AU2020294218A1

AU2020294218A1 - Method for intensive recovery of valuable components from rare earth tailings

Info

Publication number: AU2020294218A1
Application number: AU2020294218A
Authority: AU
Inventors: Zhen Hu; Hanwen LI; Peilun Li; Qiang Li; Xianyang Qiu; Chenghang WANG; Tai WANG; Kaizhi YANG; Yanqing YAO; Jianjian ZOU
Original assignee: Institute Of Resources Comprehensive Utilization Guangdong Academy Of Sciences
Current assignee: Institute Of Resources Comprehensive Utilization Guangdong Academy Of Sciences
Priority date: 2019-10-14
Filing date: 2020-06-30
Publication date: 2021-04-29
Anticipated expiration: 2040-06-30
Also published as: CN110624685B; AU2020294218B2; WO2021073162A1; CN110624685A

Abstract

The present invention relates to a method for intensive recovery of valuable components from rare earth tailings. The method includes the following steps: Si. magnetic separation and enrichment of a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing; S2. leaching and recovery of molybdenum to obtain a molybdate solution and a leached residue; S3. gravity separation and flotation of the rare earth to obtain a rare earth concentrate and a flotation rare earth tailing; S4. leaching of lead to obtain a lead-containing solution; S5. flotation of barium to obtain a barite concentrate and a barite flotation tailing. The invention achieves effective enrichment and intensive recovery of useful components of rare earth, molybdenum, lead, and barium through a low-intensity magnetic separation and a high-intensity magnetic separation, laying a good foundation for subsequent centralized recovery; adopts the leaching to recover molybdenum, associates the gravity separation with the flotation, to achieve the effective recovery of rare earth minerals and to obtain rare earth concentrates with a high grade and recovery; adopts the leaching to recover lead, and the flotation to recover barium from the leached residue, to effectively comprehensively recover co-associated useful components of rare earth, lead, molybdenum, and barium in rare earth tailings, turning waste into treasure, having a good effect on emission reduction and realizing a change of solid waste into resources.

Description

METHOD FOR INTENSIVE RECOVERY OF VALUABLE COMPONENTS FROM RARE EARTH TAILINGS

TECHNICAL FIELD The present invention relates to the technical field of beneficiation, and more specifically, relates to a method for intensive recovery of valuable components from rare earth tailings.

TECHNICAL BACKGROUND Rare earth as a strategic resource in industry, a rational development and utilization thereof has important research values. Although China is rich in rare earth resources, due to defects in production technologies and lack of knowledge of resources, a lot of waste is present in a process of self-exploitation and beneficiation of each rare earth ore, leading to a relatively low resource utilization rate. For example, main valuable associated minerals such as fluorite, barite, fine rare earth ores, and lead minerals, etc. in rare earth tailings are largely surplus, which have a quite high grade and great utilization values. A Chinese patent with publication No. CN104096633A discloses a beneficiation technology for comprehensive recovery and utilization of resources from a rare earth tailing, which is used to achieve the comprehensive recovery of a rare earth concentrate, an iron concentrate, a sulfur concentrate, a niobium concentrate and a scandium concentrate from rare earth separation tailings of polymetallic paragenetic mineral deposit containing rare earth, iron, niobium, sulfur, fluorite and scandium, in which a technology of recovery of the rare earth concentrate is given priority; a bulk flotation operation achieves grouping and sorting of easily floating minerals and iron, niobium and silicate minerals. A sedimentation of the grouping and sorting adopts a technology of sulfur and iron separation-gravity separation-secondary sulfur and iron separation, where the gravity separation achieves a purpose of early discarding of tailings, and finally achieves the flotation separation of ferroniobium, and iron, sulfur and niobium concentrates are obtained; a fluorite concentrate is obtained by fine grinding and flotation of a mixed foam; a scandium concentrate is obtained by a high-intensity magnetic separation of a niobium separation tailing. Although the method of this invention effectively recovers part of valuable components, the technology is relatively complicated, and an energy consumption of the fine grinding in the fluorite flotation technology is relatively high, increasing a production cost. WANG Guo-xiang, et al. (Discussion on Comprehensive Utilization of Rare Earth Tailings in Maoniuping, Mianning County, Sichuan Province, Resources Environment & Engineering, 2007(5): 624-628) conducted an exploration experiment on the recovery and utilization of valuable components of rare earth tailings in Maoniuping, which adopted once rough separation and twice fine separation to select a mixture concentrate of barite and fluorite, and then four times fine separation to select a barite concentrate and a fluorite concentrate with the test results of a fluorite grade 98.30% with a recovery 75.86%, a barite grade 82.50% with a recovery 75.86%. Although barite is recovered in this method, a variety of valuable components (such as molybdenum, lead, etc.) are still not effectively recovered. QIU Xue-ming (Beneficiation Technology of a Rare Earth Ore in Sichuan, Nonferrous Metals Engineering, 2015(5), 46-49) reported a beneficiation method for a rare earth ore with a raw ore REO grade 6.62%, in which a main rare earth mineral is bastnaesite and gangue minerals are mainly fluorite, barite and quartz. A table-flotation technology is adopted for beneficiation, and a grinding fineness of -0.07 mm accounts for 60%. A table concentrate with a REO grade 63.68% and a recovery 47.43%, and a flotation concentrate with a REO grade 60.37% and a recovery 39.25% are finally obtained, and a comprehensive recovery of the rare earth ore is 86.68%. Although this method has certain improvements over original rare earth indicators, it still has large room for improvement, and direct use of table beneficiation has problems of management and maintenance inconvenience in actual production, and there are still many valuable components to be recovered.

