A method for co-disposing electroplating waste liquid by cement kiln

Abstract

The present invention relates to the field of building materials, and specifically to a method for co-disposing electroplating waste liquid with a cement kiln, and belongs to the technical field of electroplating waste liquid treatment. Sodium carbonate solution is added to the electroplating waste liquid, and after stirring, it is pumped to a plate and frame filter press for filtration. A stepping feeder is used to feed the material into a rotary kiln pyrolysis device connected to the cement kiln for pyrolysis. The waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln. The residue generated by the pyrolysis is fed into a grate cooler from the tail end of the pyrolysis rotary kiln. After rapid quenching, the obtained material is mixed with limestone, shale, and tailings slag, and calcined to obtain cooked cement. The method adds chromium adsorption materials to effectively improve the recovery rate of chromium and related metal elements in the electroplating waste liquid, and realizes the transformation of electroplating wastewater into treasure and green and environmentally friendly treatment.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating waste liquid treatment, in particular to a method for co-disposing electroplating waste liquid with a cement kiln. Background Art

[0002] The sources of electroplating wastewater are generally: (1) water for washing plated parts; (2) waste electroplating liquid; (3) other wastewater, including water from washing workshop floors, washing plates, condensed water from ventilation equipment, and various tank liquids and drainage caused by leakage of plating tanks or improper operation and management; (4) equipment cooling water. The cooling water is not polluted except for the increase in temperature during use. The water quality and quantity of electroplating wastewater are related to factors such as the process conditions, production load, operation management and water use of electroplating production. The water quality of electroplating wastewater is complex and its composition is difficult to control. It contains heavy metal ions such as chromium, cadmium, nickel, copper, zinc, gold, silver, and cyanide, some of which are highly toxic substances that are carcinogenic, teratogenic, and mutagenic.

[0003] For example, Chinese patent CN103553249B discloses a method for acid separation and heavy metal recovery in electroplating waste liquid. The electroplating waste liquid first uses electrodialysis integrated technology to quickly separate the acid in the electroplating waste liquid. The selection of anionic and cationic membranes in the electrodialysis process can well separate the acid in the electroplating waste liquid, while the heavy metal ions still remain in the electroplating solution. The acidity of the separated acid entering the concentration tank can reach more than 4%, and can be used for electroplating or plated parts cleaning processes after recovery. The pH value of the treated electroplating waste liquid reaches more than 3. The low-acid electroplating waste liquid containing heavy metals can quickly recover the valuable heavy metals in the waste liquid by using hydrogen sulfide gas and jet process integrated technology. The heavy metal ions are precipitated and recovered in the form of sulfide. The recovery rate of heavy metal ions reaches more than 95%. The collected sulfide precipitate can be used as a raw material to recover the valuable metals therein. The electroplating waste liquid is separated and the heavy metal ions therein are recovered by acid, and the residual heavy metal ion wastewater is reused or discharged after treatment.

[0004] Another example is Chinese patent CN105601000B which discloses an acidic electroplating waste liquid purification system, comprising: a plurality of magnetic stirring bases arranged adjacent to each other, each of which can generate a magnetic field; a waste liquid storage tank; a sodium bicarbonate solution injection device, which comprises a sodium bicarbonate solution storage tank and an inverted L-shaped pipe; a filtering device; and a pH detector. The present invention first adds a sodium bicarbonate solution to the acidic electroplating waste liquid to obtain a treated neutral waste liquid, and by arranging a plurality of magnetic stirring bases, the waste liquid storage tank is divided into a plurality of storage spaces, a stirring magnet is placed in each storage space, and the liquid therein is stirred, so that the sodium bicarbonate solution is more evenly distributed in the acidic electroplating waste liquid, thereby promoting a rapid reaction between the two; and a M-shaped pipe is arranged, and three nozzles are arranged at intervals on the annular pipe, so that the sodium bicarbonate is sprayed more evenly, mixed more evenly with the acidic electroplating waste liquid, and the reaction effect is better.

[0005] However, the applicant believes that the above patents and prior art generally have problems of unsatisfactory operability and low adsorption efficiency, which in turn increases the treatment cost of electroplating waste liquid and is not conducive to market promotion. Summary of the invention

[0006] The present invention aims to solve the technical problem of low adsorption efficiency of electroplating waste liquid in the prior art, thereby providing a method for co-disposing electroplating waste liquid with a cement kiln.

