JP4526672B2 - Utilization of waste gypsum in gypsum board waste as a raw material for cement - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、ポルトランドセメントを製造する際の２水石膏源として、石膏ボード廃材中の石膏を利用する方法に関するものである。
【０００２】
【従来の技術】
石膏ボード廃材から紙を分離して得た石膏の利用方法として、加熱脱水して半水化せしめ、石膏ボードを製造する際の石膏源とする方法および所定の粒度に篩い分け、または粉砕して、土等を固める固化材の石膏源とする方法が、既に実用化されている。
また、石膏ボード廃材から分離した石膏あるいは粉砕のみを行った紙付きの石膏ボード廃材を焼成し、無水石膏として回収する利用方法が現在研究されている。
【０００３】
【発明が解決しようとする課題】
一般の石膏ボードには、その製造工程において、凝結促進剤として硫酸カリウムが、板紙との接着力向上を目的として酸化デンプンが、製造時におけるスラリーの流動性向上を目的として減水剤が、軽量化を目的として泡剤等が少量添加されおり、さらに防水ボードには、防水剤としてパラフィンエマルジョンが、耐火ボードにはガラス繊維、ひる石、抗火石等が、それぞれ添加されている。
【０００４】
これらの添加剤の影響により、石膏ボード廃材中の石膏をポルトランドセメントを製造する際の２水石膏源として使用した場合、ＪＩＳモルタル強度が低下することが知られており、排煙脱硫石膏等の２水石膏への２５重量％置換が、ポルトランドセメントを製造する際の使用限度であるとされている。
本発明は、上記問題点に鑑みてなされたものであり、その目的はモルタルの強度発現性を損なうことなく、石膏ボード廃材中の石膏をポルトランドセメントの２水石膏源として、２５重量％以上利用する方法を提供することである。
【０００５】
【課題を解決するための手段】
上述した本発明の目的は、紙分が２．５重量％以下となるように石膏ボード廃材から分離して得た石膏を含む２水石膏とクリンカとをＳＯ３量が１．６〜３．０重量％となるように計量し、粉砕機出口製品温度が１００〜１８０℃の条件下で混合粉砕することにより達成される。
【０００６】
本発明は、石膏ボード製造工程において使用されている添加剤が、ポルトランドセメントの性能に及ぼす影響および、その改善策を室内試験により検証し、改善策の有効性をセメント製造工程のボールミルを用いた実機試験において立証したことにより完成したものである。なお、以後の記述では、紙分が２．５重量％以下となるように石膏ボード廃材から分離して得た石膏を廃石膏と、セメント工場において定常使用されている排煙脱硫石膏等の石膏を２水石膏と、それぞれ記す。
請求項１に係る石膏ボード廃材中の廃石膏のセメント原料としての利用方法は、紙分が２．５重量％以下となるように石膏ボード廃材から分離して得た廃石膏を２５重量％以上含む２水石膏と、セメントクリンカとをＳＯ 3 量が１．６〜３．０重量％となるように計量し、粉砕機出口セメント製品温度が１００〜１８０℃となる条件下で混合粉砕することで、前記廃石膏中に含まれる合成界面活性剤系の泡剤の気泡性能を低下させて用いるようにしたことを特徴とするものである。
請求項２に係る発明は、請求項１に係る石膏ボード廃材中の廃石膏のセメント原料としての利用方法において、前記廃石膏の粒度が１０ｍｍ以下となるようにすることを特徴とするものである。
請求項３に係る発明は、請求項２に係る石膏ボード廃材中の廃石膏のセメント原料としての利用方法において、前記廃石膏中の紙分の混入率が１．０〜２．５重量％の場合は、前記２水石膏への廃石膏の置換率を２５〜７５重量％とし、前記廃石膏中の紙分の混入率が１．０重量％未満の場合は、前記２水石膏への廃石膏の置換率を２５〜１００重量％とすることを特徴とするものである。
【０００７】
【発明実施の形態】
