阅读说明：本技术 退役梯黑铝***的分离回收方法 (Separation and recovery method of retired ladder black aluminum explosive ) 是由 黄风雷 仝毅 王远芳 张世潇 于 2019-10-23 设计创作，主要内容包括：本发明公开了一种退役梯黑铝炸药的分离回收方法。该分离回收原理是根据组成梯黑铝(TNT-RDX-Al)炸药的各组分(梯恩梯,黑索金,铝粉)的物理性质,主要是熔点和密度的差别,采取分步分离方法,实现各组分的分离和回收。第一步,采用控温离心的方法先把算组分中熔点最低的梯恩梯分离出来；第二本,采用密度液的方法把黑索金和铝粉分离开来,全程不发生化学反应,各组分属性保真度高、工艺条件简单、分离效率高、安全环保,成本低。(The invention discloses a separation and recovery method of retired ladder black aluminum explosive. The separation and recovery principle is that according to the physical properties of all components (TNT-RDX-Al) composing the TNT-RDX-Al explosive, mainly the difference of melting points and densities, a step-by-step separation method is adopted to realize the separation and recovery of all components. Firstly, separating the trinitrotoluene with the lowest melting point in the calculated components by adopting a temperature-controlled centrifugation method; secondly, the hexogen and the aluminum powder are separated by adopting a density liquid method, no chemical reaction occurs in the whole process, the property fidelity of each component is high, the process conditions are simple, the separation efficiency is high, the method is safe and environment-friendly, and the cost is low.)

1. The separation and recovery method of the retired TNT aluminum explosive comprises the following steps:

(1) temperature-controlled centrifugal separation: heating the decommissioned TNT-Al explosive to 86-96 ℃ to melt the material, carrying out heat preservation and centrifugation to obtain a bottom precipitate consisting of a supernatant and RDX-Al, and cooling the supernatant to obtain TNT solid;

(2) hot water elution: adding water into the bottom sediment, heating to 86-96 ℃, fully dispersing the sediment in hot water, separating out emulsion and solid sediment, and cooling the emulsion to separate out TNT solid;

(3) density liquid separation: placing the solid precipitate in a density liquid, fully dispersing and separating, wherein the upper layer is RDX, the lower layer is Al powder, and the density liquid is a mixture of a crystal with a specific gravity greater than that of the RDX and less than that of the aluminum powder;

(4) respectively collecting, cleaning and drying: and (3) combining the TNT solids in the steps (1) and (2), respectively collecting the RDX powder and the Al powder in the step (3), cleaning with water, and drying for storage.

2. The separation and recovery method according to claim 1, wherein the density liquid has a specific gravity of 2.0 to 2.5g/cm³。

3. The separation and recovery method according to claim 2, wherein the density liquid is an aqueous solution of sodium chloride, ammonium sulfate and/or zinc bromide.

4. The separation and recovery method according to claim 1, wherein the solid precipitate content of the mixed liquid formed by the solid precipitate and the density liquid in the step (3) is 1-2%.

5. The separation and recovery method according to claim 4, wherein the separation in the step (3) is a standing separation or a centrifuge separation; the separation conditions of the centrifugal machine are as follows: the temperature of the mixed liquid is 30-50 ℃, the rotating speed of a centrifugal machine is 500-2500 r/min, and the centrifugal time is 10-20 minutes.

6. The separation and recovery method according to claim 5, wherein the solid precipitate in the step (3) is dried at 30-50 ℃ and then placed in a density liquid, and the density liquid obtained after separation by the centrifuge is filtered, measured, adjusted to a specified value and recycled.

7. The separation and recovery method according to claim 1, wherein the sufficient dispersion in the step (3) is sufficient stirring or/and ultrasonic homogenization or/and refining.

8. The separation and recovery method according to claim 1, wherein the mass ratio of the bottom sediment to the water in the step (2) is 1: 25-35; the sufficient dispersion is ultrasonic dispersion.

9. The separation and recovery method according to claim 1, wherein the hot water elution in the step (2) is circulated for a plurality of times until the emulsion becomes clear supernatant, and the emulsions eluted for a plurality of times are combined together.

10. The separation and recovery method according to claim 1, wherein in the step (1), the material temperature is kept at 86-96 ℃, the rotation speed of the centrifuge is 1000-3000 rpm, and the centrifugation time is 20-40 min.

