KR100345296B1 - Treatment method of waste water containing hexavalent chromium compound_ - Google Patents
Treatment method of waste water containing hexavalent chromium compound_ Download PDFInfo
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- KR100345296B1 KR100345296B1 KR1019980054395A KR19980054395A KR100345296B1 KR 100345296 B1 KR100345296 B1 KR 100345296B1 KR 1019980054395 A KR1019980054395 A KR 1019980054395A KR 19980054395 A KR19980054395 A KR 19980054395A KR 100345296 B1 KR100345296 B1 KR 100345296B1
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/70—Treatment of water, waste water, or sewage by reduction
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
- C02F2101/22—Chromium or chromium compounds, e.g. chromates
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Abstract
본 발명은 6가 크롬 화합물 함유 폐수의 처리 방법에 관한 것으로,The present invention relates to a method for treating hexavalent chromium compound-containing wastewater.
코크스 오븐 가스로부터 배출된 탈류폐액의 pH를 3이하로 조절한 다음, 산성으로 pH가 조절된 탈류폐액에 처리하고자 하는 6가 크롬 화합물 함유 폐수를 폐수 대 탈류폐액의 부피비가 1:0.5∼1.5배가 되도록 혼합한 다음 교반하고, 상기 6가 크롬 함유 폐수와 탈류폐액의 교반물을 pH 7이상으로 조절한 다음 침전물이 형성되도록 방치하고, 방치함에 따라 생성된 침전물을 제거하는 방법이 제공된다.After adjusting the pH of the desulfurization liquid discharged from the coke oven gas to 3 or less, the volume ratio of the hexavalent chromium compound wastewater to be treated in the acidic pH-controlled desulfurization liquid is 1: 0.5 to 1.5 times. The mixture is mixed and stirred to adjust the pH of the hexavalent chromium-containing wastewater and the deflux waste to a pH of 7 or higher, and then left to form a precipitate, thereby providing a method for removing the precipitate formed.
본 발명에 따르면, 6가 크롬 화합물 함유 폐수용 환원제로서 유기물을 함유한 탈류폐액을 사용함으로써 6가 크롬을 3가 크롬으로 환원 제거함과 동시에 유기물 함유 폐수의 화학적 산소 요구량도 저감시키게 되어 결과적으로 두가지 폐수를 동시에 처리할 수 있다.According to the present invention, by using a dehydration waste liquid containing organic matter as a reducing agent for waste water containing hexavalent chromium compounds, the reduction of hexavalent chromium to trivalent chromium is reduced and the chemical oxygen demand of the organic matter-containing waste water is also reduced. Can be processed simultaneously.
Description
본 발명은 6가 크롬 화합물 함유 폐수의 처리 방법에 관한 것으로, 보다 상세하게는 6가 크롬 화합물에 의해서 산화될 수 있는 유기물을 함유한 또다른 폐수를 이용하여 크롬 도금 공정후 발생되는 6가 크롬을 3가 크롬으로 환원시키고 유기물은 산화됨으로써 두가지 폐수를 동시에 처리하는 방법에 관한 것이다.The present invention relates to a method for treating wastewater containing hexavalent chromium compounds, and more particularly, to hexavalent chromium generated after a chromium plating process using another wastewater containing organic matter which can be oxidized by hexavalent chromium compounds. Reduction of trivalent chromium and the oxidation of organics relates to a process for treating two wastewaters simultaneously.
일반적으로 도금 공장에서는 열연 코일을 소재로 하여 산세, 냉각 압연, 전기청정, 소둔 및 도금 공정을 통하여 미려한 냉연 및 도금 제품을 생산한다. 이러한 도금 과정에서 오일, 산, 알칼리, 탈류폐액, 유기물 함유 폐수, 크롬 함유 폐수등 다양한 폐수가 발생하게 된다.In general, the plating plant uses hot rolled coils to produce beautiful cold rolled and plated products through pickling, cold rolling, electrocleaning, annealing, and plating processes. In this plating process, various wastewaters such as oil, acid, alkali, deflux waste, organic matter-containing wastewater, and chromium-containing wastewater are generated.
이러한 도금 과정중 크롬 도금 및 크롬 후처리 공정에서 다량의 6가 크롬을 사용하며 이에 따라 6가 크롬을 다량 함유한 폐수가 발생하게 되며, 이러한 6가 크롬을 함유한 폐수는 일반 폐수와는 별도의 처리 공정을 거치게 된다.During the plating process, a large amount of hexavalent chromium is used in the chromium plating and chrome post-treatment processes, thereby generating wastewater containing a large amount of hexavalent chromium, and the wastewater containing hexavalent chromium is separated from general wastewater. It goes through the treatment process.
