TWI668328B - Method for zero-discharge phosphatization and saponification based on high-pressure closed circulation system - Google Patents

Abstract

The invention discloses a zero-emission phosphating and saponification method based on a high-pressure closed-cycle system, which includes an autoclave, a separation kettle, a buffer kettle, and a hydraulic pump. The following steps are adopted: Step 1. Load a workpiece into an autoclave, and then perform Sealing makes the autoclave pressure resistance range above 20MPa; step two, CO ₂ degreasing and rust removal; step three, circulating separation; step four, high pressure phosphating; step five, circulating separation two; step six, high pressure saponification; step seven, Separate three cycles; Step eight, open the autoclave, ventilate and dry. Adopting the technical scheme of the invention can greatly reduce the consumption of acid, alkali and industrial water, good labor conditions, convenient collection and treatment of production residues, no sewage, no environmental pollution problems, and zero emissions.

Description

Zero-emission phosphating and saponification method based on high-pressure closed cycle system

The invention relates to the field of phosphating and saponification pretreatment in the metal cold processing industry, and particularly relates to a zero-emission phosphating and saponification method based on a high-pressure closed cycle system.

In the metal cold working industry, in the processes of wire drawing, extrusion, deep drawing, etc., the surface of the workpiece must first be phosphatized-saponified. After the treatment, it can reduce the friction between the workpiece and the mold and provide good lubrication. effect.

The specific production process of phosphating treatment is: first, the surface of the metal workpiece is degreased and derusted by acid and alkali, and the surface of the treated metal workpiece is washed with water; the second is the zinc-based phosphating treatment, and the treated metal The surface of the workpiece is washed with water, and the surface of the metal workpiece is saponified again with sodium stearate. After the processing is completed, the surface is dried. The reason for using zinc-based phosphating is that first, zinc-based phosphating film forms a zinc stearate layer with good lubricity after saponification. Second, zinc-based phosphating has a relatively low operating temperature, which can be at 40, 60 or 90 ° C. Phosphate treatment.

When the above-mentioned production of metal workpieces is used for derusting, it will be washed and derusted with hydrochloric acid, nitric acid and sulfuric acid according to different metals, which will generate toxic, stinging yellow and red smoke, produce severe corrosive three waste pollution, and easy to clean. The metal itself: the outer layer dissolves to form over-corrosion, and the internal hydrogen permeation generates hydrogen embrittlement, which endangers the safety of use and shortens the service life. In addition, the entire process needs to be washed with water multiple times. Washing and diluting the waste working fluid with water will consume and lose a large amount of water resources, resulting in serious pollution and great waste.

In view of this, our inventors are concentrating on further research and proceeding with research and development and improvement, with a better design to solve the above problems, and the invention came out after continuous testing and modification.

In order to solve the problems existing in the prior art, the present invention provides a high-pressure closed cycle system and a zero-emission phosphating and saponifying method using the system.

To achieve the above objective, the technical solution adopted by the present invention is: a zero-emission phosphating and saponification method based on a high-pressure closed cycle system, including an autoclave, a separation kettle, a buffer kettle, a hydraulic pump, and a recovery barrel; the steps are as follows:

Step 1: Put the workpiece into the autoclave, and then seal it so that the pressure range of the autoclave is above 20MPa;

Step 2: CO ₂ degreasing and rust removal, carbon dioxide is buffered by a buffer tank, and then sent to the autoclave by a hydraulic pump, and then a high-pressure carbon dioxide gas stream is sprayed onto the workpiece through a venturi nozzle in the autoclave to derust and degrease the workpiece;

Step 3: Circulating separation: The supercritical CO _{2 is} transported into the autoclave by means of a buffer tank and a hydraulic pump for cyclic cleaning until the autoclave is clean, and oil and solid residues are pushed into the separating tank by supercritical CO ₂ ;

Step 4. High-pressure phosphatization: Inject the phosphating solution into the autoclave under pressure by a hydraulic pump, mix and dilute it with the high-pressure fluid in the autoclave under the action of the agitator of the autoclave, and raise the autoclave to the reaction temperature. The surface of the workpiece is subjected to phosphating treatment; the phosphating solution chemically reacts on the surface of the workpiece to form a phosphating film; after the reaction is completed, the fluid in the autoclave is led to a separation kettle to separate and collect the phosphating residue;