石膏ボード製造工程において使用される添加剤の量は、硫酸カリウムが０．３〜０．５重量％、酸化デンプンが０．４〜０．６重量％、泡剤が０．０４〜０．１４重量％、減水剤が０．１〜０．２重量％であり、防水ボードには、さらにパラフィンエマルジョンが１．５〜６．０重量％添加されている。
【０００８】
これらの添加剤の中で、ＪＩＳモルタルにおける強度低下の主たる原因は泡剤であり、この強度低下については実施例に基づいて後述するが、モルタル混練り時に泡剤が空気を巻き込み、供試体中の空隙が増加したことによるものと考えられ、強度低下に伴い供試体重量の低下がみられる。
【０００９】
泡剤には、ポリオキシエチレンアルキルエーテルサルフェート、ポリオキシエチレンアルキルフェニルエーテルサルフェート、α−オレフィンスルホン酸塩等の合成界面活性剤系、ロジンせっけん、マレイン化ロジンせっけん等の樹脂せっけん系、加水分解タンパク系などがある。
本発明における廃石膏の利用方法は、石膏ボード製造時に使用される合成界面活性剤系の泡剤が１００℃以上の温度にさらされると、その気泡性能が極端に低下するという事実を見いだして完成したものである。
【００１０】
石膏ボード廃材は、ロール型クラッシャー等の破砕機でせん断力を加えることにより、容易に紙分を分離することができる。
本発明における廃石膏の粒度は、特に限定するものでないが、廃石膏への紙分の混入率を２．５重量％以下とするには、破砕機の構造にもよるが、１０ｍｍアンダーとするのが好ましい。
【００１１】
本発明において、廃石膏への紙分の混入率を２．５重量％以下と限定したのは、２．５重量％を超えると、クリンカとの混合粉砕時に粉砕機内詰りが発生すること、およびポルトランドセメントの粉末度（ブレーン）が上昇し、かつ凝結水量が増えることによるためである。
【００１２】
このため本発明において、廃石膏への紙分の混入率が１．０〜２．５重量％の場合は、２水石膏への廃石膏の置換率を５０〜７５重量％程度として使用することが好ましい。一方、紙分の混入率が１．０重量％未満の場合は、廃石膏を単味使用しても粉砕機の運転およびポルトランドセメントの性能上問題はない。
【００１３】
本発明におけるポルトランドセメント中のＳＯ３量１．６〜３．０重量％は、ポルトランドセメントの凝結調整剤として、石膏添加量を管理する際の一般的な値である。
【００１４】
本発明における粉砕機出口の製品温度は、１００〜１８０℃の範囲とする必要がある。
１００℃未満では、泡剤の気泡性能を完全に低下させることが難しく、１８０℃を超えると、ポルトランドセメント中の石膏の半水化および可溶性無水化に伴い、偽凝結が発生する可能性があるため、好ましくない。
【００１５】
粉砕機出口の製品温度を１００〜１８０℃に調整する方法は特に限定しないが、衝撃と摩擦により粉砕を行うボールミルを用いる場合は、運転中に出口製品温度が１２０℃程度となるため、熱風発生装置を必要とせず、経済的である。
なお、休止していたボールミルの運転開始時には、空転をして内部を１００℃以上にするか、２水石膏で運転を開始し、出口製品温度が１００℃を超えてから、廃石膏を使用した運転に切り替えることが好ましい。
【００１６】
以下、試験例に基づいて本発明を説明する。なお、実施例および比較例の粉末度試験、凝結試験、強さ試験は、「ＪＩＳＲ ５２０１（セメントの物理試験方法）」の規定にしたがっておこなった。
【００１７】
〔試験例１〕
石膏ボード廃材から手作業で紙部分を分離し、試製した廃石膏と２水石膏をそれぞれ乾燥後、試験室ミルで９０μｍ全通となるまで粉砕した。そして、２水石膏への廃石膏の置換率を０、２５、５０、７５、１００重量％とした混合石膏を試製し、実機ボールミルで粉砕した普通ポルトランドセメントクリンカ粉末にＳＯ3量が２．０重量％となるように混合した後、凝結試験および強さ試験を実施した。
【００１８】
試験結果を表１に示す。
この結果から、２水石膏に廃石膏を２５重量％を超えて置換した場合、モルタルの脱型重量および強度の低下が著しく、２５重量％程度の置換が廃石膏の使用限度であることが判る。
【００１９】
【表１】
〔試験例２〕