11. The separation and recovery method according to claim 1, wherein the supernatant obtained by the heat-preservation centrifugation in the step (1) is kept at a temperature for standing separation, the upper layer is TNT supernatant, and the lower layer is solid precipitate; or keeping the temperature and centrifuging the obtained supernatant again to obtain TNT supernatant and bottom sediment.

12. The separation and recovery method according to claim 1, wherein the temperature-controlled centrifuge in step (1) is provided with a jacket, and the water bath or the water vapor in the jacket heats the decommissioned stephanite black aluminum to a molten state.

Technical Field

The invention relates to a physical separation technology of retired thermoplastic composite explosives, in particular to a separation and recovery method of TNT-RDX-Al explosive components.

Background

Weapons and ammunition are important strategic resources for national military combat and need to be stored in large quantities, but due to the fact that weapons are changed and the service life of the weapons is expired, a large quantity of waste explosives can be stored in the military, and due to inherent combustion, explosion characteristics and toxicity of the explosives, huge potential danger hazards are brought to social safety and natural environment, so that the waste explosives must be effectively and safely treated. The traditional treatment methods, such as a deep sea dumping method, an open-air burning method, a deep soil burying method and the like, are simple to operate, but cannot eliminate the potential danger of explosives, and can cause secondary pollution to the environment.

At present, all countries pay more attention to green recycling treatment, so that the harm to the society and the environment can be reduced, waste can be changed into valuable, and good social and economic benefits are generated. The treatment idea of waste ammunition in China is mainly safety, the treatment means is mainly destruction, and the technical strength in the aspect of recovery is relatively weak.

From the outside at home, the separation and recovery methods of explosive components are mainly divided into two types: solvent extraction and melt separation. Hywon Kang et al [ Kang H, Kim H, Lee C H, et al.extraction-based recovery of RDXfrom the object Composition B [ J ]. Journal of Industrial & Engineering Chemistry,2017,56 ] extract TNT from Composition B by exploiting the different solubilities of TNT and RDX in acetonitrile; wu Yi, etc. (Wu Yi, Ding Yu Qu, Liu national Qing, etc.. solvent extraction method for recovering RDX and aluminum powder [ J ] in waste and old TNT explosive, 2014(6):35-39.] first using toluene to extract TNT in TNT explosive, then using acetone and dimethyl sulfoxide as solvents respectively, extracting, cooling, crystallizing and filtering to obtain RDX; the organic solvent extraction method has the advantages of low temperature and good safety, but the method has many working procedures and complex operation, needs large amount of organic solvent and has most toxicity, thereby improving the production cost. Morris et al [ Morris J B.separation of RDX from Composition B Via a Supercritical fluid extraction Process [ J ].1997 ] extracting B explosive with Supercritical carbon dioxide, and the purity of the recovered RDX is more than 99%; the recovery and characterization of TNT and RDX in waste TNT and RDX in Wangbuo, Chongqing city people government, China institute of engineering and physics, national hazardous substance and safety emergency technology workshop proceedings (hereinafter) [ C ] Chongqing city people government, China institute of engineering and physics, 2011:6 ] separation of TNT and RDX in waste TNT and aluminum explosive is carried out by utilizing a supercritical carbon dioxide extraction technology; however, supercritical equipment is expensive and not suitable for large-scale production. Arthur et al [ Arthur F, Spencer, David F, Hartline, recovery of secondary application from application composition: US,5977354[ P ].1999-11-2 ] heating a mixed explosive containing TNT and nitramine with steam by a melting method, separating the mixed explosive through a screen by the weight of the explosive, and although the operation method is simple, the separation efficiency is extremely low; the method for separating TNT [ J ] energetic materials in the waste TNT aluminum explosive by a fusion method is improved, namely the TNT [ J ] energetic materials in the waste TNT aluminum explosive are heated and melted by water, the TNT recovery rate is 76.2%, the separation efficiency of the differential pressure separation method is still to be improved after improvement, and the problem of wastewater treatment exists.

Disclosure of Invention

Aiming at the defects in the field, the invention adopts a temperature-controlled centrifugation and density liquid method to realize the physical separation and recovery of the components of the TNT-black aluminum explosive.

