JP2004002169A

JP2004002169A - Explosive composition

Info

Publication number: JP2004002169A
Application number: JP2003097596A
Authority: JP
Inventors: Hideaki Sugihara; 杉原　秀明; Yoshimasa Sato; 佐藤　善政
Original assignee: Nippon Kayaku Co Ltd
Current assignee: Nippon Kayaku Co Ltd
Priority date: 2002-04-01
Filing date: 2003-04-01
Publication date: 2004-01-08

Abstract

<P>PROBLEM TO BE SOLVED: To provide an explosive composition which has the low initiation sensitivity, has a high loading density as compared with ANFO explosive now in use without damaging the advantage that the handling of the ANFO explosive is convenient, is considerably improved not only in crushing effect but also in work effect and can make the perforation operation more efficient by widening a perforation interval. <P>SOLUTION: The explosive composition indispensably consists of ammonium nitrate porous prill which has an oil absorption rate of 5.0-20.0%, has a bulk density of 0.80-0.90 and contains no hollow fine particles and/or its crushed material and a fuel component. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、採石、採鉱、採炭、ずい道掘進等の産業用発破作業に広く利用される爆薬組成物に関する。更に詳しくは、被破壊物の穿孔に直接装填して使用し得るポーラスプリル硝酸アンモニウム（硝安）系の粒状の爆薬組成物に関する。
【０００２】
【従来の技術】
爆破作業等に用いられる産業用爆薬としては、ダイナマイト、含水爆薬、硝安爆薬、硝安油剤爆薬（ＡＮＦＯ爆薬）等が良く知られている。これらの爆薬のうち、ＡＮＦＯ爆薬は比較的簡単に製造できる爆薬であり、通常流動性のある粒状を呈しているので、穿孔内に直接流し込んだり、ローダー等の装填機によって装填したりすることもできるという特徴がある。
【０００３】
ポーラスプリル硝安の反応性がニトログリセリンやニトログリコールのような爆発性化合物に比べてかなり低いことは良く知られている。従って、ポーラスプリル硝安が酸化剤として爆薬全体の９０重量％以上を占めることの多いＡＮＦＯ爆薬は、他の産業用爆薬と比較して威力は低いが安価で安定、また、その起爆感度は、火薬学会規格ＥＳ−３２（２）に爆轟起爆試験方法として規定されている塩ビ雨どい試験又はカートン試験において６号雷管で完爆しないこととされており、その低感度故に例えば２５ｋｇ入り重袋への収納及びそれによる輸送が許されている等優れた取扱性を有するという点から、広く使用されている。
【０００４】
近年、粒径、嵩比重及び吸油率等において特定の物性を有するポーラスプリル硝安を使用した低比重・高威力ＡＮＦＯ爆薬（特許文献１、特許文献２、特許文献３及び特許文献４）により使用爆薬量の低減が達成され、発破作業の効率化が図られることから、同ＡＮＦＯ爆薬は従来のポーラスプリル硝安を用いて製造されたＡＮＦＯ爆薬に替わって、採石、採鉱等の産業用爆破用途に広く利用され始めている。
【０００５】
【特許文献１】
特開平７−６９７７２号公報
【特許文献２】
特開平９−２７８５７８号公報
【特許文献３】
特開２００１−３９７８９号公報
【特許文献４】
特開２００１−１８１０８０号公報
【特許文献５】
特開昭５５−５１７９４号公報
【特許文献６】
特開平１１−１４７７８４号公報
【特許文献７】
特開平１１−２７８９７４号公報
【特許文献８】
特開平１０−２９１８８３号公報
【特許文献９】
特開平１１−３２２４８１号公報
【特許文献１０】
特開平８−２９５５８８号公報
【特許文献１１】
特開平８−２６８７７号公報
【特許文献１２】