SUMMARY A purpose of the present invention is to overcome the defect and shortcoming that beneficiation methods in the prior art cannot achieve effective comprehensive recovery of co-associated components of rare earth, lead, molybdenum and barium from rare earth tailings, and to provide a method for intensive recovery of valuable components in rare earth tailings. The method of the present invention achieves effective comprehensive recovery of co-associated components of rare earth, lead, molybdenum and barium from rare earth tailings, turning waste into treasure, having a good effect on emission reduction and realizing a change of solid waste into resources. To achieve the purpose of the present invention, the present invention adopts the following solutions: A method for intensive recovery of valuable components from rare earth tailings, includes the following steps: Si. magnetic separation and enrichment: performing a low-intensity magnetic separation on a rare earth tailing sample to obtain a magnetite and a low-intensity magnetically separated tailing; performing a high-gradient wet magnetic separation on the low-intensity magnetically separated tailing to obtain a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing; S2. leaching and recovery of molybdenum: adjusting a liquid-solid ratio of the high-intensity magnetically separated concentrate to 2:1-5:1, adding a molybdenum leaching agent, leaching at 80-96°C, and then washing and filtering, to obtain a molybdate solution and a leached residue; an added amount of the molybdenum leaching agent is 90-150 g/t; S3. gravity separation and flotation of rare earth: after a classification of the leached residue, performing a table gravity separation, to obtain a gravity-separated concentrate and a table tailing; performing a flotation on the table tailing to obtain a rare earth concentrate and a flotation rare earth tailing; S4. leaching of lead: grinding the high-intensity magnetically separated concentrate till a fineness of -0.074 mm accounts for 60-75%, de-sliming to obtain a lead-containing slime and a sediment; adjusting a liquid-solid ratio of the lead-containing slime to 1:1-3:1, adding a lead leaching agent, leaching at 40-70°C, and filtering, to obtain a lead-containing solution; an added amount of the lead leaching agent is 30-200 g/t; S5. flotation of barium: adjusting a mash concentration of the sediment to 30-45%, in sequence adding a regulator and a collector to perform a flotation closed circuit process: once rough separation, then four times fine separation, three times scavenging, and sequential return of a middling, to obtain a barite concentrate and a barite flotation tailing; the added amount of the regulator is 200-1000 g/t; an added amount of the collector is 20-60 g/t; The invention achieves effective enrichment and intensive recovery of useful components of rare earth, molybdenum, lead, and barium through a low-intensity magnetic separation and a high-intensity magnetic separation, laying a good foundation for subsequent centralized recovery; adopts the leaching to recover molybdenum, associates the gravity separation with the flotation, to achieve the effective recovery of rare earth minerals and to obtain rare earth concentrates with a high grade and recovery; adopts the leaching to recover lead and the flotation to recover barium from the leached residue, to effectively comprehensively recover co-associated useful components of rare earth, lead, molybdenum, and barium in rare earth tailings, turning waste into treasure, having a good effect on emission reduction and realizing a change of solid waste into resources. Preferably, a background magnetic field strength selected for the low-intensity magnetic separation in Si is 0.1-0.2 T. Preferably, a background magnetic field strength selected for the high-gradient wet magnetic separation in S Iis 0.9-1.4 T.

