CA1110039A - Reduction of ferric chloride - Google Patents
Reduction of ferric chlorideInfo
- Publication number
- CA1110039A CA1110039A CA327,370A CA327370A CA1110039A CA 1110039 A CA1110039 A CA 1110039A CA 327370 A CA327370 A CA 327370A CA 1110039 A CA1110039 A CA 1110039A
- Authority
- CA
- Canada
- Prior art keywords
- chloride
- sulphur
- product
- gaseous
- chlorine
- 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
- 229910021578 Iron(III) chloride Inorganic materials 0.000 title claims abstract description 36
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 claims abstract description 54
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000005864 Sulphur Substances 0.000 claims abstract description 43
- 239000000460 chlorine Substances 0.000 claims abstract description 36
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 33
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 32
- FWMUJAIKEJWSSY-UHFFFAOYSA-N sulfur dichloride Chemical compound ClSCl FWMUJAIKEJWSSY-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 18
- 229960002089 ferrous chloride Drugs 0.000 claims abstract description 16
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 claims abstract description 16
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 claims abstract description 9
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 8
- 239000007789 gas Substances 0.000 claims description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 9
- 238000004508 fractional distillation Methods 0.000 claims description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 238000006722 reduction reaction Methods 0.000 claims description 7
- PXJJSXABGXMUSU-UHFFFAOYSA-N disulfur dichloride Chemical compound ClSSCl PXJJSXABGXMUSU-UHFFFAOYSA-N 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 238000004064 recycling Methods 0.000 claims description 4
- 238000005660 chlorination reaction Methods 0.000 abstract description 10
- 238000011084 recovery Methods 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 11
- 238000004821 distillation Methods 0.000 description 9
- 239000007787 solid Substances 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000006298 dechlorination reaction Methods 0.000 description 4
- XDLNRRRJZOJTRW-UHFFFAOYSA-N thiohypochlorous acid Chemical compound ClS XDLNRRRJZOJTRW-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910001570 bauxite Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 241000861718 Chloris <Aves> Species 0.000 description 1
- 101000742346 Crotalus durissus collilineatus Zinc metalloproteinase/disintegrin Proteins 0.000 description 1
- 101000872559 Hediste diversicolor Hemerythrin Proteins 0.000 description 1
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 1
- 229910018105 SCl2 Inorganic materials 0.000 description 1
- 101001135436 Urodacus yaschenkoi Antimicrobial peptide scorpine-like-2 Proteins 0.000 description 1
- HYJODZUSLXOFNC-UHFFFAOYSA-N [S].[Cl] Chemical compound [S].[Cl] HYJODZUSLXOFNC-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- -1 ilmenite Chemical compound 0.000 description 1
- 229910001026 inconel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- FNKUJDADVODZOY-UHFFFAOYSA-N sulfanyl thiohypochlorite Chemical compound SSCl FNKUJDADVODZOY-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 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
- C01B17/00—Sulfur; Compounds thereof
- C01B17/45—Compounds containing sulfur and halogen, with or without oxygen
- C01B17/4507—Compounds containing sulfur and halogen, with or without oxygen containing sulfur and halogen only
- C01B17/4538—Compounds containing sulfur and halogen, with or without oxygen containing sulfur and halogen only containing sulfur and chlorine only
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/10—Halides
Abstract
ABSTRACT
The invention relates to a method for the reduction of ferric chloride to produce ferrous chloride.
The method comprises using gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 as the reducing agent. The reaction is conveniently performed in a fluidised bed.
According to a particular aspect, the ferric chloride reduction forms part of a process for the recovery of chlorine values from iron chloride by-produced by industrial processes such as the chlorination of a titaniferrous or aluminous material.
The invention relates to a method for the reduction of ferric chloride to produce ferrous chloride.
The method comprises using gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 as the reducing agent. The reaction is conveniently performed in a fluidised bed.
According to a particular aspect, the ferric chloride reduction forms part of a process for the recovery of chlorine values from iron chloride by-produced by industrial processes such as the chlorination of a titaniferrous or aluminous material.
Description
This invention relates to a method for the reduction of ferric chloride.
More particularly this invention relates to a method for the partial dec~lorination of ferric 5 chloride to ferrous chloride in the presence of one or more suitable reducing agents.
