CN102643987A

CN102643987A - Method for preparing rare earth by reducing ammonia nitrogen oxygen demand (COD) and adjusting potential of hydrogen (pH) value from rare earth mine leach liquor

Info

Publication number: CN102643987A
Application number: CN2012101443597A
Authority: CN
Inventors: 郑耀秋
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-05-09
Filing date: 2012-05-09
Publication date: 2012-08-22

Abstract

The invention relates to a method for preparing rare earth by reducing an ammonia nitrogen oxygen demand (COD) and adjusting a potential of hydrogen (pH) value from rare earth mine leach liquor, which is the method for preparing chloride rare earth products from the rare earth mine leach liquor by using lime milk or deposits and treats ammonia nitrogen, chemical oxygen demand (COD), the pH value and the like in dissolved ocyhydrate. The method can be used for environmental protection management, comprehensive utilization and the like, and has the advantages of being small in pollution, low in cost, free of secondary pollution, capable of achieving continuous operation and production and the like.

Description

A kind of ammonia nitrogen oxygen requirement (COD) that from the rare-earth mineral leach liquor, reduces is adjusted the method that the pH value is produced rare earth

Technical field

The invention belongs to methods such as chemical neutralization precipitation, clarification, cohesion, aeration, stripping, from the rare-earth mineral leach liquor, extract rare earth and make rare earth chloride liquid.Be particularly related to from the re dip solution of low concentration of rare earth element very and raffinate and extract rare earth, reduce ammonia nitrogen, heavy metal, suspended substance, SO ₄ ^2-Deng, the process method of adjustment pH value.

Background technology

China's rare-earth ore resource accounts for 36% reserves in the world; Particularly southern weathered superficial leaching rare-earth ore; It extensively is distributed in provinces and regions such as the southern Jiangxi of China, Guangdong, Fujian, Guangxi, Hunan, Yunnan and Hainan Island; And countries such as the Vietnam in South East Asia, Burma, be the weathered superficial leaching rare-earth ore that a kind of ion adsorption type constitutes, but that the weathered superficial leaching rare-earth ore leach liquor contain rare earth element concentration is low; Generally containing rare earth oxide concentration is 0.3g/L-10g/L, and to give off the ammonia nitrogen height, show acid, concentration be the humble rare earth waste liquid of 0.006g/L.

At present, the technology of extraction REE is from the lower concentration leach liquor of ionic adsorption rare earth mine: bicarbonate of ammonia or oxalic acid precipitation.And rare earth oxalate must calcination become rare earth oxide, after rare-earth smelting factory buys rare earth oxide and carbon ammonium rare earth, needs dissolving to produce rare earth chloride liquid and carries out the REE separation, and when the precipitating rare earth element, supernatant has a large amount of oxalates or ammonia nitrogen etc.

Though bicarbonate of ammonia belongs to chemical fertilizer, and bicarbonate of ammonia weak base medium precipitates, and causes the ammonia nitrogen of solution high density and forms water pollution and influence the basin, mine; Oxalic acid is poisonous, the waste water severe contamination water body and the ecotope of production.Jiangxi, Guangdong, Fujian, Guangxi etc. are all discharged waste water because of each rare-earth mineral and are flowed into reservoir and river course, cause fishes and shrimps dead, and the total crop failure of standing grain rice causes that the common people are discontented, produce dispute, and production cost is high.

Reported the employing organic extraction in addition and carried out the organic extraction rare earth from weathered superficial leaching type (ionic adsorption) rare-earth mineral leach liquor.But naphthenic acid is water-soluble big, and loss is serious, and in operating process; The impurity such as Fe2+, Al3+, Ca2+ of keeping under strict control, emulsification etc. easily, two-(2-ethylhexyl) phosphoric acid (P2O4) and 2-ethylhexyl phosphonic acid list (2-ethylhexyl) ester (P507) are made extraction agent simultaneously; Invest greatlyyer, fully little the and diffusing characteristic of incompatibility weathered superficial leaching (ionic adsorption) type rare-earth mineral ore deposit point is difficult in the mine application; And sour regurgitation equivalent concentration is high, and organic contamination is big.

