CA3184586A1 - Method for recovery of silica from magnesium silicates - Google Patents
Method for recovery of silica from magnesium silicates Download PDFInfo
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- CA3184586A1 CA3184586A1 CA3184586A CA3184586A CA3184586A1 CA 3184586 A1 CA3184586 A1 CA 3184586A1 CA 3184586 A CA3184586 A CA 3184586A CA 3184586 A CA3184586 A CA 3184586A CA 3184586 A1 CA3184586 A1 CA 3184586A1
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- leaching
- magnesium
- hydrochloric acid
- magnesium silicates
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- 239000000391 magnesium silicate Substances 0.000 title claims abstract description 37
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 35
- 238000000034 method Methods 0.000 title claims abstract description 22
- 239000000377 silicon dioxide Substances 0.000 title claims abstract description 17
- 238000011084 recovery Methods 0.000 title claims abstract description 10
- 235000012243 magnesium silicates Nutrition 0.000 title claims description 26
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 66
- 230000029087 digestion Effects 0.000 claims abstract description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 3
- 239000011707 mineral Substances 0.000 claims abstract description 3
- 239000002699 waste material Substances 0.000 claims abstract description 3
- 238000002386 leaching Methods 0.000 claims description 42
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 31
- 239000002253 acid Substances 0.000 claims description 16
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 16
- 239000011777 magnesium Substances 0.000 claims description 15
- 239000000347 magnesium hydroxide Substances 0.000 claims description 15
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 15
- 235000012254 magnesium hydroxide Nutrition 0.000 claims description 15
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 14
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 13
- 229910052749 magnesium Inorganic materials 0.000 claims description 13
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 10
- 229910017604 nitric acid Inorganic materials 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 7
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 5
- 239000001110 calcium chloride Substances 0.000 claims description 4
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 4
- LRCFXGAMWKDGLA-UHFFFAOYSA-N dioxosilane;hydrate Chemical compound O.O=[Si]=O LRCFXGAMWKDGLA-UHFFFAOYSA-N 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 229960004029 silicic acid Drugs 0.000 claims description 4
- 239000000920 calcium hydroxide Substances 0.000 claims description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 3
- 150000004653 carbonic acids Chemical class 0.000 claims description 2
- 235000010755 mineral Nutrition 0.000 claims description 2
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 abstract description 11
- 235000019792 magnesium silicate Nutrition 0.000 abstract description 11
- 229910052919 magnesium silicate Inorganic materials 0.000 abstract description 11
- 239000000126 substance Substances 0.000 abstract description 3
- 238000011282 treatment Methods 0.000 abstract description 3
- 238000000746 purification Methods 0.000 abstract description 2
- 238000000605 extraction Methods 0.000 description 9
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000010953 base metal Substances 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 229910052620 chrysotile Inorganic materials 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- CWBIFDGMOSWLRQ-UHFFFAOYSA-N trimagnesium;hydroxy(trioxido)silane;hydrate Chemical compound O.[Mg+2].[Mg+2].[Mg+2].O[Si]([O-])([O-])[O-].O[Si]([O-])([O-])[O-] CWBIFDGMOSWLRQ-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 2
- 235000019341 magnesium sulphate Nutrition 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910000343 potassium bisulfate Inorganic materials 0.000 description 2
- 230000019635 sulfation Effects 0.000 description 2
- 238000005670 sulfation reaction Methods 0.000 description 2
- JTNCEQNHURODLX-UHFFFAOYSA-N 2-phenylethanimidamide Chemical compound NC(=N)CC1=CC=CC=C1 JTNCEQNHURODLX-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- -1 color Chemical compound 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hcl hcl Chemical compound Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- DHRRIBDTHFBPNG-UHFFFAOYSA-L magnesium dichloride hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-] DHRRIBDTHFBPNG-UHFFFAOYSA-L 0.000 description 1
- GMLLYEDWRJDBIT-UHFFFAOYSA-J magnesium;dipotassium;disulfate Chemical compound [Mg+2].[K+].[K+].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GMLLYEDWRJDBIT-UHFFFAOYSA-J 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- CHKVPAROMQMJNQ-UHFFFAOYSA-M potassium bisulfate Chemical compound [K+].OS([O-])(=O)=O CHKVPAROMQMJNQ-UHFFFAOYSA-M 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
- C01B33/187—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by acidic treatment of silicates
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Silicon Compounds (AREA)
Abstract
A method for the recovery of silica from magnesium silicate by digestion with hydrochloric acid followed by physical and chemical purification. The magnesium silicate is selected as a serpentinic mineral or waste resulting from treatments of a magnesium silicate.