According to a particu]ar aspect of this invention the partial dechlorination of ferric chloride is a step in a method for the recovery of the chlorine 10 values from iron chloride obtained as a by-product, for example, from the chlorination of a titaniferrous material containing more than 5% by~eight iron oxide such as ilmenite, or obtained as a by-product from the chlorination of an aluminous material, such as bauxite.
United States Patent No, 41407ll6 describes a process ior the recovery of the chlorine values Lrom iron ch]oride obtained as a by-product from the chlor-ination of a titaniferrous material cont~ining more than 5% by weight iron oxide which comprises the steps of:
(a) subjecting ferric chloride to partial dechlorination in the presence of one or more suitable reducing a~ents to produce ferrous chloride and a chloride compound;
(~) subjecting ferrous chloride to an oxidation "~ reaction in the presence of oxygen or a molecular ox~en-11~0039 containin~ ~as at a temperature between 300C and 1200C to produce ferric chloride and ferric oxide; and (c) recycling the resulting ferric chloride to the ~artial dechlorination step (a).
Similar methods for recovering the chlorine values from iron chloride are disclosed in Canad~an application No. 327,367 relatin~ to iron chloride by-produe~d in thc chlorination o~ an aluminolls material e.g. bauxite.
In those processes, a suitable reducin~
agent for ~age (a) is defined as one which meets t~le two following conditions: ~irst that it is effective in dec}llorinating ferric chloride to ferrous chloride;
second, that in reaction wit~ ferric chloride, it produces 15 a chlolide compound which, directly or after further processin~, is either suitable for recycle to the chlorination process (if appropriate) or has other industrial utility.
One such suitable reducin~ agent described 20 in the United States Patent No. 4140746 and Canadian Application No. 327,367 is sulphur, and the method o~ usin~ it was summarised in the followin~
equation (1):-Fe2C16(s) + 2S(l)--~FeC12(s) + S2C12(~)....(1) 5 (where (s) represents solid, (1) represents liquid andtg) r~presents gas).
~0039 Thus in equation (1) liquid sulphur is reacted with solid ferric chloride to produce solid ferroujchloride and gaseous sulphur monochloride.
The method of using sulphur as the reducing 5 agent for ferric chloride, which is summarised in equation (1), has been established experimentally as an effective and successful procedure. Howe~er, it has two major drawbacks. First, it requires that the ferric chloride produced in the oxi~ation stage (b) is condensed from the ~as stream, which is a costly an~ elaborate procedure. Second, the equipment required for contacting and mixing liquid sulphur with solid ferric chloride is, again, costly and elaborate.
It has now surprisingly been found that the 15 reaction represented by equation (1) can be carried out much more conveniently and advantageously using gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of the sulphur to chlorine is more than 1:1.
The fact that this reaction can be successfully ~0 carried out is surprising because the literature sug~ests that sulphur monochloride is increasingly decomposed into sulphur and chlorine as its temperature nses, until at the boiling point of sulphur (444C) it is iully decomposed. Thus the use of gaseous su]phur or ~aseous sulphur chloride in which the atomic ratio of sulphur to ll~Q039 chlorine is more than 1:1 to produce sulphur monochloride and ferrous chloride by reaction with l'erric chloride did not appear promising.
Nevertheless, it has been found that sulphur 5 or gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 is an effective reducin~ agent for ~aseous ferric chloride, particularly when used in a gas fluidised bed of solid ferrous chlorde.
Thus, the present invention provides a method 10 of reducing ferric chloride to ferrous chloride wherein ferric chloridc in ~e gaseous or solid statc is partially dechlorinated in the presence of gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 to form ferrous 15 chloride in the solid state in accordance with the following reaction equations:
Fe2cl6(g/s) + S2(g)--~ 2~eC12(s) ~ S2C12(g) --(2)
More particularly this invention relates to a method for the partial dec~lorination of ferric 5 chloride to ferrous chloride in the presence of one or more suitable reducing agents.
According to a particu]ar aspect of this invention the partial dechlorination of ferric chloride is a step in a method for the recovery of the chlorine 10 values from iron chloride obtained as a by-product, for example, from the chlorination of a titaniferrous material containing more than 5% by~eight iron oxide such as ilmenite, or obtained as a by-product from the chlorination of an aluminous material, such as bauxite.
