystals in the gypsum crystal slurry grow further during the oxidation process. This results in acicular gypsum crystals having a relatively large particle size.
［実施例］
以下、本発明の実施例を図面を参照して具体的に説明す
る。[Example] Hereinafter, an example of the present invention will be specifically described with reference to the drawings.
第１図は、本発明の方法を示す工程図である。FIG. 1 is a process diagram showing the method of the present invention.
ます、ＳＯ２ガス吸収工程１０において、ＳＯ２ガス吸
収塔内で石灰乳にＳＯ２ガスを吸収させる。また、Ｓ
Ｏ２ガスを吸収させた石灰乳（以下、ＳＯ２吸収石灰乳
と省略する）の固液比は、１０〜２０重−％であること
か好ましい。ここで、固液比とは、固型物と液体の割合
をいう。次いて、酸化工程１２において、ＳＯ２吸収石
灰乳を酸化して、石膏結晶スラリーを得る。ＳＯ２吸収
石灰乳を酸化する方法としては、高圧酸化方式等が用い
られる。このとき、石膏結晶スラリーの固液比は、５〜
１０であることか好ましい。次いて、濃縮工程１４にお
いて、石膏結晶スラリーをンックナーにより濃縮する。First, in the SO2 gas absorption step 10, SO2 gas is absorbed into milk of lime in an SO2 gas absorption tower. Also, S
The solid-liquid ratio of the milk of lime that has absorbed O2 gas (hereinafter abbreviated as SO2-absorbed milk of lime) is preferably 10 to 20% by weight. Here, the solid-liquid ratio refers to the ratio of solid matter to liquid. Next, in an oxidation step 12, the SO2-absorbed milk of lime is oxidized to obtain a gypsum crystal slurry. As a method for oxidizing SO2-absorbing lime milk, a high-pressure oxidation method or the like is used. At this time, the solid-liquid ratio of the gypsum crystal slurry is 5 to
It is preferable that it is 10. Next, in a concentration step 14, the gypsum crystal slurry is concentrated using a cooker.
このとき、濃縮は、石膏結晶スラリーの固液比か１０〜
２０重量０６の範囲内になるように行う。その後、脱水
工程１６において、濃縮後の石膏結晶スラリーを遠心分
離機により脱水して石膏結晶を製造する。At this time, the concentration is determined by the solid-liquid ratio of the gypsum crystal slurry from 10 to
Do this so that the weight is within the range of 20 weight 06. Thereafter, in a dehydration step 16, the concentrated gypsum crystal slurry is dehydrated using a centrifuge to produce gypsum crystals.
二の一連の操作において、ＳＯ２カス吸収工程１０て発
生する右耳結晶を含む石膏結晶スラリを連続的にＳＯ２
ガス吸収工程１０に帰還させる。In the second series of operations, the gypsum crystal slurry containing the right ear crystals generated in the SO2 scum absorption step 10 is continuously
The gas is returned to the gas absorption step 10.
ここで、帰還させる石膏結晶スラリーの量は、ＳＯ２カ
ス吸収工程１０て発生した石膏結晶（以下、発生石膏結
晶と省略する）の１倍〜５倍量の石膏結晶を含む−に設
定する。これは、帰還させる石膏結晶スラリー中の石膏
結晶（以下、帰還石膏結晶と省略する）の量が発生石膏
結晶の量の１倍未満であると比較的大きな粒径を持つ石
膏結晶が得られず、帰還石膏結晶の量か発生石膏結晶の
量の５倍を超えると得られる石膏結晶スラリーのｐＨか
高くなるからである。ｐＨか高くなる原因は、ＳＯ２ガ
ス吸収石灰乳中のＣａＨ３Ｏ，か酸化工程で充分に酸化
されず石膏結晶とならすに残存するためである。Here, the amount of the gypsum crystal slurry to be returned is set to - containing 1 to 5 times the amount of gypsum crystals generated in the SO2 scum absorption step 10 (hereinafter abbreviated as generated gypsum crystals). This is because if the amount of gypsum crystals in the gypsum crystal slurry to be returned (hereinafter abbreviated as returned gypsum crystals) is less than one time the amount of generated gypsum crystals, gypsum crystals with a relatively large particle size cannot be obtained. This is because if the amount of returned gypsum crystals exceeds five times the amount of generated gypsum crystals, the pH of the resulting gypsum crystal slurry becomes high. The reason for the high pH is that CaH3O in the SO2 gas-absorbing lime milk is not sufficiently oxidized in the oxidation process and remains as gypsum crystals.
