JP3664830B2

JP3664830B2 - Papermaking wastewater sludge molding method and molded product

Info

Publication number: JP3664830B2
Application number: JP35993296A
Authority: JP
Inventors: 吉永松本; 卓伊藤
Original assignee: 株式会社日本水処理技研
Priority date: 1996-12-30
Filing date: 1996-12-30
Publication date: 2005-06-29
Anticipated expiration: 2016-12-30
Also published as: JPH10192895A

Description

【０００１】
【産業上の利用分野】
本発明は製紙業における抄紙工程において膨大に排出される廃水中のスラッジを、二次公害がなく且有効に再利用するための成形方法及び成形品に関するものである。
【０００２】
【従来技術】
製紙業においてはその抄紙工程で膨大な水が使用されるものであるから、抄紙後の廃水量も膨大であり且該廃水は当然に所定の廃水処理基準に適合した廃水処理がなされて放流される。
そしてかかる廃水処理に際しては該廃水中に多量に浮遊混在する有機物や無機物を捕捉し浮上分離或いは沈澱分離を図るうえから、活性汚泥菌や硫酸アルミニウム等の凝集剤によりフロックを形成させる手段が用いられている。
【０００３】
従来廃水処理で発生するスラッジは産業廃棄物処理業社に廃棄費用を以って処理させていたが、製紙業におけるスラッジ発生量は膨大で且該スラッジは含水率が８０乃至９０％にも昇るものであるから廃棄費用も極めて莫大なものとなり、特に近年では環境保全の見地から廃棄場所が著しく制限されるに至っている。
【０００４】
これがため製紙業界としては可能な限り発生するスラッジの減量減嵩化を図る必要に迫られており、かかる経緯から発生するスラッジを更に高温加熱処理することにより乾燥状で且実質的に１／５乃至１／１０程度まで減量減嵩化される乾燥スラッジとなすことに遂次転換されつつあるが、依然として多量に発生する乾燥スラッジの廃棄の問題を解決せねばならない。
加えて抄紙工程において排出される廃水中には、抄紙原料であるパルプ材の残滓やパルプ材に付着する砂泥分並びに各種微量金属分或いは凝集剤成分等が混在しているため、高温加熱処理された該乾燥スラッジの灰分中には少なくとも酸化珪素が３０％以上、酸化アルミニウム２０％以上、酸化マグネシウムや酸化鉄等の酸化金属類１０％が含まれ、更には固定炭素が９、０％以上及び微量の重金属類や揮発分類が含まれた組成のものである。
【０００５】
【発明が解決しようとする課題】
発明者等はかかる問題に鑑み鋭意研究を重ねた結果本発明に至ったものであって、本発明は製紙廃水スラッジを高温加熱処理してなる乾燥スラッジを、仮焼し破砕して所要粒度に整粒して仮焼スラッジ粉体となし且水、結合材、充填材及び潤滑材を適宜割合に配合して成形原料となしたるうえ、所要の成形型で加圧且焼成させ、以って使用安全性に優れ而も軽量で強靭性、耐火性、耐候性、断熱性及び吸音性に優れた汎用性の高い製品を形成することの可能な成形方法及び成形品を提供することにある。
【０００６】
【課題を解決するための手段】
上述の課題を解決するために本発明が用いた技術的手段は、製紙廃水より分離されたスラッジを高温加熱処理してなる乾燥スラッジを、予め９００乃至１３００℃の温度で仮焼し含有する水分や揮発分及び低沸点の混合物を分解揮散消去せしめたうえ破砕し、均質な成形品を形成させるうえから所要の粒度に整粒して仮焼スラッジ粉体となしたるうえ、安定した成形性と所望の性能を保持させるため該仮焼スラッジに対し水分５乃至２０％重量、澱粉やポリビニルアルコール、メチルセルロース或いはロジンからなる結合材を７乃至１５％重量、粘土からなる充填材を２０乃至３０％重量及び潤滑材を０、５乃至５、０％重量割合で配合させて成形原料となし、該成形原料を所要の成形型に注入若しくは填入させ且少なくとも５０ｋｇ／ｃｍ^２以上に加圧させながら９００乃至１３００℃の温度で焼成させる廃水スラッジの成形方法及びその成形品の構成、並びに成形原料に更に珪砂が２０乃至３０％重量配合されてなる廃水スラッジの成形方法及びその成形品の構成に存する。
【０００７】
上述の如き技術的手段を用いた本発明は以下のような作用を有する。即ち廃水スラッジを高温加熱処理して形成される乾燥スラッジを、その温度が９００乃至１３００℃で仮焼するため乾燥スラッジ内に残留する水分や揮発分、或いは固定炭素分等低沸点の混合物が完全に分解揮散し除去されるとともに、極めて微量に混在する重金属類も一部は揮散除去され且残余についても主成分たる酸化珪素や酸化アルミニウムに熔化封入されて固定される。
そして仮焼された乾燥スラッジは破砕され所要の粒度に整粒されて仮焼スラッジ粉体が形成されるものであるから、成形品の所望特性に合せた成形原料配合に際して結合材や充填材或いは潤滑材との分散性が高まり、且形成される成形品も均質な物性を保持する。
【０００８】
