AU2021254543B2 - Green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag - Google Patents
Green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag Download PDFInfo
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- AU2021254543B2 AU2021254543B2 AU2021254543A AU2021254543A AU2021254543B2 AU 2021254543 B2 AU2021254543 B2 AU 2021254543B2 AU 2021254543 A AU2021254543 A AU 2021254543A AU 2021254543 A AU2021254543 A AU 2021254543A AU 2021254543 B2 AU2021254543 B2 AU 2021254543B2
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 154
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 144
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 title claims abstract description 119
- 229910052731 fluorine Inorganic materials 0.000 title claims abstract description 119
- 239000011737 fluorine Substances 0.000 title claims abstract description 119
- 239000002893 slag Substances 0.000 title claims abstract description 117
- 239000003513 alkali Substances 0.000 title claims abstract description 63
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 40
- 238000006115 defluorination reaction Methods 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 31
- 239000007787 solid Substances 0.000 title claims abstract description 31
- 239000000126 substance Substances 0.000 title claims abstract description 21
- 238000002386 leaching Methods 0.000 claims abstract description 116
- 239000007788 liquid Substances 0.000 claims abstract description 70
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 57
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000000926 separation method Methods 0.000 claims abstract description 34
- 238000010438 heat treatment Methods 0.000 claims abstract description 30
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims abstract description 19
- 238000004064 recycling Methods 0.000 claims abstract description 12
- 239000008367 deionised water Substances 0.000 claims abstract description 10
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 10
- 239000002994 raw material Substances 0.000 claims abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 18
- 239000012141 concentrate Substances 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 14
- 229910052593 corundum Inorganic materials 0.000 claims description 10
- 239000010431 corundum Substances 0.000 claims description 10
- -1 rare earth fluoride Chemical class 0.000 claims description 9
- 238000005119 centrifugation Methods 0.000 claims description 8
- 238000000227 grinding Methods 0.000 claims description 8
- 229910052590 monazite Inorganic materials 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 238000011084 recovery Methods 0.000 abstract description 15
- 229910001404 rare earth metal oxide Inorganic materials 0.000 abstract description 8
- 239000002351 wastewater Substances 0.000 abstract description 4
- 238000000605 extraction Methods 0.000 abstract description 3
- 239000012535 impurity Substances 0.000 abstract description 3
- 239000002253 acid Substances 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 239000002699 waste material Substances 0.000 abstract description 2
- 229910020261 KBF4 Inorganic materials 0.000 abstract 1
- 238000004364 calculation method Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 239000002912 waste gas Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 231100001234 toxic pollutant Toxicity 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/02—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
- C22B3/10—Hydrochloric acid, other halogenated acids or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B59/00—Obtaining rare earth metals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The present invention discloses a green chemical alkali conversion and
defluorination method by roasting fluorine-containing rare earth ore and solid slag,
comprising four steps: step 1: traditional roasting of fluorine-containing rare earth ore
and slag for alkali conversion and defluorination, step 2: heating for leaching NaF,
step 3: solid-liquid separation, and step 4: heating for leaching rare earth. The present
invention can realize complete separation of fluorine and rare earth in ore and slag so
that a hydrochloric acid solution for leaching rare earth contains no fluoride ion,
which completely avoids fluorine interference in subsequent processes such as
impurity removal and separation of rare earth, leaching NaF twice can realize
complete recovery of fluorine in alkali converted slag and high-value recycling into a
raw material of KBF4, no fluoride-containing wastewater is discharged, and leaching
once can realize complete extraction of rare earth, so the present invention has the
outstanding advantages of simplifying process flow, significantly reducing alkali and
acid consumption, reducing production cost and effectively avoiding discharge of
three fluorine-containing wastes and can realize complete recovery of fluorine and
rare earth resources in fluorine-containing rare earth ore and slag and the safe
utilization of residue.