特開平１１−７９８７８号公報
【特許文献１３】
特開２０００−１６８９１号公報
【特許文献１４】
特開２０００−３２７４７３号公報
【０００６】
【発明が解決しようとする課題】
一方、実際の発破作業において装薬孔の穿孔作業はコスト及び効率面で大きなウェイトを占めており、穿孔間隔の拡張、即ち穿孔数の削減が可能となれば、発破作業の顕著な効率化が図られることは間違いないものの、これを実現するには１孔当たりに限られた装薬長で十分な薬量が装薬可能な高性能の爆薬が必要となる。穿孔径を増大させることにより、１孔当たりの装薬量の増加及び薬径効果による爆薬の威力増加を利用することも可能であるが、１孔当たりの穿孔時間が長くなり、根本的な解決には至らない。
【０００７】
一般的に爆薬の性能は、動的効果と静的効果に分けられ、前者は爆轟圧による破砕効果、後者は爆発生成ガスの断熱膨張による仕事効果とみられており、それぞれ爆速、弾動振子値の測定により求められる。爆轟圧は近似的にＰ≒１／４ρＤ^２（ρは爆薬の初期密度、Ｄは爆速）で表され、爆薬の初期密度、即ち装填比重及び爆速が高いほど大きくなる。しかしながら、装填比重の高い爆薬は一般的に起爆感度が低いため弾動振子値が低く、従って仕事効果が小さくなることは当業者の常識である。前記課題を達成するための高性能爆薬としては、高比重、且つ高感度であるという相反する特性が要求され、それ故、その解決方法は未だ見出されていない。
【０００８】
【課題を解決するための手段】
本発明者らは、ＡＮＦＯ爆薬において使用するポーラスプリル硝安の吸油率、嵩比重等の物性及びＡＮＦＯ爆薬の静的効果について鋭意研究をした結果、特定の物性を有するポーラスプリル硝安を使用したＡＮＦＯ爆薬が、雷管起爆性を示すことなく従来のＡＮＦＯ爆薬同様の優れた取扱性を有し、装填比重の上昇にも拘わらず、優れた破砕効果と共に著しく高い静的効果を示すことを見出し、本発明を完成させたものである。
【０００９】
すなわち本発明は、
（１）吸油率が５．０〜２０．０％、嵩比重が０．８０〜０．９０であり、中空微粒子を含有しないポーラスプリル硝酸アンモニウム（ａ）及び／又はその粉砕品及び燃料油を必須成分として含有することを特徴とする爆薬組成物、
（２）ポーラスプリル硝酸アンモニウム（ａ）及び／又はその粉砕品を全ポーラスプリル硝酸アンモニウム中、２０重量％以上の割合で含有する上記（１）に記載の爆薬組成物、
（３）全ポーラスプリル硝酸アンモニウム中、粒径１．６８〜２．３６ｍｍのものが６０．０重量％以上の割合で含有される上記（１）又は（２）に記載の爆薬組成物、
（４）ポ−ラスプリル硝酸アンモニウム（ａ）の硬度が０．５〜５．０％である上記（１）乃至（３）のいずれか１項に記載の爆薬組成物、
（５）装填比重が０．８８〜１．２０である上記（１）〜（４）のいずれか１項に記載の爆薬組成物
に関する。
【００１０】
【発明の実施の形態】
以下本発明を詳細に記載する。
本発明の爆薬組成物において必須成分として使用するポーラスプル硝安は、吸油率が５．０〜２０．０％で、嵩比重が０．８０〜０．９０であるポーラスプリル硝安（以下、ポーラスプリル硝安（ａ）という）又はその粉砕品であって、従来、低嵩比重のポーラスプリル硝安として、使用されてきたような中空微粒子を含有するものでなければ特に制限はない。ポーラスプリル硝安（ａ）は、爆薬組成物全体に対して通常６５〜９６重量％、好ましくは７５〜９５重量％の範囲で使用される。
本発明の爆薬組成物において、ポーラスプリル硝安（ａ）又はその粉砕品は、吸油率や嵩比重がこの範囲以外にある他のポーラスプリル硝安と併用することができる。他のポーラスプリル硝安と併用する場合、全ポーラスプリル硝安中、ポーラスプリル硝安（ａ）又はその粉砕品が２０重量％以上の割合で含有されることが好ましい。
更に本発明の爆薬組成物に使用されるポーラスプリル硝安としては、その粒径が１．６８〜２．３６ｍｍのものの含有量が６０．０重量％以上であるものが好ましい。
更に本発明の爆薬組成物に使用されるポーラスプリル硝安としては、その硬度が０．５〜５．０％、好ましくは０．５〜３．０％であるものが好ましい。
【００１１】
本発明の爆薬組成物において、ポーラスプリル硝安（ａ）（好ましくは前記粒度分布を有するポーラスプリル硝安）とその粉砕品とは、任意の比率で混合し得るものであるが、好ましくは非粉砕品に対するその粉砕品の混合割合は２０〜８０重量％である。このようにポーラスプリル硝安はそれ自身を粉砕したり、粉砕品を混合したりして所望の嵩比重のものとすることができる。
【００１２】