そして該仮焼スラッジ粉体には水分５乃至２０％重量、結合材７乃至１５％重量、充填材２０乃至３０％重量及び潤滑材０、５乃至５、０％重量割合で配合されて成形原料が形成されるため、粘性や可塑性が付与され多様な形状の成形型でも成形加工がなしえ、且成形加工に際しては少なくとも５０ｋｇ／ｃｍ^２以上の加圧と９００乃至１３００℃の温度で焼成されるものであるから、加圧条件を変えることにより多孔性から緻密性の構造が自在に形成しえ、更には焼成温度により成形原料の組成成分が熔化結合されて強靭性や耐摩耗性が著しく向上し、而も該焼成温度においては成形原料中の有機質からなる結合材等も分解消去されて成形品が形成される。
【０００９】
【実施例】
以下に本発明実施例を図に基づき詳細に説明すれば、図１は本発明の成形方法を示す工程図であって、乾燥スラッジ１は製紙業における抄紙工程で排出される廃水中のスラッジを脱水し若しくは直接燃焼ドラム内或いは赤外線ヒーター等で高温度で処理し略残余含水率が３％以下に加熱乾燥させてなるもので、抄紙に係るパルプ材の種類やその廃水処理に際して使用する凝集剤の種類や量によっても多少の変動はあるが、概ねその成分割合は灰分８０乃至８５％、固定炭素９乃至１２％、揮発分５乃至７％、その他リン、イオウ、ナトリウム及び塩酸等が１、５乃至２、５％重量割合からなる不定形状の炭化物であり、且灰分についての組成割合を見ると酸化珪素３０％以上、酸化アルミニウム２０％以上、金属酸化物１０％以上及び微量の重金属類からなるものである。
【００１０】
かかる乾燥スラッジ１を成形品の形成のために使用するには、焼成による成形加工上或いは製品に所要の特性を保持させるうえで障害となる揮発分を初め固定炭素或いは焼成温度以下の沸点を有する混在物等を揮散消去せしめ、更には微量重金属類を熔化固定するうえから仮焼２がなされる。この仮焼２の温度としては焼成に際しての成形加工温度と略等しい９００乃至１３００℃の温度範囲が好適であり、且仮焼２の時間は乾燥スラッジ１の組成如何で適宜に決定される。
【００１１】
仮焼２がなされた乾燥スラッジ１は製品の成形加工のための成形原料５の作成に際して各種の配合材料と均質な分散配合を図るため、及び製品に均質な品質と特性を保持させるうえから破砕し且所要の粒度に整粒３させて、予め所要粒度の仮焼スラッジ粉体４を形成する。かかる場合において製品が吸音材や断熱材等の建装材や、濾材やフィルター材の如く内部に多量の空隙所謂多孔質のものが要求される場合では粒径のやや大きなもの、即ち粒径としては略０、１乃至１、０ｍｍ程度のものが望ましく、反面製品に強靭性や耐摩耗性等の特性が要求されるものでは、緻密な構造のものが望まれるため粒径も１０乃至１００μｍ程度のものが好適である。
【００１２】
かくしてなる仮焼スラッジ粉体４は、成形に際しての加工性と形成される製品に所要の特性を付与せしめるため水分５乃至２０％重量、結合材７乃至１５％重量、充填材２０乃至３０％重量及び潤滑材０、５乃至５、０％重量割合とともに配合され、或いは更に珪砂２０乃至３０％重量割合とともに配合されて成形原料５とされる。かかる場合において成形原料５に水分５乃至２０％重量、結合材７乃至１５％重量及び潤滑材０、５乃至５、０％重量割合が配合される所以は、成形原料５に粘性と可塑性を付与せしめて成形型への注入や填入等成形加工を容易ならしめるためのものであり、且製品の形成時には分解或いは揮散消去されるものが好適であるところから結合材としては澱粉を初めポリビニルアルコールやメチルセルロース或いはロジン等が選択される。
更に潤滑材としては極めて多種に亘るものが使用できるが、代表的なものとしては、ポリエチレングリコールアルキルエステルやワックスエマルジョン、ステアリン酸エマルジョン或いはジブチルフタレート等が挙げられる。
【００１３】
而して製品の保持特性に合せて配合された成形原料５は、適宜の成形型に注入或いは填入させて所要の形状に成形させながら、少なくとも５０ｋｇ／ｃｍ^２以上の加圧のもとに９００乃至１３００℃の温度で焼成６させることにより図２に示す如き成形品７が形成されるものである。
かかる場合において形成される成形品７に多孔質７Ａの構造を求める場合には、成形原料５の配合として充填材や珪砂を少なくし且成形圧も５０乃至８０ｋｇ／ｃｍ^２と比較的低い圧力で而も９００乃至１１００℃程度の低い温度で焼成６させることが好ましく、他方成形品７に緻密且強靭な構造を求める場合では、成形原料５の配合として充填材や珪砂を多くして且成形圧も８０乃至１２０ｋｇ／ｃｍ^２と高い圧力で而も１１００乃至１３００℃程度の高い温度で焼成６させることが望まれる。
【００１４】
以下に成形原料５の配合組成を種々に変えて板状に成形のうえ焼成６してなる成形品７の性能について報告すれば、成形原料５の主成分として用いる仮焼スラッジ粉体４は、乾燥スラッジ１を１０８０℃の温度で３時間仮焼２したうえ破砕し、而してその平均粒径が０、３２ｍｍのものを用いた。
かかる仮焼スラッジ２に結合材として澱粉を、充填材には粘土或いは珪砂を、更に潤滑材にはステアリン酸エマルジョンを用いてそれぞれ配合組成のうえ、長さ６０ｍｍ、幅４０ｍｍ、厚さ１０ｍｍの板状に成形し、且６０ｋｇ／ｃｍ^２の加圧で而も１０８０℃の焼成温度で３時間焼成し形成した成形品７の性能は表１の通りである。
【００１５】
【表１】