일반적으로 6가 크롬 화합물은 인체에 매우 유해하기 때문에 6가 크롬 화합물을 인체에 보다 덜 유해한 3가 크롬 화합물로 전환시켜 처리하는데 종래에는 화학적 환원법 및 응집 침전법을 주로 사용하고 있다.In general, since hexavalent chromium compounds are very harmful to the human body, the hexavalent chromium compounds are converted to trivalent chromium compounds which are less harmful to the human body, and conventionally, chemical reduction and coagulation precipitation methods are mainly used.
화학적 환원법이란 6가 크롬 화합물을 아황산 나트륨과 같은 환원제를 사용하고 반응 및 pH 조절에 필요한 황산을 사용하여 산성 조건하에서 반응시켜 6가 크롬 화합물을 3가 크롬 화합물로 만든 다음, pH 조절 및 응집제로 사용되는 소석회를 사용하여 pH를 중성으로 만들어 3가 크롬 화합물을 응집, 침전시켜 제거하는 방법이다.The chemical reduction method is used to reduce the hexavalent chromium compound under acidic conditions by using a reducing agent such as sodium sulfite and sulfuric acid necessary for reaction and pH control to make the hexavalent chromium compound into a trivalent chromium compound, and then to be used as a pH adjusting agent and a flocculant. It is a method of coagulation, precipitation and removal of trivalent chromium compound by making pH neutral by using calcined lime.
이외에도, 일본 공개특허 93-289743에 의하면, 6가 크롬 화합물을 처리하기 위한 환원제로서 제1철염을 사용하였으며, 이러한 환원제를 사용한 화학적 환원법이외에도 6가 크롬 화합물을 제거하는 방법으로 일본 공개 특허 94-122246, 미국 특허 4,824,576에 활성화된 활성탄 및 활성화된 알루미나등의 흡착제를 이용하여 6가 크롬 화합물을 처리한 방법들이 있다.In addition, according to Japanese Patent Application Laid-Open No. 93-289743, ferrous salt was used as a reducing agent for treating a hexavalent chromium compound, and in addition to the chemical reduction method using such a reducing agent, the method for removing the hexavalent chromium compound was disclosed. US Pat. No. 4,824,576 discloses methods for treating hexavalent chromium compounds using adsorbents such as activated carbon and activated alumina.
그러나 종래의 화학적 환원법 및 흡착제를 사용한 방법들에서는 환원제와 같은 화학약품을 사용하므로 약품 비용이 많이 들고, 또한 흡착제를 이용한 방법 역시 흡착제의 비용 및 사용후 흡착제의 처리 비용이 고가인 단점이 있다.However, conventional chemical reduction methods and methods using an adsorbent use a chemical agent such as a reducing agent, so the chemical cost is high, and the method using the adsorbent also has the disadvantage that the cost of the adsorbent and the treatment cost of the used adsorbent are expensive.
이에 본 발명은 상기와 같은 제반 문제점을 감안하여 이를 해소하고자 하는 것으로, 6가 크롬 화합물을 함유한 폐수를 그 환원제로서 유기물을 함유하는 다른 폐수를 이용하여 6가 크롬 화합물을 3가 크롬 화합물로 환원시켜 처리함으로써 두가지 폐수를 동시에 효과적으로 처리하는 방법을 제공하려는 것이다.In view of the above problems, the present invention is intended to solve the above problems, and the hexavalent chromium compound is reduced to the trivalent chromium compound by using the wastewater containing the hexavalent chromium compound as another reducing water containing organic matter as the reducing agent. It is intended to provide a way to effectively treat both wastewaters by treating them at the same time.
본 발명에 의하면,According to the invention,
코크스 오븐 가스로부터 배출된 탈류폐액의 pH를 3이하로 조절하는 단계;Adjusting the pH of the degassing liquid discharged from the coke oven gas to 3 or less;
산성으로 pH가 조절된 탈류폐액에 처리하고자 하는 6가 크롬 화합물 함유 폐수를 폐수 대 탈류폐액의 부피비가 1:0.5∼1.5배가 되도록 혼합한 다음 교반하는 단계; 및Mixing the hexavalent chromium compound-containing wastewater to be treated in the acid-controlled deflowing wastewater so that the volume ratio of the wastewater to the defluent wastewater is 1: 0.5 to 1.5 times and then stirring; And
상기 6가 크롬 함유 폐수와 탈류폐액의 교반물을 pH 7이상으로 조절한 다음 침전물이 형성되도록 방치하고, 방치함에 따라 생성된 침전물을 제거하는 단계;를 포함하는 6가 크롬 화합물 함유 폐수 처리 방법이 제공된다.The hexavalent chromium compound-containing wastewater treatment method comprising the step of adjusting the agitated mixture of the hexavalent chromium-containing wastewater and the dehydration wastewater to pH 7 or more, and then leaving a precipitate formed, and removing the precipitate generated as it is left. Is provided.
