KR100416476B1 - A method for efficient controlling of total nitrogen content in waste water produced in manufacturing process of copper phthalocyanine - Google Patents

Abstract

PURPOSE: A wastewater treatment method is provided which is capable of controlling total nitrogen content in wastewater containing nitrogen content produced in production process of copper phthalocyanine more efficiently compared with a wastewater treatment method according to the prior art. CONSTITUTION: The method comprises a step (a) of agitating and filtering the mixture after putting dried copper phthalocyanine; a step (b) of washing wet cake filtered in the step (a) using water, agitating and filtering the mixture after putting an acid solution into the water washed wet cake, and evaporating and concentrating first filtered liquid produced in the step (a); and a step (c) of preparing copper phthalocyanine by drying wet cake filtered in the step (b), neutralizing the second filtered liquid by acid treating and alkali treating second filtered liquid produced in the step (b), removing sludge from the neutralized second filtered liquid by organic coagulant treatment and pressing flotation, removing monovalent copper ions from the sludge removed filtered liquid by inorganic coagulant treatment and sedimentation, removing nitrogen from the monovalent copper ion removed filtered liquid by chlorine gas treatment, and discharging a neutralized filtered liquid after neutralizing the nitrogen removed filtered liquid.

Description

A method for efficient controlling of total nitrogen content in waste water produced in manufacturing process of copper phthalocyanine}

The present invention relates to an efficient control method for the total amount of nitrogen in the nitrogen-containing wastewater generated in the copper phthalocyanine (CPC) production process.

Phthalocyanine-based pigments have a clear color tone, excellent coloring power, excellent heat resistance, light resistance and solvent resistance, and thus occupy a very important position in the organic pigment manufacturing industry. Such phthalocyanine pigments include pigments such as copper phthalocyanine, metal-free phthalocyanine or chlorinated copper phthalocyanine. It accounts for most of the market demand for blue organic pigments.

Copper phthalocyanine pigments are prepared by reacting phthalic anhydride (Phthalic anhydride), urea (Urea) and cuprous chloride (CuCl) and the like in the presence of a catalyst such as ammonium molybdate. However, the wastewater generated during the phthalocyanine production process has high chemical oxygen demand (COD) and biological oxygen demand (BOD), and contains a large amount of environmental pollutants such as nitrogen, copper ions and suspended solids. There is a problem to include.

Therefore, there is a need to efficiently treat the wastewater generated in the phthalocyanine production process, and in this regard, Korean Patent Publication No. 2000-63167 (Method for efficiently purifying pigment wastewater containing a large amount of nitrogen) Iii) a first treatment step of treating wastewater with acid and alkali, flocculation and pressure flotation to remove sludge, ii) a second treatment step of removing monovalent copper ions by precipitant and flocculant treatment, iii) a microorganism. A method for purifying a pigment wastewater containing a large amount of nitrogen consisting of a tertiary treatment step of treating sludge in an aeration tank, and iii) a fourth treatment step of injecting and denitrifying chlorine gas and finally oxidizing and neutralizing organic matter. To provide.

The method has the advantage of lowering the COD and BOD levels in the treated wastewater to below the environmentally acceptable standard and removing copper ions and suspended solids by purifying wastewater containing nitric oxide with superior treatment efficiency compared to the conventional activated sludge process. .

However, the Ministry of Environment recently revised the Water Environment Conservation Act to further strengthen wastewater treatment standards (Attachment 5 of the Enforcement Regulations of the Water Environment Conservation Act, Amendment Standards for Contaminant Emissions, Dec. 22, 2001). Under the standard, the total nitrogen (TN) content of the effluent must meet the criteria of 60 mg / l based on the rest of the world except for the clean area, but the above method cannot meet the above standard. There is this.

Therefore, the present invention has a technical problem to provide a new wastewater treatment method capable of controlling the total amount of nitrogen in the nitrogen component-containing wastewater generated in the phthalocyanine production process more efficiently than the prior art.

1 is a schematic process flowchart of a wastewater treatment method according to the present invention.

The present invention is a method for controlling the total amount of nitrogen components in the nitrogen component-containing wastewater generated in the phthalocyanine production step,

(a) putting dried copper phthalocyanine into an alkaline solution and stirring and filtering;

(b) washing the wet cake filtered in step (a) with water, then putting it in an acid solution, stirring and filtering, and evaporating and concentrating the primary filtrate generated in step (a); And

(c) preparing copper phthalocyanine by drying the wet cake filtered in step (b), and neutralizing the secondary filtrate generated in step (b) by acid and alkali treatment, followed by organic coagulant treatment and pressurization. Removing sludge, removing monovalent copper ions by inorganic coagulant treatment and precipitation, treating chlorine gas to remove nitrogen, and neutralizing and then discharging the same.