【００１６】
【発明の効果】
本発明は上述の如く、製紙業における抄紙工程で多量に発生する廃水スラッジを高温加熱処理してなる乾燥スラッジを、９００乃至１３００℃の温度で仮焼することで含有水分や揮発分を初め固定炭素分並びに低沸点の混在分が分解揮散されて消去され、残余主成分が酸化珪素や酸化アルミニウム及び酸化金属類となり且微量の重金属類もこれら残余主成分と熔化されて封入固定される。そして該残余主成分が破砕されたうえ所要粒径に整粒させた仮焼スラッジ粉体に、僅かな結合材と潤滑材とともに充填材としての粘土や珪砂を配合させて成形原料となすものであるから、多様な製品形状のものでもその粘性並びに可塑性で成形加工でき、而も成形圧力と焼成温度によって多孔質のものから緻密構造のものまで広範囲な性質と性能を具備させた成形品が形成しえ、特に耐火性や吸音性、断熱性に優れることから各種の建装材はもとより濾材やフィルター材に好適であって、廃棄処理と環境汚染の問題の解決とも相俟って再利用性が高い等、極めて特長の多い製紙廃水スラッジの成形方法及び成形品である。
【図面の簡単な説明】
【図１】本発明成形方法を示す工程図である。
【図２】本発明成形品の説明図である。
【符号の説明】
１乾燥スラッジ
２仮焼
３整粒
４仮焼スラッジ粉体
５成形原料
６焼成
７成形品
７Ａ多孔質[0001]
[Industrial application fields]
The present invention relates to a molding method and a molded product for effectively reusing sludge in wastewater discharged enormously in a papermaking process in the paper industry without secondary pollution.
[0002]
[Prior art]
Since a large amount of water is used in the papermaking process in the paper industry, the amount of wastewater after papermaking is also enormous, and the wastewater is naturally discharged after being subjected to wastewater treatment that complies with the specified wastewater treatment standards. The
In such wastewater treatment, a means for forming flocs by a flocculant such as activated sludge bacteria or aluminum sulfate is used to capture organic substances and inorganic substances floating in a large amount in the wastewater to achieve floating separation or precipitation separation. ing.
[0003]
Conventionally, sludge generated in wastewater treatment has been processed by industrial waste processing companies with disposal costs. However, the amount of sludge generated in the paper industry is enormous, and the sludge has a water content of 80 to 90%. Therefore, the disposal cost is extremely enormous, and in recent years, in particular, the disposal site has been remarkably restricted from the viewpoint of environmental conservation.
[0004]
For this reason, the paper industry is forced to reduce the volume and volume of sludge generated as much as possible. The sludge generated from such circumstances is further dried at a high temperature by substantially 1/5. Although being gradually converted to dry sludge that is reduced to about 1/10, the problem of disposal of dry sludge generated in large quantities must still be solved.
In addition, the wastewater discharged in the papermaking process contains residues of pulp material, which is the raw material for papermaking, sand and mud adhering to the pulp material, various trace metals, and flocculant components. The ash content of the dried sludge contains at least silicon oxide at least 30%, aluminum oxide at least 20%, metal oxides such as magnesium oxide and iron oxide at 10%, and further, fixed carbon at 9, 0% or more. And a composition containing a trace amount of heavy metals and volatilization classification.
[0005]
[Problems to be solved by the invention]
As a result of intensive studies in view of such problems, the inventors have arrived at the present invention, and the present invention preliminarily fires and crushes dry sludge obtained by heat-treating paper wastewater sludge to the required particle size. After sizing to form calcined sludge powder, water, binder, filler and lubricant are mixed in appropriate proportions to form a raw material for molding, and pressurized and fired in the required mold. The object of the present invention is to provide a molding method and a molded product capable of forming a highly versatile product that is excellent in safety in use, lightweight, toughness, fire resistance, weather resistance, heat insulation and sound absorption. .
[0006]
[Means for Solving the Problems]