United States Patent No, 41407ll6 describes a process ior the recovery of the chlorine values Lrom iron ch]oride obtained as a by-product from the chlor-ination of a titaniferrous material cont~ining more than 5% by weight iron oxide which comprises the steps of:
(a) subjecting ferric chloride to partial dechlorination in the presence of one or more suitable reducing a~ents to produce ferrous chloride and a chloride compound;
(~) subjecting ferrous chloride to an oxidation "~ reaction in the presence of oxygen or a molecular ox~en-11~0039 containin~ ~as at a temperature between 300C and 1200C to produce ferric chloride and ferric oxide; and (c) recycling the resulting ferric chloride to the ~artial dechlorination step (a).
Similar methods for recovering the chlorine values from iron chloride are disclosed in Canad~an application No. 327,367 relatin~ to iron chloride by-produe~d in thc chlorination o~ an aluminolls material e.g. bauxite.
In those processes, a suitable reducin~
agent for ~age (a) is defined as one which meets t~le two following conditions: ~irst that it is effective in dec}llorinating ferric chloride to ferrous chloride;
second, that in reaction wit~ ferric chloride, it produces 15 a chlolide compound which, directly or after further processin~, is either suitable for recycle to the chlorination process (if appropriate) or has other industrial utility.
One such suitable reducin~ agent described 20 in the United States Patent No. 4140746 and Canadian Application No. 327,367 is sulphur, and the method o~ usin~ it was summarised in the followin~
equation (1):-Fe2C16(s) + 2S(l)--~FeC12(s) + S2C12(~)....(1) 5 (where (s) represents solid, (1) represents liquid andtg) r~presents gas).
~0039 Thus in equation (1) liquid sulphur is reacted with solid ferric chloride to produce solid ferroujchloride and gaseous sulphur monochloride.
The method of using sulphur as the reducing 5 agent for ferric chloride, which is summarised in equation (1), has been established experimentally as an effective and successful procedure. Howe~er, it has two major drawbacks. First, it requires that the ferric chloride produced in the oxi~ation stage (b) is condensed from the ~as stream, which is a costly an~ elaborate procedure. Second, the equipment required for contacting and mixing liquid sulphur with solid ferric chloride is, again, costly and elaborate.
It has now surprisingly been found that the 15 reaction represented by equation (1) can be carried out much more conveniently and advantageously using gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of the sulphur to chlorine is more than 1:1.
The fact that this reaction can be successfully ~0 carried out is surprising because the literature sug~ests that sulphur monochloride is increasingly decomposed into sulphur and chlorine as its temperature nses, until at the boiling point of sulphur (444C) it is iully decomposed. Thus the use of gaseous su]phur or ~aseous sulphur chloride in which the atomic ratio of sulphur to ll~Q039 chlorine is more than 1:1 to produce sulphur monochloride and ferrous chloride by reaction with l'erric chloride did not appear promising.
Nevertheless, it has been found that sulphur 5 or gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 is an effective reducin~ agent for ~aseous ferric chloride, particularly when used in a gas fluidised bed of solid ferrous chlorde.
Thus, the present invention provides a method 10 of reducing ferric chloride to ferrous chloride wherein ferric chloridc in ~e gaseous or solid statc is partially dechlorinated in the presence of gaseous sulphur or a gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1 to form ferrous 15 chloride in the solid state in accordance with the following reaction equations:
Fe2cl6(g/s) + S2(g)--~ 2~eC12(s) ~ S2C12(g) --(2)
2-z~e2C16(g/S) + S5C12(g)--~ 5FeC12(s) + 2-1-S2C12(g)..(3) In these equations, the second term in equation 2~ (3) represents an example of a sulphur chloride on which the atomic ratio ~ sulphur to chlorine is more than 1:1.
In practice a ~aseous mixture of S2Cl" and S may be employed as the sulphur chloride.
The method according to the present invention is particularly suited to be the partial dechlorination step (a) of' a method for the recovery of -tlle chlorine values 1110~39 ~, from iron chloride, Thus the ferric chloride input to the method summarised in equations (2) ~md (3) preferably deri~es from the processes disclosed in United States Patent No. 4140746 and Canadian Application No. 327,367. However, the present invention is not limited to ~erric chloride derive~
from any ~articular source, The reaction between ~seous sulphur/gaseous sulphur chloride and ferric chloride is preferably carrie~ out in a fluidised bed of (product) ferrous chlori~e, The be~ temperature should be at least suf~icient to maintain the sulphur or sull)hur chloride in the gas phase, The actual minimum temperature for this purpose will vary with the composition of the source of sulphur values and with thc 4uantity of any inert ~ases present in thc n~ctor, Thus the overall temperature limits for the reaction are ~)etween 120C
and 650C, preferably between ~()0C aJId ~50C and more particularly between 300C and 450C, Alternatively, a stirred hed ~actor or a rotary kiln coul(l be used. The reaction is prcferably carried out continuously, The sulphur ~alues, either as elemental sulphur or as a sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1, are 1~10039 preferably introduced to the reactor as a gas, but may a1so be introduced as a liqui~l in which case the liquid is immediately gasified by contact with the hot reaction bed prior to reaction of the sulphur chloride with the ferric chloride.
