1. A method for removing organic impurities in waste 2-ethyl anthraquinone sulfuric acid water is characterized by comprising the following steps:

s1: filtering waste acid water generated in the production of 2-ethyl anthraquinone, and filtering solid particles in the waste acid water to produce magnesium sulfate;

s2: the waste acid water filtered in the step S1 is sent to a reaction kettle of magnesium sulfate mother liquor added with magnesium oxide, sulfuric acid water and magnesium oxide solution are neutralized and reacted until the pH value is 6.5-7, the concentration of the magnesium sulfate solution after the reaction is controlled at 41-42 Baume ℃, and the temperature is kept at 98-100 ℃;

s3: flocculating and settling the reaction solution obtained in the step S2 by using anionic polyacrylamide to separate solid impurities brought by magnesium oxide and the like from the solution;

s4, standing the reaction solution flocculated in the step S3 for 30-60min, controlling the temperature of the solution to be equal to or more than 75 ℃, and extracting the reaction solution flocculated and settled in the upper layer in batches to a separation tank for flocculation separation of organic impurities in the reaction solution:

1) preparation of a coagulant: the polymeric ferric sulfate is prepared into the specific gravity of 1.6g/cm³An aqueous solution; preparing polyaluminium sulfate into a specific gravity of 1.35-1.4g/cm³An aqueous solution;

2) determining the dosage proportion of a coagulant in a small experiment, taking 800ml of the solution after flocculation and sedimentation in a 1000ml beaker in the step S4, adding a polymeric ferric sulfate aqueous solution by using a glass rod at the speed of 120 revolutions per minute while stirring, observing the change of the polymeric ferric sulfate aqueous solution, stopping adding the polymeric ferric sulfate aqueous solution and recording the addition amount when a solid is just separated out, continuing stirring at 60 revolutions per minute, simultaneously adding a polymeric aluminum sulfate aqueous solution until the separated solid is coagulated into a cluster, and recording the addition amount;

3) determining the required addition amount of a coagulant in a solution of a separation tank according to the ratio of the two coagulants in a pilot test, adding the coagulants in a pilot test step, controlling the stirring speed to be 24 r/min, adding a polymeric ferric sulfate solution, adjusting the stirring speed to be 14 r/min, and adding a polymeric aluminum sulfate solution;

4) after the coagulant is added, the stirring speed is controlled to be 10 revolutions per minute, the stirring is continued for 5 minutes, the stirring is stopped for 20 to 25 minutes, at the moment, the solution is below, and the solid organic oily matter is coagulated on the solution;

5) under the condition that the temperature is not less than 60 ℃, discharging the solution from a discharge valve at the bottom of the separation tank while the solution is hot, sending the solution to a cooling crystallization tank, cooling the solution to 35-40 ℃ for crystallization, wherein the crystallization time is 12 hours; then carrying out centrifugal solid-liquid separation, wherein the centrifuged mother liquor is purified mother liquor, and the chroma of the mother liquor is reduced from more than 5000 times to less than 150 times before treatment; the COD value is reduced from more than 30000mg/L to less than 250mg/L before treatment; the solid magnesium sulfate obtained by centrifugation enters the subsequent process for treatment;

6) discharging the upper oily organic waste from the bottom, filling the oily organic waste in a basin, cooling to normal temperature, solidifying, and filling the oily organic waste in a bag for hazardous waste treatment;

7) and (3) purifying all mother liquor by the same method, recovering the normal requirement of the mother liquor, and recycling the mother liquor into the magnesium sulfate heptahydrate produced by recovering the waste sulfuric acid water generated by the 2-ethyl anthraquinone.

2. The method for removing organic impurities from waste sulfuric acid water containing 2-ethylanthraquinone as claimed in claim 1, wherein the filtration of the waste acid water in the step S1 is a preliminary filtration of 40% of the waste sulfuric acid water discharged from the production of 2-ethylanthraquinone, and is required to filter out all suspended solids.