이하, 본 발명에 대하여 상세히 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.
본 발명에서는 6가 크롬 화합물을 함유한 폐수를 별도의 환원제를 사용하는 대신 코크스 오븐 가스로부터 탈류 공정을 거쳐 배출된 유기물을 함유하는 폐수(이하, '탈류폐액'이라 한다)를 환원제로 이용하여 3가 크롬 화합물로 처리한다.In the present invention, instead of using a separate reducing agent for wastewater containing a hexavalent chromium compound, wastewater containing organic matter discharged from the coke oven gas through a degassing process (hereinafter referred to as 'drainage waste liquid') is used as a reducing agent. Is treated with a chromium compound.
상기 탈류폐액이란 코크스 오븐 가스(COG)로부터 탈황 설비를 거쳐 제조된 폐액을 의미하는 것으로, 주성분은 티오시안 및 시안 화합물로 이루어지며, 기타 피크린산과 같은 고농도의 유기물을 함유한 폐수이다.The demineralization waste liquid means a waste liquid prepared from a coke oven gas (COG) through a desulfurization facility. The main component consists of thiocyanide and cyanide compound, and wastewater containing high concentration of organic matter such as picric acid.
먼저 탈류폐액의 산도를 차후에 6가 크롬 화합물과의 반응성을 개선시키도록 pH 3이하로 조절한다. 만일 pH를 3이상으로 조절하게 되면, 차후에 6가 크롬 화합물과의 반응이 느려지므로 바람직하지 않다. 경제적인 측면에서는 pH를 2∼3으로 조절하는 것이 보다 바람직하다.The acidity of the effluent is first adjusted to pH 3 or below to improve the reactivity with the hexavalent chromium compound. If the pH is adjusted to 3 or higher, the reaction with the hexavalent chromium compound is slowed later, which is not preferable. From an economic point of view, it is more preferable to adjust the pH to 2-3.
상기 pH는 무기산이나 유기산등 일반적인 산을 이용하여 조절할 수 있으며, 또한 제철소에서 나오는 폐수를 활용한다는 측면에서 염산을 함유한 폐산으로도 조절가능하다.The pH can be adjusted using a common acid such as inorganic acid or organic acid, and can also be adjusted to waste acid containing hydrochloric acid in terms of utilizing wastewater from steel mills.
이와 같이 산성화된 탈류폐액에 처리하고자 하는 6가 크롬 화합물 함유 폐수를 혼합한 다음 교반시킨다.The waste water containing the hexavalent chromium compound to be treated is mixed with the acidified deflux and then stirred.
여기서 6가 크롬 화합물 함유 폐수는 제철소의 크롬 도금 공정후 발생되는 폐수로서, 탈류폐액 대비 1:0.5∼1.5 부피비로 혼합하는 것이 적절하다. 상기 범위를 벗어나면 6가 크롬 화합물이 충분히 제거되지 않고 잔류하게 되거나 혹은 유기물을 함유한 탈류폐액의 화학적 산소 요구량이 원하는 만큼 충분히 감소되지 않아 두가지 폐수를 동시에 처리하려는 본 발명의 효과를 충분히 얻지 못하게 된다.Here, the hexavalent chromium compound-containing wastewater is wastewater generated after the chromium plating process of the steel mill, and is preferably mixed at a volume ratio of 1: 0.5 to 1.5 with respect to the dehydration waste liquid. Outside the above range, the hexavalent chromium compound is not sufficiently removed or remains, or the chemical oxygen demand of the organic-containing demineralization waste liquid is not sufficiently reduced as desired so that the effect of the present invention for simultaneously treating two wastewaters is not obtained. .
이와 같이 혼합된 혼합물을 교반하면 전자의 이동 즉, 탈류폐액중 유기물은 전자를 빼앗겨 산화되고 그 전자를 6가 크롬 이온이 받아들여 3가 크롬으로 환원되는 반응에 의해, 출발 물질인 녹색을 띠는 6가 크롬 함유 용액으로 부터 보다 진한 청록색을 띠는 3가 크롬 함유 용액이 생성된다.When the mixed mixture is agitated, the movement of electrons, that is, organic matter in the deflux, is deprived of electrons and oxidized, and the electrons are accepted by hexavalent chromium ions and reduced to trivalent chromium. From the hexavalent chromium containing solution, a darker turquoise trivalent chromium containing solution is produced.