The technical means used by the present invention in order to solve the above-described problem is that moisture contained by pre-calcining dry sludge obtained by heat-treating sludge separated from papermaking wastewater at a temperature of 900 to 1300 ° C. In addition, it decomposes and volatilizes the mixture of volatile matter and low boiling point, and then crushes to form a homogeneous molded product. Then, the mixture is sized to the required particle size to become a calcined sludge powder and stable formability. In order to maintain the desired performance, the calcined sludge has a moisture content of 5 to 20%, a binder of starch, polyvinyl alcohol, methylcellulose or rosin of 7 to 15%, and a filler of clay of 20 to 30%. Weight and lubricant are blended in a proportion of 0, 5 to 5, 0% by weight to form a molding raw material, and the molding raw material is injected or filled into a required mold and at least 50 kg / cm. ^A method for forming wastewater sludge that is fired at a temperature of 900 to 1300 ° C. while being pressurized to ² or more, a structure of the molded product, a method for forming wastewater sludge in which 20 to 30% by weight of silica sand is further added to the forming raw material, and It exists in the composition of the molded product.
[0007]
The present invention using the technical means as described above has the following operations. That is, dry sludge formed by heat treatment of wastewater sludge is calcined at a temperature of 900 to 1300 ° C., so that a low boiling point mixture such as moisture, volatile components, or fixed carbon content remaining in the dry sludge is completely obtained. In addition to being decomposed and volatilized and removed, some of the heavy metals mixed in an extremely small amount are volatilized and removed, and the remainder is fixed by being melted and sealed in silicon oxide or aluminum oxide as the main component.
The calcined dry sludge is crushed and sized to the required particle size to form a calcined sludge powder. Therefore, a binder, filler or The dispersibility with the lubricant is increased, and the formed product also maintains uniform physical properties.
[0008]
The calcined sludge powder is blended at a moisture content of 5 to 20%, a binder of 7 to 15%, a filler of 20 to 30%, and a lubricant of 0, 5 to 5, and 0% by weight. Therefore, the molding process can be performed even with molds having various shapes and imparted with viscosity and plasticity, and the molding process is performed at a pressure of at least 50 kg / cm ² and a temperature of 900 to 1300 ° C. Therefore, by changing the pressing conditions, a porous to dense structure can be formed freely, and the composition components of the molding raw material are melted and combined with the firing temperature to significantly improve toughness and wear resistance. However, at the firing temperature, the organic binder in the molding raw material is also decomposed and erased to form a molded product.
[0009]
【Example】
The embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a process diagram showing the molding method of the present invention. The dry sludge 1 is a sludge in waste water discharged in the paper making process in the paper industry. Coagulant used for papermaking and its wastewater treatment, which is dehydrated or directly heated in an internal combustion drum or at a high temperature with an infrared heater and dried by heating to a residual water content of approximately 3% or less. Although there are some fluctuations depending on the type and amount, the component ratio is roughly 80 to 85% ash, 9 to 12% fixed carbon, 5 to 7% volatiles, other phosphorus, sulfur, sodium and hydrochloric acid, etc. 1, It is an irregularly shaped carbide consisting of 5 to 2, 5% by weight, and the composition ratio of ash is 30% or more of silicon oxide, 20% or more of aluminum oxide, 10% or more of metal oxide, and a trace amount It is made of metals.
[0010]
In order to use such dry sludge 1 for forming a molded article, it has a fixed carbon or a boiling point lower than the calcination temperature at the beginning of volatile matter which obstructs the molding process by firing or maintaining the required characteristics of the product. The calcination 2 is performed after volatilizing and erasing the mixed materials and further melting and fixing trace heavy metals. The temperature of the calcination 2 is preferably a temperature range of 900 to 1300 ° C., which is substantially equal to the molding processing temperature at the time of calcination, and the time of the calcination 2 is appropriately determined depending on the composition of the dry sludge 1.