3. The method for removing organic impurities from waste sulfuric acid water produced in the production of 2-ethylanthraquinone according to claim 1, wherein the separation of the organic impurities is not required for each time of the waste acid water and the mother liquor water added with magnesium oxide and the solution obtained by the reaction, and the process operation for removing the organic impurities according to claim 1 is performed only after the magnesium sulfate mother liquor is recycled for N times, the organic impurities in the magnesium sulfate mother liquor are accumulated to a certain degree, and the filtration of the reaction solution for producing magnesium sulfate heptahydrate from the waste sulfuric acid water and the yellowing of the color of the magnesium sulfate heptahydrate are affected.

4. The method for removing organic impurities in 2-ethylanthraquinone waste sulfuric acid water as claimed in claim 1, wherein the organic impurities are anthraquinone, anthraquinone derivatives, tar, benzoic acid, benzene derivatives and other organic mixtures generated in the production of 2-ethylanthraquinone.

5. The method for removing organic impurities from waste sulfuric acid water containing 2-ethylanthraquinone according to claim 1, wherein the mass percentage of the waste acid water after filtration in the step S1 is as follows: waste acid, 40%; anthraquinone derivative, 1.5%; 2% of tar; benzoic acid, 0.5%; benzene derivative, 1.45%; 54.55 percent of water.

6. The method for removing organic impurities from waste sulfuric acid water containing 2-ethylanthraquinone according to claim 1, wherein the step of S3 is to separate solid impurities from the solution, such as magnesium oxide, by settling the silt, such as magnesium oxide, with anionic polyacrylamide in the reaction kettle.

7. The method for removing organic impurities in 2-ethylanthraquinone waste sulfuric acid water as claimed in claim 1, wherein in the step S3, sediment at the last bottom of the reaction kettle is washed with a proper amount of clear water, and then is subjected to plate-and-frame filter pressing, and the filtrate returns to the mother liquor pool to be treated and is treated again together with the mother liquor to be treated.

8. The method for removing organic impurities in 2-ethylanthraquinone waste sulfuric acid water according to claim 3, wherein the organic impurities in the magnesium sulfate mother liquor are accumulated to a certain extent, namely, the chroma of the magnesium sulfate mother liquor is higher than 4500 times, and the COD value is higher than 25000 mg/L.

Background

In the synthesis production process of 2-ethyl anthraquinone, a large amount of organic impurity sulfuric acid waste water containing anthraquinone, anthraquinone derivatives, tar, benzoic acid and benzene derivatives (mainly benzene sulfonate) is produced, and the waste water must be subjected to harmless treatment. The most economical and effective method for producing magnesium sulfate by using magnesium oxide and acid water for neutralization is available, but organic impurities in the acid water have great influence on the solution filtering process in the production process of the magnesium sulfate, and colloidal fine particles are formed in the solution, so that filter cloth holes are easily blocked and the solution cannot be filtered. Meanwhile, the color of the finished product is yellow due to high chromaticity, the product quality is greatly influenced, and the finished product needs to be separated, otherwise, the recycling of the sulfuric acid wastewater is greatly disturbed. At present, 30% -40% of acid water is distilled to 50% -60%, a large amount of organic mixtures are solidified and separated out when the acid water is quenched to the normal temperature at the high temperature of 140 ℃, but the organic mixtures are not completely separated out, and part of the acid water is dissolved in the acid water, enters an acid water recycling process, is finally collected in magnesium sulfate mother liquor, affects continuous production, consumes a large amount of waste steam, and increases cost. Other recycling methods of waste sulfuric acid water, such as strengthening the recycling of oxidizing organic impurities by an oxidant or recycling the waste sulfuric acid water to acid after high-temperature incineration, have the disadvantages of complex process, high corrosivity, high equipment requirement, quite large investment, high production cost and equipment maintenance cost, and no environmental influence.

Disclosure of Invention

Aiming at the problems of incomplete separation, high steam consumption, high equipment maintenance cost (enamel equipment is quenched at high temperature and is easy to damage) and influence on continuous production of a mixture of organic impurities separated by high-temperature distillation and quenching solidification, the invention provides the method for separating the organic mixture by coagulation by adding the coagulant through salting out, which does not need steam, has good separation effect, achieves long-period cyclic use of magnesium sulfate mother liquor, does not influence the continuous production of magnesium sulfate produced by waste acid, and ensures the quality of magnesium sulfate heptahydrate products.