ポーラスプリル硝安の吸油率は、一定量の試料ポーラスプリル硝安を、軽油に一定時間浸しておいた後、吸引ろ過し、試験前後の重量差より軽油の吸着量を算出することによって測定される。詳しくは試料ポーラスプリル硝安５０ｇを直径４０ｍｍ、深さ５０ｍｍのガラスフィルター（１１Ｇ−１）に入れ、上皿直示天秤で秤量し、これを真空装置にセットする。ついでガラスフィルター中に軽油４０ｍｌを注入し、細い棒でよく撹拌し、ポーラスプリル硝安と軽油の混合接触を図る。５分間放置後、ガラスフィルターに付属した外部のコックを開放し、２分間軽油を自然流下させる。引き続き真空ポンプにて５分間吸引（流速：約３０ｌ／ｍｉｎ）した後、軽油を吸着した試料のポーラスプリル硝安の入ったままのガラスフィルターを、上皿直示天秤で秤量する。ここで増量分が軽油の吸着分である。以上の測定を終えた後、元の試料ポ−ラスプリル硝安５０ｇに対する軽油吸着分（ｇ）の比率（％）を、吸油率（％）として表示する。計算式は下記（１）式の通りである。
【００１３】
吸油率（％）＝軽油吸着分（ｇ）／試料５０（ｇ）×１００　　（１）
【００１４】
硝安の吸油率は、主として粒子の内部に分布する細孔の容積や有効径によって左右されるものであり、例えば細孔容積が大きければ、粒子内部に軽油を保持し得る空間が大となるので、吸油率が大となる。
【００１５】
ポーラスプリル硝安の嵩比重はＪＩＳ　Ｋ−６７２１に規定の方法に準じて測定される。即ち、一定量の試料ポーラスプリル硝安を一定の高さから、支持棒に支持された下部にダンパーを有する漏斗を用いて、支持台上に設置した円筒形コップ内に落下させ、コップ上に盛り上がった試料のポーラスプリル硝安を除去した後、コップ内の試料ポーラスプリル硝安を秤量することによって測定される。詳しくは、上端の直径９０ｍｍ、下端の直径１５ｍｍ、高さ１１５ｍｍの漏斗を、漏斗下端と支持台上の深さ８０ｍｍ、容積１００ｃｍ^３のコップ上端との距離が４５ｍｍとなるように設置し、漏斗内に試料のポーラスプリル硝安１００ｇを入れ、ダンパーをスライドさせてコップ内に試料のポーラスプリル硝安を落下させる。振動を与えないように注意してコップの上に盛り上がった試料のポーラスプリル硝安をヘラでコップの上端と同じ高さで水平になるように払いのける。次いでコップの外側に付着した試料のポーラスプリル硝安はこれを除去して、コップ内の試料ポーラスプリル硝安の重量を上皿直示天秤で秤量する。以上の測定を終えた後、下記（２）式により嵩比重を算出する。
【００１６】
嵩比重＝試料重量（ｇ）／１００（ｃｍ^３）　　（２）
【００１７】
ポーラスプリル硝安の粒度分布（重量％）は、一定量のポーラスプリル硝安を篩目の異なる各種篩を通し、各篩目毎の篩網上の残留分重量から測定される。
【００１８】
ポーラスプリル硝安の硬度は、一定量のポーラスプリル硝安の試料を硬度測定装置により一定の条件で機械的に粉砕し、粉砕された量を計ることにより測定される。
測定に使用される装置は、試料注入用漏斗、圧縮空気流入孔（内径４ｍｍ、長さ５５ｍｍ）に接続した流送管（内径１６ｍｍ、長さ１７５ｍｍ）、それら接続部上部と漏斗を垂直に接続する試料注入管（内径１２ｍｍ、長さ５２ｍｍ）及び流送管と垂直に接続した試料粉砕管（内径５０ｍｍ、長さ３１５ｍｍ）から構成されている。
【００１９】
３５ｍｅｓｈ篩で粉末を除去した試料硝安１００ｇを漏斗から試料注入管を通して流送管に落下注入し、流入孔から流入した圧縮空気（４ｋｇ／ｃｍ^２）により、試料を流送管を通して粉砕管内壁に衝突させ試料硝安を粉化させる。流送後の試料ポ−ラスプリル硝安を３５ｍｅｓｈで篩分けし、＋３５ｍｅｓｈ量（Ｎ）を秤量し、元の試料硝安１００ｇに対する粉化量の比率（％）として表示する。計算式は下記（３）式の通り。
硬度（％）＝１００（ｇ）−Ｎ（ｇ）　　　　（３）
【００２０】
本発明の爆薬組成物に用いられる燃料油としては、混合時に液体である燃料油を用いるのが好ましい。使用し得る燃料としては軽油、灯油等の鉱物油、植物油、動物油等が挙げられる。
【００２１】
この他、用途によってメチルアルコール、エチルアルコール等のアルコール類、パラフィンワックス、マイクロクリスタリンワックス等のワックス類、ジニトロトルエン、ジニトロキシレン等のニトロ化合物等を燃料油として単独又は混合して用いることができる。融点の高い燃料油は、それが液状になる温度以上で、ポーラスプリル硝安と混合する事によって用いることができる。
本発明の爆薬組成物に用いられる燃料油の使用量は、通常爆薬組成物全体の２．５〜２５重量％、好ましくは４〜１０重量％の範囲である。
【００２２】
本発明の爆薬組成物は必要によって、静電気発生防止の措置を施すことができる。例えば水溶性又は油溶性の帯電防止剤（特許文献５、特許文献６及び特許文献７）として知られる各種界面活性剤や、デンプン類（特許文献８）、脂肪酸アミド（特許文献９）等の添加剤を加えることができる。
【００２３】
本発明の爆薬組成物は、必要によりポーラスプリル硝安以外の酸化剤、例えば硝酸カリウムや過塩素酸塩、更には木粉、アルミニウム粉のような粉末追加燃料、あるいはポリアクリル酸ナトリウムのような増粘安定剤（特許文献１０）、シラスバルーンのような比重調整材（特許文献１１）、アンモニアガス抑制剤として知られる有機酸（特許文献１２）、吸水剤（特許文献１３、特許文献１４）等、他の添加剤を加えることが可能である。
