CN111392922A

CN111392922A - Coal washing wastewater and mine wastewater comprehensive treatment system

Info

Publication number: CN111392922A
Application number: CN202010421875.4A
Authority: CN
Inventors: 范誉委; 解晖; 万华凯; 张蒙; 刘旋
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2020-07-10

Abstract

The invention discloses a coal mine coal washing wastewater and mine wastewater comprehensive treatment system, which comprehensively treats common mine wastewater and coal washing wastewater in a coal mine, regulates the coal washing wastewater through the acidity of waste and mine wastewater after the mine wastewater treatment, greatly improves the medicament hydrolysis performance after adding acid wastewater, greatly reduces the PAM adding amount in the prior art by a colloid system capable of breaking negative charges in an oxidation environment, reduces the wastewater treatment cost and improves the wastewater recovery rate.

Description

Coal washing wastewater and mine wastewater comprehensive treatment system

Technical Field

The invention belongs to the field of wastewater treatment, and particularly relates to a comprehensive treatment system for coal washing wastewater and mine wastewater of a coal mine.

Background

The raw coal mined from the underground contains a large amount of impurities and ash, and if the raw coal is directly combusted, the waste of coal resources is caused, and the pollution of the atmosphere is also aggravated. Therefore, coal dressing is an essential link in the coal mining and processing processes. In China, coal is mostly selected by a wet separation method, 1t of raw coal needs 3-5 cubic meters of circulating water, and clear water is continuously supplemented, then wastewater containing a large amount of fine particles is generated, and the coal washing water containing suspended particles with the particle size smaller than 1mm is generally called coal washing wastewater.

In the process of coal mining, a large amount of water permeates into a mining space to form coal mine water or mine wastewater, the water quality of the wastewater has the characteristics of high mineralization degree, high hardness, high acidity and the like, and particularly when coal seams and surrounding rocks thereof contain reduced sulfides such as pyrite and the like, the original reducing environment can be damaged in the process of coal mining, the coal seams are exposed in the air, the sulfide minerals originally in the strong reducing environment are subjected to a series of physicochemical reactions such as oxidation, hydrolysis and the like under the action of microorganisms, the mine water is acidic, and the iron concentration in the acidic mine wastewater can reach hundreds of mg/L.

The water shortage phenomenon of key coal mines in northern China is very serious, and the normal life of mine production and coal mine workers is severely restricted. The mine water utilization technology level in China is low, and the process technologies such as coagulation, precipitation, filtration, disinfection, reverse osmosis and the like are generally adopted. The coal washing wastewater treatment system has large investment and production cost, and some coal yards only adopt simple processes such as gravity concentration or gravity precipitation, and the quality of treated water is difficult to ensure.

Because the coal washing wastewater and the mine wastewater have unique characteristics, such as alkalinity of the coal washing wastewater and acidity of the mine wastewater, the coal washing wastewater and the mine wastewater are not comprehensively treated aiming at the characteristics in the prior art, so that a large amount of reagents are wasted, and the treatment efficiency is low.

Disclosure of Invention

The invention aims to provide a comprehensive treatment system for coal washing wastewater and mine wastewater.

The purpose of the invention is realized by adopting the following technical scheme:

the invention discloses a coal washing wastewater and mine wastewater comprehensive treatment system, which comprises a pretreatment device 2, a PRB system 4, a negative pressure filter 6, a mixing reactor 8, a coagulation reaction system 13 and a secondary sedimentation tank 14, wherein an acid mine water inlet pipe 1 is arranged on the pretreatment device 2 to introduce acid mine water for pretreatment, the pretreatment device 2 is connected with a PRB water collecting tank 3, the PRB water collecting tank 3 is communicated with the PRB system 4, and a water outlet weir 5 is arranged at the upper part of the PRB system and used for discharging wastewater treated by the PRB system; PRB system bottom intercommunication negative pressure filtering pond 6, PRB system operation after the definite time, send into the filter material in the PRB system in the negative pressure filtering pond 6, the negative pressure filtering pond will through negative pressure treatment moisture solid-liquid separation in the filter material obtains filtrating, filtrating gets into through 7 transport of filtrating conveyer pipe in the mixed

reactor

8, 8 tops of mixed reactor set up coal washing waste water inlet tube 9, 8 bottoms of mixed reactor are provided with acid mine

non-tax conveyer pipe

10, 8 intercommunication coagulation reaction system 13 of mixed reactor, the coagulation reaction system top is provided with the dosing pipe, coagulation reaction system 13 intercommunication two heavy ponds 14 carry out solid-liquid separation.

Further, the solid waste obtained after the solid-liquid separation in the secondary sedimentation tank 14 is dehydrated and dried, and then calcined and pressed into a porous material, which is used as a filter material in a PRB system.

Further, the weight ratio of iron powder, zeolite, iron oxide and municipal digestion sludge in the filter material in the PRB system is 1: 10-15: 2-3:20-30.

Further, the weight ratio of the adding amount of the porous material to the adding amount of the zeolite is 1-2: 2-3.