The technical scheme for realizing the purpose of the invention is as follows:

the method for removing organic impurities in 2-ethyl anthraquinone waste sulfuric acid water is characterized by comprising the following steps of:

s1: filtering waste acid water generated in the production of 2-ethyl anthraquinone, and sending the waste acid water into a storage tank for later use after solid particles suspended in the waste acid water are completely filtered out for production of magnesium sulfate;

s2: the waste acid water filtered in the step S1 is sent to a reaction kettle of magnesium sulfate mother liquor added with magnesium oxide to carry out neutralization reaction between magnesium oxide water solution and sulfuric acid water, the final temperature is 98-100 ℃, the pH value is 6.5-7, and the concentration of the magnesium sulfate solution after the reaction is controlled at 41-42 Baume degrees;

s3: the reaction solution from the S2 step is flocculated and settled with anionic polyacrylamide to separate solid impurities (such as silt) from the solution, such as magnesium oxide.

The method comprises the following specific operations: 1) at a rate of 1.25g/m³And (3) preparing 0.1% of diluted solution from anionic polyacrylamide with molecular weight of more than 800 ten thousand by using the dosage of the solution. 2) And (3) small trial: 2000ml of the reaction solution is dripped into the prepared polyacrylamide solution for several drops until the solution on the upper layer is transparent and has no suspended particles. When the effect is not good, the pH value of the solution is finely adjusted until the sedimentation effect of the reaction solution is optimal. 3) And after the small test is qualified, stirring the reaction kettle for 24 revolutions per minute, adding the prepared polyacrylamide solution, continuing stirring for 15 minutes, and stopping stirring.

S4, standing the reaction solution flocculated and settled in the step S3 for 30-60min, controlling the temperature of the solution to be not less than 75 ℃ after full settlement, extracting the reaction solution flocculated and settled at the upper layer in batches to a separation tank for flocculation separation of organic impurities in the reaction solution:

1) preparation of a coagulant: at normal temperature, the polyferric sulfate is prepared into the specific gravity of 1.6g/cm³An aqueous solution; preparing polyaluminium sulfate into the specific gravity of 1.35-1.4g/cm at normal temperature³An aqueous solution;

2) small experiments confirm the coagulant dosage ratio: and (3) putting 800ml of the solution after flocculation sedimentation into a 1000ml beaker, adding the polymeric ferric sulfate aqueous solution at the speed of 120 revolutions per minute by using a glass rod while stirring, observing the change, stopping adding the polymeric ferric sulfate aqueous solution when a solid is just separated out, recording the addition amount, continuing stirring, simultaneously adding the polymeric aluminum sulfate aqueous solution until the separated solid is coagulated into a mass, and recording the addition amount.

3) Determining the addition amount of a coagulant in a solution of a separation tank according to the ratio of the two coagulants in a pilot plant, adding the coagulants in a pilot plant step, controlling the stirring speed to be 24 r/min, and adding a polymeric ferric sulfate solution; then the stirring speed is adjusted to 14 r/min, and polyaluminium sulfate solution is added.

4) After the coagulant is added, the stirring speed is controlled to be 10 revolutions per minute, the stirring is stopped for 20 to 25 minutes after the stirring is continued for 5 minutes, and at the moment, the solution is below and the solid oily matter is coagulated on the solution;

5) discharging the solution from a discharge valve at the bottom of the separation tank while the solution is hot (the temperature is not less than 60 ℃), sending the solution to a cooling crystallization tank, cooling and crystallizing to 35-40 ℃, wherein the crystallization time is 12 hours, and centrifuging and performing solid-liquid separation. The mother liquor obtained by centrifugation is purified mother liquor, and the chroma of the mother liquor is reduced from more than 5000 times to less than 150 times before treatment; the COD value is reduced from more than 30000mg/L to less than 250mg/L before treatment. And (4) carrying out subsequent treatment on the solid magnesium sulfate obtained by centrifugation.

