CN213924044U - System for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence - Google Patents
System for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence Download PDFInfo
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- CN213924044U CN213924044U CN202022859584.1U CN202022859584U CN213924044U CN 213924044 U CN213924044 U CN 213924044U CN 202022859584 U CN202022859584 U CN 202022859584U CN 213924044 U CN213924044 U CN 213924044U
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Abstract
The utility model belongs to the technical field of calcium method bleaching powder, concretely relates to retrieve system of calcium hypochlorite from useless mother liquor of calcium method bleaching powder. The system for recovering calcium hypochlorite from the waste mother liquor of calcium bleaching powder is characterized by comprising a size mixing kettle, wherein the size mixing kettle is respectively connected with a waste mother liquor pipe for adding the waste mother liquor, a calcium hydroxide pipe for adding calcium hydroxide and a calcium chloride pipe for adding calcium chloride, an outlet of the size mixing kettle is connected with a cooling crystallizer through a pipeline, and the cooling crystallizer is connected with a centrifugal drying mechanism through a pipeline. The utility model provides a system for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence through adding calcium chloride and calcium hydroxide.
Description
Technical Field
The utility model belongs to the technical field of calcium method bleaching powder, concretely relates to retrieve system of calcium hypochlorite from useless mother liquor of calcium method bleaching powder.
Background
The main component of the bleaching powder is Ca (ClO)2As an efficient inorganic bleaching agent and disinfectant, the bleaching powder has the advantages of strong stability, no toxic residue, environmental protection and the like, and is widely applied to the fields of epidemic prevention, swimming pool disinfection, aquaculture disinfection, industrial and domestic water treatment and the like. The technological routes for producing the bleaching powder essence mainly comprise two processes, namely a calcium process and a sodium process. The calcium bleaching powder contains 3Ca (ClO) as effective component2·2Ca(OH)2·2H2O, by Ca (OH)2And Cl2Prepared by reaction, the waste mother liquor mainly contains 10 percent of Ca (ClO)2And 20% of CaCl2。
The calcium method bleaching powder has a byproduct of about 6 to 8 tons of waste mother liquor per ton of product,the traditional waste mother liquor treatment mode has two types: the first mode is that the bleaching liquor is sold to textile and paper making enterprises, but because the bleaching liquor contains calcium chloride, paper and textiles bleached by the bleaching powder waste mother liquor are easy to absorb water and regain moisture, and the quality is poor; the second method is to add hydrochloric acid to the mother liquor to make Ca (ClO) as a by-product of calcium chloride after acidolysis2Reacting with hydrochloric acid to produce CaCl2And Cl2，Cl2Sending to alkaline washing tower, CaCl2The solution was evaporated to dryness to prepare solid calcium chloride for sale as a by-product.
But because the environmental protection policy is tightened in recent years, the paper mill with small scale is closed by a large margin, the supply of mother liquor is greater than the demand, and the market atrophy is serious; the acidolysis method needs to consume a large amount of hydrochloric acid and caustic soda, and the extra cost brought by waste liquid treatment leads to high production cost of the bleaching powder and weak competitiveness in similar products in the disinfection bleaching market. How to treat the waste mother liquor at low cost in an environment-friendly way is a key problem of the long-term survival of calcium method bleaching powder enterprises.
Ca (ClO) in calcium bleaching powder product2The content of the calcium carbonate is 60-65 percent, and 6 tons of mother liquor are produced as a byproduct for producing 1 ton of bleaching powder, so Ca (ClO) carried away by the mother liquor2The amount is large, estimated as 1 ton of bleaching powder per production:
calcium (ClO) in bleaching powder2Quality: 1 tx (60-65%) < 0.6-0.65 t%
Ca (ClO) in waste mother liquor2Quality: 1t × 6t/t × (10%) -0.6 t
From the results of calculation, Ca (ClO) dissolved in the mother liquor2Take up Ca (ClO)245-50% of the bleaching solution, for example, Ca (ClO) in the bleaching solution can be effectively recovered2The consumption of raw materials can be reduced, the discharge of waste liquid is reduced, the caustic soda amount of hydrochloric acid consumed by the acidolysis process can be saved, and the production cost of the bleaching powder concentrate enterprise is greatly reduced.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems existing in the prior art, the utility model aims to provide a system for recovering calcium hypochlorite from waste mother liquor of calcium bleaching powder by adding calcium chloride and calcium hydroxide.