Further, the volume ratio of the filtrate to the acid mine wastewater to the coal washing wastewater in the mixing reactor is 1: 10-15: 50-100.

Further, the dosing pipe comprises a PAM dosing pipe 11 and a lime dosing pipe 12.

Further, the medicament added by the PAM adding pipe is PAM, the PAM is a cationic and/or nonionic PAM solution, and the dosage of the PAM is 10-60 mg/L.

Furthermore, lime added into the lime dosing pipe is lime suspension with the concentration of 3-5%, and the dosage is 1.8-3.5 g/L.

Further, an aeration device is arranged at the bottom of the mixing reactor, aeration gas of the aeration device is air and/or ozone, and the air and/or ozone are aerated by adopting a microporous aerator; the gas-water ratio is 0.5-4.

Furthermore, the filter materials are packed by a net bag, and a mechanical arm is arranged at the bottom of the PRB system close to the side surface of the negative pressure filter 6, and the net bag is taken out from the PRB system and thrown into the negative pressure filter;

further, the calcination pressing is carried out in a calcination furnace, and the sintering temperature in the calcination furnace is 1250-1800 ℃.

The coal washing wastewater and mine wastewater comprehensive treatment system at least has the following advantages:

1. additional alkaline materials (such as lime or phosphate and the like) in the prior art are not added into the PRB system, so that the operation cost is reduced;

2, the reaction solution after PRB system treatment contains a large amount of iron ions and acidic substances; after the reaction liquid treated by the PRB system is mixed with the coal washing wastewater, the alkalinity of the coal washing wastewater is greatly reduced, the subsequent PAM hydrolysis performance is improved while the waste is prepared by the waste, and the adding amount of the PAM is solved;

3. the notification that the mine wastewater is acidic and the acidity in the coal washing wastewater is reduced can play a role in catalytic oxidation due to the fact that the mine wastewater contains a large amount of iron ions and manganese ions, and the notification that the manganese ions are oxidized under the condition of introducing oxygen and ozone can play a role in catalytic oxidation, generated free radicals have a strong catalytic effect on organic matters in the coal washing wastewater, and the COD content in the wastewater is reduced;

4. because the coal washing wastewater is alkaline, small particle substances in a water body can be aggregated together, and the surfaces of particles have negative charges, so that a large amount of PAM (polyacrylamide) is difficult to hydrolyze during adding, and a large amount of medicament is wasted;

5. SiO with oil content of about 40 percent in solid waste obtained by coagulating sedimentation of coal washing wastewater₂About 15-25% of C, about 10-15% of alumina, about 3-5% of iron and the like, and when the carbon is sintered at high temperature, a large amount of porous structures are generated in the process of forming carbon dioxide at high temperature, and the alumina,Iron oxide and SiO₂The composite porous material is formed, and the obtained porous material is added into a PRB system, so that the wastewater can be filtered, the acidity of the acidic wastewater is reduced by iron and aluminum oxides under the action of the acidic wastewater, aluminum and iron ions are dissociated, and a positive effect on subsequent treatment can be achieved.

Drawings

FIG. 1 is a schematic view of a comprehensive treatment system for coal washing wastewater and mine wastewater.

Detailed Description

The present invention is further described in detail below with reference to examples so that those skilled in the art can practice the invention with reference to the description.

It will be understood that terms such as "having," "including," and "comprising," when used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Example 1

The water quality of a certain coal mine water is 2.84 of pH value, 693 mg/L of SS and 230 mg/L of Fe;

the water quality of coal washing wastewater of a certain coal mine has the pH value of 8.45, the SS of 69.198 g/L and the COD of 24245638 mg/L;

by adopting the coal washing wastewater and mine wastewater comprehensive treatment system disclosed in the application, the system comprises a pretreatment device 2, a PRB system 4, a negative pressure filter 6, a mixing reactor 8, a coagulation reaction system 13 and a secondary sedimentation tank 14, wherein the pretreatment device 2 is provided with an acid mine water inlet pipe 1 for introducing acid mine water for pretreatment, the pretreatment device 2 is connected with a PRB water collecting tank 3, the PRB water collecting tank 3 is communicated with the PRB system 4, and the upper part of the PRB system is provided with a water outlet weir 5 for discharging wastewater treated by the PRB system; PRB system bottom intercommunication negative pressure filtering pond 6, PRB system operation after the definite time, send into the filter material in the PRB system in the negative pressure filtering pond 6, the negative pressure filtering pond will through negative pressure treatment moisture solid-liquid separation in the filter material obtains filtrating, filtrating gets into through 7 transport of filtrating conveyer pipe in the mixed

reactor

8, 8 tops of mixed reactor set up coal washing waste water inlet tube 9, 8 bottoms of mixed reactor are provided with acid mine non-tax