The ferric chloride is preferably introduced to the reactor as a gas, but may also be introduced as a solid.
The off-gas from the reactor is preferably condensed to a liquid and centrifu~ed to remove solid lO particles (ferric and ferrous chlonde). The resulting sulphur chloride, which is predominantly S2Cl2, may then be treated by various methods depending on the industrial circumstances to the plant. If the ferric chloride feed to t~le process accordin~ to the invention has been 15 obtained by a sulpho-chlorination process, for example a bauxitc sulpho-ch10rination process, it is preferred to recycle the S~C12 to the sulpho-cl-l~rination process.
However, if the ferric chloride feed has been obtained by a carbo-chlorination process, for example 20 an ilmenite carbo-chlorination, it is preferred to pass the S2Cl2 to a fractional distillation p~oce~s.
By fractional distillation, chlorine is recovered as the overhea~ product an(l a sulphur chloride with between 60~/o and 80~o atomic percent sulphur i~ obtained as the 1~10C)39 bottom produet whieh ean then be reeyeled to the re~uetion proeess aeeording to the invention.
Alternatively, the S2Cl2 obtained from the off-gas may be reae~ed with earbon disulphide to produee earbon tetraehloride whieh ean be used either for reeyele to the earbo-elllorination reaetion or for sale to other industrial l)rocesses, with the by-product sulphur being rccyclcd to the re(llletion reaction: or the S2Cl2 product may be reactc(l with carbon monoxide to produee phosgene whieh may be recyeled to the earbo-ehlorination reaetion or ~)assc(l f`or sale to other industrual proeGsses, with the by-l)roduet sulptlur or sulphur ehloride being recycle(l to -the reduetion reaction.
Where fraetional distillation is employed, 1~ it is preferred to perform the disti]lation in two sta~cs. In a first sta~e S2Cl2 is fcd to a first distillation eolumn whieh operates at atmospherie pressure with an overhead temperature of between 2~3C an~ 60C
and a bottom temperature of between 140C and 180C
such that there are pro(iuced a swlphur-rich bottom pro~uct an(l a ehlorine-rich overhead prolluct. The bottom product which preferably contains between 60 and 8~3% atomie percent of sulphur is recycled for the reductiorl oL ferric ehloride. In a second stage, the chlorine-rich sulphur chloride overhead pro(luct g from the first distillation column is fed to a second distillation column which is operated at a pressure of about 10 atmospheres with an overhead temperature of between 20C and 60C and a bottom temperature of 5 between 160C and 220C. Pure elemental chlorine is produced as t~ overhead product and a sulphur chloride in which the atomic ratio of sulphur to chlorine is approximately equal is produced as the bottom product.
The chlorine overhead product can, for e~ample, be 10 recycled to the chlorination process from which the ferric chlorisie was ob~ained and the s~lphur chloride bottom product may be recycled to the first distillation column.
Instead of the two-sta~e distillation process, 15 just described, a single-sta~e distillation process may be employed although this is more energy intensive. In ~he sase of a single-sta~e distillation process~ it is preferred to use an elevated pressure of about 10 atmos-pheres, with an overhead temperature of bctween 20C
20 and 60C and a bottom temperature between 200C and '40C to produce the same products as in th~ -two-stage process.
The ferrous chloride bed overflow from the 25 reduction reactor is preferably converted to ferric chloride and ferric oxide by reaction with a controlled ~110~!39 4uantity of oxy~en or air, as disclosed for stage (b) of the process, described in United States Patent No.
]~l0746 and in Canadian Application No. 327,367 re~,ating to the recovery of-chlorine values from iron 5 ch]oride derived from various sources. The resultin~
iron chloride is preferably recycled to the reduction reaction which is the subject of this invention.