Description
TITLE OF THE INVENTION
Method for recovery of silica from magnesium silicates FIELD OF THE INVENTION
[0001] The present invention relates to recovery of silica from magnesium silicates.
More specifically, the present invention relates to recovery of silica from magnesium silicates such as chrysotile tailings (3Mg0.2Si02.2H20).
BACKGROUND OF THE INVENTION
Method for recovery of silica from magnesium silicates FIELD OF THE INVENTION
[0001] The present invention relates to recovery of silica from magnesium silicates.
More specifically, the present invention relates to recovery of silica from magnesium silicates such as chrysotile tailings (3Mg0.2Si02.2H20).
BACKGROUND OF THE INVENTION
[0002] The extraction of magnesium from magnesium silicates such as serpentinic tailings leaves a silica of variable composition, according on the acid used and the operational conditions. Methods using nitric acid (US patent 1,454,583), sulfuric acid (US
patent 4,277,449), hydrochloric acid (US patent 7,780,941) or even carbonic acid (CA patent 2,378,721) have been presented. Typically, the obtained silica remains tainted with insoluble elements such as awaruite (Ni3Fe); the magnesium extraction is far from complete and the physical properties of silica such as color, specific surface or level of hydration is not optimal. Moreover, the resulting salt of magnesium has no significant market (ex: Mg (NO3)2) or poor commercial value (ex: MgSO4, MgCl2), being accessible as naturally occurring species (Epsom salt, bischofite) in brines.
patent 4,277,449), hydrochloric acid (US patent 7,780,941) or even carbonic acid (CA patent 2,378,721) have been presented. Typically, the obtained silica remains tainted with insoluble elements such as awaruite (Ni3Fe); the magnesium extraction is far from complete and the physical properties of silica such as color, specific surface or level of hydration is not optimal. Moreover, the resulting salt of magnesium has no significant market (ex: Mg (NO3)2) or poor commercial value (ex: MgSO4, MgCl2), being accessible as naturally occurring species (Epsom salt, bischofite) in brines.
[0003] Therefore, there is a need in the art for a method for recovery of silica from magnesium silicates.
BRIEF DESCRIPTION OF THE DRAWINGS
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] In the appended drawings:
[0005] FIG. 1 is a flowchart of a method according to an embodiment of an aspect of the present disclosure.
Date Recue/Date Received 2023-06-20 DESCRIPTION OF EMBODIMENTS OF THE INVENTION
Date Recue/Date Received 2023-06-20 DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0006] The present invention is illustrated in further details by the following non-limiting examples.
[0007] A method according to an embodiment of an aspect of the present disclosure as illustrated in the flowchart of FIG. 1 for example, comprises using a magnesium silicate derived from chrysotile tailings (3Mg0.2Si02.2H20) as a source of silica. By using residual magnesium silicates resulting from partial extraction of magnesium by carbonation or sulfation, the ratio of magnesium to be extracted per unit weight of silica obtained is thus reduced from 3 Mg0.2SiO to 1.5 Mg0.2Si02.
Extraction of magnesium chloride (MgCl2) is performed using hydrochloric acid (HCl) as an extraction reagent in a countercurrent extraction (steps 1- 8). After separation of dense impurities, by cycloning through vortex separation or gravity extraction leveraging the different specific weighs (step 9), the extraction is completed in a polishing circuit using nitric acid (HNO3) (step 10). Pure silica (98-99%
SiO2) is obtained (step 12) by calcination of the hydrated product at 1000 C
(step 11).