Preferably, before performing the low-intensity magnetic separation on the rare earth tailing sample in Si, a step of grinding to a fineness of -1.0 mm to 0.7 mm is further included. More preferably, the grinding is performed till the fineness of -1.0 mm. Any conventional leaching agents for leaching molybdenum and lead in the art can be used in the present invention. Preferably, the molybdenum leaching agent in S2 is one or more of sodium hydroxide and sodium sulfide. Preferably, the leaching in S2 lasts for 0.5-3 hours. Preferably, the lead leaching agent in S4 is one or more of nitric acid and hydrochloric acid. Any conventional regulators and collectors in the art can be used in the present invention. Preferably, the regulator in S5 is water glass. More preferably, a modulus of the water glass in S5 is 2.0-3.0. Preferably, the collector in S5 is one or more of oxidized paraffin soap and sodium octadecenoate. Preferably, the valuable components are rare earth, molybdenum, lead and barium. Compared with the prior art, the present invention has the following beneficial effects: The invention achieves effective enrichment and intensive recovery of useful components of rare earth, molybdenum, lead, and barium through a low-intensity magnetic separation and a high-intensity magnetic separation, laying a good foundation for subsequent centralized recovery; adopts the leaching to recover molybdenum, associates the gravity separation with the flotation, to achieve the effective recovery of rare earth minerals and to obtain rare earth concentrates with a high grade and recovery; adopts the leaching to recover lead and the flotation to recover barium from the leached residue, to effectively comprehensively recover co-associated useful components of rare earth, lead, molybdenum, and barium in rare earth tailings, turning waste into treasure, having a good effect on emission reduction and realizing a change of solid waste into resources.