상기 6가 크롬을 함유하는 폐수와 탈류폐액의 혼합 교반물을 pH 7이상으로 조절한 다음 방치하면 3가 크롬 함유 용액으로부터 생성된 3가 크롬 침전물이 형성되며, 형성된 침전물을 제거함으로써 폐수중의 6가 크롬 화합물이 처리된다.When the mixed agitated mixture of the hexavalent chromium-containing wastewater and the dehydration wastewater is adjusted to pH 7 or more, and left to stand, trivalent chromium precipitates formed from the trivalent chromium-containing solution are formed, and the precipitates are removed. The chromium compound is treated.
상기 산도는 pH 7이상으로 조절하는 것이 바람직한데, 7이하가 되면 3가 크롬의 침전물을 생성하지 못하므로 궁극적으로는 본 발명에서 얻고자 하는 6가 크롬 화합물 제거 효과를 얻지 못하게 되기 때문이다. 상기 pH를 7∼8로 조절하는 것이 경제적인 측면에서 보다 바람직하다.The acidity is preferably adjusted to pH 7 or higher, because if it is less than or equal to 7 it will not produce a precipitate of trivalent chromium and ultimately will not obtain the hexavalent chromium compound removal effect to be obtained in the present invention. It is more preferable to economically adjust the pH to 7-8.
상기 pH조절은 NaOH등을 사용하여도 가능하나, 생성된 3가 크롬 이온을 Cr(OH)3침전물의 형태로 제거하기 위해서는 소석회를 사용하는 것이 좋다. 상기 침전물의 형성은 육안 관찰로 녹색에서 청록색으로의 색변화에 의해 확인할 수 있으며, 또한 방치후 반응의 종료 시점을 결정할 수 있다.The pH may be adjusted by using NaOH, but in order to remove the generated trivalent chromium ion in the form of Cr (OH) 3 precipitate, it is preferable to use slaked lime. The formation of the precipitate can be confirmed by the color change from green to cyan by visual observation, and can also determine the end time of the reaction after standing.
이와 같은 방법에 의하면, 6가 크롬이 거의 내지는 전혀 검출되지 않는 것으로부터 효과적으로 처리됨을 알 수 있으며, 또한 탈류폐액내 유기물양을 가늠해볼 수 있는 화학적 산소 요구량이 75%이상 저감된다는 결과로부터 유기물이 최종 분해 산물인 CO2와 H2O상태로 분해됨을 알 수 있다. 따라서 두가지 폐수를 동시에 처리할 수 있는 것이다.According to this method, it can be seen that the hexavalent chromium is effectively treated from the fact that little or no hexavalent chromium can be effectively treated. It can be seen that the decomposition products are decomposed to CO 2 and H 2 O state. Therefore, both wastewaters can be treated simultaneously.
이하, 본 발명에 대하여 실시예를 통하여 상세히 설명한다.Hereinafter, the present invention will be described in detail through examples.
<실시예 1><Example 1>
6가 크롬 화합물 함유 폐수중 6가 크롬의 농도가 660ppm이며, 유기물 함유 탈류폐액의 화학적 산소 요구량은 13,300ppm이었다.The concentration of hexavalent chromium in the hexavalent chromium compound-containing wastewater was 660 ppm, and the chemical oxygen demand of the organic-containing demineralization waste solution was 13,300 ppm.
티오시안 및 시안 화합물이 주성분이며, 기타 피크린산등 고농도의 유기물을 함유한 탈류폐액 100㎖에 4% 염산 및 120g/ℓ의 철이온을 포함한 폐산 2㎖를 첨가하여 pH를 3으로 조절하였다.The pH was adjusted to 3 by adding 2 ml of waste acid containing 4% hydrochloric acid and 120 g / l iron ion to 100 ml of demineralized waste liquid containing thiocyanate and cyan compound, and other organic acids such as picric acid.
여기에 6가 크롬 화합물을 함유한 폐수 50㎖를 첨가하여 30분간 교반시킨 후 방치하였다. 이때 청록색의 용액이 생성되는 것을 확인하였으며, 여기에 소석회를 투입하여 pH를 7로 조절한 다음 방치하고 침전물은 제거하였다.50 ml of wastewater containing a hexavalent chromium compound was added thereto, stirred for 30 minutes, and left to stand. At this time, it was confirmed that a turquoise solution was produced, and the lime was added thereto to adjust the pH to 7, and then left to remove the precipitate.