The i,nvention is further illustrated by the following Examples:
10 EXAMPLE 1:
A 100 mm diameter bed of ferrous chloride was fluidised at 380C usin~r a ~as mixture analysing:-4~/min ferric chloride gas 2 ~min nitrogen 4~/min sulphur chlorine mixture (atomic ratio sulphur to chlorine:- 2:1) The ferric chloride and sulphur/chlorine mi~ture entered the bed t}lrough separate orifices and the off-gas was found to have reacted completely to give a sulphur 20 monochloride off-gas with ne~ ible reidual ferric e~llori~e. The ferrous chloride reaction product reported to the reaction bed.
l~X~MPII~ 2:
The distillation of S2C12 produced according to the equation (~) was carned out in a 80 mm diameter ~ . .
1110~39 B Inconel column, which was used for ~oth stages as ~et out helow. For convenience, the quantities of feed material used in each stage were not matched since the critical constraint was the heat load on 5 the condcnser. Samples were collected for analysis after three hours runnin~ time, and the results are ~iven below. The theoretical heats (i.e. the heat input at the ~ottom and the heat load on the condensers) were up to 50,o greater in practice , at the feed rates l0 specified.
Sta~e l Sta~e "
Pressure: Atmospheric 10 Atmospheres Packin~: 1.06 metre~ of Knitmesh 1.G metres of Knitmesh Multifil packin~ (equiv- Multifil packin~ (equiv-alent to 20 theoretical ~ent to 30 theoretical platcs) plates) Location Centre of Column 60~o of packing below of Feed and ~0,~ above.
Plate:
Theoretical 47 Kcal/mole/feed l4 Kcal/mole/feed Heat Input at Bottom:
lIeat Load on Condenser: 34 Kcal/mole/feed ~.5 Kcal/mole/feed Feed Analy~is:
lOO~ S Cl 9O mole' SCl~ l0 mole '~
S Cl,~
Top Product 25 Analysis: 90 mole ~0 SCl2 l lOO~,o Cl (99.7 - 3%) 1~10039 _Sta~e l Sta~e 2 Bottom Product Analysis: 80 mole% S 20 mole % 100~/ S2C12 ( 78- 2~o) Reflux Ratio: 5 3 5 Feed Rate &
Temperature: 27 moles/hour at 20C 170 moles/ho~ 20C
Top Production R~.te & Temp. 22 moles/hour at 50C 76 moles/hour 30C
Bottom Production Rate & Temp. 25 moles/hour at 160C 93 moles/hour 210C
In practice a ~aseous mixture of S2Cl" and S may be employed as the sulphur chloride.
The method according to the present invention is particularly suited to be the partial dechlorination step (a) of' a method for the recovery of -tlle chlorine values 1110~39 ~, from iron chloride, Thus the ferric chloride input to the method summarised in equations (2) ~md (3) preferably deri~es from the processes disclosed in United States Patent No. 4140746 and Canadian Application No. 327,367. However, the present invention is not limited to ~erric chloride derive~
from any ~articular source, The reaction between ~seous sulphur/gaseous sulphur chloride and ferric chloride is preferably carrie~ out in a fluidised bed of (product) ferrous chlori~e, The be~ temperature should be at least suf~icient to maintain the sulphur or sull)hur chloride in the gas phase, The actual minimum temperature for this purpose will vary with the composition of the source of sulphur values and with thc 4uantity of any inert ~ases present in thc n~ctor, Thus the overall temperature limits for the reaction are ~)etween 120C
and 650C, preferably between ~()0C aJId ~50C and more particularly between 300C and 450C, Alternatively, a stirred hed ~actor or a rotary kiln coul(l be used. The reaction is prcferably carried out continuously, The sulphur ~alues, either as elemental sulphur or as a sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1, are 1~10039 preferably introduced to the reactor as a gas, but may a1so be introduced as a liqui~l in which case the liquid is immediately gasified by contact with the hot reaction bed prior to reaction of the sulphur chloride with the ferric chloride.
The ferric chloride is preferably introduced to the reactor as a gas, but may also be introduced as a solid.
The off-gas from the reactor is preferably condensed to a liquid and centrifu~ed to remove solid lO particles (ferric and ferrous chlonde). The resulting sulphur chloride, which is predominantly S2Cl2, may then be treated by various methods depending on the industrial circumstances to the plant. If the ferric chloride feed to t~le process accordin~ to the invention has been 15 obtained by a sulpho-chlorination process, for example a bauxitc sulpho-ch10rination process, it is preferred to recycle the S~C12 to the sulpho-cl-l~rination process.
