CN101555053B

CN101555053B - Compound coagulant used for treating rare-earth highly concentrated ammonian wastewater to recover industry ammonium chloride and treatment method

Info

Publication number: CN101555053B
Application number: CN2008100273450A
Authority: CN
Inventors: 黄海明; 肖贤明; 晏波
Original assignee: 中国科学院广州地球化学研究所
Priority date: 2008-04-11
Filing date: 2008-04-11
Publication date: 2011-02-09
Also published as: CN101555053A

Abstract

The invention provides a compound coagulant used for treating rare-earth highly concentrated ammonian wastewater to recover industry ammonium chloride and a treatment method, belonging to the technical field of chemical environment protection and resource recovery. The compound coagulant is a mixed liquor of ammonium oxalate, ammonium sulphate, heavy metal precipitator DTCR and polyacrylamide (PAM). The treatment method for treating wastewater by using the compound coagulant comprises the following steps: firstly, oil substances in the wastewater are removed through a separation tank and an air floating chamber; secondly, the wastewater enters a pH adjusting precipitation tank to adjust the pH value to be 7.5-8.5; thirdly, the wastewater enters a coagulative precipitation tank, the compound coagulant is added, the wastewater after being coagulated and precipitated enters the pH adjusting precipitation tank to adjust the pH value to be 2.5-4, the wastewater after being adjusted the pH value enters an active carbon filter tower to be absorbed and filtered and then is evaporated and concentrated under the condition of negative pressure. The compound coagulant has simple treatment method, low cost and good effect. The treatment method has short process and simple and easy treatment, not only solves the problem of the pollution of the highly concentrated ammonian wastewater, but also achieves the purpose of recovering valuable materials.

Description

A kind of compound coagulant and treatment process that can be used for handling rare-earth highly concentrated ammonia nitrogen waste water recovery industrial grade ammonium chloride

Technical field

The present invention relates to a kind of coagulating agent and treatment process that can be used for handling rare-earth highly concentrated ammonia nitrogen waste water recovery industrial grade ammonium chloride, belong to chemical industry environmental protection and resource recovery technology field.

Background technology

Rare-earth wet method is smelted and is adopted extraction process to carry out each component separation, this technology need have a large amount of alkali lye to participate in reaction, consider the production cost problem, present most enterprise all adopts ammoniacal liquor to carry out saponification, and the waste water that is produced will be if not treated direct discharging will bring extremely serious ammonia and nitrogen pollution to the water body that is entered.The ammonia nitrogen waste water of high density is the emphasis and the difficult point of rare-earth smelting business processes, at present more at the treatment process of such waste water, at home and abroad present stage can be used to handle the ripe of ammonia nitrogen waste water and is in the technology and the method in research and development stage and mainly contains: evaporative crystallization method, reverse osmosis desalination, electrodialysis, soil irrigation; Kinds more than ten such as air stripping (or steam stripping), chemical precipitation method, breakpoint chlorination, emulsion film adsorption method of separation, absorption, ion exchange method, senior catalytic oxidation, hypergravity denitrogenation, biochemical treatment process, but can really be used for having only of industrial application very few several.

Because the wastewater property difference of different process section discharging is big in the rare-earth smelting, it is low that ammonia nitrogen concentration has height to have.According to ammonia nitrogen in waste water concentration, can be divided into three kinds of different concns waste water: greater than the intermediate concentration ammonia nitrogen waste water of the high-concentration ammonia nitrogenous wastewater (rare earth soap waste water, carbon ammonium precipitation mother liquor) of 10000mg/L, 500-10000mg/L with less than the low-concentration ammonia-nitrogen waste water of 500mg/L.It is the most economically viable adopting the evaporative crystallization method for the ammonia nitrogen waste water greater than the 10000mg/L high density, and water treatment at home and abroad of evaporative crystallization method and chemical industry are widely applied, and technology maturation is reliable.

Adopt the evaporative crystallization method to reclaim ammonium salt (ammonium chloride), can offset the equipment working cost, but owing to oils and extraction agent in the waste water, other foreign matter contents such as heavy metal are many, evaporative crystallization after adopting traditional hydro-oxidation sodium as precipitation agent removal heavy metal, though can remove most of heavy metal, but also introduced sodium simultaneously, reduced product purity, the quality and the sale of reclaiming ammonium salt product have been had a strong impact on, if adopt the ammoniacal liquor neutralization because the pH value can only be adjusted to 9～10 at most, counterweight metal impurities poor removal effect, the product that reclaims preferably can only be accomplished agricultural rank, and the agricultural grade ammonium chloride price of selling on the market only be technical grade half, therefore impurity in the reduction waste water in preprocessing process how, making and can be recovered to industrial grade ammonium chloride behind evaporative crystallization will be the treatment process that has economic benefit.