Step 5: Circulating separation 2: The supercritical CO _{2 is} transported into the autoclave by means of a buffer kettle and a hydraulic pump for circulating cleaning until the inside of the autoclave is clean;

Step 6. High-pressure saponification: Inject the saponification into the autoclave by means of a hydraulic pump, mix and dilute it with the high-pressure fluid in the autoclave under the action of the agitator of the autoclave; warm the autoclave to the reaction temperature, and carry out the work surface Phosphating treatment; the chemical reaction of the phosphating solution on the surface of the workpiece to form a saponification film; after the reaction is completed, the fluid in the autoclave is led to a separation kettle to separate and collect the residue after saponification;

Step 7. Circulation separation III: The supercritical CO _{2 is} transported into the autoclave by means of a buffer kettle and a hydraulic pump for circulation cleaning until the autoclave is clean;

Step 8. Drying: Open the autoclave and ventilate and dry.

In a further improvement, the carbon dioxide separated from the separation kettle in steps 5 and 7 is cooled and pressurized, and then passed into the autoclave for cycle cleaning.

Compared with the prior art, the beneficial effect of the present invention is that after the technical solution of the present invention is adopted, the solubility of oil stains, phosphoric acid, phosphates, and sodium stearate can be changed by adjusting changes in temperature and pressure to achieve circulation separation and collection. The purpose is to greatly reduce the amount of acid, alkali and working water. The chemical solution flows in the closed pipeline without volatilization and leakage. It does not exclude sewage and waste liquid from the environment. The working conditions are good. The production residues are easy to collect and treat without causing environmental pollution. .

Regarding the technical means of our inventors, several preferred embodiments are described in detail below in conjunction with the drawings, for the purpose of understanding and agreeing with the present invention.

The preferred solutions of the present invention will be further described below with reference to the drawings:

As shown in Figures 1 and 2, a zero-emission phosphating and saponification method based on a high-pressure closed cycle system includes an autoclave, a separation kettle, a buffer kettle, a hydraulic pump, and a recovery barrel; the steps are as follows:

Step 1: Put the workpiece into the autoclave, and then seal it so that the pressure range of the autoclave is above 20MPa;

Step 2: CO ₂ degreasing and rust removal, carbon dioxide is buffered by a buffer tank and then sent to the autoclave by a hydraulic pump, and then a high-pressure carbon dioxide gas stream is sprayed onto the workpiece through a venturi nozzle in the autoclave to perform derusting and degreasing on the workpiece; In the step, the kinetic energy and momentum of the generated carbon dioxide “snow” (containing small particles of dry ice) are mainly used to remove rust, and the chemical dissolution of the carbon dioxide “snow” is used to remove oil; then the supercritical carbon dioxide fluid is passed in and the dissolution of the supercritical fluid is used The oil and solid particles in the container are exported to the separation kettle by the washing effect and separated and collected;

Step 3: Circulating separation: The supercritical CO _{2 is} transported into the autoclave by means of a buffer tank and a hydraulic pump for cyclic cleaning until the autoclave is clean, and oil and solid residues are pushed into the separating tank by supercritical CO ₂ ;

Step 4. High-pressure phosphatization: Inject the phosphating solution into the autoclave under pressure by a hydraulic pump, mix and dilute it with the high-pressure fluid in the autoclave under the action of the agitator of the autoclave, and raise the autoclave to the reaction temperature. The surface of the workpiece is subjected to phosphating treatment; the phosphating solution chemically reacts on the surface of the workpiece to form a phosphating film; after the reaction is completed, the fluid in the autoclave is led to a separation kettle to separate and collect the phosphating residue;

Step 5: Circulation separation 2: The supercritical CO _{2 is} transported into the autoclave by means of a buffer tank and a hydraulic pump to be circulated and cleaned until the autoclave is clean; the carbon dioxide separated by the separation tank is cooled, pressurized, and then passed into the high pressure The kettle was circulated for cleaning.