However, if the ferric chloride feed has been obtained by a carbo-chlorination process, for example 20 an ilmenite carbo-chlorination, it is preferred to pass the S2Cl2 to a fractional distillation p~oce~s.
By fractional distillation, chlorine is recovered as the overhea~ product an(l a sulphur chloride with between 60~/o and 80~o atomic percent sulphur i~ obtained as the 1~10C)39 bottom produet whieh ean then be reeyeled to the re~uetion proeess aeeording to the invention.
Alternatively, the S2Cl2 obtained from the off-gas may be reae~ed with earbon disulphide to produee earbon tetraehloride whieh ean be used either for reeyele to the earbo-elllorination reaetion or for sale to other industrial l)rocesses, with the by-product sulphur being rccyclcd to the re(llletion reaction: or the S2Cl2 product may be reactc(l with carbon monoxide to produee phosgene whieh may be recyeled to the earbo-ehlorination reaetion or ~)assc(l f`or sale to other industrual proeGsses, with the by-l)roduet sulptlur or sulphur ehloride being recycle(l to -the reduetion reaction.
Where fraetional distillation is employed, 1~ it is preferred to perform the disti]lation in two sta~cs. In a first sta~e S2Cl2 is fcd to a first distillation eolumn whieh operates at atmospherie pressure with an overhead temperature of between 2~3C an~ 60C
and a bottom temperature of between 140C and 180C
such that there are pro(iuced a swlphur-rich bottom pro~uct an(l a ehlorine-rich overhead prolluct. The bottom product which preferably contains between 60 and 8~3% atomie percent of sulphur is recycled for the reductiorl oL ferric ehloride. In a second stage, the chlorine-rich sulphur chloride overhead pro(luct g from the first distillation column is fed to a second distillation column which is operated at a pressure of about 10 atmospheres with an overhead temperature of between 20C and 60C and a bottom temperature of 5 between 160C and 220C. Pure elemental chlorine is produced as t~ overhead product and a sulphur chloride in which the atomic ratio of sulphur to chlorine is approximately equal is produced as the bottom product.
The chlorine overhead product can, for e~ample, be 10 recycled to the chlorination process from which the ferric chlorisie was ob~ained and the s~lphur chloride bottom product may be recycled to the first distillation column.
Instead of the two-sta~e distillation process, 15 just described, a single-sta~e distillation process may be employed although this is more energy intensive. In ~he sase of a single-sta~e distillation process~ it is preferred to use an elevated pressure of about 10 atmos-pheres, with an overhead temperature of bctween 20C
20 and 60C and a bottom temperature between 200C and '40C to produce the same products as in th~ -two-stage process.
The ferrous chloride bed overflow from the 25 reduction reactor is preferably converted to ferric chloride and ferric oxide by reaction with a controlled ~110~!39 4uantity of oxy~en or air, as disclosed for stage (b) of the process, described in United States Patent No.
]~l0746 and in Canadian Application No. 327,367 re~,ating to the recovery of-chlorine values from iron 5 ch]oride derived from various sources. The resultin~
iron chloride is preferably recycled to the reduction reaction which is the subject of this invention.
The i,nvention is further illustrated by the following Examples:
10 EXAMPLE 1:
A 100 mm diameter bed of ferrous chloride was fluidised at 380C usin~r a ~as mixture analysing:-4~/min ferric chloride gas 2 ~min nitrogen 4~/min sulphur chlorine mixture (atomic ratio sulphur to chlorine:- 2:1) The ferric chloride and sulphur/chlorine mi~ture entered the bed t}lrough separate orifices and the off-gas was found to have reacted completely to give a sulphur 20 monochloride off-gas with ne~ ible reidual ferric e~llori~e. The ferrous chloride reaction product reported to the reaction bed.
l~X~MPII~ 2:
The distillation of S2C12 produced according to the equation (~) was carned out in a 80 mm diameter ~ . .
1110~39 B Inconel column, which was used for ~oth stages as ~et out helow. For convenience, the quantities of feed material used in each stage were not matched since the critical constraint was the heat load on 5 the condcnser. Samples were collected for analysis after three hours runnin~ time, and the results are ~iven below. The theoretical heats (i.e. the heat input at the ~ottom and the heat load on the condensers) were up to 50,o greater in practice , at the feed rates l0 specified.