【００２４】
本発明の爆薬組成物は、ニーダーあるいは回転ミキサーのような混合機で、ポーラスプリル硝安と燃料油を必須の成分として、さらに必要によりその他の添加剤を均一に混合することによって製造される。また、撹拌、混合の機能を備えているならば、他の混合機も使用可能である。
こうして得られた本発明の爆薬組成物は、その嵩比重が０．８１〜１．２０程度となる。爆薬組成物の嵩比重は、添加した油類はその添加量にもよるが、殆どポーラスプリル硝安に吸収されるためポーラスプリル硝安の嵩比重によって決定される度合いが大きく、ポーラスプリル硝安の嵩比重と大きな差は生じない。また、得られた爆薬組成物の装填比重は、通常０．８８〜１．２０である。装填比重は、爆薬組成物１，０００ｇを内径６８ｍｍ、長さ６００ｍｍの鋼管内に漏斗を使用して流し込み、１０回ほど上下に振動を与えることによってタンピングした後、装薬長を測定し、これから算出した装薬容積と装填薬量（１，０００ｇ）により算出することができる。
【００２５】
本発明の爆薬組成物は、穿孔径の増大を必要とせず１孔当たりの装薬量を一定の装薬長で増加させることを可能とし、その高い装填比重にも拘わらず現在使用されているＡＮＦＯ爆薬に比べて優れた破砕効果と共に著しく高い静的効果を示すことから、穿孔作業、延いては発破作業の効率化を図り得るという特徴を有し、またＡＮＦＯ爆薬の有する本来の利点を損なうことのない高比重・高感度のＡＮＦＯ爆薬である。
【００２６】
【実施例】
本発明を実施例を挙げてさらに詳しく説明するが、本発明がこれらの実施例のみに限定されるものではない。尚、実施例において部は重量部を示す。
【００２７】
実施例１
吸油率８．０％、嵩比重０．８０、粒径１．６８〜２．３６ｍｍのものが８０．５重量％、硬度３．０％であって中空微粒子を含有しないポーラスプリル硝安９５．５部を室温のシグマ翼を備えた横型ニーダーに移し、室温の２号軽油４．５部を添加し、１分当たり９０回転の速度で５分間混合し、本発明の爆薬組成物１００部を得た。
【００２８】
実施例２
吸油率８．５％、嵩比重０．８２、粒径１．６８〜２．３６ｍｍのものが８５．４重量％、硬度２．３％であって中空微粒子を含有しないポーラスプリル硝安８４．７部とその粉砕品１０．０部を室温のコンクリートミキサーに移し、室温の２号軽油５．１部、塩化ジメチルジアリルアンモニウム・アクリルアミド共重合体の２０％水溶液（カヤクリルレジンＥＣ−３１５：日本化薬（株）製）０．２部を添加し、１分当たり８０回転の速度で５分間混合し、本発明の爆薬組成物１００部を得た。
【００２９】
実施例３
吸油率８．５％、嵩比重０．８２、粒径１．６８〜２．３６ｍｍのものが８５．４重量％、硬度２．３％であって中空微粒子を含有しないポーラスプリル硝安９４．０部を室温のコンクリートミキサーに移し、室温の２号軽油６．０部を添加し、１分当たり１００回転の速度で３分間混合し、本発明の爆薬組成物１００部を得た。
【００３０】
実施例４
吸油率８．３％、嵩比重０．８３、粒径１．６８〜２．３６ｍｍのものが７８．０重量％、硬度２．２％であって中空微粒子を含有しないポーラスプリル硝安６０．０部と吸油率１１．７％、嵩比重０．７６、粒径１．６８〜２．３６ｍｍのものが７０．３重量％、硬度２．１％であって中空微粒子を含有しないポーラスプリル硝安３４．７部を室温のシグマ翼を備えた横型ニーダーに移し、室温の２号軽油５．０部、脂肪酸アミド（脂肪酸アマイドＳ：花王（株）製）０．３部を添加し、１分当たり８０回転の速度で５分間混合し、本発明の爆薬組成物１００部を得た。
【００３１】
比較例１
吸油率１０．５％、嵩比重０．７６、粒径１．６８〜２．３６ｍｍのものが５５．２重量％、硬度１２．０％であって中空微粒子を含有しないポーラスプリル硝安９３．７部を室温のシグマ翼を備えた横型ニーダーに移し、ポリオキシエチレンアルキルエーテル（エマルゲン１０８：花王（株）製）０．３部を溶解した室温の２号軽油６．０部を添加し、１分当たり７０回転の速度で３分間混合し、比較用の爆薬組成物１００部を得た。
（特許文献６に記載の爆薬）
【００３２】
性能試験
（１）爆速試験
実施例１〜４及び比較例１で得られた各爆薬組成物を内径６８ｍｍ、厚さ４ｍｍの鋼管中に１，２００〜１，５００ｇ流し込み、１００ｇのペントライトをブースターとして６号雷管で起爆し、爆速を測定した。同時に装填比重を算出した。
【００３３】
（２）起爆感度試験
実施例１〜４及び比較例１で得られた各爆薬組成物を火薬学会規格ＥＳ−３２（２）で規定されている塩ビ雨どい試験において６号雷管で起爆した。
【００３４】
（３）弾動振子試験
実施例１〜４及び比較例１で得られた各爆薬組成物を内径３０ｍｍ、厚さ５．０ｍｍの紙管中に９０ｇ流し込み、１０ｇの含水爆薬（アルテックス：日本化薬（株）製）をブースターとして６号雷管で起爆し、弾動振子値を測定した。
【００３５】
これらの試験結果を装填比重と共に表１に示す。
【表１】