市販の普通ポルトランドセメント（第一セメント社製、ＳＯ3＝２．０重量％）に、硫酸カリウム、酸化デンプン、泡剤、減水剤、パラフィンエマルジョンをそれぞれ添加し、凝結試験および強さ試験を行った。なお、それぞれの添加量は、石膏源として廃石膏を単味使用した場合に、ポルトランドセメントに混入すると考えられる量を想定したものである。
【００２１】
それぞれの添加物の添加量および試験結果を表２に示す。
この結果から、ポルトランドセメントを製造する際の石膏源として、廃石膏を使用した場合にみられる、モルタルの脱型重量および強さの低下の主たる原因は、泡剤であることが判る。
【００２２】
【表２】
〔試験例３〕
市販の普通ポルトランドセメント（第一セメント社製、ＳＯ3＝２．０重量％）に対して、ポリオキシエチレンアルキルエーテルサルフェート系泡剤を１００ｍｇ／ｋｇ（石膏源として廃石膏を単味使用した場合に、ポルトランドセメントに混入する泡剤量）添加した。この普通ポルトランドセメントを２０℃、７５℃、１００℃、１５０℃、１８０℃、２００℃の条件下に２時間静置し、２０℃まで冷却した後、凝結試験および強さ試験を行った。
【００２４】
試験結果を表３に示す。
この結果より、ポリオキシエチレンアルキルエーテルサルフェート系泡剤は、１００℃以上の温度にさらされると、その起泡性能が極端に低下し、モルタルの脱型重量および強さの低下は見られなくなる。
しかしながら、普通ポルトランドセメントを２００℃の温度にさらした場合、石膏の半水化および可溶性無水化に伴う偽凝結が確認され、１８０℃を超える温度雰囲気に普通ポルトランドセメントをさらすことは、好ましくない。
【００２５】
【表３】
〔試験例４〕
石膏ボード廃材（厚さ９〜１２ｍｍ、紙の割合７ｗｔ％）を破砕機により破砕後、篩い分けにより２０ｍｍアンダー品、１０ｍｍアンダー品、５ｍｍアンダー品をそれぞれ試製した。これらの廃石膏を２水石膏へ０、２５、５０、７５、１００重量％置換後、石膏と普通ポルトランドセメントクリンカとをＳＯ3量が２．０重量％となるように計量し、実機ボールミルを用いて、セパレータ回転数一定の条件で、それぞれ混合粉砕した。粉砕後の普通ポルトランドセメントについては、粉末度試験、凝結試験および強さ試験を実施した。
【００２７】
なお、各粒度に調整した廃石膏については、９００℃で１５分間加熱し、強熱減量を測定することにより、紙分の混入率を算出した。
また、混合粉砕時の出口製品温度は、ミル内散水により１２０〜１４０℃の範囲となるように制御した。
【００２８】
試験結果を表４に示す。
この結果より、紙分の混入率が０．８重量％の５ｍｍアンダー品を単味使用（１００重量％置換）しても、普通ポルトランドセメントの性能上問題がないことが判る。
【００２９】
一方、紙分の混入率が１．９重量％の１０ｍｍアンダー品を単味使用した場合、ミル内詰まりによる過粉砕現象が原因であると考えられる粉末度の上昇および凝結水量の増加が確認された。このような現象を防ぐためには、２水石膏への廃石膏の置換率を低下させることが有効であり、紙分の混入率が１．９重量％の場合には、置換率の上限を５０重量％程度とすることが好ましい。
【００３０】
紙分の混入率が５．０重量％である、本発明範囲外の２０ｍｍアンダー品は、２５重量％置換においても、普通ポルトランドセメントの粉末度の上昇および凝結水量の増加がみられ、普通ポルトランドセメントの石膏源としては使用できない。
【００３１】
【表４】
【発明の効果】
本発明は、以上詳記したように、石膏ボード廃材中の石膏をセメント原料として大量に再利用することが出来るため、廃棄物処理に量的質的に多大に貢献する点、および温度雰囲気が粉砕熱の範囲内であるため、工業化するにあたり特別な手段を講じる必要がないので、実施化が容易なうえ経済的負担が軽微である点など、効果は極めて大きい。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of using gypsum in gypsum board waste as a source of two water gypsum when producing Portland cement.