[0007] The technical solution provided by the present invention is:

[0008] A method for co-disposing electroplating waste liquid in a cement kiln, the operating steps of which are as follows:

[0009] Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 20 to 30 minutes, pumping to a plate and frame filter press for filtration, and obtaining a material (a) having a water content of 30 to 40%;

[0010] Step 2: using a stepping feeder to feed material (a) into a rotary kiln pyrolysis device connected to a cement kiln, the head of the rotary kiln pyrolysis device is connected to the outside of the cement kiln secondary preheater, and the tail is connected to the cement kiln grate cooler; pyrolysis of material (a) is carried out in the rotary kiln in an atmosphere of isolating oxygen for 60 to 90 minutes, the waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln, and the residue generated by the pyrolysis is fed from the tail end of the pyrolysis rotary kiln into the grate cooler, and material (b) is obtained after rapid cooling;

[0011] Step 3: Send material (b) to the cement kiln raw material storage and mix it with limestone, shale and tailings.

[0012] Preferably, the addition ratio of sodium carbonate in step 1 is 10-20%.

[0013] Preferably, the filter pressure in step 1 is 5 to 10 kg / cm2 The filtration time is 30 to 40 minutes.

[0014] Preferably, the pyrolysis heat source in step 2 is 500-550 degree flue gas extracted from the secondary preheater of the cement kiln, and the flue gas volume is 3,000-6,000 cubic meters per hour.

[0015] Preferably, the quenching temperature in step 2 is 55 to 60 degrees.

[0016] Preferably, the proportion of material (b) in step 3 is 8-10%.

[0017] Preferably, in step 3, the chromium adsorption material is added in an amount of 0.03-0.2% of the mass percentage of the raw material, and the mixture is mixed by grinding.

[0018] Preferably, the chromium adsorption material preparation scheme is as follows:

[0019] S1: 100-120 parts of ZrCl4, 60-80 parts of 2,5-dimercaptoterephthalic acid and 1460-1580 parts of an organic solvent are mixed and then heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material;

[0020] S2: Then put it into 500-1000 parts of methyl pyrrolidone, add 4-7 parts of vinyl sulfone, 2-5 parts of triethanolamine, control the temperature at 50-60℃ and stir to react for 40-100 minutes, then add 0.05-0.3 parts of vinyl pyrrolidone, stir to react at 50-60℃ for 40-100 minutes, then add 300-400 parts of organic bentonite, control the temperature at 30-40℃ and stir to react for 10-30 minutes, after completion, filter and dry to obtain the chromium adsorption material.

[0021] Preferably, the organic solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide, chloroform, carbon tetrachloride, cyclohexane, acetone or acetonitrile.

[0022] Preferably, the S1 reaction temperature is 100-140° C., and the reaction time is 10-20 h.

[0023] The excellent effects of the present invention are:

[0024] (1) Electroplating sludge is a hazardous solid waste, which contains a large amount of heavy metals (such as Zn, Cr, Ni, Cu, etc.). Trivalent chromium and hexavalent chromium have great differences in volatility, leaching toxicity, etc. During the combustion process, CrOOH and CrO2(OH)2 are the main gaseous substances. The present invention effectively improves the recovery rate of chromium and related metal elements in electroplating waste liquid by preparing a chromium adsorption material.

[0025] (2) The present invention realizes the transformation of electroplating wastewater into valuables through the coordinated treatment of electroplating wastewater by cement kilns, and realizes green and environmentally friendly treatment. The metal elements are recovered after treatment, and the treated wastewater residue is mixed with limestone, shale, and tailings to obtain cement raw material, which is then calcined to obtain cement clinker. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The specific implementation scheme of the present invention detects the heavy metal content in solid waste according to HJ 766-2015 "Determination of Metal Elements in Solid Waste by Inductively Coupled Plasma Mass Spectrometry".

[0028] Original heavy metal content of electroplating sludge:

[0029] Cr Ni Cu Zn Heavy metal content / (mg / kg) 8919 6665 3514 13320

[0030] Example 1

[0031] A method for co-disposing electroplating waste liquid in a cement kiln, the operating steps of which are as follows:

[0032] Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 20 minutes, pumping to a plate and frame filter press for filtration, and obtaining a material (a) having a water content of 30%;

[0033] Step 2: using a stepping feeder to feed material (a) into a rotary kiln pyrolysis device connected to a cement kiln, the head of the rotary kiln pyrolysis device is connected to the outside of the secondary preheater of the cement kiln, and the tail is connected to the grate cooler of the cement kiln; pyrolysis of material (a) is carried out in the rotary kiln in an atmosphere of isolating oxygen for 60 minutes, the waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln, and the residue generated by the pyrolysis is fed from the tail end of the pyrolysis rotary kiln into the grate cooler, and material (b) is obtained after rapid cooling;

[0034] Step 3: Send material (b) to the cement kiln raw material storage and mix it with limestone, shale and tailings.