【００３６】
試験例
特許文献４に記載された低嵩比重のポーラスプリル硝安について、比較のため装填比重を測定した。結果を表２に示す。
【００３７】
【表２】

【００３８】
実施例１〜４の本発明の爆薬組成物は、比較例１の爆薬に比べて装填比重が１０〜２０％程度大きく、同等の薬長とした場合、１孔当たりの装薬量を増加させ得ることが明らかであり、爆速値は同等若しくは若干高いため、優れた破砕効果を有することが分かる。更に、高い装填比重にも拘わらず弾動振子値が著しく大きく、非常に優れた仕事効果を有することが分かる。以上の結果から、実施例１〜４の本発明の爆薬組成物は、実際の発破作業において穿孔間隔の拡張、即ち穿孔数の削減を実現し得る高比重・高感度のＡＮＦＯ爆薬であることが明らかである。また、起爆感度は６号雷管で何れも不完爆（塩ビ法）であり、ＡＮＦＯ爆薬本来の優れた取扱性が損なわれないことが確認される。
【００３９】
【発明の効果】
起爆感度が低いため、従来のＡＮＦＯ爆薬と同様に取扱うことが可能であるという特性が損なわれず、従来のＡＮＦＯ爆薬に比べて装填比重が著しく上昇し、高威力で破砕効果に優れると共に非常に優れた仕事効果を有するため、穿孔間隔の拡張、即ち穿孔作業の効率化、延いては発破作業の効率化を図り得る爆薬組成物が得られた。[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an explosive composition widely used for industrial blasting operations such as quarrying, mining, coal mining, and digging on steep roads. More specifically, the present invention relates to a porous prill ammonium nitrate (ammonium nitrate) -based granular explosive composition that can be used by being directly loaded into a perforation of an object to be destroyed.
[0002]
[Prior art]
As industrial explosives used for blasting operations and the like, dynamite, hydrous explosives, nitrite explosives, and nitrate oil explosives (ANFO explosives) are well known. Of these explosives, the ANFO explosive is an explosive that can be manufactured relatively easily, and is usually in the form of fluid particles, so that it can be poured directly into a perforation or loaded by a loading machine such as a loader. There is a feature that can be.
[0003]
It is well known that the reactivity of porous prill ammonium nitrate is significantly lower than explosive compounds such as nitroglycerin and nitroglycol. Accordingly, ANFO explosives, in which porous prill nitrate often occupies 90% by weight or more of the entire explosive as an oxidizing agent, are less powerful than other industrial explosives, but are cheaper and more stable. In a PVC gutter test or a carton test specified as a detonation detonation test method in the Society Standard ES-32 (2), it is stipulated that the detonation will not be completed with a No. 6 detonator. It is widely used because it has excellent handling properties such as storage and transport by the container.
[0004]
In recent years, explosives used by low specific gravity and high power ANFO explosives (Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4) using porous prill ammonium nitrate having specific physical properties such as particle size, bulk specific gravity, oil absorption rate, etc. Due to the reduction in volume and the efficiency of the blasting work, the ANFO explosive is widely used for industrial blasting such as quarrying and mining, replacing the ANFO explosive manufactured using conventional porous prill nitrate. It is starting to be used.
[0005]
[Patent Document 1]
JP-A-7-69772 [Patent Document 2]
JP-A-9-278578 [Patent Document 3]
JP 2001-39789 A [Patent Document 4]
JP 2001-181080 A [Patent Document 5]
JP-A-55-51794 [Patent Document 6]
JP-A-11-147784 [Patent Document 7]
JP-A-11-278974 [Patent Document 8]
JP-A-10-291883 [Patent Document 9]
JP-A-11-322481 [Patent Document 10]
JP-A-8-295588 [Patent Document 11]
JP-A-8-26877 [Patent Document 12]
JP-A-11-79878 [Patent Document 13]
Japanese Patent Application Laid-Open No. 2000-16891 [Patent Document 14]
JP 2000-327473 A
[Problems to be solved by the invention]
On the other hand, in the actual blasting operation, the operation of piercing the charging hole occupies a large weight in terms of cost and efficiency, and if the interval between the piercing operations, that is, the number of piercing operations can be reduced, the efficiency of the blasting operation can be significantly improved. There is no doubt that to achieve this, a high-performance explosive that can be charged in a sufficient amount with a limited charge length per hole is required. By increasing the perforation diameter, it is possible to use the increase in the amount of charge per hole and the power of explosives due to the diameter effect, but the perforation time per hole is prolonged, which is a fundamental solution. Does not reach.
[0007]
Generally, the performance of explosives is divided into dynamic effects and static effects.The former is considered to be a crushing effect due to detonation pressure, and the latter is considered to be a work effect due to adiabatic expansion of explosive gas. It is determined by measuring the value. The detonation pressure is approximately expressed as P ≒ 1 / 4D ² (where ρ is the initial density of the explosive, and D is the explosion velocity), and increases as the initial density of the explosive, that is, the loading specific gravity and the explosion velocity, increase. However, it is common knowledge to those skilled in the art that explosives with a high loading specific gravity generally have low detonation sensitivity and thus have low ballistic pendulum values, and thus have low work effects. High-performance explosives for achieving the above-mentioned object require contradictory characteristics of high specific gravity and high sensitivity, and no solution has been found yet.
[0008]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the physical properties such as oil absorption, bulk density and the like of the porous prill nitrate used in the ANFO explosive and the static effect of the ANFO explosive. Have the same excellent handling properties as conventional ANFO explosives without exhibiting primer detonation properties, and show a remarkably high static effect together with an excellent crushing effect despite the increase in the loading specific gravity. Is completed.
[0009]
That is, the present invention
(1) Porous prill ammonium nitrate (a) having an oil absorption rate of 5.0 to 20.0%, a bulk specific gravity of 0.80 to 0.90 and containing no hollow fine particles, and / or a crushed product thereof and a fuel oil are essential. Explosive composition characterized by containing as an ingredient,
(2) The explosive composition according to the above (1), wherein the porous prill ammonium nitrate (a) and / or its pulverized product is contained in an amount of 20% by weight or more of the total porous prill ammonium nitrate,
(3) The explosive composition according to the above (1) or (2), wherein the total porous prill ammonium nitrate has a particle size of 1.68 to 2.36 mm in a proportion of 60.0% by weight or more,
(4) The explosive composition according to any one of the above (1) to (3), wherein the hardness of porous prill ammonium nitrate (a) is 0.5 to 5.0%,
(5) The explosive composition according to any one of (1) to (4), wherein the loading specific gravity is 0.88 to 1.20.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The porous pull ammonium nitrate used as an essential component in the explosive composition of the present invention has an oil absorption of 5.0 to 20.0% and a bulk specific gravity of 0.80 to 0.90 (hereinafter, porous prill ammonium nitrate). (Referred to as (a)) or a pulverized product thereof, as long as it does not contain hollow fine particles as conventionally used as porous prill nitrate having a low bulk specific gravity. Porous prill nitrate (a) is generally used in the range of 65 to 96% by weight, preferably 75 to 95% by weight, based on the entire explosive composition.