Extraction of magnesium chloride (MgCl2) is performed using hydrochloric acid (HCl) as an extraction reagent in a countercurrent extraction (steps 1- 8). After separation of dense impurities, by cycloning through vortex separation or gravity extraction leveraging the different specific weighs (step 9), the extraction is completed in a polishing circuit using nitric acid (HNO3) (step 10). Pure silica (98-99%
SiO2) is obtained (step 12) by calcination of the hydrated product at 1000 C
(step 11).
[0008] The magnesium chloride (MgC12) resulting from the extraction with hydrochloric acid (HCI) (steps 1-8) is purified by pH adjustment with a base such as chrysotile tailings or magnesium oxide (MgO) or magnesium hydroxide (Mg(OH)2) (step 6) to precipitate the traces of iron, nickel, chromium, manganese, and aluminium dissolved along with magnesium. This cleaned solution (step 7) is then contacted at room temperature with equimolar amounts of calcium hydroxide (Ca(OH)2) under attritional conditions selected to renew reactive surfaces, under ball milling or grinding for example (step 13). A spontaneous reaction yields magnesium hydroxide (Mg(OH)2) (step 14) and calcium chloride (CaCl2) (step 15), a commodity of broad uses for dust control and de-icing of roads for instance.
[0009] In a system leading to silica (SiO2) and magnesium hydroxide (Mg(OH)2), the starting magnesium silicate is the residual material Y2 Mg0.2Si02 left by the formation of schoenite from potassium bisulfate (KHSO4) and serpentinic tailings as follows:
Date Recue/Date Received 2023-06-20 5.5H20 + 3Mg0. 2Si02. 2H20 + 3KHSO4 ¨> 1 ¨2 (K2SO4. M gSO4. 6H20) + 1 ¨2 Mg0. 2Si02 (relation 1)
Date Recue/Date Received 2023-06-20 5.5H20 + 3Mg0. 2Si02. 2H20 + 3KHSO4 ¨> 1 ¨2 (K2SO4. M gSO4. 6H20) + 1 ¨2 Mg0. 2Si02 (relation 1)
[0010] Using residual 1/2Mg0.2Si02 instead of the tailings 3Mg0.2Si02 reduces by half the amount of magnesium to be digested with hydrochloric acid (HCI). Referring to FIG. 1, the residual magnesium silicate 1/2 Mg0.2Si02 is digested twice in the counter current system, the first digestion being done mainly in a first reactor (1) with the residual acid from a second reactor (8) which is fed with concentrated HCI (37%). The resulting magnesium chloride (MgCl2) is filtered and a neutralizing agent, such as of one of: Mg (OH)2, MgO and serpentinic tailings, is added to raise the pH to a range between 4 and 5 (step 4) in order to precipitate the base metals Fe, Ni, Co, Mn, Cr, Al extracted by the hydrochloric acid (HCI) (step 5). A second filtration leads to a clean solution of MgCl2 (7) which has been concentrated by evaporation (6).
[0011] The hydrated silica from the second digestion (8) after recycling the residual acid and rinsings to the first reactor (1) (step 2) is freed by gravity or cyclone (step 9) from dense products such as awaruite (Ni3Fe). A final treatment of the hydrated silica is applied in a closed loop with nitric acid (HNO3) (10) to remove the last traces of impurities, particularly those that need oxidations, such as Fe, Mn, Cr. The obtained purified hydrated silica is then transformed into anhydrous silica by a thermal treatment at 10000C (step 11) that reduces the water content from 6% to 1% or less.
[0012] Experiments were done using the residual material left after the carbonatation of calcined tailings, with a composition of 2.2Mg0.2Si02. The obtained silica had a composition of 97.9% SiO2. With residual material from sulfation of tailings, the purity of the obtained SiO2 was 98.3%;
the removal of magnesium and traces of base metals was done by between 90 and 95% in the first reactor (1), by between 4 and 8% in the second reactor (8) and by less than 1%
in the nitric acid loop (step 10). These leachings were done at a temperature of 85 C for 90 minutes.
The recovery of SiO2 from the starting residual magnesium was 96% and the chemical analysis indicated a SiO2 at 98.3%.