6) And finally discharging the upper oily organic waste from the bottom, filling the oily organic waste into a basin, cooling to normal temperature, and filling the oily organic waste into a bag after solidification for hazardous waste treatment.

7) And (3) purifying all mother liquor by the same method, recovering the normal requirement of the mother liquor, and recycling the mother liquor into the magnesium sulfate heptahydrate produced by recovering the waste sulfuric acid water generated in the production of 2-ethyl anthraquinone.

The step S1, namely filtering the waste acid water, is to filter out all solid suspended matters, wherein all the waste acid water is 40% in the process of producing the 2-ethylanthraquinone. The filtered waste acid water comprises the following components in percentage by mass: waste acid: 40 percent; 1.5 percent of anthraquinone derivative; tar oil: 2 percent; benzoic acid: 0.5 percent; benzene derivatives (mainly benzene sulfonate) 1.45%; water: 54.55 percent.

The concentration of the reaction solution in the step S2 is controlled to be 41-42 Baume degrees, the concentration of the separated magnesium sulfate solution which meets the requirements of subsequent cooling crystallization and centrifugation is balanced, a high-salt environment is created, and conditions are created for precipitation and separation of organic impurities. The high-concentration strong electrolyte destroys the hydrated film on the surface of the organic impurity molecules, and simultaneously, the electrolyte ions neutralize the charges carried by the organic impurities. Thereby eliminating the stability of organic matters in water, leading organic impurity molecules to collide with each other and to be coagulated and separated out, and leading the organic impurities to be flocculated and agglomerated under the action of a coagulant.

S3 the reaction solution settles the silt brought by magnesium oxide with anion polyacrylamide in the reaction kettle, mainly utilizes the characteristic that anion polyacrylamide has unobvious flocculation effect on the organic impurities and good settling effect on particles such as silt, separates the silt with large specific gravity effect, and is convenient for the next step of layering the organic impurities. The organic impurities have a smaller specific gravity than magnesium sulfate solution, and become sticky at a temperature of above 60 ℃, so the magnesium sulfate solution has certain fluidity. This makes it easier to achieve a simple and fast separation.

In the step S4, two flocculants, namely polyferric sulfate and polyaluminium sulfate, are adopted, wherein the polyferric sulfate solution is fast in flocculation and good in effect, and the polyaluminium sulfate is slow in flocculation and poor in effect. However, the excessive iron ion can influence the color of the magnesium sulfate product to cause the magnesium sulfate product to turn yellow, so the mixing effect of the two flocculating agents is the best.

The method removes most of organic impurities in the mother liquor after the organic impurities are separated by coagulation sedimentation in the high-salt environment, reduces the chroma of the mother liquor from more than 5000 times to 150 times, and reduces the COD value from more than 30000mg/L to less than 250mg/L.

The method for removing the organic impurities in the 2-ethyl anthraquinone waste sulfuric acid water does not need to separate the organic impurities from the waste acid water, the magnesium oxide added mother liquor and the solution obtained by reaction every time, and the process operation of removing the organic impurities in the claim 1 is only carried out when the organic impurities in the magnesium sulfate mother liquor are accumulated to a certain degree after the magnesium sulfate mother liquor is recycled for N times, the filtration of the reaction solution for producing the magnesium sulfate heptahydrate from the waste sulfuric acid water and the color yellowing of the magnesium sulfate heptahydrate are influenced, and the whiteness is below 70. The impurity accumulation to a certain degree generally means that the chroma of the magnesium sulfate mother liquor is higher than 4500 times, and the COD value is higher than 25000 mg/L.

And (3) washing sediments at the last bottom of the reaction kettle in the step S3 with a proper amount of clear water, performing filter pressing through a plate frame, returning filtrate to the mother liquor pool to be treated, and retreating the filtrate together with the mother liquor to be treated.