Drawing of Description
Fluorine-containing rare earth ore
(slag) + NaOH
Coasting for alkali conversion and
defluorination
Rare earth oxide slag + deionized
water
Heating for leaching NaF
Cenentrifugalsolid-liquidseparation
NaF leaching liquid Fd Cnrfglsldlqi eaainRare earth hydrate slag +
hydrochloric acid
Recycling NaF into KFHeating
for leaching rare earth
Centrifugal solid-liquid separation
Rare earth hydrochloric acid
solution
FIG. 1
1
Description
Drawing of Description Fluorine-containing rare earth ore (slag) + NaOH
Coasting for alkali conversion and defluorination
Rare earth oxide slag + deionized water
Heating for leaching NaF
NaF leaching liquid Fd Cnrfglsldlqi eaainRare earth hydrate slag
+ hydrochloric acid Cenentrifugalsolid-liquidseparation for leaching rare earth Recycling NaF into KFHeating
Centrifugal solid-liquid separation
Rare earth hydrochloric acid solution
FIG. 1
Description GREEN CHEMICAL ALKALI CONVERSION AND DEFLUORINATION METHOD BY ROASTING FLUORINE-CONTAINING RARE EARTH ORE AND SOLID SLAG Technical Field The present invention relates to the technical field of rare earth hydrometallurgy, and particularly relates to a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag. Background The compound of fluorine (F) and rare earth (REEs) is not only a valuable industrial raw material, but also a toxic pollutant in the ecological environment. Due to the mineral chemical characteristics of fluorine, it is difficult to realize complete alkali conversion and defluorination of the F-REEs coordination compound in fluorine-containing rare earth concentrate and solid slag, thereby resulting in difficulty to realize complete separation of F- and REE", so as to cause F and REEs resources to be difficult to recover completely, which seriously restricts the green and sustainable development and recycling of fluorine and rare earth resources in fluorine-containing rare earth ore and slag and seriously hinders the coordinated development of comprehensive utilization of rare earth resources and ecological environment. Fluorine-containing rare earth ore and solid slag is subjected to alkali conversion and defluorination with sodium hydroxide. Since the requirement for the grade of rare earth is high, the decomposition rate of the F-REEs coordination compound is low, and a large amount of wastewater containing fluorine and alkali is produced and is difficult to treat, the method is applied limitedly in rare earth industrial production and only applied to the alkali conversion and defluorination process of fluorine-containing rare earth slag of bastnaesite, which is selectively dissolved by hydrochloric acid. Therefore, the present invention proposes a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag to solve the problems in the prior art. Summary In view of the above problems, the purpose of the present invention is to propose a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, which has the outstanding advantages of simplifying process flow, significantly reducing alkali and acid
Description consumption, reducing production cost and effectively avoiding discharge of three fluorine-containing wastes and can realize complete recovery of fluorine and rare earth in fluorine-containing rare earth ore and solid slag and the safe utilization of residue. To achieve the purpose of the present invention, the present invention is realized by the following technical solution: a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprises the following steps: Step 1: traditional roasting of fluorine-containing rare earth ore and slag for alkali conversion and defluorination: adding fluorine-containing rare earth ore and slag into a 100 mL corundum crucible, and then adding sodium hydroxide for uniform mixing to make fluorine and rare earth alkali in fluorine-containing rare earth ore and slag thoroughly alkali converted to NaF and RExOy to obtain alkali converted slag; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, and conducting stirring and leaching for 6-20 min at a temperature of 40-80°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the operation of step 2 and the operation of step 3 for 1-3 times to make fluorine and rare earth completely separated to obtain hydroxide slag containing rare earth; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid, and leaching rare earth in the slag with RECl3 .