The utility model discloses the technical scheme who adopts does:
the utility model provides a system for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence, includes the mixing of slurry cauldron, is connected with the useless mother liquor pipe that is used for adding useless mother liquor, the calcium hydrate pipe that is used for adding calcium hydrate and the calcium chloride pipe that is used for adding calcium chloride on the mixing of slurry cauldron respectively, and the export of mixing of slurry cauldron has the cooling crystallizer through the pipe connection, and the cooling crystallizer has centrifugal drying mechanism through the pipe connection.
When the waste mother liquor is sent into the size mixing kettle, calcium chloride and calcium hydroxide are added into the size mixing kettle. According to Ca (ClO)2-CaCl2-Ca(OH)2-H2The solubility curve of the O quaternary system can be known as follows: CaCl2The higher the concentration, Ca (ClO)2The lower the solubility, but CaCl2Too much addition of CaCl will not be produced26H2O, so that the content of active ingredients in the filter cake is reduced. Ca (OH)2The higher the concentration, Ca (ClO)2The lower the solubility, and a small amount of Ca (OH)2The particles may act as seeds and may accelerate the crystallization process. Adding solid CaCl into mother liquor2Mixing with lime milk, adjusting CaCl2Ca (OH) in a concentration of 30 to 35%2And (4) to 8 percent, fully stirring to uniformly mix the solution.
And (3) after the concentration suitable for calcium hydroxide crystallization is obtained, sending the calcium hydroxide to a cooling crystallizer, cooling the mixed waste mother liquor to 10-15 ℃ by an external cooler, and completing the generation and growth of calcium chloride crystals in the cooling crystallizer, wherein the crystallization time is 1-2 h. Thus, most of Ca (ClO) in the waste mother liquor2Is recovered, Ca (ClO) in the mother liquor2The concentration is reduced from 10% to 2-4%, and the main component of the generated crystal is Ca (ClO)2·3H2O, also contains a small amount of Ca (ClO)2·4Ca(OH)2And Ca (ClO)2·2Ca(OH)2. And centrifugally drying the crystallized slurry to obtain the low-quality bleaching powder (the available chlorine is about 50-55%).
As the utility model discloses an optimal scheme, install the axial compressor circulating pump on the cooling crystallizer, the import of axial compressor circulating pump is located the liquid upper strata in the cooling crystallizer, and the export of axial compressor circulating pump has the external cooler through the pipe connection, and the export of external cooler is passed through the pipeline and is connected with the cooling crystallizer. The external cooler can cool the blending liquid, and the cooled blending liquid is pumped back into the cooling crystallizer by the axial-flow circulating pump. When the mixed solution is at 10-15 ℃, calcium hypochlorite crystals can be fully analyzed.
As the preferred proposal of the utility model, the overflow port of the cooling crystallizer is connected with the overflow pipe which discharges the overflow clarified liquid out of the boundary area. The overflow clarified liquid contains calcium chloride and calcium hydroxide, and is discharged.
As the utility model discloses a preferred scheme, centrifugal drying mechanism includes centrifuge and drying system, and centrifuge's import is passed through the pipeline and is connected with the cooling crystallizer, and centrifuge's export is passed through the pipeline and is connected with drying system. And (3) sending the crystallized slurry to a centrifuge for solid-liquid separation to obtain a filter cake with the water content of 20-25%, wherein the available chlorine of the filter cake is about 40-45%, and the recovered filter cake is dried and dehydrated to prepare the low-quality bleaching powder (the available chlorine is about 50-55%).
As the preferred scheme of the utility model, be provided with freezing mouth of a river and freezing return water mouth on the external cooler. The middle part of the external cooler is a heat exchange pipe for the waste mother liquor to pass through, an annular cooling cavity is arranged outside the heat exchange pipe, and a freezing water feeding port and a freezing water return port are arranged on the cooling cavity. The waste mother liquor flows through the heat exchange tube of the external cooler, the chilled water flows through the cooling cavity, and the waste mother liquor and the chilled water exchange heat sufficiently, so that the waste mother liquor is cooled.
As the preferred proposal of the utility model, the overflow clarified liquid of the cooling crystallizer is sent out of the battery limits through a pipeline. The content of calcium hypochlorite in the clear liquid overflowing from the top of the cooling crystallizer is 2 to 4 percent and the clear liquid is sent out of the boundary region for treatment.