第２図は、発生石膏結晶の量に対する帰還石膏結晶の量
の比（以下、帰還比と省略する）と、酸化工程で得られ
た石膏結晶スラリーのｐＨとの関係を示すグラフである
。第２図から明らかなようこ、帰還比か５、すなわち帰
還石膏結晶の量が発生石膏結晶の量の５倍を超えると、
酸化工程で得られた右耳結晶スラリーのｐＨか急激に上
昇する。FIG. 2 is a graph showing the relationship between the ratio of the amount of returned gypsum crystals to the amount of generated gypsum crystals (hereinafter abbreviated as feedback ratio) and the pH of the gypsum crystal slurry obtained in the oxidation step. It is clear from Figure 2 that when the feedback ratio exceeds 5, that is, the amount of returned gypsum crystals exceeds the amount of generated gypsum crystals,
The pH of the right ear crystal slurry obtained in the oxidation process increases rapidly.
このようにして、比較的大きな粒径を何する針状石膏結
晶を製造することかできる。In this way, acicular gypsum crystals with relatively large particle sizes can be produced.
以下、本発明の効果を確認するために行った実験例を示
す。Examples of experiments conducted to confirm the effects of the present invention are shown below.
実験例１
３０００ｋｇの石灰乳にＳＯ２カス吸収塔により９００
ｍ３の８０２ガスを吸収させた。このとき、得られたＳ
Ｏ２ガス吸収石灰乳は、流量か４５ｍ３／ｈてあり、固
液比が１０重量％であった。次いて、ＳＯ２ガス吸収石
灰乳を空気により酸化して石膏結晶スラリーを得た。得
られた石膏結晶スラリーは、流量か４５ｍ”／ｈてあり
、固液比が１０重量％てあった。次いて、石膏結晶スラ
リーをンソクナーにより濃縮した。濃縮後の石膏結晶ス
ラリーは、流量が３０ｍ３／ｈてあり、固液比か１５重
量９６てあった。その後、濃縮後の石膏結晶スラリーを
遠心分離機により脱水して針状石膏結晶を得た。Experimental example 1 3000 kg of milk of lime was heated to 900 kg using an SO2 sludge absorption tower.
m3 of 802 gas was absorbed. At this time, the obtained S
The O2 gas-absorbing milk of lime had a flow rate of 45 m3/h and a solid-liquid ratio of 10% by weight. Next, the SO2 gas-absorbing milk of lime was oxidized with air to obtain a gypsum crystal slurry. The obtained gypsum crystal slurry had a flow rate of 45 m''/h and a solid-liquid ratio of 10% by weight.Then, the gypsum crystal slurry was concentrated using a soaker.The gypsum crystal slurry after concentration had a flow rate of The solid-liquid ratio was 15 and the weight was 96.Then, the concentrated gypsum crystal slurry was dehydrated using a centrifuge to obtain acicular gypsum crystals.
この操作は、濃縮後の石膏結晶スラリーを流量８ ｍ
３／ ｈ ％すなわち帰還比が約０６９でＳＯ２ガス吸
収工程に連続的に帰還させながら行った。In this operation, the concentrated gypsum crystal slurry was processed at a flow rate of 8 m
3/h%, that is, the feedback ratio was about 069, and the SO2 gas absorption step was continuously fed back.
なお、帰還比を算出する際に用いられる石膏結晶量は、
以下のようにして算出した。The amount of gypsum crystals used when calculating the feedback ratio is
It was calculated as follows.
石膏結晶量−流量×密度Ｘ固液比×石膏含有率・・・式
（Ｉ）
発生石膏結晶量は、流ｊｉ４５ ｍ ３／ ｈ、密度１
１００ｋｇ／ｍ３、固液比０．１、石膏含有率０゜３を
式（１）に代入して、１４８５ｋｇ／ｈである。Amount of gypsum crystals - flow rate × density
Substituting 100 kg/m3, solid-liquid ratio 0.1, and gypsum content rate 0°3 into equation (1), it is 1485 kg/h.