In a further improved solution, the fluorine-containing rare earth ore and slag in step 1 contains 20%-66% of REO and 3.0%-15.0% of fluorine, and the fluorine-containing rare earth ore and slag is one of bastnaesite, bastnaesite concentrate, rare earth fluoride slag or rare earth oxyfluoride slag (REOF) and bastnaesite-monazite bulk concentrate. In a further improved solution, after sodium hydroxide is added and mixed in step 1, the corundum crucible is heated to 500-700°C, and then the temperature is preserved for 10-50 min so that fluorine and rare earth in the fluorine-containing rare earth ore and slag are alkali converted to NaF and RExOy more fully. In a further improved solution, the water-solid ratio for heating for leaching
Description fluorine in step 2 is 4-8:1. In a further improved solution, the first leaching liquid obtained by repeated leaching in step 3 is used as a raw material for recycling fluorine into KBF 4, and the second and the third leaching fluorine-containing aqueous solutions are used for leaching fluoride in the next batch of alkali converted ore. In a further improved solution, the hydroxide slag containing rare earth in step 4 and hydrochloric acid are mixed at an acid-ore ratio of 4-8:1, and stirred and leached for 8-20 min at a temperature of 30-80°C. In a further improved solution, after hydrochloric acid is used for mixing and leaching in step 4, the leaching liquid and the residue are subjected to solid-liquid separation by centrifugation with a centrifuge to obtain RECl3 solution and residue containing no fluoride or rare earth. The present invention has the beneficial effects that: the coordination bond of the coordination compound of fluorine and rare earth in fluorine-containing rare earth ore and slag is completely opened with a theoretical amount of sodium hydroxide to thoroughly break the bottleneck constraint of complete separation of fluorine and rare earth, which not only avoids the generation of fluorine-containing waste gas, but also guarantees the complete recovery of fluorine and rare earth, and completely avoids fluorine interference in subsequent processes such as impurity removal and separation of rare earth due to no fluoride ion contained in the rare earth hydrochloric acid solution, the leaching of fluorine and rare earth has high speed and takes short time, leaching twice can realize complete leaching of fluorine and a small amount of residual alkali in slag, no fluoride-containing wastewater is discharged, leaching once can realize complete extraction of rare earth, and the residue can be utilized safely. Description of Drawing Fig. 1 is a process flow chart of the present invention. Detailed Description To deepen the understanding of the present invention, the present invention will be further described below in detail in combination with embodiments. The embodiments are only used to explain the present invention, and do not constitute a limitation to the protection scope of the present invention. Embodiment 1 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid
Description slag, comprising the following steps: Step 1: roasting of bastnaesite concentrate in a muffle furnace for alkali conversion and defluorination: adding bastnaesite concentrate into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of bastnaesite concentrate to sodium hydroxide of 25:12 for uniform mixing, heating the muffle furnace to 700°C, and preserving heat for 40 min to fully alkali convert and defluorinate the bastnaesite concentrate to make fluorine and rare earth in the bastnaesite concentrate converted to NaF and RExOy; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, wherein the water-solid ratio is 6:1, and conducting stirring and leaching for 15 min at a temperature of 70°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain completely leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion, the total yield of leaching fluorine twice is 99.78%, no residual fluorine is detected in the slag leached with fluoride by the fluoride ion selective electrode method, and no fluorine-containing waste gas is produced. Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 8:1, conducting stirring and leaching for 20 min at a temperature of 60°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the fluorine-containing residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The bastnaesite concentrate used in the embodiment contains 65.2% of REO and 8.3% of fluorine, the total yield of rare earth after leaching is 99.07%, the concentration of fluoride ions is determined by the fluoride ion selective electrode method, and the concentration of rare earth elements in the hydrochloric acid leaching liquid is determined by the ICP-OES method. Embodiment 2 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion
Description and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprising the following steps Step 1: heating of rare earth fluoride slag in a muffle furnace for alkali conversion and defluorination: adding rare earth fluoride slag into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of rare earth fluoride slag to sodium hydroxide of 7:3 for uniform mixing, heating the muffle furnace to 700°C, and preserving heat for 40 min to defluorinate the rare earth fluoride slag to make fluorine and rare earth in the rare earth fluoride slag converted to NaF and RExOy; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, wherein the water-solid ratio is 8:1, and conducting stirring and leaching for 6 min at a temperature of 80°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain completely leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , and the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 5:1, conducting stirring and leaching for 20 min at a temperature of 40°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The rare earth fluoride slag used in the embodiment contains 20.4% of REO and 8.5% of fluorine, the determination and calculation method of the recovery rates of fluorine and rare earth in the embodiment is the same as that in embodiment 1, and the recovery rates of fluorine and rare earth in the embodiment are respectively 99.22% and 98.95%. Embodiment 3 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprising the following steps