Summary of the invention

Goal of the invention: the invention provides a kind of with Ca (OH) ₂Deng the basic cpd neutralization precipitation, process colloid hydrogen-oxygen rare earth, reduce ammonia nitrogen, COD (COD), heavy metal etc., use the process method of hydrochloric acid direct production rare earth chloride liquid again.

Technical scheme: will contain low concentration of rare earth element ore deposit leach liquor; Produce hydrolysis through the neutralization of control pH value; Produce colloid hydrogen-oxygen rare earth; Simultaneously degradation of ammonia nitrogen, COD (COD), suspended substance, heavy metal ion etc. make supernatant and waste water reach two, three grades of emission standards, simultaneously with colloid hydrogen-oxygen rare earth produce the process method of rare earth chloride liquid.

In the above-mentioned neutralization precipitation system; Utilize rare earth metal and other heavy metal in the precipitation of hydroxide hydrating solution; Add hydroxide solution control pH in the 7-11 scope, make it generate hydrogen-oxygen rare earth and oxyhydroxide metal, and with the free volatilization of the ammonia nitrogen in the leach liquor; Ammonia nitrogen in the reduction leach liquor and suspended substance etc., the present invention is suitable for re dip solution and contains the solution of rare earth concentration greater than 0.006g/L.

Technical process of the present invention is:

Leaching liquid is that 2.0-5.0% (weight percent) ammonium salt (1) injects rare earth mine filling liquid well; Carrying out the original place soaks ore deposit (2) and weathered superficial leaching type (ionic adsorption) rare-earth mineral and is replaced into rare earth mother solution leach liquor (3); Carry out the neutralization precipitation hydrolysis again; Through multistage neutralization clarification cohesion (4) (pH=9-11), the supernatant after the clarification (5) is through reaching two, three grades of emission standards dischargings (7) or dosings except that ammonia nitrogen, aeration, stripping (6); Through sizing mixing (9) with hydrochloric acid after multistage neutralization, the clarifying colloid rare earth compression (8), pre-treatment then, deposition (10) are carried out acid molten (11) with technical hydrochloric acid, make rare earth chloride liquid (12) again, and its concentration is greater than 1.2mol/L, RECl ₃(13) directly send into rare-earth smelting factory and further separate, pressing filtering liquid drains into the supernatant liquid pool.Assorted slag is high alumina, high calcium impurities, can be used as refractory materials and material of construction.

Beneficial effect:

1. adopt the neutralization precipitation hydrolysis method; Extraction agent and oxalic acid and carbon ammonium that need not be expensive have reduced secondary pollution, have reduced the increase of ammonia nitrogen and acid number; Direct production becomes rare earth chloride liquid M＞1.20mol/L; Not only saved rare earth oxalate and the calcination of carbon ammonium rare earth, and deducted the molten operation of smeltery's acid, production cost reduces.

The present invention select for use be prone to produce, inexpensive oxyhydroxide, for example Ca (OH) ₂, NaOH, KOH etc. are as the neutralization precipitation agent, form colloid hydrogen-oxygen rare earth.

3. neutralization precipitation adopts multistage neutralization, multistage clarification, and rare earth and heavy metal are formed the precipitation of hydroxide thing, and the recovery is more than 96%.

4. whole technological process is easy to operate, belongs to closed system, does not have contaminated wastewater and secondary pollution, is improving water quality, administers environment, protects ecological aspect to have meliority.The acid regulation and control of leach liquor pH in the 7-9 scope, is made ammonia nitrogen, and COD (COD), suspended substance, heavy metal ion descend, and water quality reaches secondary discharge standard, and rare earth yield is more than 96%.Neutralization-clarification, cohesion-backflow-technological operations such as aeration-stripping are stablized, and be easy to control, makes things convenient for continuous production.

