Ammonium nitrate blasting agent and method of production

Abstract

A method of producing an ammonium nitrate blasting agent and such an agent. The method comprises the steps of first combining together a crystal habit modifier with an aqueous solution of ammonium nitrate. Using the mixture of the crystal habit modifier and the ammonium nitrate solution, ammonium nitrate crystals are formed having a particle size of about 1 to about 500 microns. The ammonium nitrate crystals are then combined with an organic carbonaceous fuel at a ratio such that the organic carbonaceous fuel is from about 2 to about 10 percent by weight of the blasting agent.

1 . A blasting agent comprising from 90 to 98 percent by weight of an ammonium nitrate component and from 2 to 10 percent by weight of an organic carbonaceous fuel component, said ammonium nitrate component comprised of ammonium nitrate crystals having a particle size of from about 1 to about 500 microns and including a crystal habit modifier at a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate component.  
     
     
         2 . The blasting agent as claimed in  claim 1  wherein said blasting agent further includes a gelling agent at a concentration of 0.1 to 10 percent by weight of said ammonium nitrate component.  
     
     
         3 . The blasting agent as claimed in  claim 1  including a cross-linking agent at a concentration of 0.001 to 1.0 percent by weight of said blasting agent.  
     
     
         4 . The blasting agent as claimed in  claim 1  including water at a concentration of less than 1 percent to 15 percent by weight of said blasting agent.  
     
     
         5 . A blasting agent comprising from 90 to 98 percent by weight of an ammonium nitrate component and from 2 to 10 percent by weight of an organic carbonaceous fuel component, said ammonium nitrate component comprised of ammonium nitrate crystals having a particle size of from about 1 to about 500 microns and including a crystal habit modifier comprised of an amine at a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate component.  
     
     
         6 . A blasting agent comprising from 90 to 98 percent by weight of an ammonium nitrate component and from 2 to 10 percent by weight of an organic carbonaceous fuel component, said ammonium nitrate component comprised of ammonium nitrate crystals having a particle size of from about 1 to about 500 microns and including a crystal habit modifier comprises of dodecylamine C 5 H 25 NH 2  at a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate component.  
     
     
         7 . The blasting agent as claimed in  claim 2  wherein said gelling agent is a hydrophilic colloid.  
     
     
         8 . The blasting agent as claimed in  claim 7  wherein said gelling agent is guar gum, hydroxyethyl guar, hydroxyphopyl guar, polyacrylamide, carboxy methyl cellulose, carboxy ethyl cellulose or xanthan gum.  
     
     
         9 . The blasting agent as claimed in  claim 3  wherein said cross-linking agent is potassium pyroantinonate, boric acid, feric chloride, potassium antimony tartrate, sodium dichromate or sodium tetraborate.  
     
     
         10 . The blasting agent as claimed in  claim 1  wherein said organic carbonaceous fuel is from about 4 to about 8 percent by weight of said blasting agent.  
     
     
         11 . The blasting agent as claimed in  claim 1  wherein the ratio of ammonium nitrate to organic carbonaceous fuel is 94:6.  
     
     
         12 . The blasting agent as claimed in  claim 1  having an oxygen balance more positive that −15 percent.  
     
     
         13 . The blasting agent as claimed in  claim 1  wherein the velocity of detonation is from 3,000 to 7,000 meters per second in a confined charge diameter ranging from less than 10 millimeters to 500 millimeters.  
     
     
         14 . The blasting agent as claimed in  claim 1  having a density from 0.55 to 1.4 grams per cubic centimeter.  
     
     
         15 . A blasting agent comprising: 
 (i) from 90 to 98 percent by weight of an ammonium nitrate component, said ammonium nitrate component comprised of ammonium nitrate crystals having a particle size of from about 1 to about 500 microns and including a crystal habit modifier at a concentration of 0.01 to 2.0 percent by weight of said ammonium nitrate component;    (ii) from 2 to 10 percent by weight of an organic carbonaceous fuel component;    (iii) a gelling agent at a concentration of from 0.1 to 10 percent by weight of said ammonium nitrate component; and,    (iv) a cross linking agent at a concentration of 0.001 to 1.0 percent by weight of said blasting agent.    
     
