System for preparing calcium sulfate whiskers by using aramid byproduct gypsum

Abstract

The utility model belongs to the technical field of aramid byproduct gypsum recycling, and particularly relates to a system for preparing calcium sulfate whiskers by using aramid byproduct gypsum. Comprising a batching device, a heating and stirring kettle and a filtering and aging device, the batching device comprises a slurry pool, a gypsum powder tank and a diluted hydrochloric acid liquid storage tank, a byproduct gypsum outlet of the aramid fiber production system is connected with an inlet of the gypsum powder tank, and an outlet of the gypsum powder tank and an outlet of the diluted hydrochloric acid liquid storage tank are both connected with an inlet of the slurry pool; an outlet of the slurry pool is communicated with an inlet of the heating and stirring kettle, an outlet of the heating and stirring kettle is connected with an inlet of the filtering and aging device, a filter cake outlet of the filtering and aging device is a calcium sulfate whisker outlet, and a liquid outlet is connected with the diluted hydrochloric acid storage tank. By using the aramid byproduct gypsum as the raw material, industrial byproducts can be effectively utilized, the problem of environmental pollution caused by stacking of waste materials is solved, the purpose of green chemical industry is achieved, the aramid industry chain can be extended, and the aramid industry value can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of recycling aramid by-product gypsum, and specifically relates to a system for preparing calcium sulfate whiskers by utilizing aramid by-product gypsum. Background Art

[0002] Calcium sulfate whiskers are fibrous single crystals of calcium sulfate. They have the advantages of high temperature resistance, chemical corrosion resistance, and good toughness. Compared with other whisker materials, they are cheaper. They are a green material with excellent performance, high cost performance, and non-toxicity, and have strong market competitiveness.

[0003] The main raw materials of calcium sulfate whiskers are natural gypsum and industrial by-product gypsum. However, the reserves of natural gypsum are limited. On the other hand, the storage volume of various types of industrial by-product waste gypsum in my country is 70.43 billion tons, including some by-product gypsum obtained by treating the waste sulfuric acid produced in the aramid production process. Aramid by-product gypsum is a gray sludge-like waste residue obtained by the neutralization reaction of quicklime and dilute sulfuric acid after reaction. The comprehensive utilization rate of industrial by-product gypsum in my country is only 38%. If all unused industrial by-product gypsum is landfilled, it will cause a considerable burden on the environment. Summary of the invention

[0004] In view of this, the utility model provides a system for preparing calcium sulfate whiskers by utilizing aramid by-product gypsum, so as to solve the technical problem of low utilization efficiency of aramid by-product gypsum in my country in the prior art.

[0005] To achieve the above objectives, this application adopts the following scheme:

[0006] A system for preparing calcium sulfate whiskers by using aramid by-product gypsum, which is connected to the by-product gypsum outlet of the aramid production system, and comprises a batching device, a heating and stirring kettle, and a filtering and aging device; the batching device comprises a slurry pool, a gypsum powder tank, and a dilute hydrochloric acid storage tank; the by-product gypsum outlet of the aramid production system is connected to the inlet of the gypsum powder tank, and the outlet of the gypsum powder tank and the outlet of the dilute hydrochloric acid storage tank are both connected to the inlet of the slurry pool; the outlet of the slurry pool is communicated with the inlet of the heating and stirring kettle, and the outlet of the heating and stirring kettle is connected to the inlet of the filtering and aging device, the filter cake outlet of the filtering and aging device is a calcium sulfate whisker outlet, and the liquid outlet is connected to the dilute hydrochloric acid storage tank.

[0007] Preferably, the heating stirring kettle is provided with a condensation reflux device, the inlet of the condensation reflux device is connected to the top of the heating stirring kettle, and the outlet of the condensation reflux device is connected to the inlet of the heating stirring kettle.

[0008] Preferably, it also includes a first drying device and a crushing device, the by-product gypsum outlet of the aramid production system is connected to the inlet of the first drying device, the outlet of the first drying device is connected to the inlet of the crushing device, and the outlet of the crushing device is connected to the inlet of the gypsum powder tank.

[0009] Preferably, it also includes a cleaning tank and a second drying device which are connected in sequence, and the filter cake outlet of the filtering and aging device is connected to the inlet of the cleaning tank.

[0010] Preferably, the filtering and aging device includes a first filter, an aging tank and a second filter, the outlet of the heated and stirred kettle is connected to the inlet of the first filter, the first filter has an impurity outlet, the liquid outlet of the first filter is connected to the inlet of the aging tank, the outlet of the aging tank is connected to the inlet of the second filter, the filter cake outlet of the second filter is the calcium sulfate whisker outlet, and the liquid outlet of the second filter is connected to the dilute hydrochloric acid storage tank.