The specific surface (BET) was 423 m2/g.
the removal of magnesium and traces of base metals was done by between 90 and 95% in the first reactor (1), by between 4 and 8% in the second reactor (8) and by less than 1%
in the nitric acid loop (step 10). These leachings were done at a temperature of 85 C for 90 minutes.
The recovery of SiO2 from the starting residual magnesium was 96% and the chemical analysis indicated a SiO2 at 98.3%.
The specific surface (BET) was 423 m2/g.
[0013] The magnesium chloride solution (7) can be treated by an equimolar amount of calcium hydroxide (Ca(OH)2) at 25 C in a reactor (13) with a ball milling capability for the renewal of Date Recue/Date Received 2023-06-20 surfaces. After two hours, filtration gave 96% of the expected Mg(OH)2 (14) and the solution of calcium chloride (15).
[0014] Thus, essentially all the magnesium and silicium in the starting residual silicate was transformed into useful products.
[0015] There is thus presented a method for the recovery of silica from magnesium silicate by digestion with hydrochloric acid followed by physical and chemical purification. The magnesium silicate is selected as one of: a serpentinic minerals and waste resulting from treatments of a magnesium silicate. Such residual serpentinic silicates can be deprived serpentinic magnesium silicate can be deprived of between 20% and 80% of its magnesium content by leaching either by sulfuric, hydrochloric, or carbonic acids.
[0016] The hydrochloric acid leaching is done in a counter current system with at least two reactors, at a temperature in a range between about 80 oC and about 900C, for example at about 85 C. The hydrochloric acid leaching is followed by a gravimetric physical separation of impurities of density above about 3, including products of the awaruite family Ni3Fe, then followed by a final acid leaching with an acid different than the hydrochloric acid, such as nitric acid for example.
[0017] The magnesium chloride solution resulting from the hydrochloric acid leaching of the magnesium silicate is deprived of the traces of base metals by raising the pH of this solution to a pH in a range between 4 and 5 by addition of one of: Mg(OH)2, MgO and serpentinic tailings. The reaction is done at a temperature in a range between about 80 C and about 90 C, lasting between about one hour and about two hours, for example at about 85 C during about 90 minutes. The purified solution of magnesium chloride is treated with a stoichiometric amount of calcium hydroxide using attritional mixing, yielding magnesium hydroxide and calcium chloride.
[0018] The scope of the claims should not be limited by the embodiments set forth in the examples but should be given the broadest interpretation consistent with the description as a whole.
Date Recue/Date Received 2023-06-20
Date Recue/Date Received 2023-06-20
Claims (20)
1. A method for recovery of silica from magnesium silicates, comprising leaching the magnesium silicates with hydrochloric acid, separating a resulting silica from dense material and purifying with nitric acid.
2. The method of claim 1, comprising selecting the magnesium silicates as ones of: i) serpentinic minerals and ii) wastes from previously treated magnesium silicates.
3. The method of any claim 1, wherein the magnesium silicates are serpentinic magnesium silicates deprived from 20% to 80% of a magnesium content thereof by leaching by one of:
sulfuric, hydrochloric and carbonic acids.
sulfuric, hydrochloric and carbonic acids.
4. The method of any one of claims 1 to 3, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C.
5. The method of any one of claims 1 to 3, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C; and said hydrochloric acid leaching is followed by gravimetric physical separation of impurities of density above 3.5.
6. The method of any one of claims 1 to 3, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C; and said hydrochloric acid leaching is followed by gravimetric physical separation of Ni3Fe.
7. The method of any one of claims 1 to 3, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in Date Recue/Date Received 2023-06-20 a range between 80 C and 90 C; said hydrochloric acid leaching being followed by gravimetric physical separation of impurities and a final acid leaching with an acid other than hydrochloric acid.
8. The method of any one of claims 1 to 3, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C; said hydrochloric acid leaching is followed by gravimetric physical separation of impurities and a final acid leaching with nitric acid.
9. The method of any one of claims 1 to 8, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C; the method further comprising raising a pH of a magnesium chloride solution resulting from the hydrochloric acid leaching to a range between 4 and 5 by addition of one of:
Mg(OH)2, Mg0 and serpentinic tailings.