Summary of the invention

An object of the present invention is to provide a kind of compound coagulant of removing impurity such as heavy metal in the rare-earth highly concentrated ammonia nitrogen waste water.

Another object of the present invention provides a kind of this compound coagulant that uses and handles the treatment process that rare-earth highly concentrated ammonia nitrogen waste water reclaims industrial grade ammonium chloride, has not only reached the purpose of processing waste water but also reclaimed valuable resource.

Purpose of the present invention is achieved by the following technical solutions: compound coagulant is the mixed solution of ammonium oxalate, ammonium sulfate, heavy metal precipitator DTCR and polyacrylamide (PAM).By four kinds of medicament weight proportions promptly: it is soluble in water that ammonium oxalate: ammonium sulfate: DTCR: PAM=0.6～3: 0.4～1.5: 1: 0.01～0.03 takes by weighing medicament, mixing and stirring then is mixed with four kinds of medicament total mass concentrations and is 3.5%～10% mixed solution.Contain more oils and extraction agent in the rare-earth highly concentrated ammonia nitrogen waste water, heavy metal element and calcium ion, use this compound coagulant to handle waste water, ammonium oxalate provides the calcium ion in the oxalate denominationby precipitation waste water, ammonium sulfate provides sulfate ion to remove the barium ion in the waste water, the powerful chelating of DTCR and heavy metal ion, generate insolubles, can form good flocculation, so that sedimentation is quick, reach the purpose of removing heavy metal ion, polyacrylamide forms " bridging " between the particle that is adsorbed, generate bigger floc sedimentation, helps effectively adsorb organic compound of particulate sinking and energy.

Do not bring other impurity into for making when handling waste water, the heavy metal precipitator DTCR in the compound coagulant among the present invention is: chelate group-NH-CSSNH ₄Pattern.

Use the treatment process and the step of compound coagulant processing waste water reclamation industrial grade ammonium chloride as follows:

A, rare-earth highly concentrated ammonia nitrogen waste water at first enter oil trap, make that the bigger oil droplet of particle rises to the surface in oil slick in the RE waste water and the dispersed oil, by the Oil scraper frizing to reach the purpose of removing oil slick, waste water enters gas-floating chamber then, by oil in water emulsion and the trickle suspended solid of hydrophobicity in the air supporting removal waste water.

B, the waste water after oil removing enter the pH regulator settling tank, and adding concentration then and be 25%～30% strong aqua in waste water, to regulate pH be 7.5～8.5, again to every m ³Add 1～2g PAM stirring reaction, 10～15min in the waste water, leave standstill 35～50min, the shore pipe of the mud of generation at the bottom of the pond discharged, and supernatant liquor and mud filtrate enter coagulative precipitation tank.

C, in the coagulative precipitation tank by every m ³Add 3～15L compound coagulant in the waste water, stir 5～10min fast, leave standstill 30～40min after stirring 10～15min at a slow speed then, the shore pipe of the mud that produces at the bottom of the pond discharged, supernatant liquor and mud filtrate enter the pH regulator pond, and adding mass concentration then and be 30%～38% concentrated hydrochloric acid in waste water, to regulate pH be 2.5～4.

D, the waste water after regulating pH enter active carbon filter tower again, and the control filtering velocity is 3～5m/h, and heavy metal and the micro-oily substance of remnants enter evaporating and crystallizing tower evaporation concentration under condition of negative pressure again through the waste water after the activated carbon treatment in absorption and the filtered wastewater.

Beneficial effect of the present invention:

The compound coagulant treatment process of using among a, the present invention is simple, expense is low, can accomplish under the situation of contents of many kinds of heavy metal ion coexistence after primary treatment, to make various heavy metal ions in waste water and calcium ion reach denier, though to the salt of heavy metal complexing (as NH ₃) also can play one's part to the full, and have that flocs unit is thick, precipitation is fast, dehydration is fast, aftertreatment is easy, sludge quantity is few and it is nontoxic to stablize, do not bring other impurity into, do not have characteristics such as secondary public hazards to waste water.

Treatment process technical process among b, the present invention is short, handle simple, waste water after this method is handled is after the ammonium chloride that evaporative crystallization reclaims can reach the technical grade qualified product, obtain great economic profit with less cost, not only solved the high-concentration ammonia nitrogenous wastewater pollution problems, simultaneously also reclaim valuable substance, realized high economic benefit and environmental benefit.

Description of drawings

Fig. 1 is to use the compound coagulant among the present invention to handle the schematic flow sheet that rare-earth highly concentrated ammonia nitrogen waste water reclaims the treatment process of industrial grade ammonium chloride.

Embodiment

Further describe technical scheme of the present invention below in conjunction with embodiment, protection scope of the present invention is not limited to following embodiment.