In addition, the present invention is a method for controlling the total amount of nitrogen components in the nitrogen component-containing wastewater generated in the phthalocyanine production step,

(a) putting dried copper phthalocyanine into the first acid solution and stirring and filtering;

(b) washing the wet cake filtered in step (a) with water, stirring and filtering in a second acid solution, and evaporating and concentrating the primary filtrate generated in step (a); And

(c) preparing copper phthalocyanine by drying the wet cake filtered in step (b), and neutralizing the secondary filtrate generated in step (b) by acid and alkali treatment, followed by organic coagulant treatment and pressurization. Removing sludge, removing monovalent copper ions by inorganic coagulant treatment and precipitation, treating chlorine gas to remove nitrogen, and neutralizing and then discharging the same.

The method according to the invention will be described in more detail with reference to the accompanying drawings.

Among the ammonia produced in the phthalocyanine manufacturing process, the ammonia released into the atmosphere is led to the manufacturing process through the first and second collection by water absorption and the third collection by sulfuric acid absorption. The treatment process according to the invention is carried out.

After the copper phthalocyanine prepared from the copper phthalocyanine manufacturing process is dried, it is placed in an alkali solution, stirred, and then filtered. It is preferable to use 2 to 3% NaOH solution for the alkaline solution. The filtration process by the alkali solution is a process for removing impurities such as ammonia-based impurities contained in the crude phthalocyanine crude product.

The primary filtrate generated in the filtration step by the alkaline solution is a wastewater containing high concentration of nitrogen, undergoes an evaporation concentration process, and the steam generated in the evaporation concentration process is reused as a heating means in the filtration process.

In addition, the wet cake obtained from the filtration step with the alkaline solution is washed with water, and then put in an acid solution and stirred and filtered. It is preferable to use 2-3% sulfuric acid solution as the acid solution. The filtration process using the acid solution is a process for removing remaining impurities that are not hydrolyzed in the filtration process with an alkaline solution, and in particular, a process for removing inorganic impurities.

For the second filtrate generated in the filtration step by the acid solution, a wastewater treatment process similar to that disclosed in Korean Laid-Open Patent Publication No. 2000-63167 is performed. The patent publication includes: i) a primary treatment step of neutralizing the filtrate by acid and alkali treatment, and treating the inorganic / organic coagulant by pressure flotation; ii) treating the precipitant against the copper ion and the inorganic / organic coagulant to obtain copper ions. The secondary treatment step of removing iii), iii) a third treatment step of performing activated sludge treatment in a microbial aeration tank, and iii) a fourth treatment step of carrying out neutralization discharge after denitrification by chlorine gas injection and oxidation of the final organic matter.

However, in the present invention, the process is shortened by omitting the step (i) of the above steps, that is, the activated sludge treatment step, and thus the present invention is almost equivalent to the conventional wastewater treatment process in spite of this process shortening. Since the BOD to COD values can be obtained to some extent, there is an effect that the treatment cost and the operation time can be drastically reduced.

In addition, the present invention, unlike the method disclosed in the above patent publication, significantly reduced the amount of chlorine gas used in the denitrification reaction used. That is, while the above method maintains chlorine gas at a rate of 5 kg / hour or less and 7 to 9 hours until it reaches a concentration of 170 to 190 ppm, the present invention provides chlorine gas at a rate of 2 kg / hour or less, It is characterized by the retention for 1 to 3 hours until the concentration of 60 to 70ppm.

In addition to the reduction in the amount of chlorine gas used, the treatment cost and the possibility of causing air pollution can be said to have a very excellent effect compared to the conventional method in that the risk of generating chloride at elevated temperature is reduced.

The present invention also provides a treatment method according to filtration with a second acid solution after filtration with a first acid solution of copper phthalocyanine, in addition to a treatment method with acid filtration after alkali filtration of copper phthalocyanine.

2 to 3% sulfuric acid solution may be used as the first acid solution according to the present invention, and 1 to 2% sulfuric acid solution may be used as the second acid solution.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example 1 Synthesis of Copper Phthalocyanine

630 g of phthalic anhydride (Aekyung Emulsification: 99.94%) and 862 mL of an alkyl benzene organic solvent, Essolve-350P (Isu Chemical), were added to a 3 L primary reactor and stirred. Next, 626 g of phthalimide synthesized in the first reactor in a 5 L secondary reactor, 630 g of urea (Namhae Chemical: 99.9%), 103.35 g of CuCl (Hanseo Chemical: 98.4%), 1.72 g of ammonium molybdate, and an organic solvent Essolve 15350 mL -350P was added and stirred.