[0035] The addition ratio of sodium carbonate in step 1 is 10%.

[0036] The filter press pressure in step 1 is 5 kg / cm 2 , the filtration time is 40 minutes.

[0037] In the step 2, the pyrolysis heat source is 500-degree flue gas extracted from the secondary preheater of the cement kiln, and the flue gas volume is 3,000 cubic meters per hour.

[0038] The quenching temperature in step 2 is 55 degrees.

[0039] The proportion of material (b) in step 3 is 8%.

[0040] In the step 3, a chromium adsorption material is added in an amount of 0.05% of the raw material mass percentage, and the mixture is ground and mixed.

[0041] The preparation scheme of the chromium adsorption material is as follows:

[0042] S1: 100 kg ZrCl4, 60 kg 2,5-dimercaptoterephthalic acid and 1460 kg organic solvent are mixed and heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material;

[0043] S2: Then put it into 500kg of methyl pyrrolidone, add 4kg of vinyl sulfone and 2kg of triethanolamine, control the temperature at 50℃ and stir to react for 40min, then add 0.1kg of vinyl pyrrolidone, stir to react for 40min at 50℃, then add 300kg of organic bentonite, control the temperature at 30℃ and stir to react for 10min, after completion, filter press and dry to obtain the chromium adsorption material.

[0044] The organic solvent is selected from dimethylformamide.

[0045] The S1 reaction temperature is 100° C. and the reaction time is 10 h.

[0046] In this embodiment, after the electroplating waste liquid is treated:

[0047] Cr Ni Cu Zn Heavy metal content / (mg / kg) 171.8 121.1 63.3 199.8

[0048] Example 2

[0049] A method for co-disposing electroplating waste liquid in a cement kiln, the operating steps of which are as follows:

[0050] Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 25 minutes, and pumping to a plate and frame filter press for filtration to obtain a material (a) having a water content of 35%;

[0051] Step 2: using a stepping feeder to feed material (a) into a rotary kiln pyrolysis device connected to a cement kiln, the head of the rotary kiln pyrolysis device is connected to the outside of the cement kiln secondary preheater, and the tail is connected to the cement kiln grate cooler; oxygen is isolated in the rotary kiln to pyrolyze material (a), the pyrolysis time is 75 minutes, the waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln, and the residue generated by the pyrolysis is fed from the tail end of the pyrolysis rotary kiln into the grate cooler, and the material (b) is obtained after rapid cooling;

[0052] Step 3: Send material (b) to the cement kiln raw material storage and mix it with limestone, shale and tailings.

[0053] The addition ratio of sodium carbonate in step 1 is 15%.

[0054] The filter press pressure in step 1 is 8 kg / cm 2 , the filtration time is 35 minutes.

[0055] In step 2, the pyrolysis heat source is 520-degree flue gas extracted from the secondary preheater of the cement kiln, and the flue gas volume is 4,500 cubic meters per hour.

[0056] The quenching temperature in step 2 is 58 degrees.

[0057] The proportion of material (b) in step 3 is 9%.

[0058] In the step 3, a chromium adsorption material is added in an amount of 0.12% of the raw material mass percentage, and the mixture is ground and mixed.

[0059] The preparation scheme of the chromium adsorption material is as follows:

[0060] S1: 110 kg ZrCl4, 70 kg 2,5-dimercaptoterephthalic acid and 1520 kg organic solvent are mixed and heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material;

[0061] S2: Then put it into 750kg of methyl pyrrolidone, add 5kg of vinyl sulfone and 4kg of triethanolamine, control the temperature at 55°C and stir to react for 70min, then add 0.2kg of vinyl pyrrolidone, stir to react at 55°C for 75min, then add 350kg of organic bentonite, control the temperature at 35°C and stir to react for 20min, after completion, filter press and dry to obtain the chromium adsorption material.

[0062] The organic solvent is selected from dimethyl sulfoxide.

[0063] The reaction temperature of S1 is 120°C and the reaction time is 15h.