The separation and recovery method of the retired TNT aluminum explosive comprises the following steps:

(1) temperature-controlled centrifugal separation: heating the decommissioned TNT-Al explosive to 86-96 ℃ to melt the material, carrying out heat preservation and centrifugation to obtain a bottom precipitate consisting of a supernatant and RDX-Al, and cooling the supernatant to obtain TNT solid;

(2) hot water elution: adding water into the bottom sediment, heating to 86-96 ℃, fully dispersing the sediment in hot water, separating out emulsion and solid sediment, and cooling the emulsion to separate out TNT solid;

(3) density liquid separation: placing the solid precipitate in a density liquid, fully dispersing and separating, wherein the upper layer is RDX, the lower layer is Al powder, and the density liquid is a mixture of a crystal with a specific gravity greater than that of the RDX and less than that of the aluminum powder;

(4) respectively collecting, cleaning and drying: and (3) combining the TNT solids in the steps (1) and (2), respectively collecting the RDX powder and the Al powder in the step (3), cleaning with water, and drying for storage.

The specific gravity of the density liquid is 2.0-2.5 g/cm³。

The density liquid is an aqueous solution of sodium chloride, ammonium sulfate and/or zinc bromide.

And (3) the content of the solid precipitate in the mixed liquid formed by the solid precipitate and the density liquid is 1-2%.

The separation in the step (3) is static separation or centrifugal separation, and the centrifugal separation conditions are as follows: the temperature of the mixed liquid is 30-50 ℃, the rotating speed of a centrifugal machine is 500-2500 r/min, and the centrifugal time is 10-20 minutes.

And (3) drying the solid precipitate at 30-50 ℃, putting the dried solid precipitate into density liquid, filtering the density liquid obtained after separation by the centrifugal machine, measuring and adjusting the density of the density liquid to a specified value, and recycling the density liquid.

The sufficient dispersion in the step (3) is sufficient stirring or/and ultrasonic homogenization or/and refining.

The mass ratio of the bottom sediment to the water in the step (2) is 1: 25-35; the sufficient dispersion is ultrasonic dispersion.

And (3) circulating the hot water elution for multiple times in the step (2) until the emulsion becomes clear supernatant, and combining the emulsions eluted for multiple times.

In the step (1), the temperature of the materials is kept at 86-96 ℃, the rotating speed of a centrifuge is 1000-3000 rpm, and the centrifugation time is 20-40 min.

Performing heat preservation and standing separation on the supernatant obtained by heat preservation and centrifugation in the step (1), wherein the upper layer is TNT supernatant, and the lower layer is solid precipitate; or keeping the temperature and centrifuging the obtained supernatant again to obtain TNT supernatant and bottom sediment.

The temperature control centrifugal machine in the step (1) is provided with a jacket, and the retired ladder black aluminum is heated to a molten state by water bath or water vapor in the jacket.

The main principle of the invention is based on the main physical properties of three components of the TNT-alumina explosive, namely the difference between melting point and density, the technology of separating TNT by a temperature-controlled centrifugal method and separating the rest RDX and Al powder by a density liquid method is designed and implemented, and suitable process parameters are determined.

The separation technology of the invention comprises the following implementation steps:

1. controlling temperature and melting materials:

materials: retired ladder black aluminum-dry powder or granules; equipment: a jacketed temperature-controlled centrifuge; the operating conditions are as follows: heating by water bath or low pressure (0.1 MPa) steam until the molten state is completely formed.

2. Temperature-controlled centrifugal separation:

introducing the molten-state black aluminum ladder material into a centrifuge through a heat-insulating pipeline, wherein the material metering volume is limited by a centrifuge chamber 1/3-1/2; and controlling the temperature to be kept at a level of 5-15 ℃ higher than the TNT melting point, namely 81+ 5-15 ℃. The rotating speed of the centrifugal machine is 1000-3000 rpm, and the centrifugal time is 20-40 min.

3. Discharging heat-preservation separate device

After the centrifugal operation is finished, immediately discharging after stopping the machine, respectively taking out the mixture of the supernatant TNT and the bottom precipitated hexogen and the aluminum powder, standing and storing the mixture in a heat-insulating container so that the TNT can further precipitate a small amount of hexogen and the aluminum powder possibly contained in the mixture, or further performing centrifugal separation according to the requirement; and also to prevent the separated hexogen and aluminum powder from being agglomerated and hardened due to the small amount of TNT, which causes difficulty in subsequent processing.

4. Hot water elution

Since complete separation of TNT from the TNT-RDX-Al mixture is impossible by centrifugal separation, small amounts of TNT must be included between the surface and the inner particles of the precipitate obtained by centrifugation, which affects the subsequent separation effect and the purity of the product. Is dissolved and eluted by hot water. Placing the material in a temperature-controlled ultrasonic pool, adding 25-35 times of water, heating and controlling the temperature at 86-96 ℃, fully performing ultrasonic dispersion for 30-60 minutes, standing for 1-2 hours, or performing temperature-controlled centrifugation, separately storing the RDX-Al precipitate and the TNT-containing dilute emulsion (supernatant), repeating the steps for 2-3 times, enabling the supernatant to become clear, cooling and standing the collected supernatant, and recovering the TNT after the TNT is crystallized and separated out; and the obtained RDX-Al precipitate enters the next step of density liquid separation.