[0011] Preferably, the second filter has a jacket cooling device.

[0012] Preferably, the first filter is a suction filter.

[0013] Preferably, the second filter is a filter press.

[0014] Preferably, it further comprises a filtrate pool, wherein the liquid outlet of the second filter is connected to the inlet of the filtrate pool, the outlet of the filtrate pool is connected to the inlet of the dilute hydrochloric acid storage tank, and the filtrate pool is provided with a first pH detector.

[0015] Preferably, it also includes a filtrate treatment tank, the outlet of the filtrate treatment tank is connected to the inlet of the filtrate treatment tank, the outlet of the filtrate treatment tank is connected to the inlet of the dilute hydrochloric acid storage tank, the inlet of the filtrate treatment tank is also connected to a concentrated hydrochloric acid feed pipe, and the filtrate treatment tank is provided with a second pH detector.

[0016] The technical solution adopted in this application can achieve the following beneficial effects:

[0017] The system for preparing calcium sulfate whiskers using aramid by-product gypsum provided in the present application uses the aramid by-product gypsum in the gypsum powder tank and the dilute hydrochloric acid solution in the dilute hydrochloric acid storage tank to prepare a reaction slurry in the slurry pool. The reaction slurry enters the filtering and aging device after being heated and stirred in the heating and stirring kettle, and calcium sulfate whiskers are obtained after filtering and aging. The present application uses aramid by-product gypsum as raw material, which can not only effectively utilize industrial by-products, solve the problem of environmental pollution caused by waste stacking, and achieve the purpose of green chemical industry, but also extend the aramid industry chain and improve the value of the aramid industry. The system for preparing calcium sulfate whiskers using aramid by-product gypsum provided in the present application does not need to add other additives to control the morphology and promote the growth of whiskers in the process of preparing calcium sulfate whiskers. It only needs to control the solid-liquid ratio, reaction temperature, time and slow cooling during the static aging process to obtain calcium sulfate whiskers with high added value, thereby reducing the cost of raw materials. In the present application, no high-pressure conditions are required, and the produced hydrochloric acid solution can be recycled. The raw materials only require by-product gypsum and common chemical raw material hydrochloric acid. The system is simple to operate. The present application has obvious environmental protection and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a system for preparing calcium sulfate whiskers using aramid by-product gypsum in this application.

[0019] In the figure, there are shown an aramid production system 1, a slurry tank 110, a gypsum powder tank 120, a dilute hydrochloric acid storage tank 130, a heating and stirring kettle 200, a condensation reflux device 210, a first filter 310, an impurity outlet 311, an aging tank 320, a second filter 330, a jacket cooling device 331, a first drying device 410, a second drying device 420, a crushing device 500, a cleaning tank 600, a filtrate tank 700, a first pH detector 710, a filtrate treatment tank 800, a second pH detector 810, a concentrated hydrochloric acid feed pipe 820, a liquid replenishment tank 900, and a desalted water feed pipe 910. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below in conjunction with the accompanying drawings. And the preferred implementation of the present application is given. However, the present application can be implemented in many different forms and is not limited to the implementation described herein. On the contrary, the purpose of providing these implementations is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] In this embodiment, please refer to Figure 1 A system for preparing calcium sulfate whiskers using aramid by-product gypsum is connected to the by-product gypsum outlet of the aramid production system 1, and includes a batching device, a heating and stirring kettle 200, and a filtering and aging device; the batching device includes a slurry pool 110, a gypsum powder tank 120, and a dilute hydrochloric acid storage tank 130. The by-product gypsum outlet of the aramid production system 1 is connected to the inlet of the gypsum powder tank 120, and the outlet of the gypsum powder tank 120 and the outlet of the dilute hydrochloric acid storage tank 130 are both connected to the inlet of the slurry pool 110; the outlet of the slurry pool 110 is connected to the inlet of the heating and stirring kettle 200, and the outlet of the heating and stirring kettle 200 is connected to the inlet of the filtering and aging device, the filter cake outlet of the filtering and aging device is a calcium sulfate whisker outlet, and the liquid outlet is connected to the dilute hydrochloric acid storage tank 130.