Description Step 1: roasting of bastnaesite in a muffle furnace for alkali conversion and defluorination: adding bastnaesite into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of bastnaesite to sodium hydroxide of 25:12 for uniform mixing, heating the muffle furnace to 500°C, and preserving heat for 50 min to defluorinate the bastnaesite to make fluorine and rare earth in the bastnaesite converted to NaF and RExOy; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, wherein the water-solid ratio is 6:1, and conducting stirring and leaching for 15 min at a temperature of 80°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , and the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 5:1, conducting stirring and leaching for 20 min at a temperature of 60°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The bastnaesite used in the embodiment contains 65.2% of REO and 7.1% of fluorine, the determination and calculation method of the recovery rates of fluorine and rare earth in the embodiment is the same as that in embodiment 1, and the recovery rates of fluorine and rare earth in the embodiment are respectively 78.83% and 84.27%. Embodiment 4 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprising the following steps Step 1: roasting of bastnaesite in a muffle furnace for alkali conversion and defluorination: adding bastnaesite into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of bastnaesite to sodium hydroxide of 26:10 for
Description uniform mixing, heating the muffle furnace to 700°C, and preserving heat for 30 min to defluorinate the bastnaesite to make fluorine and rare earth in the bastnaesite converted to NaF and RExOy; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, wherein the water-solid ratio is 6:1, and conducting stirring and leaching for 15 min at a temperature of 70°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , and the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 6:1, conducting stirring and leaching for 20 min at a temperature of 60°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the fluorine-containing residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The bastnaesite used in the embodiment contains 50% of REO and 7.9% of fluorine, the determination and calculation method of the recovery rates of fluorine and rare earth in the embodiment is the same as that in embodiment 1, the recovery rates of fluorine and rare earth in the embodiment are respectively 99.62% and 99.51%, and the residue can be utilized safely. Embodiment 5 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprising the following steps Step 1: roasting of bastnaesite-monazite bulk concentrate in a muffle furnace for alkali conversion and defluorination: adding bulk concentrate into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of bulk concentrate to sodium hydroxide of 25:11 for uniform mixing, heating the muffle furnace to 700°C, and preserving heat for 40 min to defluorinate the bulk concentrate to make fluorine and rare earth in the bulk concentrate converted to NaF and RExOy;
Description Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, wherein the water-solid ratio is 6:1, and conducting stirring and leaching for 15 min at a temperature of 80°C to obtain leaching liquid and hydroxide slag containing rare earth; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , and the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 7:1, conducting stirring and leaching for 20 min at a temperature of 60°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the fluorine-containing residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The bastnaesite-monazite bulk concentrate used in the embodiment contains 56.1% of REO and 8.6% of fluorine, the determination and calculation method of the recovery rates of fluorine and rare earth in the embodiment is the same as that in embodiment 1, and the recovery rates of fluorine and rare earth in the embodiment are respectively 99.45% and 98.74%. Embodiment 6 As shown in Fig. 1, the embodiment provides a green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag, comprising the following steps Step 1: roasting of rare earth oxyfluoride (REOF) slag in a muffle furnace for alkali conversion and defluorination: adding rare earth oxyfluoride slag into a 100 mL corundum crucible, and then adding sodium hydroxide at a mass ratio of rare earth oxyfluoride slag to sodium hydroxide of 25:17 for uniform mixing, heating the muffle furnace to 700°C, and preserving heat for 40 min to defluorinate the rare earth oxyfluoride slag to make fluorine and rare earth in the rare earth oxyfluoride slag converted to NaF and RExOy; Step 2: heating for leaching NaF: grinding the alkali converted slag obtained in
Description step 1, adding deionized water, wherein the water-solid ratio is 6:1, and conducting stirring and leaching for 15 min at a temperature of 80°C to obtain leaching liquid; Step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the above operation and the operation of step 2 once to obtain leached NaF solution and hydroxide slag containing rare earth, wherein the first NaF-containing solution is used as a raw material for recycling fluorine into KBF 4 , and the second leaching liquid is used for leaching fluoride from rare earth oxide slag in the next batch of alkali conversion; Step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid at an acid-ore ratio of 6:1, conducting stirring and leaching for 20 min at a temperature of 60°C, leaching rare earth in the slag with RECl 3 , and carrying out solid-liquid separation on the leaching liquid and the fluorine-containing residue by centrifugation to obtain RECl3 solution and residue containing no fluorine or rare earth. The fluorine-containing rare earth slag used in the embodiment contains 75.6% of REO and 8.4% of fluorine, the determination and calculation method of the recovery rates of fluorine and rare earth in the embodiment is the same as that in embodiment 1, and the recovery rates of fluorine and rare earth in the embodiment are respectively 99.53% and 99.03%. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag thoroughly breaks the bottleneck constraint of complete separation of fluorine and rare earth, which not only avoids the generation of fluorine-containing waste gas, but also guarantees the complete recovery of fluorine and rare earth, and completely avoids fluorine interference in subsequent processes such as impurity removal and separation of rare earth due to no fluoride ion contained in the rare earth hydrochloric acid solution, the leaching of fluorine and rare earth has high speed and takes short time, leaching twice can realize complete leaching of fluorine and a small amount of residual alkali in slag, no fluoride-containing wastewater is discharged, leaching once can realize complete extraction of rare earth, and the residue can be utilized safely. The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art shall understand that the present invention is not limited by the above embodiments. The above embodiments and the
Description description merely illustrate the principle of the present invention. Various changes and improvements can also be made to the present invention without departing from the spirit and scope of the present invention, and shall fall into the protection scope of the present invention. The protection scope of the present invention is defined by the appended claims and equivalents.