[0002]
[Prior art]
As a method of using gypsum obtained by separating paper from gypsum board waste material, heat dehydration to make it semi-hydrated, a method of using gypsum board when producing gypsum board and sieving to a predetermined particle size, or crushing A method of using a gypsum source of a solidifying material that hardens soil and the like has already been put into practical use.
In addition, a method of using gypsum separated from gypsum board waste or gypsum board waste with paper that has only been crushed and recovered as anhydrous gypsum is currently being studied.
[0003]
[Problems to be solved by the invention]
In general gypsum board, potassium sulfate is used as a setting accelerator in the production process, starch starch is used to improve adhesion to paperboard, and water reducing agent is used to improve the fluidity of the slurry during production. For this purpose, a small amount of foaming agent or the like is added. Further, paraffin emulsion is added as a waterproofing agent to the waterproof board, and glass fiber, vermiculite, anti-fluorite, etc. are added to the fireproof board.
[0004]
Due to the influence of these additives, it is known that when gypsum in gypsum board waste is used as a source of 2-water gypsum when producing Portland cement, the strength of JIS mortar is reduced. A 25% by weight replacement with 2 gypsum is considered to be the limit of use in producing Portland cement.
The present invention has been made in view of the above problems, and its purpose is to use 25% by weight or more of gypsum in gypsum board waste as a source of dihydrate gypsum for Portland cement without impairing the strength development of mortar. Is to provide a way to do.
[0005]
[Means for Solving the Problems]
An object of the present invention described above, a 2 gypsum and clinker containing gypsum obtained by separating from gypsum board wastes as paper fraction is 2.5 wt% or less SO 3 amount 1.6 to 3. It is achieved by weighing to 0% by weight and mixing and grinding under conditions where the product temperature at the crusher outlet is 100 to 180 ° C.
[0006]
In the present invention, the effects of additives used in the gypsum board manufacturing process on the performance of Portland cement and its improvement measures were verified by laboratory tests, and the effectiveness of the improvement measures was determined using a ball mill in the cement manufacturing process. It was completed by demonstrating in the actual machine test. In the following description, gypsum obtained by separating from gypsum board waste so that the paper content is 2.5% by weight or less and gypsum such as flue gas desulfurization gypsum used regularly in cement factories. Are described as 2 gypsum.
The method for using waste gypsum in gypsum board waste according to claim 1 as a cement raw material is 25% by weight or more of waste gypsum obtained by separating from gypsum board waste so that the paper content is 2.5% by weight or less. 2 gypsum containing and cement clinker are weighed so that the amount of SO 3 is 1.6 to 3.0% by weight, and mixed and pulverized under the condition that the cement product temperature at the crusher exit is 100 to 180 ° C. Thus, the foam performance of the synthetic surfactant-based foaming agent contained in the waste gypsum is reduced and used.
The invention according to claim 2 is characterized in that, in the method of using waste gypsum in the gypsum board waste material according to claim 1 as a cement raw material, the waste gypsum has a particle size of 10 mm or less. .
The invention according to claim 3 is the method of using waste gypsum in the gypsum board waste material according to claim 2 as a cement raw material, wherein the mixing ratio of the paper in the waste gypsum is 1.0 to 2.5% by weight. In this case, the replacement rate of the waste gypsum to the dihydrate gypsum is 25 to 75% by weight, and when the mixing ratio of the paper in the waste gypsum is less than 1.0% by weight, the waste to the dihydrate gypsum is discarded. The substitution rate of gypsum is 25 to 100% by weight.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The amount of additive used in the gypsum board manufacturing process is 0.3 to 0.5% by weight of potassium sulfate, 0.4 to 0.6% by weight of oxidized starch, and 0.04 to 0.14 of foam. The water-reducing agent is 0.1 to 0.2% by weight, and the waterproof board is further added with a paraffin emulsion of 1.5 to 6.0% by weight.