帰還石膏結晶量は、流量８ｍ’／ｈ、密度１１００ｋｇ
／ｍ３、固液比０．１５、石膏含有率１゜０を式（１）
に代入して、１３２０ｋｇ／ｈである。The amount of returned gypsum crystals is a flow rate of 8 m'/h and a density of 1100 kg.
/m3, solid-liquid ratio 0.15, gypsum content 1゜0 using formula (1)
Substituting into , it is 1320 kg/h.
したがって、帰還比は、約０．９となる。Therefore, the feedback ratio is approximately 0.9.
得られた針状石膏結晶の平均粒径をレーザ解析方法によ
り測定したところ２５μｍであった。The average particle size of the obtained acicular gypsum crystals was measured by a laser analysis method and was found to be 25 μm.
実験例２〜４
帰還させる濃縮後の石膏結晶スラリーの流量をそれぞれ
２０ｍ３／ｈ （帰還比約２．２）、３０ｍ３／ｈ（帰
還比約３．３） 、４５ｍ’ ／ｈ （帰還比５）にす
ることを除いて実験例１と同様にして実験例２〜４の針
状石膏結晶を得た。Experimental Examples 2 to 4 The flow rates of the concentrated gypsum crystal slurry to be returned are 20 m3/h (feedback ratio approximately 2.2), 30 m3/h (feedback ratio approximately 3.3), and 45 m'/h (feedback ratio 5), respectively. Acicular gypsum crystals of Experimental Examples 2 to 4 were obtained in the same manner as Experimental Example 1 except that
得られた各々の針状石膏結晶の平均粒径を実験例１と同
様にして測定したところ、それぞれ４０μｍ（実験例２
）、４５μｍ（実験例３）、５０μｍ（実験例４）であ
った。The average particle size of each of the obtained acicular gypsum crystals was measured in the same manner as in Experimental Example 1, and was found to be 40 μm (Experimental Example 2).
), 45 μm (Experimental Example 3), and 50 μm (Experimental Example 4).
比較例
３０００ ｋｇの石灰乳にＳＯ２ガス吸収塔により９０
０ｍ３のＳＯ２ガスを吸収させた。このとき、得られた
ＳＯ２ガス吸収石灰乳は、流量か４５ｍ’／ｈてあり、
固液比か１０重量９６てあった。次いて、ＳＯ２ガス吸
収石灰乳を空気により酸化して石膏結晶スラリーを得た
。得られた石膏結晶スラリーは、流量が４５ｍ３／ｈて
あり、固液比が１０重量％であった。次いて、石膏結晶
スラリーをシックナーにより濃縮した。濃縮後の石膏結
晶スラリーは、流量が３０ｍ３／ｈてあり、固液比か１
５重量％であった。その後、濃縮後の石膏結晶スラリー
を遠心分離機により脱水して針状石膏結晶を得た。Comparative Example 3000 kg of milk of lime was heated to 90 kg using an SO2 gas absorption tower.
0 m3 of SO2 gas was absorbed. At this time, the obtained SO2 gas-absorbing lime milk had a flow rate of 45 m'/h,
The solid-liquid ratio was 10% by weight and 96%. Next, the SO2 gas-absorbing milk of lime was oxidized with air to obtain a gypsum crystal slurry. The resulting gypsum crystal slurry had a flow rate of 45 m3/h and a solid-liquid ratio of 10% by weight. The gypsum crystal slurry was then concentrated using a thickener. The flow rate of the gypsum crystal slurry after concentration is 30 m3/h, and the solid-liquid ratio is 1.
It was 5% by weight. Thereafter, the concentrated gypsum crystal slurry was dehydrated using a centrifuge to obtain acicular gypsum crystals.
得られた針状石膏結晶の平均粒径を実験例１と同様にし
て測定したところ５０μｍであった。The average particle size of the obtained acicular gypsum crystals was measured in the same manner as in Experimental Example 1 and found to be 50 μm.