[0023] The batching device, the heating stirring kettle 200 and the filtering and aging device in the system for preparing calcium sulfate whiskers using aramid by-product gypsum are sequentially manufactured and connected to form the system for preparing calcium sulfate whiskers using aramid by-product gypsum. The gypsum powder tank 120 is used to store aramid by-product gypsum powder; the dilute hydrochloric acid storage tank 130 is provided with a preset concentration of dilute hydrochloric acid solution, and the concentration of the dilute hydrochloric acid can be 1% to 10%; the slurry pool 110 is used to hold the reaction slurry, and the solid-liquid ratio of the aramid by-product gypsum powder to the dilute hydrochloric acid in the reaction slurry can be 1:10 to 1:25. The heating stirring kettle 200 is used to stir and heat the reaction slurry therein, heating it to 80°C to 100°C, and keeping it warm for 0.5 h to 3 h after heating to obtain the slurry to be decontaminated; the slurry to be decontaminated is filtered and decontaminated in a filtering and aging device to obtain a solution to be crystallized, and the obtained crystallized solution is allowed to stand for 1 h to 6 h for aging, and the aging process is a slow cooling process. After solid-liquid separation treatment, a filter cake and a filtrate are obtained.

[0024] When in use, the by-product gypsum of the aramid production system 1 is processed into powder and stored in the gypsum powder tank 120; the dilute hydrochloric acid solution prepared to a preset concentration is stored in the dilute hydrochloric acid storage tank 130; the control valve on the pipeline connecting the slurry pool 110, the gypsum powder tank 120 and the dilute hydrochloric acid storage tank 130 is opened, so that the aramid by-product gypsum powder in the gypsum powder tank 120 and the dilute hydrochloric acid solution in the dilute hydrochloric acid storage tank 130 enter the slurry pool 110, and the aramid by-product gypsum powder in the slurry pool 110 reacts with the dilute hydrochloric acid solution to generate a reaction slurry. The reaction slurry enters the heating stirring kettle 200 through the outlet of the slurry pool 110, and the heating stirring kettle 200 stirs and heats the reaction slurry therein to make it fully react, and keeps the temperature for a predetermined time after heating to a predetermined time. After the insulation is completed, the reaction slurry in the heating stirring kettle 200 enters the filtering and aging device through the outlet of the heating stirring kettle 200. After filtering and aging, a filter cake and a filtrate are obtained, and the filter cake is calcium sulfate whiskers.

[0025] The system for preparing calcium sulfate whiskers using aramid by-product gypsum provided in the present application uses the aramid by-product gypsum and dilute hydrochloric acid solution in the gypsum powder tank 120 and the dilute hydrochloric acid storage tank 130 to prepare a reaction slurry in the slurry pool 110. The reaction slurry enters the filtering and aging device after being heated and stirred in the heating and stirring kettle 200, and calcium sulfate whiskers are obtained after filtering and aging. The present application uses aramid by-product gypsum as raw material, which can not only effectively utilize industrial by-products, solve the problem of environmental pollution caused by waste stacking, achieve the purpose of green chemical industry, but also extend the aramid industry chain and improve the value of the aramid industry. The system for preparing calcium sulfate whiskers using aramid by-product gypsum provided in the present application does not need to add other additives to control the morphology and promote the growth of whiskers in the process of preparing calcium sulfate whiskers. It only needs to control the solid-liquid ratio, reaction temperature, time and slow cooling during the static aging process to obtain calcium sulfate whiskers with high added value, thereby reducing the cost of raw materials. In the present application, no high-pressure conditions are required, and the produced hydrochloric acid solution can be recycled. The raw materials only require by-product gypsum and common chemical raw material hydrochloric acid. The system is simple to operate. The present application has obvious environmental protection and economic benefits.

[0026] In order to ensure the concentration of dilute hydrochloric acid in the reaction slurry in the heating and stirring kettle 200 and the ratio of dilute hydrochloric acid to aramid by-product gypsum powder, in some preferred embodiments, the heating and stirring kettle 200 is provided with a condensation reflux device 210, the inlet of the condensation reflux device 210 is connected to the top of the heating and stirring kettle 200, and the outlet of the condensation reflux device 210 is connected to the inlet of the heating and stirring kettle 200. The condensation reflux device 210 pumps the hydrogen chloride (hydrochloric acid) gas escaping from the heating and stirring kettle 200 into the condensation reflux device 210, and the hydrogen chloride gas condenses in the condensation reflux device 210 to form a hydrogen chloride solution, which is refluxed into the heating and stirring kettle 200 to avoid the escape of hydrogen chloride and the loss of the concentration of hydrochloric acid in the reaction slurry in the heating and stirring kettle 200.

[0027] Specifically, it also includes a first drying device 410 and a crushing device 500. The by-product gypsum outlet of the aramid production system 1 is connected to the inlet of the first drying device 410, the outlet of the first drying device 410 is connected to the inlet of the crushing device 500, and the outlet of the crushing device 500 is connected to the inlet of the gypsum powder tank 120.