The utility model has the advantages that:
1. the utility model discloses according to Ca (ClO)2-CaCl2-Ca(OH)2-H2Dissolving property and crystal composition of O quaternary system, adding appropriate amount of CaCl into waste mother liquor by using size mixing kettle2And Ca (OH)2The concentration of calcium hypochlorite crystals is adjusted to a suitable level. Recovering calcium hypochlorite from the waste mother liquor by cooling crystallization, crystallizing and separating out the calcium hypochlorite from the mixed waste mother liquor, and passing throughCentrifugally drying to obtain the low-quality bleaching powder with the available chlorine of about 50-55%. The utility model discloses recycle Ca (ClO) in the useless mother liquor2On the premise of the same raw material quantity, more bleaching powder products are produced.
2. The concentration of calcium hypochlorite in the waste mother liquor is reduced from 10% to 2-4%, and the caustic soda hydrochloride amount consumed by the treatment of the waste mother liquor can be greatly reduced. The utility model discloses can effectively reduce the fine bleaching powder manufacturing cost, improve the market competition of fine bleaching powder enterprise.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
In the figure, 1-size mixing kettle; 2-cooling the crystallizer; 3-an axial flow circulating pump; 4-external cooling; 5-a centrifuge; 6-a drying system; 11-spent mother liquor pipe; 12-calcium hydroxide tube; 13-calcium chloride tube.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.
As shown in fig. 1, the system for recovering calcium hypochlorite from waste mother liquor of calcium bleaching powder comprises a size mixing kettle 1, wherein a waste mother liquor pipe 11 for adding waste mother liquor, a calcium hydroxide pipe 12 for adding calcium hydroxide, and a calcium chloride pipe 13 for adding calcium chloride are respectively connected to the size mixing kettle 1, an outlet of the size mixing kettle 1 is connected with a cooling crystallizer 2 through a pipeline, and the cooling crystallizer 2 is connected with a centrifugal drying mechanism through a pipeline.
When the waste mother liquor is sent into the size mixing kettle 1, calcium chloride and calcium hydroxide are added into the size mixing kettle 1. According to Ca (ClO)2-CaCl2-Ca(OH)2-H2The solubility curve of the O quaternary system can be known as follows: CaCl2The higher the concentration, Ca (ClO)2The lower the solubility, but CaCl2Too much addition of CaCl will not be produced26H2O, so that the content of active ingredients in the filter cake is reducedLow. Ca (OH)2The higher the concentration, Ca (ClO)2The lower the solubility, and a small amount of Ca (OH)2The particles may act as seeds and may accelerate the crystallization process. Adding solid CaCl into mother liquor2Mixing with lime milk, adjusting CaCl2Ca (OH) in a concentration of 30 to 35%2And (4) to 8 percent, fully stirring to uniformly mix the solution.
And (3) after the concentration suitable for calcium hydroxide crystallization is obtained, sending the calcium hydroxide to a cooling crystallizer 2, cooling the mixed waste mother liquor to 10-15 ℃ by an external cooler 4, crystallizing for 1-2 h, and completing the generation and growth of calcium chloride crystals in the cooling crystallizer 2. Thus, most of Ca (ClO) in the waste mother liquor2Is recovered, Ca (ClO) in the mother liquor2The concentration is reduced from 10% to 2-4%, and the main component of the generated crystal is Ca (ClO)2·3H2O, also contains a small amount of Ca (ClO)2·4Ca(OH)2And Ca (ClO)2·2Ca(OH)2. And centrifugally drying the crystallized slurry to obtain the low-quality bleaching powder (the available chlorine is about 50-55%).
The utility model discloses recycle Ca (ClO) in the useless mother liquor2On the premise of the same raw material quantity, more bleaching powder products are produced.
The concentration of calcium hypochlorite in the waste mother liquor is reduced from 10% to 2-4%, and the caustic soda hydrochloride amount consumed by the treatment of the waste mother liquor can be greatly reduced. The utility model discloses can effectively reduce the fine bleaching powder manufacturing cost, improve the market competition of fine bleaching powder enterprise.