The invention has the beneficial effects that:

in the process of producing magnesium sulfate from waste sulfuric acid water of 2-ethyl anthraquinone, a large amount of organic matters are gathered after the mother liquor is recycled for a long time. The magnesium sulfate mother liquor is required to be extracted and separated, so that the production of the magnesium sulfate and the product quality are not influenced, the quality of the magnesium sulfate is improved, and the aims of saving energy and reducing consumption are fulfilled.

In the invention, under the high-salt environment, organic matters are precipitated and coagulated into clusters by a coagulant coagulation sedimentation method, so that a solution is formed below a separation tank, and solid oily matters are coagulated above the solution to achieve the purpose of separating the organic matters.

The technical scheme of the invention does not need high-temperature concentration, saves steam, does not need to consume oxidant, does not need to invest a large amount of equipment, and realizes the most effective and most economical recycling of acid water containing organic wastes.

Description of the drawings:

FIG. 1 is a schematic diagram of coagulation-sedimentation separation

Wherein: 1-magnesium sulfate solution pretreated from a reaction kettle, 2-polymeric ferric sulfate solution metering tank, 3-polymeric aluminum sulfate solution metering tank and 4-coagulation sedimentation separation tank

Detailed Description

The method for separating the organic mixture brought by the waste acid water from the magnesium sulfate solution comprises the following steps:

s1: filtering waste acid water generated in the production of 2-ethyl anthraquinone, and sending the waste acid water into a storage tank for later use after solid particles suspended in the waste acid water are completely filtered out. The method is used for producing magnesium sulfate;

s2: the waste acid water filtered in the step S1 is sent to a reaction kettle of magnesium sulfate mother liquor added with magnesium oxide to carry out neutralization reaction between magnesium oxide water solution and sulfuric acid water, the final temperature is 98-100 ℃, the pH value is 6.5-7, and the concentration of the magnesium sulfate solution after the reaction is controlled at 41-42 Baume degrees;

s3: the reaction solution from the S2 step is flocculated and settled with anionic polyacrylamide to separate solid impurities (such as silt) from the solution, such as magnesium oxide. The method comprises the following specific operations: 1) at a rate of 1.25g/m³The dosage of the solution is that the anionic polyacrylamide with the molecular weight more than 800 ten thousand is prepared0.1% of a dilution solution. 2) And (3) small trial: 2000ml of the reaction solution is dripped into the prepared polyacrylamide solution for several drops until the solution on the upper layer is transparent and has no suspended particles. When not in use, the pH value of the solution is finely adjusted by acid water or magnesium oxide until the reaction solution is optimally settled. 3) And after the small test is qualified, stirring the reaction kettle for 24 revolutions per minute, adding the prepared polyacrylamide solution, continuing stirring for 15 minutes, and stopping stirring.

S4, standing the reaction solution flocculated and settled in the step S3 for 30-60min, fully settling, and extracting the reaction solution flocculated and settled at the upper layer in batches to a separation tank for flocculation separation of organic impurities in the reaction solution, wherein the solution temperature is not lower than 75 ℃:

1) preparation of a coagulant: at normal temperature, the polyferric sulfate is prepared into the specific gravity of 1.6g/cm³An aqueous solution; preparing polyaluminium sulfate into the specific gravity of 1.35-1.4g/cm at normal temperature³An aqueous solution;

2) small experiments confirm the coagulant dosage ratio: and (3) putting 800ml of the solution after flocculation sedimentation into a 1000ml beaker, adding the polymeric ferric sulfate aqueous solution at the speed of 120 revolutions per minute by using a glass rod while stirring, observing the change, stopping adding the polymeric ferric sulfate aqueous solution when a solid is just separated out, recording the addition amount, continuing stirring, simultaneously adding the polymeric aluminum sulfate aqueous solution until the separated solid is coagulated into a mass, and recording the addition amount.

3) Determining the addition amount of a coagulant in a solution of a separation tank according to the ratio of the two coagulants in a pilot plant, adding the coagulants in a pilot plant step, controlling the stirring speed to be 24 r/min, and adding a polymeric ferric sulfate solution; then the stirring speed is adjusted to 14 r/min, and polyaluminium sulfate solution is added.