[0011]
The dried sludge 1 that has been calcined 2 is crushed in order to achieve a homogeneous dispersion and blending with various compounding materials in the production of a molding raw material 5 for the molding process of the product, and to keep the product homogeneous quality and characteristics Then, the particle size is adjusted 3 to a required particle size, and a calcined sludge powder 4 having a required particle size is formed in advance. In such a case, if the product requires a building material such as a sound absorbing material or a heat insulating material, or a large amount of voids in the interior such as a filter material or a filter material, a product having a slightly larger particle size, that is, a particle size Is preferably about 0, 1 to 1, 0 mm. On the other hand, if the product requires characteristics such as toughness and wear resistance, a dense structure is desired, so the particle size is also about 10 to 100 μm. Are preferred.
[0012]
The calcined sludge powder 4 thus formed has a water content of 5 to 20%, a binder of 7 to 15%, and a filler of 20 to 30% in order to impart the required workability to the formed product and the formed product. In addition, it is blended together with the lubricants 0, 5 to 5, and 0% by weight, or further blended together with 20 to 30% by weight of silica sand to form the forming raw material 5. In such a case, viscosity and plasticity are imparted to the forming raw material 5 because the forming raw material 5 is mixed with 5 to 20% by weight of moisture, 7 to 15% by weight of the binder, and 0 to 5 to 5% by weight of the lubricant. It is intended to facilitate the molding process such as pouring and filling into the mold, and it is suitable to be decomposed or volatilized during the formation of the product. Or methylcellulose or rosin is selected.
Further, a very wide variety of lubricants can be used, but typical examples include polyethylene glycol alkyl esters, wax emulsions, stearic acid emulsions, dibutyl phthalate, and the like.
[0013]
Thus, the molding raw material 5 blended in accordance with the holding characteristics of the product is injected or filled into an appropriate mold and molded into a required shape, and is subjected to a pressure of at least 50 kg / cm ² or more. A molded product 7 as shown in FIG. 2 is formed by firing 6 at a temperature of 900 to 1300 ° C.
When the structure of the porous 7A is required for the molded product 7 formed in such a case, the filler and the silica sand are reduced as the composition of the molding raw material 5 and the molding pressure is 50 to 80 kg / cm ² at a relatively low pressure. However, it is preferable to sinter 6 at a low temperature of about 900 to 1100 ° C. On the other hand, when a compact and tough structure is required for the molded product 7, the filler 5 and the silica sand are increased as the composition of the molding material 5 and the molding pressure is increased. Further, it is desirable to perform the firing 6 at a high temperature of about 1100 to 1300 ° C. at a high pressure of 80 to 120 kg / cm ² .
[0014]
If the composition of the forming raw material 5 is variously changed and the performance of the molded product 7 formed by firing into a plate shape and firing 6 is reported below, the calcined sludge powder 4 used as the main component of the forming raw material 5 is: The dried sludge 1 was calcined 2 at a temperature of 1080 ° C. for 3 hours and crushed, and the average particle size was 0, 32 mm.
A plate having a length of 60 mm, a width of 40 mm, and a thickness of 10 mm is prepared by using starch as a binder, clay or silica sand as a filler, and stearic acid emulsion as a lubricant. Table 1 shows the performance of the molded product 7 formed into a shape and fired at a firing temperature of 1080 ° C. for 3 hours under a pressure of 60 kg / cm ² .
[0015]
[Table 1]