[0008]
Among these additives, the main cause of strength reduction in JIS mortar is foaming, and this strength reduction will be described later based on examples. This is considered to be due to an increase in the voids of the specimen, and a decrease in the weight of the specimen is observed as the strength decreases.
[0009]
Foaming agents include synthetic surfactants such as polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, α-olefin sulfonate, resin soaps such as rosin soap and maleated rosin soap, hydrolyzed proteins There are systems.
The utilization method of waste gypsum in the present invention is completed by finding the fact that the foam performance of the synthetic surfactant-based foam used in the production of gypsum board is extremely lowered when exposed to a temperature of 100 ° C. or higher. It is a thing.
[0010]
Gypsum board waste can be easily separated by applying a shearing force with a crusher such as a roll crusher.
The particle size of the waste gypsum in the present invention is not particularly limited. However, in order to set the paper content in the waste gypsum to 2.5% by weight or less, although it depends on the structure of the crusher, it is under 10 mm. Is preferred.
[0011]
In the present invention, the mixing ratio of the paper to the waste gypsum is limited to 2.5% by weight or less, if it exceeds 2.5% by weight, clogging in the pulverizer occurs during mixing and pulverization with the clinker, and This is because the fineness (brane) of Portland cement increases and the amount of condensed water increases.
[0012]
For this reason, in the present invention, when the mixing ratio of the paper to the waste gypsum is 1.0 to 2.5% by weight, the replacement rate of the waste gypsum to dihydrate gypsum should be used as about 50 to 75% by weight. Is preferred. On the other hand, when the paper content is less than 1.0% by weight, there is no problem in the operation of the grinder and the performance of Portland cement even if the waste gypsum is simply used.
[0013]
The amount of SO 3 in the Portland cement in the present invention of 1.6 to 3.0% by weight is a general value when controlling the amount of gypsum added as a setting regulator of Portland cement.
[0014]
The product temperature at the exit of the pulverizer in the present invention needs to be in the range of 100 to 180 ° C.
Below 100 ° C., it is difficult to completely reduce the foam performance of the foam, and above 180 ° C., there is a possibility that pseudo-condensation may occur due to the semi-hydration and soluble dehydration of gypsum in Portland cement. Therefore, it is not preferable.
[0015]
The method of adjusting the product temperature at the crusher outlet to 100 to 180 ° C. is not particularly limited. However, when a ball mill that performs crushing by impact and friction is used, the outlet product temperature is about 120 ° C. during operation. It requires no equipment and is economical.
In addition, at the start of operation of the ball mill that had been suspended, the inside was rotated to 100 ° C or higher, or the operation was started with 2-water gypsum, and the waste product was used after the outlet product temperature exceeded 100 ° C. It is preferable to switch to driving.
[0016]
Below, the present invention will be described with reference to Test Examples. In addition, the fineness test, the setting test, and the strength test in Examples and Comparative Examples were performed according to the provisions of “JISR 5201 (cement physical test method)”.
[0017]
[Test Example 1]
The paper part was manually separated from the gypsum board waste, and the trial waste gypsum and 2-water gypsum were each dried and pulverized to 90 μm in a laboratory mill. Then, a mixed gypsum having a replacement rate of waste gypsum with dihydrate gypsum of 0, 25, 50, 75, and 100% by weight was trially produced, and an ordinary portland cement clinker powder pulverized with an actual ball mill had an SO 3 amount of 2.0. After mixing to a weight percentage, a setting test and a strength test were performed.
[0018]
The test results are shown in Table 1.
From this result, it is understood that when the amount of waste gypsum is replaced by more than 25% by weight with 2-water gypsum, the demolding weight and strength of the mortar are remarkably reduced, and replacement of about 25% by weight is the use limit of the waste gypsum. .