4) After the coagulant is added, the stirring speed is controlled to be 10 revolutions per minute, the stirring is stopped for 20 to 25 minutes after the stirring is continued for 5 minutes, and at the moment, the solution is below and the solid oily matter is coagulated on the solution;

5) discharging the solution from a discharge valve at the bottom of the separation tank while the solution is hot (the temperature is not less than 60 ℃), sending the solution to a cooling crystallization tank, cooling and crystallizing the solution to 35-40 ℃, carrying out crystallization for 12 hours, and then carrying out centrifugation and solid-liquid separation. The mother liquor obtained by centrifugation is purified mother liquor, and the chroma of the mother liquor is reduced from more than 5000 times to less than 150 times before treatment; the COD value is reduced from more than 30000mg/L to less than 250mg/L before treatment. And the solid magnesium sulfate enters subsequent procedures for treatment.

6) And finally discharging the upper oily organic waste from the bottom, filling the oily organic waste into a basin, cooling to normal temperature, and filling the oily organic waste into a bag after solidification for hazardous waste treatment.

7) And (3) purifying all mother liquor by the same method, recovering the normal requirement of the mother liquor, and recycling the mother liquor in the recovery and production of the magnesium sulfate heptahydrate from the waste sulfuric acid water of the 2-ethyl anthraquinone.

Example 1

S1: filtering the waste acid water generated by producing the 2-ethyl anthraquinone by a plate-and-frame filter press, wherein the filtering temperature is as follows: normal temperature; the filtering pressure is less than or equal to 10 Kg/cm²And after solid particles in the waste acid water are filtered, the waste acid water is sent to a waste sulfuric acid water pretreatment storage tank for later use. The filtered solid particle organic waste is contained in bags for hazardous waste treatment.

S2: extracting 49m from mother liquor pool to be purified³Adding magnesium sulfate mother liquor into a reaction kettle, starting the reaction kettle, stirring, controlling 24 revolutions per minute, then adding 5.6 tons of magnesium oxide powder (the content is 90 percent), opening an acid adding valve, sending the waste acid water filtered in the step S1 into the reaction kettle for neutralization reaction, adding acid until the acid is large and small, measuring the pH value by using B-wide test paper until the pH value of a reaction solution is 6.5-7, controlling the concentration of the magnesium sulfate solution after the reaction to be 41-42 Baume degrees, controlling the solution temperature to be 98-100 ℃, and controlling the total amount of the reaction solution to be about 65m³。

S3: the reaction solution from the S2 step is flocculated and settled with anionic polyacrylamide to separate solid impurities (such as silt) from the solution, such as magnesium oxide. The method comprises the following specific operations: 1) at a rate of 1.25g/m³And (3) weighing 82g of anionic polyacrylamide with molecular weight larger than 800 ten thousand to prepare 0.1% diluted solution. 2) And (3) small trial: 2000ml of the reaction solution is dripped into the prepared polyacrylamide solution for several drops until the solution on the upper layer is transparent and has no suspended particles. When the pH value of the solution is higher, adding proper acid water; when the pH value is lower, a proper amount of magnesium oxide is added to finely adjust the pH value of the solution until the reaction solution is optimally settled. 3) After the pilot scale is qualified, the reaction kettle is stirred for 24 timesAnd (3) rotating/min, adding the prepared polyacrylamide solution into the reaction kettle, continuing stirring for 15 min, and stopping stirring.

S4, standing the reaction solution flocculated and settled in the step S3 for 30-60min, fully settling, and extracting 15m in batches³And (3) flocculating and separating organic impurities of the reaction solution in the separation tank from the reaction solution with the upper layer flocculated and settled, wherein the temperature of the solution is controlled to be not less than 75 ℃:

1) preparation of a coagulant: at normal temperature, the polyferric sulfate is prepared into the specific gravity of 1.6g/cm³Aqueous solution, 4m³(ii) a Preparing polyaluminium sulfate into the specific gravity of 1.35-1.4g/cm at normal temperature³Aqueous solution, 5m³。

2) Small experiments confirm the coagulant dosage ratio: taking 800ml of solution after flocculation sedimentation in a 1000ml beaker, adding the polymeric ferric sulfate aqueous solution with stirring at the speed of 120 revolutions per minute by using a glass rod, observing the change until a solid is just separated out, stopping adding the polymeric ferric sulfate aqueous solution, recording the addition amount (such as 13ml), continuing stirring, simultaneously adding the polymeric aluminum sulfate aqueous solution until the separated solid is agglomerated, and recording the addition amount (such as 29 ml).