実験例１〜４および比較例の平均粒径の結果を第３図に
示すグラフに表した。第３図から明らかなように、本発
明の方法により得られた針状石膏結晶は、比較的大きな
平均粒径を有する。The results of the average particle diameters of Experimental Examples 1 to 4 and Comparative Examples are shown in the graph shown in FIG. As is clear from FIG. 3, the acicular gypsum crystals obtained by the method of the present invention have a relatively large average particle size.
［発明の効果］
以上説明した如く、本発明の針状石膏結晶の製造方法は
、比較的大きい粒径を有する石膏結晶を効率よく得るこ
とができるものである。[Effects of the Invention] As explained above, the method for producing acicular gypsum crystals of the present invention can efficiently obtain gypsum crystals having a relatively large particle size.
第１図は本発明の方法を示す工程図、第２図は、帰還比
と、酸化工程で得られた石膏結晶スラリーのｐＨとの関
係を示すグラフ、第３図は帰還比と、酸化工程で得られ
た石膏晶の平均粒径との関係を示すグラフである。
１０・・・Ｓ Ｏ２ガス吸収工程、１２・・・酸化工程
、１４・・・濃縮工程、１６・・・脱水工程。
出願人代理人 弁理士 鈴江武彦
針状石膏結晶
第１図
帰還比
第２図Fig. 1 is a process diagram showing the method of the present invention, Fig. 2 is a graph showing the relationship between the feedback ratio and the pH of the gypsum crystal slurry obtained in the oxidation process, and Fig. 3 is a graph showing the feedback ratio and the pH of the gypsum crystal slurry obtained in the oxidation process. It is a graph showing the relationship with the average particle size of gypsum crystals obtained in . 10...S O2 gas absorption step, 12... Oxidation step, 14... Concentration step, 16... Dehydration step. Applicant's representative Patent attorney Takehiko Suzue Acicular gypsum crystal Figure 1 Return ratio Figure 2
Claims (1)
程と、前記ＳＯ＿２ガス吸収後の石灰乳を酸化させて石
膏結晶スラリーを得る酸化工程と、該石膏結晶スラリー
を濃縮する濃縮工程と、濃縮後の石膏結晶スラリーを脱
水する脱水工程とを具備する針状石膏結晶の製造方法に
おいて、ＳＯ＿２ガス吸収工程で発生する石膏結晶の１
倍〜５倍量の該石膏結晶を含んだ量の石膏結晶スラリー
を前記ＳＯ＿２ガス吸収工程に連続的に帰還させるよう
にしたことを特徴とする針状石膏結晶の製造方法。an SO_2 gas absorption step in which milk of lime absorbs SO_2 gas; an oxidation step in which the milk of lime after absorption of SO_2 gas is oxidized to obtain a gypsum crystal slurry; a concentration step in which the gypsum crystal slurry is concentrated; and gypsum after concentration. In a method for producing acicular gypsum crystals comprising a dehydration step of dehydrating a crystal slurry, one of the gypsum crystals generated in the SO_2 gas absorption step
A method for producing acicular gypsum crystals, characterized in that an amount of gypsum crystal slurry containing 5 times to 5 times the amount of the gypsum crystals is continuously returned to the SO_2 gas absorption step.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20357090A JPH0489400A (en) | 1990-07-31 | 1990-07-31 | Production of acicular gypsum crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20357090A JPH0489400A (en) | 1990-07-31 | 1990-07-31 | Production of acicular gypsum crystal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0489400A true JPH0489400A (en) | 1992-03-23 |
Family
ID=16476316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20357090A Pending JPH0489400A (en) | 1990-07-31 | 1990-07-31 | Production of acicular gypsum crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0489400A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003066525A1 (en) * | 2002-02-08 | 2003-08-14 | F.L. Smidth Airtech A/S | Improvement of flue gas desulfurization gypsum-dewatering through crystal habit modification by carboxylic acids |
| CN104790041A (en) * | 2015-04-13 | 2015-07-22 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
-
1990
- 1990-07-31 JP JP20357090A patent/JPH0489400A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003066525A1 (en) * | 2002-02-08 | 2003-08-14 | F.L. Smidth Airtech A/S | Improvement of flue gas desulfurization gypsum-dewatering through crystal habit modification by carboxylic acids |
| CN104790041A (en) * | 2015-04-13 | 2015-07-22 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
| CN104790041B (en) * | 2015-04-13 | 2017-04-19 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
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