[0016]
【The invention's effect】
As described above, the present invention initially fixes moisture and volatile components by calcining dry sludge, which is produced by heat-treating wastewater sludge generated in large quantities in the papermaking process in the paper industry at a temperature of 900 to 1300 ° C. The carbon component and the low-boiling point mixture are decomposed and volatilized and erased, the remaining main components become silicon oxide, aluminum oxide, and metal oxides, and trace amounts of heavy metals are melted with these remaining main components and sealed. Then, the calcined sludge powder that has been crushed and sized to the required particle size is blended with clay and silica sand as a filler together with a small amount of binder and lubricant to form a molding raw material. As a result, it can be molded with a variety of product shapes with its viscosity and plasticity. Depending on the molding pressure and firing temperature, molded products with a wide range of properties and performance from porous to dense structures can be formed. It is particularly suitable for various building materials as well as filter media and filter materials because of its excellent fire resistance, sound absorption, and heat insulation properties, and it can be reused in combination with disposal treatment and the solution of environmental pollution problems. This is a papermaking wastewater sludge molding method and a molded product with many features such as high.
[Brief description of the drawings]
FIG. 1 is a process diagram showing a molding method of the present invention.
FIG. 2 is an explanatory diagram of the molded product of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dry sludge 2 Calcining 3 Size control 4 Calcining sludge powder 5 Molding raw material 6 Firing 7 Molded product 7A Porous

Claims

Wastewater sludge discharged in the papermaking process is dried by heating, is indefinite shape, the main component of ash is 30% or more of silicon oxide, 20% or more of aluminum oxide, 10% or more of other metal oxides, and fixed carbon is 9,0 % Or more of the simple sludge is calcined at a temperature of 900 to 1300 ° C., then crushed and sized to the required particle size to obtain a calcined sludge powder. 5 to 20% by weight of moisture, 7 to 15% by weight of a binder made of starch, polyvinyl alcohol, methyl sulrose or rosin, 20 to 30% by weight of a filler made of clay and 0, 5 to 5, 0% by weight of lubricant To form a molding raw material, and the molding raw material is poured or filled into a required mold and fired at a pressure of at least 50 kg / cm ² at a temperature of 900 to 1300 ° C. A method for forming papermaking wastewater sludge.

2. The method for forming papermaking wastewater sludge according to claim 1, wherein silica sand is further blended in the raw material composition in a proportion of 20 to 30% by weight.

A molded article formed by the molding method according to claim 1 or 2.