     
         16 . The blasting agent as claimed in  claim 15  having a density from 0.55 to 1.4 grams per cubic centimeter.  
     
     
         17 . The blasting agent as claimed in  claim 16  having a velocity of detonation from 3,000 meters per second to 7,000 meters per second in a confined charge diameter ranging from less than 10 millimeters to 500 millimeters.  
     
     
         18 . The blasting agent as claimed in  claim 15  wherein said crystal habit modifier is an amine.  
     
     
         19 . The blasting agent as claimed in  claim 18  wherein said gelling agent is a hydrophilic colloid.  
     
     
         20 . The blasting agent as claimed in  claim 19  wherein said cross-linking agent is potassium pyroantimonate.  
     
     
         21 . The blasting agent as claimed in  claim 15  including water at a concentration of less than 1 percent to 15 percent by weight of said blasting agent.  
     
     
         22 . A method of producing an ammonium nitrate blasting agent, the method comprising the steps of: 
 (i) combining together a crystal habit modifier with an aqueous solution of ammonium nitrate;    (ii) with said mixture of said crystal habit modifier and said ammonium nitrate solution, forming ammonium nitrate crystals having a particle size of about 1 to about 500 microns; and,    (iii) combining said ammonium nitrate crystals with an organic carbonaceous fuel at a ratio such that said organic carbonaceous fuel is from 2 to 10 percent by weight of said blasting agent.    
     
     
         23 . A method of producing an ammonium nitrate blasting agent, the method comprising the steps of: 
 (i) combining together a crystal habit modifier with an aqueous solution of ammonium nitrate;    (ii) with said mixture of said crystal habit modifier and said ammonium nitrate solution, forming ammonium nitrate crystals having a particle size of about 1 to about 500 microns through atomization of said mixture of said crystal habit modifier and said ammonium nitrate solution; and,    (iii) combining said ammonium nitrate crystals with an organic carbonaceous fuel at a ratio such that said organic carbonaceous fuel is from 2 to 10 percent by weight of said blasting agent.    
     
     
         24 . A method of producing an ammonium nitrate blasting agent, the method comprising the steps of: 
 (i) combining together a crystal habit modifier with an aqueous solution of ammonium nitrate;    (ii) with said mixture of said crystal habit modifier and said ammonium nitrate solution, forming ammonium nitrate crystals having a particle size of about 1 to about 500 microns through injecting said mixture of said crystal habit modifier and said ammonium nitrate solution through an atomizing nozzle in the presence of a secondary air flow; and,    (iii) combining said ammonium nitrate crystals with an organic carbonaceous fuel at a ratio such that said organic carbonaceous fuel is from 2 to 10 percent by weight of said blasting agent.    
     
     
         25 . The method as claimed in  claim 24  wherein the temperature of said secondary air flow is from about 20 degrees Celsius to about 50 degrees Celsius.  
     
     
         26 . A method of producing an ammonium nitrate blasting agent, the method comprising the steps of: 
 (i) combining together a crystal habit modifier with an aqueous solution of ammonium nitrate;    (ii) with said mixture of said crystal habit modifier and said ammonium nitrate solution, forming ammonium nitrate crystals having a particle size of about 1 to about 500 microns through injecting said mixture of said crystal habit modifier and said ammonium nitrate solution through a high velocity convergent-divergent nozzle in the presence of a secondary air flow; and,    (iii) combining said ammonium nitrate crystals with an organic carbonaceous fuel at a ratio such that said organic carbonaceous fuel is from 2 to 10 percent by weight of said blasting agent.    
     
     
         27 . The method as claimed in  claim 26  wherein the temperature of said secondary air flow is from about 20 degrees Celsius to about 50 degrees Celsius.  
     
     
         28 . The method as claimed in  claim 23  including the further step of mixing one or more additives with said blasting agent to enhance one or more characteristics of said blasting agent.  
     
     
         29 . The method as claimed in  claim 28  wherein said one or more additives are mixed with said blasting agent through the use of a ribbon blender or drum mixer.  
     
     
         30 . The method as claimed in  claim 29  wherein said one or more additives include one or more of water, gelling agents, cross-linking agents, and organic carbonaceous fuel.  
     