Compound coagulant embodiment is as follows:

Embodiment 1

Take by weighing 600g gram ammonium oxalate, 200g ammonium sulfate, 200g heavy metal precipitator DTCR and 3g PAM respectively, be dissolved in successively then in the 13L water, the preparation total mass concentration is 7.1% compound coagulant after constantly mixing.

Embodiment 2

Take by weighing 450g gram ammonium oxalate, 150g ammonium sulfate, 200g heavy metal precipitator DTCR and 2g PAM respectively, be dissolved in successively then in the 13L water, the preparation total mass concentration is 5.8% compound coagulant after constantly mixing.

Using compound coagulant to handle rare-earth highly concentrated ammonia nitrogen waste water, to reclaim the embodiment of treatment process of industrial grade ammonium chloride as follows:

Compound coagulant numbering to above-mentioned two application examples make is followed successively by No. 1 compound coagulant, No. 2 compound coagulants, and sewage is handled.Waste water is taken from rare earth soap waste water and the carbon ammonium precipitation mother liquor in certain rare-earth smelting factory, and its water quality characteristics is as follows:

Table 1 rare earth soap waste water quality (pH=0.47, [Cl ^-]=96800mg/L, unit are mg/L)

?NH ₄ ⁺	Oils	Ca ²⁺	Na ⁺	Al ³⁺	Mn ²⁺	Cu ²⁺	Zn ²⁺	Pb ²⁺	Ba ²⁺	Cr ³⁺	Ni ²⁺
												?48050	1580.5	200	42	56.3	24	3.7	17	67.8	242	1.6	2.1

Table 2 carbon ammonium precipitation mother liquor water quality (pH=6.47, [Cl ^-]=27730mg/L, unit are mg/L)

?NH ₄ ⁺	Oils	Ca ²⁺	Na ⁺	Al ³⁺	Mn ²⁺	Cu ²⁺	Zn ²⁺	Pb ²⁺	Ba ²⁺	Cr ³⁺	Ni ²⁺
												?13152	80.5	0.3	18.6	16.3	0.5	2.7	36	0.18	0.9	2.1	2

Embodiment 3

A, get 1m ³Rare earth soap waste water at first enters the inclined plate grease pond, retention time of sewage is 2.5h, make that the bigger oil droplet of particle rises to the surface in oil slick in the RE waste water and the dispersed oil, wipe the upper strata oil slick off, waste water enters the jetting type gas-floating chamber then, remove oil in water emulsion and the trickle suspended solid of hydrophobicity in the waste water by air supporting, this step is handled back oils and extraction agent content is 80mg/L.

B, the waste water after oil removing enter the pH regulator settling tank, adding 16L concentration then and be 30% strong aqua in waste water, to regulate pH be 8, in waste water, add 1.5g PAM stirring reaction 15min again, leave standstill 40min, the shore pipe of the mud that produces at the bottom of the pond discharged, and supernatant liquor and mud filtrate enter coagulative precipitation tank.

C, add No. 1 compound coagulant of 13L in the coagulative precipitation tank, stir 10min fast, leave standstill 40min after stirring 15min at a slow speed then, the shore pipe of the mud that produces at the bottom of the pond discharged, supernatant liquor and mud filtrate enter the pH regulator pond, and adding the 7L mass concentration then and be 35% concentrated hydrochloric acid in waste water, to regulate pH be 3.

D, the waste water after regulating pH enter active carbon filter tower again, and the control filtering velocity is 3m/h, and heavy metal and the micro-oily substance of remnants enter evaporating and crystallizing tower evaporation concentration under condition of negative pressure again through the waste water after the activated carbon treatment in absorption and the filtered wastewater.Gained distilled water ammonia nitrogen concentration is 13.5mg/L, and gained ammonium chloride amount is 150kg, and quality sees Table 3.

Table 3 gained ammonium chloride analytical data

The industrial grade ammonium chloride index name	Acceptable end product	Salable product	Gained ammonium chloride
				Ammonium chloride (NH ₄Cl) content (in butt), %, 〉=	99.3	99.0	99.1
Moisture, % ,≤	0.7	1.0	-
				Ignition residue, % ,≤	0.4	0.4	0.38
Iron (Fe) content, % ,≤	0.001	0.003	0.0025
				Heavy metal (in Pb) content, % ,≤	0.0005	0.001	0.0008
Vitriol is (with SO ₄) content, % ,≤	0.02	-	0.01
				PH value (200g/L solution, 25 ℃ of temperature)	4.0～5.8	4.0～5.8	4.9

Embodiment 4

A, press actual waste water amount (4: 1) the preparation 1m of rare earth soap waste water and carbon ammonium precipitation mother liquor ³Composite waste at first enters the inclined plate grease pond, retention time of sewage is 2.5h, make that the bigger oil droplet of particle rises to the surface in oil slick in the waste water and the dispersed oil, wipe the upper strata oil slick off, waste water enters the jetting type gas-floating chamber then, remove oil in water emulsion and the trickle suspended solid of hydrophobicity in the waste water by air supporting, this step is handled back oils and extraction agent content is 73mg/L.