In the explosive composition of the present invention, the porous prill nitrate (a) or a pulverized product thereof can be used in combination with another porous prill nitrate having an oil absorption rate or a bulk specific gravity outside this range. When used in combination with other porous prill nitrate, it is preferable that the porous prill nitrate (a) or its pulverized product is contained in a proportion of 20% by weight or more in all the porous prill nitrate.
Further, as the porous prill nitrate used in the explosive composition of the present invention, those having a particle size of 1.68 to 2.36 mm and a content of 60.0% by weight or more are preferable.
Further, as the porous prill nitrate used in the explosive composition of the present invention, one having a hardness of 0.5 to 5.0%, preferably 0.5 to 3.0% is preferable.
[0011]
In the explosive composition of the present invention, the porous prill nitrate (a) (preferably, the porous prill nitrate having the above-mentioned particle size distribution) and the pulverized product thereof can be mixed in any ratio, but are preferably non-pulverized products. Is 20 to 80% by weight. As described above, the porous prill nitrate can be crushed by itself or mixed with a crushed product to have a desired bulk specific gravity.
[0012]
The oil absorption rate of porous prill nitrate is measured by immersing a certain amount of sample porous prill nitrate in light oil for a certain period of time, performing suction filtration, and calculating the adsorption amount of light oil from the weight difference before and after the test. Specifically, 50 g of sample porous prill nitrate is placed in a glass filter (11G-1) having a diameter of 40 mm and a depth of 50 mm, weighed with a direct balance on an upper plate, and set in a vacuum apparatus. Then, 40 ml of light oil is poured into the glass filter, and the mixture is thoroughly stirred with a thin rod to achieve mixed contact between porous prill nitrate and light oil. After standing for 5 minutes, the external cock attached to the glass filter is opened, and light oil is allowed to flow naturally for 2 minutes. Subsequently, after suctioning with a vacuum pump for 5 minutes (flow rate: about 30 l / min), the glass filter containing the gas oil adsorbed porous prill nitrate is weighed with an upper plate direct balance. Here, the increased amount is the absorbed amount of light oil. After the above measurement is completed, the ratio (%) of the light oil adsorption (g) to 50 g of the original sample, porous prill nitrate, is indicated as the oil absorption (%). The calculation formula is as shown in the following formula (1).
[0013]
Oil absorption rate (%) = light oil adsorption (g) / sample 50 (g) x 100 (1)
[0014]
The oil absorption of ammonium nitrate mainly depends on the volume and effective diameter of the pores distributed inside the particles.For example, if the pore volume is large, the space that can hold light oil inside the particles becomes large, , The oil absorption rate becomes large.
[0015]
The bulk specific gravity of porous prill nitrate is measured according to the method specified in JIS K-6721. That is, a certain amount of sample porous prill nitrate is dropped from a certain height into a cylindrical cup placed on a support base using a funnel having a damper at the lower part supported by a support rod, and swells on the cup. After removing the porous prill nitrate from the sample, the sample is measured by weighing the sample porous prill nitrate in the glass. Specifically, a funnel having a diameter of 90 mm at the upper end, a diameter of 15 mm at the lower end, and a height of 115 mm was installed such that the distance between the lower end of the funnel and the upper end of the cup having a depth of 80 mm on the support base and a volume of 100 cm ³ was 45 mm. 100 g of porous prill nitrate of the sample is put in the inside, and the damper is slid to drop the porous prill nitrate of the sample into the cup. Carefully take care not to vibrate, and use a spatula to remove the porous prilled ammonium salt of the sample raised on the cup so that it is horizontal at the same height as the top of the cup. Next, the porous prill nitrate of the sample adhering to the outside of the cup is removed, and the weight of the sample porous prill nitrate in the cup is weighed by a direct reading balance. After the above measurement, the bulk specific gravity is calculated by the following equation (2).
[0016]
Bulk specific gravity = sample weight (g) / 100 (cm ³ ) (2)
[0017]
The particle size distribution (% by weight) of the porous prill nitrate is measured from a residual weight on a sieve mesh of each of a certain amount of the porous prill nitrate through various sieves having different sieves.
[0018]
The hardness of porous prill ammonium nitrate is measured by mechanically pulverizing a fixed amount of a sample of porous prill ammonium nitrate under a predetermined condition using a hardness measuring device, and measuring the amount of the pulverized ammonium nitrate.
The device used for the measurement is a funnel for sample injection, a flow pipe (inner diameter 16 mm, length 175 mm) connected to the compressed air inlet (inner diameter 4 mm, length 55 mm), and the upper part of these connections and the funnel are connected vertically And a sample crushing tube (inner diameter: 50 mm, length: 315 mm) which is vertically connected to a flow pipe.
[0019]
100 g of sample nitrate from which powder was removed by a 35 mesh sieve was dropped from the funnel into the flow tube through the sample injection tube, and the compressed air (4 kg / cm ² ) flowing from the inlet hole passed the sample through the flow tube to the inner wall of the grinding tube. Collision causes powder of sample ammonium nitrate. The sample porous ammonium nitrate after the flow is sieved with 35 mesh, the amount (N) of +35 mesh is weighed, and the ratio is expressed as the ratio (%) of the powdered amount to 100 g of the original sample nitrate. The calculation formula is as shown in the following formula (3).
Hardness (%) = 100 (g) −N (g) (3)
[0020]
As the fuel oil used in the explosive composition of the present invention, it is preferable to use a fuel oil that is liquid at the time of mixing. Examples of usable fuels include mineral oils such as light oil and kerosene, vegetable oils, animal oils and the like.
[0021]
In addition, alcohols such as methyl alcohol and ethyl alcohol, waxes such as paraffin wax and microcrystalline wax, and nitro compounds such as dinitrotoluene and dinitroxylene can be used alone or as a mixture as fuel oils. Fuel oils with high melting points can be used by mixing with porous prill nitrate above the temperature at which it becomes liquid.
The amount of the fuel oil used in the explosive composition of the present invention is usually in the range of 2.5 to 25% by weight, preferably 4 to 10% by weight of the entire explosive composition.
[0022]