Sta~e l Sta~e "
Pressure: Atmospheric 10 Atmospheres Packin~: 1.06 metre~ of Knitmesh 1.G metres of Knitmesh Multifil packin~ (equiv- Multifil packin~ (equiv-alent to 20 theoretical ~ent to 30 theoretical platcs) plates) Location Centre of Column 60~o of packing below of Feed and ~0,~ above.
Plate:
Theoretical 47 Kcal/mole/feed l4 Kcal/mole/feed Heat Input at Bottom:
lIeat Load on Condenser: 34 Kcal/mole/feed ~.5 Kcal/mole/feed Feed Analy~is:
lOO~ S Cl 9O mole' SCl~ l0 mole '~
S Cl,~
Top Product 25 Analysis: 90 mole ~0 SCl2 l lOO~,o Cl (99.7 - 3%) 1~10039 _Sta~e l Sta~e 2 Bottom Product Analysis: 80 mole% S 20 mole % 100~/ S2C12 ( 78- 2~o) Reflux Ratio: 5 3 5 Feed Rate &
Temperature: 27 moles/hour at 20C 170 moles/ho~ 20C
Top Production R~.te & Temp. 22 moles/hour at 50C 76 moles/hour 30C
Bottom Production Rate & Temp. 25 moles/hour at 160C 93 moles/hour 210C
Claims (23)
1. A method for the reduction of ferric chloride to produce ferrous chloride which comprises reacting, at a temper-ature of between 120°C to 650°C, ferric chloride with a reducing agent selected from the group of reducing agents consisting of gaseous sulphur, a mixture of gaseous sulphur and gaseous sulphur chloride in which the atomic ratio of total sulphur in said gaseous sulphur and said gaseous sulphur chloride to the chlorine in said gaseous sulphur chloride is more than 1:1, and gaseous sulphur chloride in which the atomic ratio of sulphur to chlorine is more than 1:1.
2. A method as claimed in claim 1, wherein the reducing agent consists of gaseous sulphur.
3. A method as claimed in claim 1, wherein the reducing agent consists of a mixture of gaseous S2Cl2 and gaseous S.
4. A method as claimed in claim 1, wherein the reaction is performed in a fluidised bed of ferrous chloride.
5. A method as claimed in claims 2 or 3, wherein the the reaction is performed in a fluidised bed of ferrous chloride.
6. A method as claimed in claim 1, 2 or 4, wherein the temperature is between 200°C and 450°C.
7. A method as claimed in claim 1, 2 or 4, wherein the temperature is between 300°C and 450°C.
8. A method as claimed in claim 1, wherein the reducing agent is introduced to a reactor in which the reaction is performed in the gaseous state.
9. A method as claimed in claim 4, wherein the reducing agent is introduced to a reactor in which the reaction is performed in the gaseous state.
10. A method as claimed in claim 1, wherein the gaseous product of the reaction is condensed and subjected to fractional distillation to produce chlorine as the overhead product and a sulphur-rich sulphur chloride as the bottom product.
11. A method as claimed in claim 9, wherein the gaseous product of the reaction is condensed and subjected to fractional distillation to produce chlorine as the overhead product and a sulphur-rich sulphur chloride as the bottom product.
12. A method as claimed in claim 10, wherein the fractional distillation is performed in two stages comprising a first stage at atmospheric pressure with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 140°C and 180°C, whereby a sulphur-rich sulphur chloride bottom product and a chlorine-rich sulphur chloride overhead product are obtained and a second stage at substantially 10 atmospheres pressure with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 160°C and 220°C, where-by a substantially pure elemental chlorine is produced as overhead product and a sulphur chloride in which tne atomic ratio of sulpher to chlorine is approximately equal is produced as bottom product.
13. A method as claimed in claim 11, wherein the fractional distillation is performed in two stages comprising a first stage at atmospheric pressure with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 140°C and 180°C, whereby a sulphur-rich sulphur chloride bottom product and a chlorine-rich sulphur chloride overhead product are obtained and a second stage at substantially 10 atmospheres pressure with an overhead temperature of between 20°C and 60°C
13. A method as claimed in claim 11, wherein the fractional distillation is performed in two stages comprising a first stage at atmospheric pressure with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 140°C and 180°C, whereby a sulphur-rich sulphur chloride bottom product and a chlorine-rich sulphur chloride overhead product are obtained and a second stage at substantially 10 atmospheres pressure with an overhead temperature of between 20°C and 60°C
Claim 13 continued ...
and a bottom temperature of between 160°C and 220°C, whereby a substantially pure elemental chlorine is produced as overhead product and a sulphur chloride in which the atomic ratio of sulphur to chlorine is approximately equal is produced as bottom product.
and a bottom temperature of between 160°C and 220°C, whereby a substantially pure elemental chlorine is produced as overhead product and a sulphur chloride in which the atomic ratio of sulphur to chlorine is approximately equal is produced as bottom product.