[0064] In this embodiment, after the electroplating waste liquid is treated:

[0065] Cr Ni Cu Zn Heavy metal content / (mg / kg) 165.2 103.8 62.4 171.5

[0066] Comparative Example 1

[0067] A method for co-disposing electroplating waste liquid in a cement kiln, the operating steps of which are as follows:

[0068] Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 20 minutes, pumping to a plate and frame filter press for filtration, and obtaining a material (a) having a water content of 30%;

[0069] Step 2: using a stepping feeder to feed material (a) into a rotary kiln pyrolysis device connected to a cement kiln, the head of the rotary kiln pyrolysis device is connected to the outside of the secondary preheater of the cement kiln, and the tail is connected to the grate cooler of the cement kiln; pyrolysis of material (a) is carried out in the rotary kiln in an atmosphere of isolating oxygen for 60 minutes, the waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln, and the residue generated by the pyrolysis is fed from the tail end of the pyrolysis rotary kiln into the grate cooler, and material (b) is obtained after rapid cooling;

[0070] Step 3: Send material (b) to the cement kiln raw material storage and mix it with limestone, shale and tailings.

[0071] The addition ratio of sodium carbonate in step 1 is 10%.

[0072] The filter press pressure in step 1 is 5 kg / cm 2 , the filtration time is 40 minutes.

[0073] In the step 2, the pyrolysis heat source is 500-degree flue gas extracted from the secondary preheater of the cement kiln, and the flue gas volume is 3,000 cubic meters per hour.

[0074] The quenching temperature in step 2 is 55 degrees.

[0075] The proportion of material (b) in step 3 is 8%.

[0076] In the step 3, a chromium adsorption material is added in an amount of 0.05% of the raw material mass percentage, and the mixture is ground and mixed.

[0077] The preparation scheme of the chromium adsorption material is as follows:

[0078] S1: 100 kg ZrCl4, 60 kg 2,5-dimercaptoterephthalic acid and 1460 kg organic solvent are mixed and heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material;

[0079] S2: Then put into 500kg methyl pyrrolidone and 2kg triethanolamine, stir and react at 50℃ for 40min, then add 0.1kg vinyl pyrrolidone, stir and react at 50℃ for 40min, then add 300kg organic bentonite, stir and react at 30℃ for 10min, filter press and dry after completion to obtain chromium adsorption material.

[0080] The organic solvent is selected from dimethylformamide.

[0081] The S1 reaction temperature is 100° C. and the reaction time is 10 h.

[0082] In this embodiment, after the electroplating waste liquid is treated:

[0083] Cr Ni Cu Zn Heavy metal content / (mg / kg) 331.4 254.6 107.8 424.1

[0084] Comparative Example 2

[0085] A method for co-disposing electroplating waste liquid in a cement kiln, the operating steps of which are as follows:

[0086] Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 20 minutes, pumping to a plate and frame filter press for filtration, and obtaining a material (a) having a water content of 30%;

[0087] Step 2: using a stepping feeder to feed material (a) into a rotary kiln pyrolysis device connected to a cement kiln, the head of the rotary kiln pyrolysis device is connected to the outside of the secondary preheater of the cement kiln, and the tail is connected to the grate cooler of the cement kiln; pyrolysis of material (a) is carried out in the rotary kiln in an atmosphere of isolating oxygen for 60 minutes, the waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln, and the residue generated by the pyrolysis is fed from the tail end of the pyrolysis rotary kiln into the grate cooler, and material (b) is obtained after rapid cooling;

[0088] Step 3: Send material (b) to the cement kiln raw material storage and mix it with limestone, shale and tailings.

[0089] The addition ratio of sodium carbonate in step 1 is 10%.

[0090] The filter press pressure in step 1 is 5 kg / cm 2 , the filtration time is 40 minutes.

[0091] In the step 2, the pyrolysis heat source is 500-degree flue gas extracted from the secondary preheater of the cement kiln, and the flue gas volume is 3,000 cubic meters per hour.

[0092] The quenching temperature in step 2 is 55 degrees.

[0093] The proportion of material (b) in step 3 is 8%.

[0094] In the step 3, a chromium adsorption material is added in an amount of 0.05% of the raw material mass percentage, and the mixture is ground and mixed.

[0095] The preparation scheme of the chromium adsorption material is as follows:

[0096] S1: 100 kg ZrCl4, 60 kg 2,5-dimercaptoterephthalic acid and 1460 kg organic solvent are mixed and heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material;

[0097] S2: Then put it into 500 kg of methyl pyrrolidone, add 4 kg of vinyl sulfone and 2 kg of triethanolamine, control the temperature at 50°C and stir to react for 80 minutes, then add 300 kg of organic bentonite, control the temperature at 30°C and stir to react for 10 minutes, after completion, filter press and dry to obtain the chromium adsorption material.