The explosive composition of the present invention can be subjected to measures for preventing generation of static electricity, if necessary. For example, various surfactants known as water-soluble or oil-soluble antistatic agents (Patent Document 5, Patent Document 6, and Patent Document 7), addition of starches (Patent Document 8), fatty acid amides (Patent Document 9), and the like. Agents can be added.
[0023]
The explosive composition of the present invention may optionally contain an oxidizing agent other than porous prill ammonium nitrate, for example, potassium nitrate or perchlorate, or wood flour, a powder additional fuel such as aluminum powder, or a thickening agent such as sodium polyacrylate. Stabilizers (Patent Literature 10), specific gravity adjusting materials such as shirasu balloons (Patent Literature 11), organic acids known as ammonia gas inhibitors (Patent Literature 12), water absorbing agents (Patent Literature 13 and Patent Literature 14), and the like. Other additives can be added.
[0024]
The explosive composition of the present invention is produced by uniformly mixing porous prill nitrate and fuel oil as essential components and, if necessary, other additives in a mixer such as a kneader or a rotary mixer. In addition, other mixers can be used as long as they have stirring and mixing functions.
The thus obtained explosive composition of the present invention has a bulk specific gravity of about 0.81 to 1.20. The bulk specific gravity of the explosive composition depends on the amount of the added oil, but is largely determined by the bulk specific gravity of the porous prill nitrate because it is absorbed by the porous prill nitrate, and the bulk specific gravity of the porous prill nitrate is large. There is no significant difference. The loading specific gravity of the obtained explosive composition is usually 0.88 to 1.20. The loading specific gravity is as follows: 1,000 g of the explosive composition is poured into a steel pipe having an inner diameter of 68 mm and a length of 600 mm using a funnel, and tamping is performed by vibrating up and down about 10 times. It can be calculated from the calculated charge volume and the charge amount (1,000 g).
[0025]
The explosive composition of the present invention enables the amount of charge per hole to be increased at a constant charge length without requiring an increase in perforation diameter, and is currently used in spite of its high loading specific gravity. Since it exhibits a significantly higher static effect as well as a superior crushing effect as compared with the ANFO explosive, it has the feature that it can improve the efficiency of drilling work and, consequently, blasting work, and also impairs the original advantages of the ANFO explosive. It is a high specific gravity and high sensitivity ANFO explosive without any problems.
[0026]
【Example】
The present invention will be described in more detail with reference to examples, but the present invention is not limited to only these examples. In the examples, parts are parts by weight.
[0027]
Example 1
85.5% by weight, oil hardness of 3.00% and a porous prill nitrate 95.5 containing no hollow fine particles having an oil absorption of 8.0%, a bulk specific gravity of 0.80 and a particle size of 1.68 to 2.36 mm. Part was transferred to a horizontal kneader equipped with a sigma wing at room temperature, 4.5 parts of No. 2 light oil at room temperature was added and mixed at a speed of 90 revolutions per minute for 5 minutes to obtain 100 parts of the explosive composition of the present invention. Was.
[0028]
Example 2
Porous prill nitrate having an oil absorption of 8.5%, a bulk specific gravity of 0.82, a particle size of 1.68 to 2.36 mm, 85.4% by weight, a hardness of 2.3% and containing no hollow fine particles, is 84.7%. And 10.0 parts of the pulverized product thereof were transferred to a concrete mixer at room temperature, and 5.1 parts of No. 2 light oil at room temperature and a 20% aqueous solution of dimethyldiallylammonium chloride-acrylamide copolymer (Kayacryl Resin EC-315: Nippon Kagaku) 0.2 part of Yakuhin Co., Ltd.) was added and mixed at a speed of 80 revolutions per minute for 5 minutes to obtain 100 parts of the explosive composition of the present invention.
[0029]
Example 3
Porous prill nitrate having an oil absorption of 8.5%, a bulk specific gravity of 0.82, a particle size of 1.68 to 2.36 mm, 85.4% by weight, a hardness of 2.3% and containing no hollow fine particles, and having a hollow particle content of 94.0%. The mixture was transferred to a concrete mixer at room temperature, 6.0 parts of No. 2 light oil at room temperature was added, and mixed at a speed of 100 revolutions per minute for 3 minutes to obtain 100 parts of the explosive composition of the present invention.
[0030]
Example 4
Porous prill nitrate 60.0% having an oil absorption of 8.3%, a bulk specific gravity of 0.83, a particle size of 1.68 to 2.36 mm, 78.0% by weight, a hardness of 2.2% and containing no hollow fine particles. Part and oil absorption rate 11.7%, bulk specific gravity 0.76, particle diameter 1.68 to 2.36 mm 70.3% by weight, hardness 2.1%, porous prill nitrate containing no hollow fine particles 34 .7 parts were transferred to a horizontal kneader equipped with a sigma wing at room temperature, and 5.0 parts of No. 2 light oil and 0.3 parts of a fatty acid amide (fatty acid amide S: manufactured by Kao Corporation) were added at room temperature. The mixture was mixed at a speed of 80 rotations for 5 minutes to obtain 100 parts of the explosive composition of the present invention.
[0031]
Comparative Example 1
55.2% by weight, oil hardness of 12.0%, and a porous prill nitrate 93.7% containing no hollow fine particles having an oil absorption of 10.5%, a bulk specific gravity of 0.76, and a particle size of 1.68 to 2.36 mm. Was transferred to a horizontal kneader equipped with a sigma wing at room temperature, and 6.0 parts of No. 2 light oil at room temperature in which 0.3 part of polyoxyethylene alkyl ether (Emulgen 108: manufactured by Kao Corporation) was dissolved was added. The mixture was mixed at a speed of 70 revolutions per minute for 3 minutes to obtain 100 parts of an explosive composition for comparison.
(Explosive described in Patent Document 6)
[0032]
Performance Test (1) Explosion Speed Test 1,200 to 1,500 g of each explosive composition obtained in Examples 1 to 4 and Comparative Example 1 was poured into a steel pipe having an inner diameter of 68 mm and a thickness of 4 mm, and a 100 g pentolite was boosted. Was detonated with a No. 6 detonator, and the explosion velocity was measured. At the same time, the loading specific gravity was calculated.
[0033]
(2) Detonation Sensitivity Test Each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was detonated with a No. 6 primer in a PVC gutter test specified by the Pharmacopoeia Standard ES-32 (2).
[0034]
(3) Ballistic pendulum test 90 g of each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was poured into a paper tube having an inner diameter of 30 mm and a thickness of 5.0 mm, and 10 g of a water-containing explosive (Altex: Japan Using a No. 6 detonator as a booster, the ballistic pendulum value was measured.
[0035]
The test results are shown in Table 1 together with the loading specific gravity.
[Table 1]