5. Separate drying

And (3) placing the material RDX-Al subjected to hot water elution pretreatment in an air-blast drying oven, controlling the temperature to be 30-50 ℃, and drying to perform density-liquid separation.

6. Preparing density liquid

The substance for preparing the density liquid has the characteristics of stability and no decomposition at the operation temperature, no reaction with the separated components (RDX, Al and TNT), high solubility in water, no biological and environmental toxicity and the like, and is convenient for preparing the solution with the density between the RDX and the Al. The RDX crystal density is 1.816g/cm³The density of the aluminum powder is 2.7g/cm³. Theoretical analysis and experimental screening are carried out to determine substances such as sodium chloride, ammonium sulfate, zinc bromide and the like suitable for the density liquid, and the concentration of the pre-prepared density liquid is 2.0-2.5 g/cm 3; according to the batch of RDX-Al materials, the density liquid separation is carried out on the RDX-Al + density liquid with the solid content of 1-2%.

7. Density liquid separation

Dispersing the RDX-Al mixture into density liquid with known density, and after full stirring, ultrasonic homogenization and refinement, floating substances with density lower than that of the density liquid on the surface of the density liquid; otherwise, the liquid is settled to the bottom of the density liquid. This process can be accelerated by centrifugation for micropowder materials having particle sizes down to the nanometer micron level. The temperature is selected to be 30-50 ℃, the rotating speed of a centrifugal machine is 500-2500 r/min, the centrifugal time is 10-20 minutes, and the RDX on the upper layer and the Al powder on the lower layer are respectively taken out.

8. Drying by baking

And respectively drying the RDX and Al powder obtained by density liquid separation at the temperature of 30-50 ℃ and 100-150 ℃, and metering and packaging.

9. Density liquor recovery

And (3) filtering the density liquid used in the density separation process, measuring and adjusting the density of the density liquid to a specified value for recycling.

The invention recovers trinitrotoluene, hexogen and aluminum powder of three components in the trinitrotoluene aluminum by a temperature-controlled centrifugation-specific gravity liquid separation and recovery technology, and realizes the separation and recovery of each component by adopting a step-by-step separation method aiming at the difference of melting points and densities of the three components. Firstly, separating the trinitrotoluene with the lowest melting point from the three components by adopting a temperature-controlled centrifugation method; firstly, a mode of melting and separating most of the TNT is adopted, so that the separation load of part of the TNT in the second step is small, the water consumption is reduced, the environmental protection performance is good, and the separation efficiency is improved; and secondly, separating the hexogen and the aluminum powder by adopting a density liquid method, wherein the density liquid adopts an inorganic salt aqueous solution, can be recycled, is economic and environment-friendly, does not generate chemical reaction in the whole process, and has the advantages of high attribute fidelity of each component, simple process condition, high separation efficiency, safety, environmental protection and low cost. The recovery rates of TNT, RDX and aluminum powder reach or are higher than 95.1%, 74% and 87.8%, and the purities are 95%, 72% and 88%, respectively.

Drawings

FIG. 1 Process flow diagram of the process of the invention

Detailed Description

The present invention will be described in further detail with reference to the following examples and the accompanying drawings.

FIG. 1 is a process flow diagram of the present invention; heating the retired TNT aluminum explosive to be in a molten state at 86-96 ℃ under the condition of controlling the temperature, centrifuging, wherein the supernatant is TNT, cooling to obtain TNT solid, and the rest explosive is a small amount of TNT, RDX and Al powder.

And (3) dissolving TNT in water by adopting a hot water elution method for the rest explosive, separating to obtain a TNT solution and a mixed precipitate of RDX and aluminum powder, and cooling and recrystallizing the TNT to separate out a TNT solid.

And (3) carrying out graded separation on the mixture of the RDX and the aluminum powder again through a density liquid value in a certain interval, wherein the upper-layer floating object with the specific gravity smaller than that of the density liquid is RDX, the bottom sediment with the specific gravity larger than that of the density liquid is aluminum powder, and the upper layer and the lower layer are respectively cleaned and dried after separation.