And when the uniform mixing liquid is cooled and crystallized, cooling the uniform mixing liquid by using an external cooler 4. The cooling crystallizer 2 is provided with an axial flow circulating pump 3, the inlet of the axial flow circulating pump 3 is positioned on the upper layer of the liquid in the cooling crystallizer 2, the outlet of the axial flow circulating pump 3 is connected with an external cooler 4 through a pipeline, and the outlet of the external cooler 4 is connected with the cooling crystallizer 2 through a pipeline. The external cooler 4 can cool the blending liquid, and the cooled blending liquid is pumped back into the cooling crystallizer 2 by the axial-flow circulating pump 3. When the mixed solution is at 10-15 ℃, calcium hypochlorite crystals can be fully analyzed. And an overflow port of the cooling crystallizer is connected with an overflow pipe which discharges overflow clarified liquid out of the boundary area. The overflow clarified liquid contains calcium chloride and calcium hydroxide, and is discharged.
In order to obtain the bleaching powder, the centrifugal drying mechanism comprises a centrifuge 5 and a drying system 6, wherein the inlet of the centrifuge 5 is connected with the cooling crystallizer 2 through a pipeline, and the outlet of the centrifuge 5 is connected with the drying system 6 through a pipeline. And (3) sending the crystallized slurry to a centrifuge 5 for solid-liquid separation to obtain a filter cake with the water content of 20-25%, wherein the available chlorine of the filter cake is about 40-45%, and the recovered filter cake is dried and dehydrated to prepare the low-quality bleaching powder (the available chlorine is about 50-55%).
Furthermore, a freezing water feeding port and a freezing water return port are arranged on the external cooler 4. The middle part of the external cooler 4 is a heat exchange pipe for the waste mother liquor to pass through, an annular cooling cavity is arranged outside the heat exchange pipe, and a freezing water feeding port and a freezing water return port are arranged on the cooling cavity. The waste mother liquor flows through the heat exchange tube of the external cooler 4, the chilled water flows through the cooling cavity, and the waste mother liquor and the chilled water exchange heat sufficiently, so that the waste mother liquor is cooled.
Furthermore, the overflow clarified liquid of the cooling crystallizer 2 is sent out of the battery limits through a pipeline. The content of calcium hypochlorite in the clear liquid overflowing from the top of the cooling crystallizer 2 is 2-4 percent and the clear liquid is sent out of the boundary region for treatment.
The process of recovering calcium hypochlorite from the waste mother liquor of calcium bleaching powder comprises the following steps:
respectively adding the waste mother liquor, calcium hydroxide and calcium chloride into the size mixing kettle 1, and fully stirring to obtain a uniform mixing solution. According to Ca (ClO)2-CaCl2-Ca(OH)2-H2The solubility curve of the O quaternary system can be known as follows: CaCl2The higher the concentration, Ca (ClO)2The lower the solubility, but CaCl2Too much addition of CaCl will not be produced26H2O, so that the content of active ingredients in the filter cake is reduced. Ca (OH)2The higher the concentration, Ca (ClO)2The lower the solubility, and a small amount of Ca (OH)2The particles may act as seeds and may accelerate the crystallization process. Adding solid CaCl into mother liquor2And lime milk, and fully stirring to uniformly mix the solution.
When solid calcium chloride and calcium hydroxide are added into the mother liquor, the concentration of the calcium chloride is adjusted to be 30-35%, and the concentration of the calcium hydroxide is adjusted to be 4-8%. To pairStirring the mixed solution for 10-20 min to accelerate the crystallization of calcium hypochlorite. By adding calcium chloride and calcium hydroxide, the solubility of calcium hypochlorite is reduced, and the calcium hypochlorite can be fully crystallized. In addition, the calcium hydroxide particles can be used as crystals to further accelerate the crystallization process of the calcium hypochlorite. By controlling the concentration of calcium chloride to be 30-35%, CaCl is prevented from being generated when calcium chloride is added too much2·6H2And O.