그 상등액을 채취하여 원소 분석기로 6가 크롬 농도를 분석한 결과, 6가 크롬은 전혀 검출되지 않았고 화학적 산소 요구량은 3,325ppm으로 최초 화학적 산소 요구량 13,300ppm대비 75%가 감소되었다.The supernatant was collected and analyzed by the element analyzer for hexavalent chromium concentration. No hexavalent chromium was detected and the chemical oxygen demand was 3,325 ppm, which was 75% lower than the initial chemical oxygen demand of 13,300 ppm.
<실시예 2><Example 2>
6가 크롬 화합물을 함유한 폐수 100㎖를 첨가한 것을 제외하고는 실시예 1과 동일한 방법을 반복하였다.The same procedure as in Example 1 was repeated except that 100 ml of wastewater containing a hexavalent chromium compound was added.
침전물을 제거한 다음, 그 상등액을 채취하여 원소 분석기로 6가 크롬 농도를 분석한 결과, 6가 크롬은 전혀 검출되지 않았고 화학적 산소 요구량은 500ppm으로 최초 화학적 산소 요구량 13,300ppm대비 96% 감소되었다.After removing the precipitate, the supernatant was collected and analyzed for hexavalent chromium concentration by an element analyzer. No hexavalent chromium was detected and the chemical oxygen demand was 500 ppm, which was 96% lower than the initial chemical oxygen demand of 13,300 ppm.
<실시예 3><Example 3>
6가 크롬 화합물을 함유한 폐수 150㎖를 첨가한 것을 제외하고는 실시예 1과 동일한 방법을 반복하였다.The same procedure as in Example 1 was repeated except that 150 ml of wastewater containing a hexavalent chromium compound was added.
침전물을 제거한 다음, 그 상등액을 채취하여 원소 분석기로 6가 크롬 농도를 분석한 결과, 6가 크롬이 67ppm 검출되었고 화학적 산소 요구량은 10ppm으로 최초 화학적 산소 요구량 13,300ppm대비 99% 감소되었다.After removing the precipitate, the supernatant was collected and analyzed for hexavalent chromium concentration using an element analyzer. As a result, 67 ppm of hexavalent chromium was detected and the chemical oxygen demand was 10 ppm, which was 99% lower than the initial chemical oxygen demand of 13,300 ppm.
6가 크롬 화합물 함유 폐수용 환원제로서 코크스 오븐 가스로부터 탈류 공정을 거쳐 배출된 유기물 함유 탈류폐액을 사용한 본 발명에 따르면, 6가 크롬을 현저하게 감소시킴과 동시에 유기물 함유 탈류폐액의 화학적 산소 요구량도 크게 감소시킬 수 있는 바, 결과적으로 두가지 폐수를 동시에 처리할 수 있다.According to the present invention using the organic matter-containing demineralization waste liquid discharged from the coke oven gas as a reducing agent for the hexavalent chromium compound wastewater, the chemical oxygen demand of the organic matter-containing demineralization waste solution is greatly reduced. As a result, both wastewaters can be treated simultaneously.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR830008930A (en) * | 1982-01-11 | 1983-12-16 | 곽윤기 | Method for preparing wastewater purification agent |
| JPS63267494A (en) * | 1987-04-27 | 1988-11-04 | Nkk Corp | Treatment of waste liquid containing hexavalent chromium |
| US5000858A (en) * | 1989-07-17 | 1991-03-19 | Coltec Industries Inc. | Method for removing hexavalent chromium from water |
| JPH05228478A (en) * | 1992-02-17 | 1993-09-07 | Nisshin Steel Co Ltd | Process to make harmless waste liquid containing hexavalent chromium |
| KR19980052462A (en) * | 1996-12-24 | 1998-09-25 | 김종진 | Wastewater treatment method to reduce fluorine and chromium hexavalent ions in wastewater |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR830008930A (en) * | 1982-01-11 | 1983-12-16 | 곽윤기 | Method for preparing wastewater purification agent |
| JPS63267494A (en) * | 1987-04-27 | 1988-11-04 | Nkk Corp | Treatment of waste liquid containing hexavalent chromium |
| US5000858A (en) * | 1989-07-17 | 1991-03-19 | Coltec Industries Inc. | Method for removing hexavalent chromium from water |
| JPH05228478A (en) * | 1992-02-17 | 1993-09-07 | Nisshin Steel Co Ltd | Process to make harmless waste liquid containing hexavalent chromium |
| KR19980052462A (en) * | 1996-12-24 | 1998-09-25 | 김종진 | Wastewater treatment method to reduce fluorine and chromium hexavalent ions in wastewater |
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