[0028] The first drying device 410 is used to dry the aramid by-product gypsum. The first drying device 410 can be a dryer or an oven. The pulverizing device 500 is used to pulverize the dried by-product gypsum. When in use, the aramid by-product gypsum is placed in an oven at 60°C to 70°C for drying, and then the dried aramid by-product gypsum is pulverized to obtain uniform aramid by-product gypsum powder. The aramid by-product gypsum is in block form and contains moisture. Therefore, it needs to be dried and ground to obtain aramid by-product gypsum powder. The aramid by-product gypsum powder can be mixed with dilute hydrochloric acid to form a reaction slurry.

[0029] Specifically, it also includes a cleaning tank 600 and a second drying device 420 which are connected in sequence, and the filter cake outlet of the filtering and aging device is connected to the inlet of the cleaning tank 600.

[0030] The cleaning pool 600 is used to wash the filter cake with cold water. After the cold water washing, the filter cake enters the second drying device 420 through the outlet of the cleaning pool 600. The second drying device 420 dries the filter cake to obtain calcium sulfate whiskers. After the cleaning pool 600 is set to rinse the stains and impurities on the surface of the filter cake, the second drying device 420 dries it to remove moisture and obtain pure calcium sulfate whiskers.

[0031] In some specific embodiments, the filtering and aging device includes a first filter 310, an aging tank 320 and a second filter 330, the outlet of the heating and stirring kettle 200 is connected to the inlet of the first filter 310, the first filter 310 has an impurity outlet 311, the liquid outlet of the first filter 310 is connected to the inlet of the aging tank 320, the outlet of the aging tank 320 is connected to the inlet of the second filter 330, the filter cake outlet of the second filter 330 is the calcium sulfate whisker outlet, and the liquid outlet of the second filter 330 is connected to the dilute hydrochloric acid storage tank 130.

[0032] After the reaction slurry in the heating stirring kettle 200 is completed, it enters the first filter 310, which is used to filter the impurities insoluble in acid in the reaction slurry. The filtered liquid enters the aging tank 320 through the liquid outlet of the first filter 310, and the impurities are discharged through the solid outlet of the first filter 310; the liquid is slowly cooled and allowed to stand for a preset time in the aging tank 320, and then enters the second filter 330. The second filter 330 filters the liquid to obtain a filter cake of calcium sulfate whiskers, and the filtrate enters the dilute hydrochloric acid storage tank 130 through the liquid outlet of the second filter 330.

[0033] The cooling of the liquid in the second filter 330 is beneficial to the crystallization of calcium sulfate. Furthermore, the second filter 330 has a jacket cooling device 331. The jacket cooling device 331 can cool the liquid in the second filter 330. After the jacket cooling device 331 is provided on the second filter 330, it is beneficial to the crystallization of calcium sulfate.

[0034] Specifically, the first filter 310 is a suction filter. The suction filter uses vacuum negative pressure as a driving force to achieve solid-liquid separation. Under the action of vacuum negative pressure, the liquid in the reaction slurry is sucked away through the filter medium and enters the aging tank 320, while the solid impurities are retained by the medium.

[0035] Specifically, the second filter 330 is a filter press, which can quickly dehydrate the material by compressing it into a filter cake, thereby reducing the moisture content of the material, and the filter cake is calcium sulfate whiskers.

[0036] In order to allow the filtrate to be reused, it further includes a filtrate pool 700, the liquid outlet of the second filter 330 is connected to the inlet of the filtrate pool 700, the outlet of the filtrate pool 700 is connected to the inlet of the dilute hydrochloric acid storage tank 130, and the filtrate pool 700 is provided with a first pH detector 710.

[0037] When in use, the filtrate filtered by the second filter 330 enters the filtrate pool 700 through the liquid outlet, and the first pH detector 710 in the filtrate pool 700 detects the acid value of the filtrate in the filtrate pool 700. After the detection result reaches a preset value, the preset value may be 0.7, and the filtrate enters the dilute hydrochloric acid storage tank 130 through the outlet of the filtrate pool 700 for repeated use.

[0038] Furthermore, it also includes a filtrate treatment tank 800, the outlet of the filtrate treatment tank 700 is connected to the inlet of the filtrate treatment tank 800, the outlet of the filtrate treatment tank 800 is connected to the inlet of the dilute hydrochloric acid storage tank 130, the inlet of the filtrate treatment tank 800 is also connected to a concentrated hydrochloric acid feed pipe 820, and the filtrate treatment tank 800 is provided with a second pH detector 810.