conveyer pipe

The filter material in the PRB system comprises iron powder, zeolite, iron oxide and municipal digested sludge; the retention time of the acidic mine wastewater in the PRB system is 48 h; the weight ratio of iron powder, zeolite, iron oxide and municipal digestion sludge in the reaction materials in the PRB system is 1: 12: 2:25, filtering the acidic mine wastewater treated by the PRB system, and then carrying out disinfection treatment for discharging or recycling;

after the solid waste obtained after the solid-liquid separation of the secondary sedimentation tank 14 is dehydrated and dried, the solid waste is calcined and pressed into a porous material which is used as a filter material in a PRB system, the calcination and the pressing are carried out in a calciner, the sintering temperature in the calciner is 1650 ℃, and the weight ratio of the addition amount of the porous material to the addition amount of zeolite is 2: 3;

the volume ratio of the filtrate to the acid mine wastewater to the coal washing wastewater is 1: 10: 50; the gas-water ratio of the gas introduction is 2, and the volume ratio of the air to the ozone is 9: 1;

the PAM is a cationic PAM solution, the dosage of the PAM is 20 mg/L, the lime is lime suspension with the concentration of 5%, and the dosage is 1.8 g/L;

and (4) conveying the effluent of the secondary sedimentation tank to a coal washing process for recycling or carrying out filtering and disinfecting treatment for discharging.

Example 2

The quality of the mine water and the quality of the coal washing wastewater are the same as those of the example 1;

the experimental conditions were the same as in example 1;

the dosage of PAM is changed to 10 mg/L, 30 mg/L, 40 mg/L and 50 mg/L.

PAM dosage (mg/L)	Sinking velocity (m)m/s)	SS(mg/L)
			10	0.146	189
20	0.163	168
			30	0.212	98
40	0.220	95
			50	0.206	107

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable to various fields of endeavor for which the invention may be embodied with additional modifications as would be readily apparent to those skilled in the art, and the invention is therefore not limited to the details given herein and to the embodiments shown and described without departing from the generic concept as defined by the claims and their equivalents.

Claims

1. A coal washing wastewater and mine wastewater comprehensive treatment system is characterized by comprising a pretreatment device 2, a PRB system 4, a negative pressure filter 6, a mixing reactor 8, a coagulation reaction system 13 and a secondary sedimentation tank 14, wherein the pretreatment device 2 is provided with an acid mine water inlet pipe 1 for introducing acid mine water for pretreatment, the pretreatment device 2 is connected with a PRB water collecting tank 3, the PRB water collecting tank 3 is communicated with the PRB system 4, and the upper part of the PRB system is provided with a water outlet weir 5 for discharging wastewater treated by the PRB system; PRB system bottom intercommunication negative pressure filtering pond 6, PRB system operation after the definite time, send into the filter material in the PRB system in the negative pressure filtering pond 6, the negative pressure filtering pond will through negative pressure treatment moisture solid-liquid separation in the filter material obtains filtrating, filtrating gets into through 7 transport of filtrating conveyer pipe in the mixed reactor 8, 8 tops of mixed reactor set up coal washing waste water inlet tube 9, 8 bottoms of mixed reactor are provided with acid mine non-tax conveyer pipe 10, 8 intercommunication coagulation reaction system 13 of mixed reactor, the coagulation reaction system top is provided with the dosing pipe, coagulation reaction system 13 intercommunication two heavy ponds 14 carry out solid-liquid separation.

2. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein the solid waste obtained after the solid-liquid separation in the secondary sedimentation tank 14 is dehydrated, dried, calcined and pressed into porous material as the filter material in PRB system.

3. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein the weight ratio of iron powder, zeolite, iron oxide and municipal digested sludge in the filter material in the PRB system is 1: 10-15: 2-3:20-30.

4. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein the weight ratio of the addition amount of the porous material to the addition amount of the zeolite is 1-2: 2-3.

5. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein the volume ratio of the filtrate, the acidic mine wastewater and the coal washing wastewater in the mixing reactor is 1: 10-15: 50-100.

6. The integrated coal washing wastewater and mine wastewater treatment system of claim 1, wherein the dosing pipes comprise a PAM dosing pipe 11 and a lime dosing pipe 12.

7. The comprehensive treatment system for the coal washing wastewater and the mine wastewater as claimed in claim 6, wherein the PAM dosing pipe is filled with PAM, the PAM is a cationic and/or nonionic PAM solution, and the dosage of the PAM is 10-60 mg/L.

8. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 6, wherein the lime added into the lime adding pipe is lime suspension with the concentration of 3-5%, and the dosage is 1.8-3.5 g/L.

9. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein an aeration device is arranged at the bottom of the mixing reactor, aeration gas of the aeration device is air and/or ozone, and the air and/or ozone is aerated by a microporous aerator; the gas-water ratio is 0.5-4.

10. The comprehensive treatment system for coal washing wastewater and mine wastewater as claimed in claim 1, wherein the filter material is packed by a net bag, and a mechanical arm is arranged at the bottom of the PRB system close to the side surface of the negative pressure filter 6, so that the net bag is taken out from the PRB system and thrown into the negative pressure filter.