[0036]
Test Example The loading specific gravity of porous prill nitrate having a low bulk specific gravity described in Patent Document 4 was measured for comparison. Table 2 shows the results.
[0037]
[Table 2]

[0038]
The explosive compositions of the present invention of Examples 1 to 4 have a loading specific gravity that is about 10 to 20% larger than that of the explosive of Comparative Example 1 and increase the amount of charge per hole when the same length is used. Obviously, the explosion velocity values are equal or slightly higher, indicating that they have an excellent crushing effect. Further, it can be seen that the elastic pendulum value is remarkably large in spite of a high loading specific gravity, and that it has a very excellent work effect. From the above results, the explosive compositions of the present invention of Examples 1 to 4 may be high specific gravity and high sensitivity ANFO explosives capable of realizing expansion of the perforation interval, that is, reduction of the number of perforations in actual blasting operation. it is obvious. In addition, the detonation sensitivity of each of the No. 6 primers was an incomplete explosion (PVC method), confirming that the original excellent handling properties of the ANFO explosive were not impaired.
[0039]
【The invention's effect】
Due to the low detonation sensitivity, the ability to be handled in the same way as conventional ANFO explosives is not impaired. The explosive composition has an improved work effect, and can provide an explosive composition that can increase the interval between perforations, that is, improve the efficiency of the perforation operation, and further increase the efficiency of the blasting operation.

Claims

Oil absorption rate is 5.0 to 20.0%, bulk specific gravity is 0.80 to 0.90, and contains porous prill ammonium nitrate (a) containing no hollow fine particles and / or its pulverized product and fuel oil as essential components An explosive composition comprising:

The explosive composition according to claim 1, wherein the porous prill ammonium nitrate (a) and / or its pulverized product is contained in an amount of 20% by weight or more based on the total amount of the porous prill ammonium nitrate.

The explosive composition according to claim 1 or 2, wherein the total porous prill ammonium nitrate has a particle size of 1.68 to 2.36 mm in a proportion of 60.0% by weight or more.

The explosive composition according to any one of claims 1 to 3, wherein the hardness of the porous spryl ammonium nitrate (a) is 0.5 to 5.0%.

The explosive composition according to any one of claims 1 to 4, having a loading specific gravity of 0.88 to 1.20.