[0039] When the acid value of the filtrate in the filtrate tank 700 does not meet the standard, it enters the filtrate treatment tank 800, and a concentrated hydrochloric acid solution is added to the filtrate treatment tank 800 through the concentrated hydrochloric acid feed pipe 820. The concentration of the concentrated hydrochloric acid solution can be 15mol / L to 20mol / L. The second pH detector 810 detects the filtrate in the filtrate treatment tank 800. After the acid value reaches a predetermined value, the predetermined value can be 0.7, and the filtrate enters the dilute hydrochloric acid storage tank 130 through the outlet of the filtrate treatment tank 800. In order to make the filtrate in the filtrate treatment tank 800 and the added hydrochloric acid solution mix more evenly, a stirrer can be set in the filtrate treatment tank 800.

[0040] Considering that the amount of dilute hydrochloric acid recovered from the filtrate pool 700 and the filtrate treatment pool 800 to the dilute hydrochloric acid storage tank 130 is insufficient, a rehydration tank 900 is further provided, the inlet of the rehydration tank 900 is connected to a concentrated hydrochloric acid feed pipe 820 and a desalted water feed pipe 910, and the outlet of the rehydration tank 900 is connected to the dilute hydrochloric acid storage tank 130. During use, when the solution recovered to the dilute hydrochloric acid storage tank 130 is insufficient, the rehydration tank 900 can replenish the solution to the dilute hydrochloric acid storage tank 130 in time to ensure the normal operation of the system and improve production efficiency.

[0041] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A system for preparing calcium sulfate whiskers using aramid by-product gypsum, connected to the by-product gypsum outlet of the aramid production system, characterized in that: It includes a batching device, a heating and stirring kettle, and a filtering and aging device; The batching device includes a slurry pool, a gypsum powder tank and a dilute hydrochloric acid storage tank. The by-product gypsum outlet of the aramid production system is connected to the inlet of the gypsum powder tank, and the outlet of the gypsum powder tank and the outlet of the dilute hydrochloric acid storage tank are both connected to the inlet of the slurry pool; the outlet of the slurry pool is connected to the inlet of the heating and stirring kettle, and the outlet of the heating and stirring kettle is connected to the inlet of the filtering and aging device, the filter cake outlet of the filtering and aging device is a calcium sulfate whisker outlet, and the liquid outlet is connected to the dilute hydrochloric acid storage tank.

2. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 1, characterized in that: The heating and stirring kettle is provided with a condensation reflux device, the inlet of the condensation reflux device is connected to the top of the heating and stirring kettle, and the outlet of the condensation reflux device is connected to the inlet of the heating and stirring kettle.

3. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 1, characterized in that: It also includes a first drying device and a crushing device. The by-product gypsum outlet of the aramid production system is connected to the inlet of the first drying device, the outlet of the first drying device is connected to the inlet of the crushing device, and the outlet of the crushing device is connected to the inlet of the gypsum powder tank.

4. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 1, characterized in that: It also includes a cleaning tank and a second drying device which are connected in sequence, and the filter cake outlet of the filtering and aging device is connected to the inlet of the cleaning tank.

5. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 1, characterized in that: The filtering and aging device includes a first filter, an aging tank and a second filter. The outlet of the heating and stirring kettle is connected to the inlet of the first filter. The first filter has an impurity outlet. The liquid outlet of the first filter is connected to the inlet of the aging tank. The outlet of the aging tank is connected to the inlet of the second filter. The filter cake outlet of the second filter is the calcium sulfate whisker outlet. The liquid outlet of the second filter is connected to the dilute hydrochloric acid storage tank.

6. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 5, characterized in that: The second filter has a jacket cooling device.

7. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 5, characterized in that: The first filter is a suction filter.

8. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 5, characterized in that: The second filter is a filter press.

9. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 5, characterized in that: It also includes a filtrate pool, the liquid outlet of the second filter is connected to the inlet of the filtrate pool, the outlet of the filtrate pool is connected to the inlet of the dilute hydrochloric acid storage tank, and the filtrate pool is provided with a first pH detector.

10. The system for preparing calcium sulfate whiskers using aramid by-product gypsum according to claim 9, characterized in that: It also includes a filtrate treatment tank, the outlet of the filtrate treatment tank is connected to the inlet of the filtrate treatment tank, the outlet of the filtrate treatment tank is connected to the inlet of the dilute hydrochloric acid storage tank, the inlet of the filtrate treatment tank is also connected to a concentrated hydrochloric acid feed pipe, and the filtrate treatment tank is provided with a second pH detector.

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