[0019]
[Table 1]
[Test Example 2]
Potassium sulfate, oxidized starch, foaming agent, water reducing agent, paraffin emulsion were added to commercially available ordinary Portland cement (Daiichi Cement Co., SO 3 = 2.0% by weight), and the setting test and strength test were conducted. It was. In addition, each addition amount assumes the quantity considered to mix in Portland cement, when waste gypsum is simply used as a gypsum source.
[0021]
The amount of each additive added and the test results are shown in Table 2.
From this result, it can be seen that the main cause of the decrease in the demolding weight and strength of mortar, which is seen when waste gypsum is used as the gypsum source when producing Portland cement, is the foaming agent.
[0022]
[Table 2]
[Test Example 3]
100 mg / kg of polyoxyethylene alkyl ether sulfate-based foaming agent for commercially available ordinary Portland cement (Daiichi Cement Co., SO 3 = 2.0% by weight) To the amount of foaming agent mixed in Portland cement). This ordinary Portland cement was allowed to stand for 2 hours at 20 ° C., 75 ° C., 100 ° C., 150 ° C., 180 ° C., and 200 ° C., cooled to 20 ° C., and then subjected to a setting test and a strength test.
[0024]
The test results are shown in Table 3.
From this result, when the polyoxyethylene alkyl ether sulfate-based foaming agent is exposed to a temperature of 100 ° C. or higher, its foaming performance is extremely lowered, and mortar demolding weight and strength are not reduced.
However, when ordinary Portland cement is exposed to a temperature of 200 ° C., pseudo-condensation associated with gypsum hemihydrate and soluble dehydration is confirmed, and it is not preferable to expose ordinary Portland cement to an atmosphere of temperature exceeding 180 ° C.
[0025]
[Table 3]
[Test Example 4]
Gypsum board waste (thickness 9 to 12 mm, paper ratio 7 wt%) was crushed with a crusher, and then 20 mm under, 10 mm under, and 5 mm under products were produced by sieving. After replacing these waste gypsum with 2-water gypsum at 0, 25, 50, 75, and 100% by weight, weigh gypsum and ordinary Portland cement clinker so that the SO 3 amount becomes 2.0% by weight. Each was mixed and pulverized under the condition of constant rotation of the separator. For ordinary Portland cement after grinding, a fineness test, a setting test and a strength test were performed.
[0027]
In addition, about the waste gypsum adjusted to each particle size, it heated at 900 degreeC for 15 minute (s), and the mixing rate of paper was calculated by measuring the ignition loss.
Moreover, the outlet product temperature at the time of mixing and pulverization was controlled to be in a range of 120 to 140 ° C. by watering in the mill.
[0028]
The test results are shown in Table 4.
From this result, it can be seen that there is no problem in the performance of ordinary Portland cement even when a 5 mm under product having a paper content of 0.8% by weight is used (100% by weight substitution).
[0029]
On the other hand, when using a 10 mm under product with a paper content of 1.9% by weight, an increase in fineness and an increase in the amount of condensed water, which are thought to be caused by excessive crushing due to clogging in the mill, were confirmed. It was. In order to prevent such a phenomenon, it is effective to reduce the replacement rate of waste gypsum into 2-water gypsum. When the mixing rate of paper is 1.9% by weight, the upper limit of the replacement rate is 50%. It is preferable to set the weight percent .
[0030]
A 20 mm under product outside the scope of the present invention with a paper content of 5.0% by weight shows an increase in the fineness of ordinary Portland cement and an increase in the amount of condensed water even when 25% by weight is substituted. Cannot be used as a source of gypsum.
[0031]
[Table 4]
【The invention's effect】
As described in detail above, the present invention can recycle a large amount of gypsum in gypsum board waste as a cement raw material, and therefore contributes greatly to the waste treatment quantitatively and in terms of temperature atmosphere. Since it is within the range of heat of pulverization, it is not necessary to take special measures for industrialization, so that the effect is extremely great in that it is easy to implement and the economic burden is small.
Claims (3)
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| JP4836143B2 (en) * | 2007-06-29 | 2011-12-14 | 太平洋セメント株式会社 | Gypsum board waste material processing method and cement manufacturing method |
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