Connect the primary reactor and the secondary reactor with a pipe of 1 cm inner diameter and then increase the temperature to 170 ° C., and maintain the external temperature of the secondary reactor at 240 ° C. when the pressure of the secondary reactor is maintained at 5 kg / cm ² . The gas generated in the reactor was transferred to the primary reactor, and the primary reactor was reacted for 5 hours while maintaining the temperature at 170 ° C. and the pressure of 3 kg / cm ² .

The ammonia generated during the reaction was absorbed by 40% sulfuric acid solution, at which time a yuan was formed and the solvent was released together with the gas. The released solvent was recovered from water and recovered, and the soluble component dissolved in water was dried after being treated with activated carbon, concentrated and crystallized.

After the copper phthalocyanine synthesis reaction was completed, the copper phthalocyanine crude product was cooled to room temperature, filtered and dried.

Example 2. Filtration Experiment

Example 2-1. Acid solution filtration after alkaline solution filtration

200 g of dried copper phthalocyanine was added to a 1 L beaker, and 400 mL of 3% alkaline solution was added thereto, followed by stirring. The temperature of the solution was maintained at 80 ° C., stirred for 1 hour and then filtered. After completion of filtration, the primary filtrate was evaporated and concentrated, and the wet cake was washed with 200 mL of water at 80 ° C. (water content of 30%), and 1000 mL of wet cake and 3% sulfuric acid solution was added to a 2 L beaker and kept at 80 ° C. Stir for hours and filter.

After completion of the filtration, the wet cake (water content: 30%) was washed with 1000 mL of water and dried at 120 ° C. for 12 hours to prepare copper phthalocyanine, and for the second filtrate (filtrate: 1900 mL), a separate secondary filtrate treatment procedure was performed. Was performed.

Example 2-2. Second acid solution filtration after first acid solution filtration

In the same manner as in Example 2-1, 400 mL of 3% sulfuric acid solution was used instead of 400 mL of 3% alkaline solution.

Comparative Example 2-1. One time filtration by acid solution

200 g of dried copper phthalocyanine was added to a 2 L beaker, 1200 mL of a 3% sulfuric acid solution was added thereto, followed by stirring. The temperature of the solution was maintained at 80 ° C., stirred for 1 hour and then filtered. After completion of the filtration, the wet cake (50% water content) was washed with 1200 mL of water and dried at 120 ° C. for 12 hours to prepare copper phthalocyanine, and a filtrate (filtrate: 2240 mL) was subjected to a separate filtrate treatment process.

Comparative Example 2-2. Secondary acid solution filtration after primary water filtration

200 g of dried copper phthalocyanine was added to a 1 L beaker, 400 mL of water was added thereto, followed by stirring. The temperature of the solution was maintained at 80 ° C., stirred for 1 hour and then filtered. After filtration was completed, the primary filtrate was evaporated and concentrated, and the wet cake was washed with 200 mL of water at 80 ° C. (50% water content), and then, 1000 mL of the wet cake and 3% sulfuric acid solution was added to a 2 L beaker and maintained at 80 ° C. 1 Stir for hours and filter.

After completion of the filtration, the wet cake (50% water content) was washed with 1000 mL of water and dried at 120 ° C. for 12 hours to prepare copper phthalocyanine, and for the second filtrate (filtrate amount: 1900 mL), a separate secondary filtrate treatment procedure was performed. Was performed.

Example 3 Filtrate Treatment Experiment

The filtrate treatment experiment was performed on the filtrate of Example 2-1, Example 2-2, Comparative Example 2-1 and Comparative Example 2-2 as follows.

1000 mL of the filtrate of Example 2-1, Example 2-2, Comparative Example 2-1, and Comparative Example 2-2 was put into a 2000 mL beaker, respectively, and 25% NaOH was each performed with stirring to adjust pH to neutral. 33 mL of the filtrate of Example 2-1, 37 mL of the filtrate of Example 2-2, 37 mL of the filtrate of Comparative Example 2-1, and 35 mL of the filtrate of Comparative Example 2-2 were added. Subsequently, after adding 0.3 mL of 0.1% nonionic polymer flocculant Polymer A (Kolon Emulsifier) and standing for 1 hour, the flocculating slurry and the clear supernatant were separated and the flocculating slurry was filtered out.

