GB1022448A - Preparation of silica and fluoride salts from waste gases - Google Patents
Preparation of silica and fluoride salts from waste gasesInfo
- Publication number
- GB1022448A GB1022448A GB3515762A GB3515762A GB1022448A GB 1022448 A GB1022448 A GB 1022448A GB 3515762 A GB3515762 A GB 3515762A GB 3515762 A GB3515762 A GB 3515762A GB 1022448 A GB1022448 A GB 1022448A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gases
- silica
- liquors
- mixer
- fluorine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/48—Halides, with or without other cations besides aluminium
- C01F7/50—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
- C01B17/76—Preparation by contact processes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/48—Halides, with or without other cations besides aluminium
- C01F7/50—Fluorides
- C01F7/54—Double compounds containing both aluminium and alkali metals or alkaline-earth metals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Treating Waste Gases (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
<PICT:1022448/C1/1> Silica is recovered and fluoride salts are obtained from waste gases containing silica in gasiform suspension, a sulphur-containing component in at least one of the forms SO2 and SO3, and a fluorine-containing component in at least one of the forms SiF4, H2SiF6, and HF by (1) electrostatically precipitating silica there-from at an elevated temperature; (2) water-washing the gases to dissolve the fluorine-containing component; and (3) precipitating a fluoride salt from the wash-water. The waste gases may be derived from phosphate rock (e.g. apatite)-H2SO4 acidulation and/or calcination. Prior to the electrostatic precipitation of silica, other solids in the gases may be separated and H2SiF6 or SiF4, if present, may be reacted with steam at a temperature sufficiently high to form silica and HF. As shown, phosphate rock is acidulated and calcined in mixer 12 and kiln 10, e.g. at 1800-2800 DEG F. Mixer and kiln gases flow via ducts 16 and 17 into dust separation means 20, e.g. cyclones and/or bag filters. The dust-free waste gases, which may be heated by gas-heater 26, then flow to electrostatic precipitators 30, wherein silica is selectively precipitated. The gases then flow to washing unit 40, comprising two packed columns. The scrubbed gases contain all the sulphur components of the gases, whereas the liquors contain all the fluorine-containing components. Non-ionic detergents may be added to the wash liquors to aid sedimentation of solids. Sulphur may be recovered from the washed gases as H2SO4 by conventional methods. Fluorides may be obtained from the scrubbing liquors, e.g. addition of a mixture of Al2O3.3H2O and Na2CO3\t from mixer 50 to the liquors in tank 49 results in the formation of Na3AlF6. The use of Al2O3.3H2O alone, gives AlF3.3 1/2 H2O. The products are separated by fractional crystallization, e.g. any Al2(SiF6)3 is first removed, then AlF3 components, and finally any Al2(SO4)3. The AlF3.3 1/2 H2O or Na3AlF6 crystals may be calcined or dried. Sodium and calcium fluoride may be obtained by addition of a sodium or calcium material, e.g. lime, to the wash liquors in tank 49.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3515762A GB1022448A (en) | 1962-09-14 | 1962-09-14 | Preparation of silica and fluoride salts from waste gases |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3515762A GB1022448A (en) | 1962-09-14 | 1962-09-14 | Preparation of silica and fluoride salts from waste gases |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1022448A true GB1022448A (en) | 1966-03-16 |
Family
ID=10374488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB3515762A Expired GB1022448A (en) | 1962-09-14 | 1962-09-14 | Preparation of silica and fluoride salts from waste gases |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1022448A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4206189A (en) | 1977-01-04 | 1980-06-03 | Belov Viktor Y | Method of producing hydrogen fluoride and silicon dioxide from silicon tetra-fluoride |
| CN114408929A (en) * | 2022-02-25 | 2022-04-29 | 何浩明 | Method and system for separating and purifying fluosilicic acid and silicon dioxide mixed slurry |
-
1962
- 1962-09-14 GB GB3515762A patent/GB1022448A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4206189A (en) | 1977-01-04 | 1980-06-03 | Belov Viktor Y | Method of producing hydrogen fluoride and silicon dioxide from silicon tetra-fluoride |
| CN114408929A (en) * | 2022-02-25 | 2022-04-29 | 何浩明 | Method and system for separating and purifying fluosilicic acid and silicon dioxide mixed slurry |
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