3) Determining the addition of the coagulant in the solution of the separating tank according to the ratio of the two coagulants in the pilot plant, adding the coagulant in the pilot plant step, firstly controlling the stirring speed to be 24 r/min, and adding 0.244m of polymeric ferric sulfate solution³(phi 1000 metering barrel is descended by 310 mm and is high); then the stirring speed is adjusted to 14 r/min, and polyaluminium sulfate solution with the thickness of 0.550m is added³(phi 1000 measuring tank is lowered by 700 mm and is high).

4) After the coagulant is added, the stirring speed is controlled to be 10 revolutions per minute, the stirring is stopped for 20 to 25 minutes after the stirring is continued for 5 minutes, and at the moment, the solution is below and the solid oily matter is coagulated on the solution;

5) discharging the solution from a discharge valve at the bottom of the separation tank while the solution is hot (the temperature is not less than 60 ℃), sending the solution to a cooling crystallization tank, cooling and crystallizing the solution to 35-40 ℃, carrying out crystallization for 12 hours, and then carrying out centrifugation and solid-liquid separation. The mother liquid obtained by centrifugation is purified mother liquid, and the magnesium sulfate mother liquid is separately placed in another mother liquid pool and can be used for the subsequent magnesium sulfate production. The chroma is reduced from more than 5000 times to less than 150 times before treatment; the COD value is reduced from more than 30000mg/L to less than 250mg/L before treatment. And the solid magnesium sulfate enters subsequent procedures for treatment.

6) And finally discharging the upper oily organic waste from the bottom, filling the oily organic waste into a basin, cooling to normal temperature, and filling the oily organic waste into a bag after solidification for hazardous waste treatment.

7) The final bottom of the reaction kettle is about 5m³Washing the sediment with proper amount of clear water, press-filtering with a plate frame, returning the filtrate to the mother liquor pool to be treated, and retreating together with the mother liquor to be treated. And (4) carrying out chemical analysis on filter residues, carrying out general solid waste treatment when the filter residues meet the general solid waste standard, and otherwise, carrying out dangerous waste solid treatment.

8) And (3) purifying all mother liquor by the same method, recovering the normal requirement of the mother liquor, and recycling the mother liquor in the recovery and production of the magnesium sulfate heptahydrate from the waste sulfuric acid water of the 2-ethyl anthraquinone.

The baume in the specification is a method of indicating the concentration of a solution. The baume gravimeter is immersed in the solution to be measured, and the degree obtained is called baume degree.

There are two types of baume gravimeters: a weighing scale for measuring liquids heavier than water; another is called a light gauge, which is used to measure liquids that are lighter than water. When the baume degree is measured, the mass percentage concentration of the solution can be conveniently checked from a comparison table of a corresponding chemical manual. For example, the baume degree of concentrated sulfuric acid measured at 15 ℃ is 66 ° baume, and a table look up indicates that the sulfuric acid concentration is 98% by mass.

The Baume degree value is large, the reading is convenient, so the Baume degree is commonly used for expressing the concentration of the solution in production (the solution with certain concentration has certain density or specific gravity).

The determination method of baume degree of different solutions is similar, and all the methods are that the specific gravity is determined, and the concentration is converted by looking up the table according to the determined specific gravity. At present, the Baume tables of different solutions are special, such as an alcohol Baume table and a saline Baume table, the concentration of the solution of the type corresponding to the Baume degree of the measured solution is arranged on the Baume table, and the reading can be directly carried out without table lookup.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.