Step 6. High-pressure saponification: Inject the saponification into the autoclave by means of a hydraulic pump, mix and dilute it with the high-pressure fluid in the autoclave under the action of the agitator of the autoclave; warm the autoclave to the reaction temperature, and carry out the work surface Phosphating treatment; the chemical reaction of the phosphating solution on the surface of the workpiece to form a saponification film; after the reaction is completed, the fluid in the autoclave is led to a separation kettle to separate and collect the residue after saponification;

Step Seven: Circulation separation III: The supercritical CO _{2 is} transported into the autoclave by means of a buffer tank and a hydraulic pump for circulation cleaning until the autoclave is clean; the carbon dioxide separated by the separation tank is cooled, pressurized, and then passed into the high pressure The kettle was circulated for cleaning.

Step 8. Drying: Open the autoclave and ventilate and dry.

In summary, the technical means disclosed in the present invention can effectively solve problems such as knowledge, and achieve the intended purpose and effect. It has not been published in publications before application, has not been publicly used, and has long-term progress. The invention referred to in the Patent Law is correct, and he filed an application in accordance with the law. He earnestly hopes that Jun will give him a detailed review and grant a patent for the invention.

However, the above are only a few preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited in this way, that is, equivalent changes and modifications made according to the scope of the patent application and the content of the invention specification of the present invention are all It should still fall within the scope of the invention patent.

〔this invention〕

no

Figure 1 is a schematic block diagram of the steps of a zero-emission phosphating and saponifying method based on a high-pressure closed cycle system. Figure 2 is a system block diagram of a zero-emission phosphating and saponifying method based on a high-pressure closed-cycle system.

Claims (2)

A method for zero-emission phosphating and saponification based on a high-pressure closed-cycle system includes an autoclave, a separation kettle, a buffer kettle, a hydraulic pump, and a recovery barrel. The method is characterized in that it includes the following steps: Step 1. Load a workpiece into an autoclave Then, it is sealed to make the pressure range of the autoclave above 20MPa; Step 2. CO ₂ degreasing and rust removal, carbon dioxide is buffered by the buffer tank and then sent to the autoclave by the hydraulic pump, and then sprayed to the workpiece through the venturi nozzle in the autoclave. High-pressure carbon dioxide gas is used to remove the rust and oil from the workpiece. Step 3. Cycle separation: Supercritical CO _{2 is} transported into the autoclave by means of a buffer tank and a hydraulic pump, and the cycle is cleaned until the autoclave is clean, oil stains and solid residues are removed. Supercritical CO _{2 is} pushed into the separation kettle; Step 4. High-pressure phosphating: the phosphating solution is injected into the autoclave by a hydraulic pump under pressure, and mixed with the high-pressure fluid in the kettle under the action of the agitator of the autoclave, and diluted; The autoclave is heated to the reaction temperature to perform phosphating on the surface of the workpiece; the phosphating solution chemically reacts on the surface of the workpiece to form a phosphating film After completion of the reaction, the autoclave was exported to the fluid separation vessel, separating the residue collected after phosphating; Step five, two separate cycle: a buffer tank and a hydraulic pump by means of supercritical CO ₂ delivery into the autoclave cycle Clean up until the autoclave is clean. Step 6. High pressure saponification: Saponification is injected into the autoclave by means of a hydraulic pump, and it is mixed and diluted with the high pressure fluid in the autoclave under the action of the agitator of the autoclave. At the reaction temperature, the surface of the workpiece is phosphated; the phosphating solution chemically reacts on the surface of the workpiece to form a saponified film; after the reaction is completed, the fluid in the autoclave is led to a separation kettle to separate and collect the saponified residue; steps VII. Cyclic separation III: The supercritical CO _{2 is} transported into the autoclave by means of a buffer kettle and a hydraulic pump for circulation cleaning until the autoclave is clean. Step 8: Drying: Open the autoclave, ventilate and dry. The zero-emission phosphating and saponification method based on the high-pressure closed-cycle system according to item 1 of the scope of the patent application, wherein the carbon dioxide separated from the separation kettle in step 5 and step 7 is cooled, pressurized, and then passed into the high pressure The kettle was circulated for cleaning.