     
         31 . The method as claimed in  claim 22  wherein said ammonium nitrate solution contains from 60 to 90 percent ammonium nitrate by weight and is heated to a temperature of between 85 and 100 degrees Celsius prior to the addition of said crystal habit modifier.  
     
     
         32 . The method as claimed in  claim 22  wherein said crystal habit modifier is added at a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate solution.  
     
     
         33 . The method as claimed in  claim 22  wherein said crystal habit modifier is an amine.  
     
     
         34 . The method as claimed in  claim 28  wherein said additive is a gelling agent added at a concentration of from 0.1 to 10 percent by weight of said mixture of ammonium nitrate solution and said crystal habit modifier.  
     
     
         35 . The method as claimed in  claim 28  wherein said additive is a cross-linking agent added at a concentration of 0.001 to 1.0 percent by weight of said blasting agent.  
     
     
         36 . The method as claimed in  claim 28  wherein said additive is water added at a concentration of less than 1% to 15% by weight of said blasting agent.  
     
     
         37 . The method as claimed in  claim 22  wherein said blasting agent has a density of from 0.55 to 1.4 grams per cubic centimeter.  
     
     
         38 . The method as claimed in  claim 22  wherein said blasting agent has an oxygen balance more positive than −15 percent.  
     
     
         39 . A method of producing an ammonium nitrate blasting agent comprising the steps of: 
 (i) forming an ammonium nitrate component through mixing a aqueous solution of ammonium nitrate with a crystal habit modifier, said crystal habit modifier having a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate component;    (ii) injecting said ammonium nitrate component through a nozzle in the presence of a secondary air flow to form ammonium nitrate crystals having a particle size of from about 1 to about 500 microns; and,    (iii) transporting said ammonium nitrate crystals to a mechanical mixing process and mechanically mixing an organic carbonaceous fuel component with said ammonium nitrate crystals, said organic carbonaceous fuel component having a concentration of from 2 to 10 percent by weight of said blasting agent.    
     
     
         40 . The method as claimed in  claim 39  wherein the temperature of said secondary air flow is from about 20 degrees Celsius to about 50 degrees Celsius.  
     
     
         41 . The method as claimed in  claim 39  including the further step of combining one or more additives to said ammonium nitrate crystals and said organic carbonaceous fuel during said mechanical mixing process.  
     
     
         42 . The method as claimed in  claim 41  wherein said additives include one or more of water, a gelling agent and a cross-linking agent.  
     
     
         43 . The method as claimed in  claim 39  including the further step of heating said ammonium nitrate solution to a temperature of between 85 and 100 degrees Celsius prior to mixing with said crystal habit modifier to create said ammonium nitrate component.  
     
     
         44 . A method of producing an ammonium nitrate blasting agent comprising the steps of: 
 (i) the forming an ammonium nitrate component through mixing an aqueous solution of ammonium nitrate with a crystal habit modifier, said crystal habit modifier having a concentration of from 0.01 to 2.0 percent by weight of said ammonium nitrate component; and,    (ii) injecting said ammonium nitrate component, together with an organic carbonaceous fuel component, through a nozzle in the presence of a secondary airflow to form ammonium nitrate crystals having a particle size of from about 1 to about 500 microns, said organic carbonaceous fuel component added at a concentration of from 2 to 10 percent by weight of said blasting agent and becoming intermixed with said ammonium nitrate crystals by means of injection through said nozzle.    
     
     
         45 . The method as claimed in  claim 44  including the further step of transporting said mixture of said ammonium nitrate crystals and said carbonaceous fuel to a mechanical mixing process and mechanically mixing one or more additives to said mixture.  
     
     
         46 . The method as claimed in  claim 45  wherein said additives include one or more of water, a gelling agent and a cross-linking agent.  
     
     
         47 . The method as claimed in  claim 44  including the further step of heating said ammonium nitrate solution to a temperature of between 85 and 100 degrees Celsius prior to mixing with said crystal habit modifier to create said ammonium nitrate component.  
     
     
         48 . The method as claimed in  claim 44  wherein the temperature of said secondary air flow is from about 20 degrees Celsius to about 50 degrees Celsius.