14. A method as claimed in claim 10, wherein the fractional distillation is performed in a single stage at a pressure of about 10 atmospheres with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 200°C and 240°C to produce substantially pure elemental chlorine as the overhead product and a sulphur-rich sulphur chloride as the bottom product.
15. A method as claimed in claim 11, wherein the fractional distillation is performed in a single stage at a pressure of about 10 atmospheres with an overhead temperature of between 20°C and 60°C and a bottom temperature of between 200°C and 240°C to produce substantially pure elemental chlorine as the overhead product and a sulphur-rich sulphur chloride as the bottom product.
16. A method as claimed in claims 10, 12 or 14, wherein the reaction temperature is between 200°C and 450°C.
17. A method as claimed in claims 10, 12 or 14, wherein the reaction temperature is between 300°C and 450°C.
18. A method as claimed in claim 1, which further com-prises subjecting the ferrous chloride product to an oxidation reaction with oxygen or an oxygen-containing gas to produce ferric chloride and ferric oxide and recycling the resulting ferric chloride to the reduction reaction.
19. A method as claimed in claims 4, 10 or 12, which further comprises subjecting the ferrous chloride product to an oxidation reaction with oxygen or an oxygen-containing gas to produce ferric chloride and ferric oxide and recycling the resulting ferric chloride to the reduction reaction.
20. A method as claimed in claims 13, 14, or 15, which further comprises subjecting the ferrous chloride product to an oxidation reaction with oxygen or an oxygen-containing gas to produce ferric chloride and ferric oxide and recycling the resulting ferric chloride to the reduction reaction.
21. A method as claimed in claim 18 wherein the ferric chloride is derived from an iron chloride by-produced in a process comprising chlorinating a material selected from the group of materials comprising titaniferous materials and aluminous materials.
22. A method as claimed in claim 18, wherein the ferric chloride is derived directly from an iron chloride by-produced in a process comprising chlorinating a material selected from the group of materials comprising titaniferous materials and aluminous materials.
23. A method as claimed in claim 18, wherein the ferric chloride is derived indirectly from an iron chloride by-produced in a process comprising chlorinating a material selected from the group of materials comprising titaniferous materials and aluminous materials.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB19989/78 | 1978-05-16 | ||
| GB1998978 | 1978-05-16 | ||
| GB1998878 | 1978-05-16 | ||
| GB19988/78 | 1978-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1110039A true CA1110039A (en) | 1981-10-06 |
Family
ID=26254352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA327,370A Expired CA1110039A (en) | 1978-05-16 | 1979-05-10 | Reduction of ferric chloride |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS54150392A (en) |
| CA (1) | CA1110039A (en) |
| DE (1) | DE2918944A1 (en) |
| FR (1) | FR2426022A1 (en) |
| IT (1) | IT1116834B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104609477B (en) * | 2015-02-03 | 2016-05-11 | 上海拱极化学有限公司 | A kind of preparation method of high-purity anhydrous ferric trichloride |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2852339A (en) * | 1955-01-21 | 1958-09-16 | Texas Gulf Sulphur Co | Process of chlorinating iron sulfide to produce ferrous chloride and sulfur |
| GB1584359A (en) * | 1976-11-17 | 1981-02-11 | Mineral Process Licensing Corp | Recovery of chlorine values from iron chloride by-produced in chlorination of ilmenite and the like |
-
1979
- 1979-05-10 CA CA327,370A patent/CA1110039A/en not_active Expired
- 1979-05-10 JP JP5641879A patent/JPS54150392A/en active Pending
- 1979-05-10 IT IT49001/79A patent/IT1116834B/en active
- 1979-05-10 DE DE19792918944 patent/DE2918944A1/en not_active Withdrawn
- 1979-05-16 FR FR7912417A patent/FR2426022A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54150392A (en) | 1979-11-26 |
| IT7949001A0 (en) | 1979-05-10 |
| IT1116834B (en) | 1986-02-10 |
| DE2918944A1 (en) | 1979-11-29 |
| FR2426022A1 (en) | 1979-12-14 |
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