B, the waste water after oil removing enter the pH regulator settling tank, adding 13L concentration then and be 30% strong aqua in waste water, to regulate pH be 8.05, in waste water, add 1.5g PAM stirring reaction 15min again, leave standstill 40min, the shore pipe of the mud that produces at the bottom of the pond discharged, and supernatant liquor and mud filtrate enter coagulative precipitation tank.

C, add No. 2 compound coagulants of 13L in the coagulative precipitation tank, stir 10min fast, leave standstill 40min after stirring 15min at a slow speed then, the shore pipe of the mud that produces at the bottom of the pond discharged, supernatant liquor and mud filtrate enter the pH regulator pond, and adding the 5.7L mass concentration then and be 35% concentrated hydrochloric acid in waste water, to regulate pH be 3.1.

D, the waste water after regulating pH enter active carbon filter tower again, and the control filtering velocity is 3m/h, and heavy metal and the micro-oily substance of remnants enter evaporating and crystallizing tower evaporation concentration under condition of negative pressure again through the waste water after the activated carbon treatment in absorption and the filtered wastewater.Gained distilled water ammonia nitrogen concentration is 10.5mg/L, and gained ammonium chloride amount is 135kg, and quality sees Table 4.

Table 4 gained ammonium chloride analytical data

The industrial grade ammonium chloride index name	Acceptable end product	Salable product	Gained ammonium chloride
				Ammonium chloride (NH ₄Cl) content (in butt), %, 〉=	99.3	99.0	99.2
Moisture, % ,≤	0.7	1.0	-
				Ignition residue, % ,≤	0.4	0.4	0.35

Iron (Fe) content, % ,≤	0.001	0.003	0.0015
				Heavy metal (in Pb) content, % ,≤	0.0005	0.001	0.0008
Vitriol is (with SO ₄) content, % ,≤	0.02	-	0.02
				PH value (200g/L solution, 25 ℃ of temperature)	4.0～5.8	4.0～5.8	4.3

Claims

1. one kind is used to handle the compound coagulant that rare-earth highly concentrated ammonia nitrogen waste water reclaims industrial grade ammonium chloride, it is characterized in that: this compound coagulant is the mixed solution of ammonium oxalate, ammonium sulfate, heavy metal precipitator DTCR and polyacrylamide (PAM), by four kinds of medicament weight proportions promptly: it is soluble in water that ammonium oxalate: ammonium sulfate: DTCR: PAM=0.6～3: 0.4～1.5: 1: 0.01～0.03 takes by weighing medicament, mixing and stirring then is mixed with four kinds of medicament total mass concentrations and is 3.5%～10% mixed solution.

2. one kind is used the described compound coagulant of claim 1 to handle the treatment process that rare-earth highly concentrated ammonia nitrogen waste water reclaims industrial grade ammonium chloride, it is characterized in that:

A, rare-earth highly concentrated ammonia nitrogen waste water at first enter oil trap, make that the bigger oil droplet of particle rises to the surface in oil slick in the RE waste water and the dispersed oil, by the Oil scraper frizing to reach the purpose of removing oil slick, waste water enters gas-floating chamber then, by oil in water emulsion and the trickle suspended solid of hydrophobicity in the air supporting removal waste water;

B, the waste water after oil removing enter the pH regulator settling tank, and adding concentration then and be 25%～30% strong aqua in waste water, to regulate pH be 7.5～8.5, again to every m ³Add 1～2g PAM stirring reaction, 10～15min in the waste water, leave standstill 35～50min, the shore pipe of the mud of generation at the bottom of the pond discharged, and supernatant liquor and mud filtrate enter coagulative precipitation tank;

C, in the coagulative precipitation tank by every m ³Add 3～15L compound coagulant in the waste water, stir 5～10min fast, leave standstill 30～40min after stirring 10～15min at a slow speed then, the shore pipe of the mud that produces at the bottom of the pond discharged, supernatant liquor and mud filtrate enter the pH regulator pond, and adding mass concentration then and be 30%～38% concentrated hydrochloric acid in waste water, to regulate pH be 2.5～4;

3. according to claim 1 being used to handled the compound coagulant that rare-earth highly concentrated ammonia nitrogen waste water reclaims industrial grade ammonium chloride, and it is characterized in that: the heavy metal precipitator DTCR in the compound coagulant is: chelate group-NH-CSSNH ₄Pattern.