Claims (6)
- Claims 1. A green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag in a furnace, comprising the following steps: step 1: traditional roasting of fluorine-containing rare earth ore and slag for alkali conversion and defluorination in a furnace: adding fluorine-containing rare earth ore and slag into a 100 mL corundum crucible, and then adding sodium hydroxide for uniform mixing, heating the corundum crucible in the furnace up to about 700°C, and then preserving the temperature for 10-50 min to make fluorine and rare earth in fluorine-containing rare earth ore and slag thoroughly alkali converted to NaF and RExOy to obtain alkali converted slag; step 2: heating for leaching NaF: grinding the alkali converted slag obtained in step 1, adding deionized water, and conducting stirring and leaching for 6-20 min at a temperature of 40-80°C to obtain leaching liquid; step 3: solid-liquid separation: using a high-speed centrifuge for solid-liquid separation of the leaching liquid obtained in step 2 to obtain NaF-containing leaching liquid and RE(OH)3-containing slag, and repeating the operation of step 2 and the operation of step 3 for 1-3 times to make fluorine and rare earth completely separated to obtain hydroxide slag containing rare earth; step 4: heating for leaching rare earth: mixing the hydroxide slag containing rare earth obtained in step 3 with 3 mol/L hydrochloric acid, and leaching rare earth in the slag with RECl3 .
- 2. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag according to claim 1, wherein the fluorine-containing rare earth ore and slag in step 1 contains 20%- 6 6 % of REO and 3.0%-15.0% of fluorine, and the fluorine-containing rare earth ore and slag is one of bastnaesite, bastnaesite concentrate, rare earth fluoride slag or rare earth oxyfluoride slag (REOF) and bastnaesite-monazite bulk concentrate.
- 3. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag according to claim 1, wherein the water-solid ratio for heating for leaching fluorine in step 2 is 4-8:1.
- 4. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag according to claim 1, wherein the first leaching liquid obtained by repeated leaching in step 3 is used as a raw material for recycling fluorine into KBF 4, and the second and the third leachingClaims fluorine-containing aqueous solutions are used for leaching fluoride in the next batch of alkali converted ore.
- 5. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag according to claim 1, wherein the hydroxide slag containing rare earth in step 4 and hydrochloric acid are mixed at an acid-ore ratio of 4-8:1, and stirred and leached for 8-20 min at a temperature of -80 0 C.
- 6. The green chemical alkali conversion and defluorination method by roasting fluorine-containing rare earth ore and solid slag according to claim 1, wherein after hydrochloric acid is used for mixing and leaching in step 4, the leaching liquid and the residue are subjected to solid-liquid separation by centrifugation with a centrifuge to obtain RECl3 solution and residue containing no fluoride or rare earth, and the residue can be utilized safely.
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| US20170022071A1 (en) * | 2015-06-25 | 2017-01-26 | Iowa State University Research Foundation, Inc. | Separation of terbium(iii,iv) oxide |
| CN113073195A (en) * | 2021-03-19 | 2021-07-06 | 四川师范大学 | Microwave chemical method for completely extracting fluorine and rare earth in bastnaesite concentrate |
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| CN101824554B (en) * | 2010-03-12 | 2013-06-12 | 瑞科稀土冶金及功能材料国家工程研究中心有限公司 | Liquid alkali roasting decomposition extraction process of mixed rare earth concentrates |
| CN102212674A (en) * | 2011-05-12 | 2011-10-12 | 包头稀土研究院 | Process for comprehensively recovering liquid alkali roasting resource of mixed rare earth concentrate |
| CN103374652B (en) * | 2012-09-29 | 2015-04-22 | 有研稀土新材料股份有限公司 | Method for comprehensively recycling rare earth and fluorine in process of treating bastnaesite |
| CN106048265B (en) * | 2016-08-17 | 2018-05-25 | 成都理工大学 | A kind of extracting method of bastnaesite rare earth elements |
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| CN113073195A (en) * | 2021-03-19 | 2021-07-06 | 四川师范大学 | Microwave chemical method for completely extracting fluorine and rare earth in bastnaesite concentrate |
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