Description of drawings

Fig. 1 is a process flow sheet of the present invention

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is elaborated:

Instance 1:

Monoammonium sulfate solution with 2.0% is as leaching agent 1; Raw ore is carried out in the rare earth mine soak ore deposit 2; Leach liquor 3 contains rare earth oxide 3.65g/L, aluminium for rare earth mother solution: lead 0.75%: 0.02g/L, calcium: 0.25g/L, copper: 0.015g/L, ammonia nitrogen: 325mg/L.pH:4.8, COD (COD): 120mg/L, through neutralization precipitation, cohesion, clarification, remove technologies such as ammonia nitrogen, backflow, aeration, stripping; The discharging supernatant detects rare earth concentration: 0.001g/L; Each heavy metal all is a trace; The pH:8.5 ammonia nitrogen: the whole technology rare earth yield of 30mg/L. COD (COD): 25mg/L is greater than 96%, and water conditioning reaches two, three grades of emission standards of country.Simultaneously, utilize the hydrogen-oxygen rare earth to produce rare earth chloride liquid C _RE: 154.54～176.46g/L, proportion: 1.28g/mL Al ₂O ₃: 1.5g/L, can directly get into rare-earth smelting factory extracting and separating, reduced the mine rare earth calcination operation molten with acid, reduced production cost.

Instance 2:

Weathered superficial leaching type (ionic adsorption) rare-earth mineral is carried out the original place deposit impregnating technology; Use 5.0% ammonium chloride solution to be leaching agent 1; Leach liquor 3 contains about rare earth concentration 6.8g/L, aluminium: 0.85g/L, lead: 0.02g/L, copper: 0.02g/L, pH:5, ammonia nitrogen: 252g/L, COD (COD): 115g/L, through neutralization precipitation hydrolysis, multistage cohesion, remove technologies such as ammonia nitrogen, backflow, aeration, stripping, supernatant discharging dosing; Detecting each heavy metal of rare earth concentration 0.001g/L. is trace; PH:9.1, ammonia nitrogen: 25g/L, COD (COD): 30mg/L.Whole technology rare earth yield reaches more than 96%, and water quality gets to be improved, and reaches two, three grades of emission standards of country.Simultaneously, utilize the hydrogen-oxygen rare earth to produce rare earth chloride liquid C _RE: 154.54～176.46g/L, proportion: 1.28g/mL Al ₂O ₃: 1.5g/L, can directly get into rare-earth smelting factory extracting and separating, reduced the mine rare earth calcination operation molten with acid, reduced production cost.

China's weathered superficial leaching type (being ionic adsorption) rare-earth mineral spreads all over East China, south China and southwestern region, and south east asia also has in addition, takes the present invention to produce rare earth chloride; Promptly can reduce soil erosion, can improve the Rare Earth Production recovery again, improve the comprehensive utilization ratio of rare earth resources; Simultaneously, the one-stop water quality of improving has reduced environmental pollution widely; Do not have secondary pollution, keep the river unimpeded, the protection peripheral ecological environment; Reduce the production cost in rare earth mine, improved the competitive power of rare-earth products, have great application prospect, remarkable economic efficiency and important social meaning.

Claims

1. one kind is reduced the method that ammonia nitrogen oxygen requirement (COD) adjustment pH value is produced rare earth from the rare-earth mineral leach liquor; From the acidic solution that contains the above REE of lower concentration 0.006g/L, extract REE; And reduce ammonia nitrogen, COD (COD), heavy metal and the suspended substance etc. of leaching solution, the pH in the adjustment solution is through the multistage clarification of neutralization precipitation, aeration, stripping; Thereby obtain rare earth chloride liquid; Direct-furnish is smelted and separated, and reduces calcination oxidation and acid solution system material, it is characterized in that: the described acidic solution that contains the above rare earth of lower concentration 0.006g/L can be various leaching agents and leaches the weathered superficial leaching rare-earth ore leach liquor.Described neutralization precipitation system is to use basic cpd.Described neutralization precipitation is multi stage precipitation, multistage clarification, aeration, stripping, with the treated rare earth chloride liquid of processing of neutralization precipitation thing.

2. according to right 1 described method, it is characterized in that: the material of using in the described alkaline neutralization precipitation system is that industry is easy to get, the Ca (OH) of cheapness ₂, NaOH etc.