US-12617737-B1 - Continuous process for producing explosive compositions

US12617737B1US 12617737 B1US12617737 B1US 12617737B1US-12617737-B1

Abstract

A continuous mixing technology is used to develop a continuous process as an alternative manufacturing technology to sigma-blade batch mixer process for producing flexible explosive formulations (e.g. Flex-X) that is composed of energetic solids and additives without any solvents. This continuous mixer's chamber is partially filled under atmospheric pressure with significant overhead space, reducing energetic hazards. The continuous mixing machine can be comprised with one or two temperature zones, wherein all ingredients are added subsequently into the mixing chamber.

Inventors

Viral Panchal
Neha Mehta
Keyur Patel
Niloufar Faridi
Zohar Ophir
Prarthana Manoj Rajai
Shiqi Li
Tianyi Huang
Mingwan Young

Assignees

U.S. GOVERNMENT AS REPRESENTED BY THE SECRETARY OF THE ARMY

Dates

Publication Date: 20260505
Application Date: 20240628

Claims (7)

1 . A process of producing an explosive composition, the process comprising: feeding an energetic material and a first binder component into a first mixer, wherein the first mixer comprises an enclosed, temperature controlled first mixing chamber, at least one rotor shaft along the interior longitudinal axis of the first mixing chamber, and wherein the rotor shaft comprises at least one mixing element fixed to the rotor shaft and wherein a continuous, partially filled volume is maintained throughout the first mixing chamber; mixing the solid energetic material and the first binder component in the first mixer; feeding the product from the first mixing chamber and a second binder component into a second mixer, wherein the second mixer comprises an enclosed, temperature controlled second mixing chamber, at least one rotor shaft along the interior longitudinal axis of the second mixing chamber and wherein the rotor shaft comprises at least one mixing element fixed to the rotor shaft and wherein a continuous, partially filled volume is maintained throughout the second mixing chamber; mixing the product from the first mixing chamber and the second binder component in the second mixer; and extracting the explosive composition from the second mixing chamber.
2 . The process of claim 1 , wherein the rotor shaft speed in the first mixing chamber is about 10 rpm to about 50 rpm.
3 . The process of claim 1 , wherein the residence time in the first mixing chamber is about 5 minutes to about 180 minutes.
4 . The process of claim 1 , wherein the rotor shaft speed in the second mixing chamber is about 15 rpm to about 80 rpm.
5 . The process of claim 1 , wherein the residence time in the second mixing chamber is about 10 minutes to about 80 minutes.
6 . The process of claim 1 , wherein the first mixing chamber is at a temperature of about 20 degrees Celsius to about 40 degrees Celsius degrees Celsius.
7 . The process of claim 1 , wherein the second mixing chamber is at a temperature of about 20 degrees Celsius to about 55 degrees Celsius.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63/524,239, filed Jun. 30, 2023, the entire disclosure of which is hereby incorporated by reference herein STATEMENT OF GOVERNMENT INTEREST The inventions described herein may be manufactured, used and licensed by or for the United States Government. FIELD OF THE INVENTION The invention relates in general to manufacturing processes and in particular to manufacturing processes for explosive compositions. BACKGROUND OF THE INVENTION Currently fielded demolition charges are packaged in two configurations for specific uses. Block demolition charges are produced using multi-batch operations and pre-packaged in rectangular form. These block demolition charges are high explosive charges that are used for general demolition operations, such as cutting, breaching and cratering. Roll demolition charges are also processed using multi-batch operations and are packaged in a circular roll shape and are used for the same operations as block charges. Roll configuration charges can be useful when confronted with irregular shapes. Currently fielded roll-shaped demolition formulations are pentaerythritol tetranitrate (PETN) based. Such formulations are currently batch processed, mode starting with the mixing of all ingredients (nitramines, binder, plasticizer, etc.) in a blade mixer for certain period of time. Subsequently, the material from the blade mixer is incrementally loaded to a ram press barrel in order to push/extrude the material through a die to obtain the extrudate of the desired configuration (e.g. roll-shaped). However, the current batch processing method described above produces unsuitable results (e.g. sharkskin-like texture on the extrudate surface) when used with alternative flexible explosive (Flex-X) formulations intended to replace PETN based formulations. Accordingly, improved processes for preparing energetic compositions are provided herein. SUMMARY OF INVENTION A first embodiment of the present disclosure includes a continuous process of preparing an explosive composition, the process comprising: feeding an energetic material and a first binder component into a first mixer, wherein the first mixer comprises an enclosed, temperature controlled mixing chamber, at least one rotor shaft along the interior longitudinal axis of the first mixing chamber, and wherein the rotor shaft comprises at least one mixing element fixed to the rotor shaft and wherein a continuous, partially filled volume is maintained throughout the first mixing chamber; mixing the solid energetic material and the first binder component in the first mixer; feeding the product from the first mixing chamber and a second binder component into a second mixer, wherein the second mixer comprises an enclosed, temperature controlled second mixing chamber, at least one rotor shaft along the interior longitudinal axis of the second mixing chamber and wherein the rotor shaft comprises at least one mixing element fixed to the rotor shaft and wherein a continuous, partially filled volume is maintained throughout the second mixing chamber; mixing the product from the first mixing chamber and the second binder component in the second mixer; and extracting the explosive composition from the second mixing chamber. A second embodiment of the present disclosure includes the process of the first embodiment, wherein the rotor shaft speed in the first mixing chamber is about 10 to about 50 rpm. A third embodiment of the present disclosure includes the process of any of the first embodiment to the second embodiment, wherein the residence time in the first mixing chamber is about 5 to about 180 minutes. A fourth embodiment of the present disclosure includes the process of any of the first embodiment to the third embodiment, wherein the rotor shaft speed in the second mixing chamber is about 15 to about 80 rpm. A fifth embodiment of the present disclosure includes the process of any of the first embodiment to the fourth embodiment, wherein the residence time in the second mixing chamber is about 10 to about 80 minutes. A sixth embodiment of the present disclosure includes the process of any of the first embodiment to the fifth embodiment, wherein the first mixing chamber is at a temperature of about 20 degrees Celsius to about 40 degrees Celsius. A seventh embodiment of the present disclosure includes the process of any of the first embodiment to the sixth embodiment, wherein the second mixing chamber is at a temperature of about 20 degrees Celsius to about 55 degrees Celsius. The invention will be better understood, and further objects, features and advantages of the invention will become more apparent from the following description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to