Mg(OH)2, Mg0 and serpentinic tailings.
10. The method of any one of claims 1 to 8, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C during between one and two hours; the method further comprising raising a pH of a magnesium chloride solution resulting from the hydrochloric acid leaching to a range between 4 and 5 by addition of one of: Mg(OH)2, Mg0 and serpentinic tailings.
11. The method of any one of claims 1 to 8, wherein the hydrochloric acid leaching of the magnesium silicates is done by counter current leaching in at least two steps, at a temperature in a range between 80 C and 90 C; the method further comprising raising a pH of a magnesium chloride solution resulting from the hydrochloric acid leaching to a range between 4 and 5 by addition of one of:
Mg(OH)2, Mg0 and serpentinic tailings; and treating a resulting purified solution of magnesium chloride with a stoichiometric amount of calcium hydroxide using attritional mixing, yielding magnesium hydroxide and calcium chloride.
Mg(OH)2, Mg0 and serpentinic tailings; and treating a resulting purified solution of magnesium chloride with a stoichiometric amount of calcium hydroxide using attritional mixing, yielding magnesium hydroxide and calcium chloride.
12. A system for recovery of silica from magnesium silicates, comprising at least a first and a second hydrochloric acid leaching reactors; a gravimetric separator; a final acid leaching Date Recue/Date Received 2023-06-20 reactor; the magnesium silicates being leached in counter current in the first reactor with residual acid from the second reactor, at a temperature in a range between 80 C and 90 C;
impurities being removed from a resulting hydrated silica in said gravimetric separator before an acid leaching with an acid other than hydrochloric acid in said final add leaching reactor.
impurities being removed from a resulting hydrated silica in said gravimetric separator before an acid leaching with an acid other than hydrochloric acid in said final add leaching reactor.
13. The system of any one of claims 11 and 12, wherein said final acid leaching reactor is a nitric acid leaching reactor.
14. The system of any one of claims 11 to 13, wherein said first and a second hydrochloric add leaching reactors are configured as a counter current system, the magnesium silicates being digested twice in the counter current system, a first digestion being done mainly in said first reactor with the residual acid from said second reactor which is fed with concentrated HCI (37%).
15. The system of any one of claims 11 to 14, wherein said first, second and final reactors have a temperature in a range between 80 C and 90 C.
16. The system of any one of claims 11 to 15, wherein said gravimetric separator removes impurities of density above 3.5.
17. The system of any one of claims 11 to 16, wherein said gravimetric separator removes Ni3Fe.
18. The system of any one of claims 11 to 17, comprising a first vessel receiving a magnesium chloride solution resulting from acid leaching in said first and second reactors and one of:
Mg(OH)2,Mg0 and serpentinic tailings, said first vessel yielding a magnesium chloride solution with a pH
to a range between 4 and 5 .
Date Recue/Date Received 2023-06-20
Mg(OH)2,Mg0 and serpentinic tailings, said first vessel yielding a magnesium chloride solution with a pH
to a range between 4 and 5 .
Date Recue/Date Received 2023-06-20
19. The system of claim 18, comprising a an attritional mixing vessel receiving a resulting purified solution of magnesium chloride and a stoichiometric amount of calcium hydroxide, said attritional mixing vessel yielding magnesium hydroxide and calcium chloride.
20. The system of any one of claims 11 to 19, wherein the magnesium silicates are serpenfinic magnesium silicates deprived from 20% to 80% of a magnesium content thereof by leaching with an acid.
Date Recue/Date Received 2023-06-20
Date Recue/Date Received 2023-06-20
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3184586A CA3184586A1 (en) | 2022-12-07 | 2022-12-07 | Method for recovery of silica from magnesium silicates |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3184586A CA3184586A1 (en) | 2022-12-07 | 2022-12-07 | Method for recovery of silica from magnesium silicates |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3184586A1 true CA3184586A1 (en) | 2023-11-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3184586A Pending CA3184586A1 (en) | 2022-12-07 | 2022-12-07 | Method for recovery of silica from magnesium silicates |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA3184586A1 (en) |
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2022
- 2022-12-07 CA CA3184586A patent/CA3184586A1/en active Pending
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