DETAILED DESCRIPTION The present invention will be further explained hereinafter in conjunction with embodiments. These embodiments are only used to illustrate the present invention but not used to limit the scope of the present invention. In the following embodiments, the experimental methods without specific conditions are usually in accordance with the conventional conditions in the art or in accordance with the conditions recommended by the manufacturer; the used raw materials, reagents, etc., unless otherwise specified, are commercially available raw materials and reagents, such as from conventional markets, etc.. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection claimed by the present invention. Embodiment 1 This embodiment provides a method for intensive recovery of valuable components from rare earth tailings, which specific process is as follows. A rare earth tailing from a certain place in China was selected, which main mineral compositions are bastnaesite, barite, and fluorite, etc.. The raw ore (the rare earth tailing) with a molybdenum grade 0.13%, a barite grade 23.71%, and a lead grade 0.69%, was ground to -1.0 mm, a low-intensity magnetic separation under a background magnetic field strength of 0.1 T was performed, and a magnetite and a low-intensity magnetically separated tailing were obtained; a high-gradient wet magnetic separation was performed on the low-intensity magnetically separated tailing under a background magnetic field strength of 1.0 T, and a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing were obtained. A liquid-solid ratio of the high-intensity magnetically separated concentrate was adjusted to 5:1, 90 grams of sodium hydroxide as a leaching agent were added per ton of ore feed, leaching was performed for 1.5 hours at a temperature of 90°C, and then washing and filtration were performed, and a sodium molybdate solution and a leached residue were obtained. After classification of the leached residue, a 6S type table was adopted to obtain a gravity separation rare earth concentrate and a table tailing; grinding was no longer performed on the table tailing, and a conventional rare earth flotation method was directly adopted to obtain a flotation rare earth concentrate and a flotation rare earth tailing. A molybdenum-containing rare earth concentrate with a total recovery 86.44% and an average grade 7.7%, and a rare earth ore with a recovery 4.1% and a grade 23.87% were obtained in total. The high-intensity magnetically separated tailing was finely ground till a fineness of -0.074 mm accounted for 75%, and a hydrocyclone was adopted for a de-sliming operation, and a lead-containing slime and a sediment were obtained; a liquid-solid ratio of the lead-containing slime was adjusted to 1:1, 150 grams of nitric acid as a leaching agent were added per ton of ore feed, and leaching was performed under 1.5 hours of agitation at a temperature of 40°C, filtration was performed, and a lead-containing solution with a grade 54.59% and a recovery 15.37% was obtained. A mash concentration of the sediment was adjusted to 35%, 200 grams of water glass with a modulus of 2 as a regulator and 20 grams of oxidized paraffin soap as a collector were added in sequence per ton of ore feed to perform a flotation closed circuit process: once rough separation, then four times fine separation, three times scavenging, and sequential return of a middling, and a barite concentrate with a grade 90.19% and a recovery 70.81% and a barite flotation tailing were obtained. Through the whole process test, a rare earth middling with a recovery 4.1% and a grade 23.87%, a molybdenum-containing rare earth concentrate with a molybdenum grade 3.29% and a recovery 22.89%, and a lead-containing solution with a grade 54.59% and a recovery 15.37% can be obtained. Embodiment 2 This embodiment provides a method for intensive recovery of valuable components from rare earth tailings, which specific process is as follows. A rare earth tailing from a certain place in China was selected, which main mineral compositions are bastnaesite, barite, and fluorite, etc.. The raw ore (the rare earth tailing) with a molybdenum grade 0.15%, a barite grade 24.2%, and a lead grade 0. 7 1%, was ground to -1.0 mm, a low-intensity magnetic separation under a background magnetic field strength of 0.15 T was performed, and a magnetite and a low-intensity magnetically separated tailing were obtained; a high-gradient wet magnetic separation was performed on the low-intensity magnetically separated tailing under a background magnetic field strength of 1.2 T, and a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing were obtained. A liquid-solid ratio of the high-intensity magnetically separated concentrate was adjusted to 3:1, 100 grams of sodium sulfide as a leaching agent were added per ton of ore feed, leaching was performed for 2 hours at a temperature of 85°C, then washing and filtration were performed, and a sodium molybdate solution and a leached residue were obtained. After classification of the leached residue, a 6S type table was adopted to obtain a gravity separation rare earth concentrate and a table tailing; grinding was no longer performed on the table tailing, and a conventional rare earth flotation method was directly adopted to obtain a flotation rare earth concentrate and a flotation rare earth tailing. A molybdenum-containing rare earth concentrate with a total recovery 89.84% and an average grade 7.67%, and a rare earth ore with a recovery 4.13% and a grade 23.92% were obtained in total. The high-intensity magnetically separated tailing was finely ground till a fineness of -0.074 mm accounted for 70%, and a hydrocyclone was adopted for a de-sliming operation, and a lead-containing slime and a sediment were obtained; a liquid-solid ratio of the lead-containing slime was adjusted to 2:1, 200 grams of hydrochloric acid as a leaching agent were added per ton of ore feed, and leaching was performed under 2 hours of agitation at a temperature of 50°C, a filtration was performed, and a lead-containing solution with a grade 55.13% and a recovery 15.26% was obtained. A mash concentration of the sediment was adjusted to 40%, 250 grams of water glass with a modulus of 2.5 as a regulator and 30 grams of sodium octadecenoate as a collector were added in sequence per ton of ore feed to perform a flotation closed circuit process: once rough separation, then four times fine separation, three times scavenging, and sequential return of a middling, and a barite concentrate with a grade 91.32% and a recovery 76.1% and a barite flotation tailing were obtained. Through the whole process test, a rare earth middling with a recovery 4.13% and a grade 23.92%, a molybdenum-containing rare earth concentrate with a molybdenum grade 3.32% and a recovery 26.56%, and a lead-containing solution with a grade 55.13% and a recovery 15.26% can be obtained. Embodiment 3 This embodiment provides a method for intensive recovery of valuable components from rare earth tailings, which specific process is as follows. A rare earth tailing from a certain place in China was selected, which main mineral compositions are bastnaesite, barite, and fluorite, etc.. The raw ore (the rare earth tailing) with a molybdenum grade 0.12%, a barite grade 22.6%, and a lead grade 0.65%, was ground to -1.0 mm, a low-intensity magnetic separation under a background magnetic field strength of 0.2 T was performed, and a magnetite and a low-intensity magnetically separated tailing were obtained; a high-gradient wet magnetic separation was performed on the low-intensity magnetically separated tailing under a background magnetic field strength of 1.4 T, and a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing were obtained. A liquid-solid ratio of the high-intensity magnetically separated concentrate was adjusted to 4:1, 120 grams of a mixture of sodium hydroxide and sodium sulfide with a mass ratio of 1:1 as a leaching agent was added per ton of ore feed, leaching was performed for 2.5 hours at a temperature of 95°C, then washing and filtration were performed, and a sodium molybdate solution and a leached residue were obtained. After a classification of the leached residue, a 6S type table was adopted to obtain a gravity separation rare earth concentrate and a table tailing; a grinding was no longer performed on the table tailing, and a conventional rare earth flotation method was directly adopted to obtain a flotation rare earth concentrate and a flotation rare earth tailing. A molybdenum-containing rare earth concentrate with a total recovery