[0098] The organic solvent is selected from dimethylformamide.

[0099] The S1 reaction temperature is 100° C. and the reaction time is 10 h.

[0100] In this embodiment, after the electroplating waste liquid is treated:

[0101] Cr Ni Cu Zn Heavy metal content / (mg / kg) 304.5 211.8 117.9 398.8

[0102] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for co-disposing electroplating waste liquid in a cement kiln, characterized in that: The operation steps are: Step 1: adding sodium carbonate solution to the electroplating waste liquid, stirring for 20 to 30 minutes, pumping to a plate and frame filter press for filtration, and obtaining material a with a water content of 30 to 40%; Step 2: Use a stepping feeder to feed material a into a rotary kiln pyrolysis device connected to the cement kiln. The head of the rotary kiln pyrolysis device is connected to the outside of the secondary preheater of the cement kiln, and the tail is connected to the grate cooler of the cement kiln. Oxygen is isolated in the rotary kiln to pyrolyze material a for 60 to 90 minutes. The waste gas generated by the pyrolysis is incorporated into the tertiary air of the cement kiln. The residue generated by the pyrolysis is fed into the grate cooler from the tail end of the pyrolysis rotary kiln, and material b is obtained after rapid cooling. Step 3: Send material b to the raw material warehouse of cement kiln and mix it with limestone, shale and tailings to obtain raw material c; Step 4: transporting the raw material c to a rotary kiln and calcining it at 1200-1400° C. to obtain cooked cement; In the step 3, a chromium adsorption material is added in an amount of 0.03-0.2% of the raw material mass percentage, and the mixture is ground and mixed; The preparation scheme of the chromium adsorption material is as follows: S1: 100 parts of ZrCl4, 60 parts of 2,5-dimercaptoterephthalic acid and 1460 parts of an organic solvent are mixed and then heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material; S2: Then put it into 500 parts of methyl pyrrolidone, add 4 parts of vinyl sulfone and 2 parts of triethanolamine, stir and react at 500°C for 40 minutes, then add 0.05 parts of vinyl pyrrolidone, stir and react at 50°C for 40 minutes, then add 300 parts of organic bentonite, stir and react at 30°C for 10 minutes, filter and dry after completion, and then obtain the chromium adsorption material; The organic solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide, chloroform, carbon tetrachloride, cyclohexane, acetone or acetonitrile; The reaction temperature of S1 is 100-140°C and the reaction time is 10-20h; or S1: 110 parts of ZrCl4, 70 parts of 2,5-dimercaptoterephthalic acid and 1520 parts of an organic solvent are mixed and then heated to react. After the reaction is completed, the solid and liquid are separated, and the solid is washed and dried to obtain an organic metal material; S2: Then put it into 750 parts of methyl pyrrolidone, add 5 parts of vinyl sulfone and 4 parts of triethanolamine, control the temperature at 55°C and stir to react for 70 minutes, then add 0.2 parts of vinyl pyrrolidone, stir to react for 75 minutes at 55°C, then add 350 parts of organic bentonite, control the temperature at 35°C and stir to react for 20 minutes, filter press and dry after completion, and then obtain the chromium adsorption material; The organic solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide, chloroform, carbon tetrachloride, cyclohexane, acetone or acetonitrile; The S1 reaction temperature is 100-140° C., and the reaction time is 10-20 h.

2. The method for co-disposal of electroplating waste liquid by cement kiln according to claim 1, characterized in that: The addition ratio of sodium carbonate in step 1 is 10-20%.

3. The method for co-disposal of electroplating waste liquid by cement kiln according to claim 1, characterized in that: In the step 1, the filtration pressure of the filter press is 5 to 10 kg / cm2, and the filtration time is 30 to 40 minutes.

4. The method for co-disposal of electroplating waste liquid by cement kiln according to claim 1, characterized in that: In step 2, the pyrolysis heat source is the 500-550 degree flue gas extracted from the cement kiln secondary preheater, and the flue gas volume is 3,000-6,000 cubic meters per hour.

5. The method for co-disposal of electroplating waste liquid by cement kiln according to claim 1, characterized in that: The quenching temperature in step 2 is 55 to 60 degrees.

6. The method for co-disposal of electroplating waste liquid by cement kiln according to claim 1, characterized in that: The proportion of material b in step 3 is 8-10%.