In order to remove the copper ions remaining in the coagulated waste water after neutralization, 30% sodium hydroxide was 0.3 mL with respect to the filtrate of Example 2-1 and 0.2 mL with respect to the filtrate of Example 2-2, respectively. 0.7 mL was added to the filtrate of Example 2-1 and 0.6 mL was added to the filtrate of Comparative Example 2-2, followed by stirring for 10 minutes. Subsequently, in order to remove excess sodium sulfide, 11% ferrous sulfate was filtered with 0.3 mL of the filtrate of Example 2-1, 0.2 mL of the filtrate of Example 2-2, and filtration of Comparative Example 2-1. 0.6 mL of the solution and 0.5 mL of the filtrate of Comparative Example 2-2 were added, followed by stirring for 1 minute, the mixture was allowed to stand for 12 to 14 hours to separate the clear supernatant, and the aggregated precipitate was removed by filtration.

Into the wastewater was put 3000mL of dilution water, 60ppm of chlorine was injected, it was left for 2 hours and the pH was adjusted to neutral.

Table 1 below shows a case where the wastewater is treated by a conventional method (existing method 1), when the wastewater is treated by the method described in Korean Laid-Open Patent Publication No. 2000-63167 (existing method 2), Comparative Example 2 The total nitrogen, copper ions, suspended solids concentrations, COD, BOD, and nitrogen removal efficiencies were shown for each of the wastewater treated according to −1 and Comparative Example 2-2 and the treated wastewater according to the present invention.

Wastewater Concentrations Generated After CPC Synthesis Process (ppm) Concentration after wastewater treatment (ppm) Total nitrogen COD BOD Copper ions Suspended solids Total nitrogen COD BOD Copper ions Suspended solids If there is no pretreatment process by filtration Existing Method 1 18000 1500 2000 1300 1000 10000 258 2000 3 10 Existing Method 2 18000 1500 2000 1300 1000 2486 80 20 Less than 1 5 If there is pretreatment process by filtration Comparative Example 2-1 4532 450 900 1300 1000 447 80 20 Less than 1 5 Comparative Example 2-2 1710 420 750 920 900 81 69 20 Less than 1 5 Example 2-1 1240 200 320 214 320 58 42 15 Less than 1 5 Example 2-2 875 280 410 510 540 44 51 18 Less than 1 5

As can be seen from Table 1, according to the wastewater treatment method according to the present invention, as mentioned above, the total nitrogen content in the discharged water according to the Attachment 5 of the Enforcement Regulations of the Water Environment Conservation Act, 60, 'Acceptance Standard for Pollutants', is 60 mg / l can be met.

The present invention can provide a new wastewater treatment method that satisfies the enhanced environmental standards by efficiently controlling the total amount of nitrogen in the nitrogen-containing wastewater generated in the phthalocyanine production process.

Claims (8)

In the method for controlling the total amount of nitrogen in the nitrogen component-containing wastewater generated in the phthalocyanine production process, (a) putting dried copper phthalocyanine into an alkaline solution and stirring and filtering; (b) washing the wet cake filtered in step (a) with water, then putting it in an acid solution, stirring and filtering, and evaporating and concentrating the primary filtrate generated in step (a); And (c) preparing copper phthalocyanine by drying the wet cake filtered in step (b), and neutralizing the secondary filtrate generated in step (b) by acid and alkali treatment, followed by organic coagulant treatment and pressurization. Removing sludge, removing monovalent copper ions by inorganic coagulant treatment and precipitation, treating chlorine gas to remove nitrogen, and discharging after neutralization. The method of claim 1, wherein the alkali solution of step (a) is characterized in that the NaOH solution of 2-3%. The method of claim 1, wherein the acid solution of step (b) is characterized in that the sulfuric acid solution of 2-3%. The method according to claim 1, wherein the chlorine gas of step (c) is held for 1 to 3 hours at a rate of 2 kg / hour or less until a concentration of 60 to 70 ppm is achieved. In the method for controlling the total amount of nitrogen in the nitrogen component-containing wastewater generated in the phthalocyanine production process, (a) putting dried copper phthalocyanine into the first acid solution and stirring and filtering; (b) washing the wet cake filtered in step (a) with water, stirring and filtering in a second acid solution, and evaporating and concentrating the primary filtrate generated in step (a); And (c) preparing copper phthalocyanine by drying the wet cake filtered in step (b), and neutralizing the secondary filtrate generated in step (b) by acid and alkali treatment, followed by organic coagulant treatment and pressurization. Removing sludge, removing monovalent copper ions by inorganic coagulant treatment and precipitation, treating chlorine gas to remove nitrogen, and discharging after neutralization. The method of claim 5, wherein the first acid solution of step (a) is a sulfuric acid solution of 2-3%. The method of claim 5, wherein the second acid solution of step (b) is a sulfuric acid solution of 1-2%. 6. The method according to claim 5, wherein the chlorine gas of step (c) is maintained for 1 to 3 hours at a rate of 2 kg / hour or less until a concentration of 60 to 70 ppm is obtained.