And cooling and crystallizing the uniformly mixed solution. The lower the temperature, Ca (ClO)2The lower the solubility, but since the crystallization reaction is endothermic, the lower the temperature will affect the crystallization speed, and increase the crystallization time, so that the equipment utilization rate will be reduced. The utility model discloses an external cooler 4 realizes that the mother liquor cools off to suitable temperature, treats that the crystal grows up the back and delivers to centrifuge 5. Thus, most of Ca (ClO) in the waste mother liquor2Is recovered, Ca (ClO) in the mother liquor2The concentration is reduced from 10% to 2-4%, and the main component of the generated crystal is Ca (ClO)2·3H2O, also contains a small amount of Ca (ClO)2·4Ca(OH)2And Ca (ClO)2·2Ca(OH)2。
Controlling the temperature of the cooling crystallizer 2 at 10-15 ℃, and crystallizing the mixed liquid in the cooling crystallizer 2 for 1-2 hours. The lower the temperature, Ca (ClO)2The lower the solubility, but since the crystallization reaction is endothermic, the lower the temperature will affect the crystallization speed, and increase the crystallization time, so that the equipment utilization rate will be reduced. Therefore, the temperature of the liquid in the cooling crystallizer 2 is controlled to be 10-15 ℃, the calcium hypochlorite is ensured to be fully crystallized, and the crystallization speed is prevented from being too slow. Mother liquor cooling is realized through an external cooler 4, and the crystallization time is 1-2 h, so that crystals grow up. The overflow clarified liquid of the cooling crystallizer 2 is sent out of the battery limit zone.
Sending the crystallized slurry to a centrifuge 5 for solid-liquid separation to obtain a filter cake; and then drying and dehydrating to obtain the bleaching powder. And (3) sending the crystallized slurry to a centrifuge 5 for solid-liquid separation to obtain a filter cake with the water content of 20-25%, wherein the available chlorine of the filter cake is about 40-45%, and the recovered filter cake is dried and dehydrated to prepare the low-quality bleaching powder (the available chlorine is about 50-55%).
The present invention is not limited to the above-mentioned optional embodiments, and any other products in various forms can be obtained by anyone under the teaching of the present invention, and any changes in the shape or structure thereof, all the technical solutions falling within the scope of the present invention, are within the protection scope of the present invention.
Claims (6)
1. The utility model provides a system for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence which characterized in that, including size mixing cauldron (1), be connected with respectively on size mixing cauldron (1) and be used for adding useless mother liquor waste mother liquor pipe (11), calcium hydroxide pipe (12) that are used for adding calcium hydroxide and calcium chloride pipe (13) that are used for adding calcium chloride, there is cooling crystallizer (2) outlet of size mixing cauldron (1) through the pipe connection, there is centrifugal drying mechanism cooling crystallizer (2) through the pipe connection.
2. The system for recovering the calcium hypochlorite from the waste mother liquor of the calcium bleaching powder concentrate according to the claim 1, wherein the cooling crystallizer (2) is provided with an axial flow circulating pump (3), the inlet of the axial flow circulating pump (3) is positioned at the upper layer of the liquid in the cooling crystallizer (2), the outlet of the axial flow circulating pump (3) is connected with an external cooler (4) through a pipeline, and the outlet of the external cooler (4) is connected with the cooling crystallizer (2) through a pipeline.
3. The system for recovering calcium hypochlorite from waste mother liquor of calcium bleaching powder according to claim 1, wherein the overflow port of the cooling crystallizer (2) is connected with an overflow pipe for discharging overflow clarified liquor out of a battery compartment.
4. The system for recovering the calcium hypochlorite from the waste mother liquor of the calcium bleaching powder concentrate as claimed in claim 1, wherein the centrifugal drying mechanism comprises a centrifuge (5) and a drying system (6), an inlet of the centrifuge (5) is connected with the cooling crystallizer (2) through a pipeline, and an outlet of the centrifuge (5) is connected with the drying system (6) through a pipeline.
5. The system for recovering the calcium hypochlorite from the waste mother liquor of the calcium bleaching powder concentrate as claimed in claim 2, wherein a freezing water feeding port and a freezing water returning port are arranged on the external cooler (4).
6. The system for recovering the calcium hypochlorite from the calcium bleaching powder waste mother liquor according to any one of claims 1 to 5, wherein the overflow clarified liquor of the cooling crystallizer (2) is sent out of a battery compartment through a pipeline.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022859584.1U CN213924044U (en) | 2020-12-02 | 2020-12-02 | System for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022859584.1U CN213924044U (en) | 2020-12-02 | 2020-12-02 | System for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence |
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| CN202022859584.1U Active CN213924044U (en) | 2020-12-02 | 2020-12-02 | System for retrieve calcium hypochlorite from useless mother liquor of calcium method bleaching powder essence |
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