91.94% and an average grade 6.8%, and a rare earth ore with a recovery 4.2% and a grade 24.01% were obtained in total. The high-intensity magnetically separated tailing was finely ground utill a fineness of -0.074 mm accounted for 65%, and a hydrocyclone was adopted for a de-sliming operation, and a lead-containing slime and a sediment were obtaiend; the liquid-solid ratio of the lead-containing slime was adjusted to 3:1, 200 grams of a mixture of nitric acid and hydrochloric acid with a mass ratio of 1:2 as a leaching agent was added per ton of ore feed, and leaching was performed under 3 hours of agitation at a temperature of 60C, filtration was performed, and a lead-containing solution with a grade 54.82% and a recovery 15.41% was obtained. A mash concentration of the sediment was adjusted to 45%, 300 grams of water glass with a modulus of 3 as a regulator and 40 grams of a mixture of oxidized paraffin soap and sodium octadecenoate with a mass ratio of 1:1 as a collector were added in sequence per ton of ore feed to perform a flotation closed circuit process: once rough separation, then four times fine separation, three times scavenging, and sequential return of a middling, and a barite concentrate with a grade 86.93% and a recovery 74.62% and a barite flotation tailing were obtained. Through the whole process test, a rare earth middling with a recovery 4.2% and a grade 24.01%, a molybdenum-containing rare earth concentrate with a molybdenum grade 3.12% and a recovery 29.9%, and a lead-containing solution with a grade 54.82% and a recovery 15.41% can be obtained. The method of the invention achieves effective comprehensive recovery of co-associated useful components of rare earth, lead, molybdenum, and barium in rare earth tailings, turning waste into treasure, having a good effect on emission reduction and realizing a change of solid waste into resources.

The above-mentioned are specific example implementations of the present invention. For those skilled in the art, without departing from the principle of the present invention, several improvements and rhetoric can be made. In fact, the scope of the present invention is defined by the appended claims and their equivalents.

Claims

What is claimed is:

1. A method for intensive recovery of valuable components from rare earth tailings, characterized in that, the method comprises the following steps: Si. magnetic separation and enrichment: performing a low-intensity magnetic separation on a rare earth tailing sample to obtain a magnetite and a low-intensity magnetically separated tailing; performing a high-gradient wet magnetic separation on the low-intensity magnetically separated tailing to obtain a high-intensity magnetically separated concentrate and a high-intensity magnetically separated tailing; S2. leaching and recovery of molybdenum: adjusting a liquid-solid ratio of the high-intensity magnetically separated concentrate to 2:1-5:1, adding a molybdenum leaching agent, leaching at 80-96°C, and then washing and filtering, to obtain a molybdate solution and a leached residue; an added amount of the molybdenum leaching agent is 90-150 g/t; S3. gravity separation and flotation of rare earth: after a classification of the leached residue, performing a table gravity separation, to obtain a gravity-separated concentrate and a table tailing; performing a flotation on the table tailing to obtain a rare earth concentrate and a flotation rare earth tailing; S4. leaching of lead: grinding the high-intensity magnetically separated concentrate till a fineness of -0.074 mm accounts for 60-75%, de-sliming to obtain a lead-containing slime and a sediment; adjusting a liquid-solid ratio of the lead-containing slime to 1:1-3:1, adding a lead leaching agent, leaching at 40-70°C, and filtering, to obtain a lead-containing solution; an added amount of the lead leaching agent is 30-200 g/t; S5. flotation of barium: adjusting a mash concentration of the sediment to 30-45%, in sequence adding a regulator and a collector to perform a flotation closed circuit process: once rough separation, then four times fine separation, three times scavenging, and sequential return of a middling, to obtain a barite concentrate and a barite flotation tailing; the added amount of the regulator is 200-1000 g/t; an added amount of the collector is 20-60 g/t.

2. The method according to claim 1, characterized in that, a background magnetic field strength selected for the low-intensity magnetic separation in S Iis 0.1-0.2 T.

3. The method according to claim 1, characterized in that, a background magnetic field strength selected for the high-gradient wet magnetic separation in Si is 0.9-1.4 T.

4. The method according to claim 1, characterized in that, the molybdenum leaching agent in S2 is one or more of sodium hydroxide and sodium sulfide.

5. The method according to claim 1, characterized in that, the leaching in S2 lasts for 0.5-3 hours.

6. The method according to claim 1, characterized in that, the lead leaching agent in S4 is one or more of nitric acid and hydrochloric acid.

7. The method according to claim 1, characterized in that, the regulator in S5 is water glass.

8. The method according to claim 7, characterized in that, a modulus of the water glass in S5 is 2.0-3.0.

9. The method according to claim 1, characterized in that, the collector in S5 is one or more of oxidized paraffin soap and sodium octadecenoate.

10. The method according to claim 1, characterized in that, the valuable components are rare earth, molybdenum, lead and barium.