CN111392921A

CN111392921A - Comprehensive treatment process for coal washing wastewater and mine wastewater

Info

Publication number: CN111392921A
Application number: CN202010421873.5A
Authority: CN
Inventors: 范誉委; 解晖; 郭峰; 李�根; 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 process, which comprehensively treats common mine wastewater and coal washing wastewater in a coal mine, adjusts 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

Comprehensive treatment process for coal washing wastewater and mine wastewater

Technical Field

The invention belongs to the field of wastewater treatment, and particularly relates to a comprehensive treatment process 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 process 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 process which is characterized in that,

1. pretreating acid mine wastewater, and conveying the pretreated acid mine wastewater to a PRB system, wherein reaction materials in the PRB system comprise iron powder, zeolite, iron oxide and municipal digested sludge; the retention time of the acid mine wastewater in the PRB system is 24-120 h;

2. filtering the acidic mine wastewater treated by the PRB system, then carrying out disinfection treatment for discharging or recycling, taking out the reaction material in the PRB system, replacing the reaction material, placing the reaction material taken out into a negative pressure filter tank, and separating the water in the reaction material from the reaction material to obtain a reaction solution I;

3. adding a certain amount of acid mine wastewater and coal washing wastewater into the reaction solution I to mix; introducing air and/or ozone gas into the mixing reactor, and reacting under the stirring action of the stirrer;

4. conveying the liquid in the mixing reactor to a coagulation reactor, and adding PAM and lime into the coagulation reactor for coagulation and precipitation treatment; after coagulating sedimentation, separating to obtain solid waste and reaction liquid II;

5. and conveying the reaction liquid II to a coal washing process for recycling or carrying out filtering and disinfecting treatment for discharging.

Further, after the solid waste is dehydrated and dried, the solid waste is calcined and pressed into a porous material which is used as a reaction material in a PRB system;

further, the weight ratio of iron powder, zeolite, iron oxide and municipal digestion sludge in the reaction materials 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 reaction solution I, the acid mine wastewater and the coal washing wastewater in the step 3 is 1: 10-15: 50-100 parts of;

further, PAM is added firstly in the step 4, and then lime is added;

further, the PAM is a cationic and/or nonionic PAM solution, and the dosage of the PAM is 10-60 mg/L;

further, the lime is lime suspension with the concentration of 3-5%, and the dosage is 1.8-3.5 g/L;

further, the air and/or ozone gas is aerated by a microporous aerator; the gas-water ratio is 0.5-4;

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 process at least has the following advantages:

1. firstly, extra 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 wastewater₂15-25% of C, 10-15% of alumina, 3-5% of iron and the like, 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, the iron oxide and the SiO₂Forming a composite porous material, and adding the obtained porous material into a PRB system, not only can filter the wastewater, but also can filter the iron and aluminum oxides in the wastewater in the acidityUnder the action of the wastewater, the acidity of the acidic wastewater is reduced, aluminum ions and iron ions are dissociated, and a positive effect is generated on subsequent treatment.

Drawings

FIG. 1 is a flow chart of a comprehensive treatment process 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;

1. pretreating acid mine wastewater, and conveying the pretreated acid mine wastewater to a PRB system, wherein reaction materials in the PRB system comprise 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;

3. adding the reaction solution I and the acidic mine wastewater into the coal washing wastewater for mixing; introducing air and/or ozone gas into the mixing reactor, and reacting under the stirring action of the stirrer; the volume ratio of the reaction liquid I to the acid mine wastewater to the coal washing wastewater is 1: 10: 50; the gas-water ratio of the gas introduction is 2;

the volume ratio of the air to the ozone is 9: 1;

4. conveying the liquid in the mixing reactor to a coagulation reactor, adding PAM and lime into the coagulation reactor for coagulation precipitation treatment, and separating after the coagulation precipitation to obtain solid waste and a reaction liquid II, wherein 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 of the lime suspension is 1.8 g/L;

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 speed (mm/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 process is characterized in that (1) acid mine wastewater is pretreated, and the pretreated acid mine wastewater is conveyed to a PRB system, wherein reaction materials in the PRB system comprise iron powder, zeolite, iron oxide and municipal digestion sludge; the retention time of the acid mine wastewater in the PRB system is 24-120 h; (2) filtering the acidic mine wastewater treated by the PRB system, then carrying out disinfection treatment for discharging or recycling, taking out the reaction material in the PRB system, replacing the reaction material, placing the reaction material taken out into a negative pressure filter tank, and separating the water in the reaction material from the reaction material to obtain a reaction solution I; (3) adding a certain amount of acid mine wastewater and coal washing wastewater into the reaction solution I to mix; introducing air and/or ozone gas into the mixing reactor, and reacting under the stirring action of the stirrer; (4) conveying the liquid in the mixing reactor to a coagulation reactor, and adding PAM and lime into the coagulation reactor for coagulation and precipitation treatment; after coagulating sedimentation, separating to obtain solid waste and reaction liquid II; (5) and conveying the reaction liquid II to a coal washing process for recycling or carrying out filtering and disinfecting treatment for discharging.

2. The process of claim 1, wherein the solid waste is dehydrated, dried, calcined, and pressed into a porous material as a reactive material in the PRB system.

3. The process of claim 1, wherein the weight ratio of iron powder, zeolite, iron oxide, and municipal digestion sludge in the reactive materials in the PRB system is 1: 10-15: 2-3:20-30.

4. The process of claim 1, wherein the weight ratio of the amount of porous material added to the amount of zeolite added is 1-2: 2-3.

5. The process of claim 1, wherein the volume ratio of the reaction solution I, the acid mine wastewater and the coal washing wastewater in the step 3 is 1: 10-15: 50-100.

6. The process of claim 1 wherein PAM is added in step 4 followed by lime.

7. The process of claim 1, wherein the PAM is a cationic and/or nonionic PAM solution and the PAM is administered in an amount of from 10 to 60 mg/L.

8. The process of claim 1, wherein the lime is a lime suspension with a concentration of 3-5%, and the dosage is 1.8-3.5 g/L.

9. The process of claim 1, wherein the air and/or ozone gas is aerated using a micro-porous aerator; the gas-water ratio is 0.5-4.