Sciencemadness Discussion Board

Making sulfur from sulfates

symboom - 24-4-2011 at 06:15

first let me say i know it is easier to buy sulfur i have some already
i was wondering whats the best way to extract sulfur from sodium sulfate one process mix aluminum or carbon and sodium sulfate in a steel container and heat forming either aluminum sulfide or (carbon reduction)sodium sulfide add water to the container that was heated forming h2s gas and lead h2s into bleach or hydrogen peroxide 3%
as long as it is not highly basic causing the sulfur to dissolve

ScienceSquirrel - 24-4-2011 at 12:59

Don't do it!
The only time it has even been considered is under war time conditions when sulphur has been impossible to obtain by conventional means.
You have to produce sulphides as the key intermediate in most of these processes and often hydrogen sulphide.
Handling these materials on a large scale without the appropriate equipment is hazardous

symboom - 24-4-2011 at 19:24

i don't mean as in large scale i already have sulfur i just want to explore the method of it. i do put great thought into something before i try it and seek a second opinion

i do have a painters/surgical mask planing on soaking it in hydrogen peroxide to avoid h2s inhalation.

(which the h2s gas will form harmless sulfur when it touches the h2o2 drenched mask)

while i am adding water or hcl to the sulfide compound to form h2s then quickly putting the hose connection into bleach

maybe instead of adding water i could add HCl acid to prevent the formed sodium hydroxide from absorbing H2S


[Edited on 25-4-2011 by symboom]

The WiZard is In - 25-4-2011 at 09:31

Quote: Originally posted by symboom  
first let me say i know it is easier to buy sulfur i have some already
i was wondering whats the best way to extract sulfur from sodium sulfate one process mix aluminum or carbon and sodium sulfate in a steel container and heat forming either aluminum sulfide or (carbon reduction)sodium sulfide add water to the container that was heated forming h2s gas and lead h2s into bleach or hydrogen peroxide 3%
as long as it is not highly basic causing the sulfur to dissolve

This is your lucky day - it is raining and I am not feeling well
so I had time to OCR this from one of the few books I own
that cannot now be found at Google.com/books, however, I did not
take the time to clean up the OCR process.


Wilfrid Wyld
Raw Materials for the Manufacture of Sulphuric Acid and the Manufacture of
Sulphur Dioxide
Gurney and Jackson
London 1923

46 MATERIALS OF SULPHURIC ACID MANUFACTURE


8. Sulphur from Sulphates of the Alkaline Earths.

E. H. Riesenfeld 1 gives a resume on the preparation of sulphur from sulphates :
I. Reduction of Kieserile by Carbon (with Alfred Faber).—A review of the literature on the utilisation of magnesium sulphate leads to preference being given to the proposal of Precht 2 to reduce kieserite by means of charcoal according to the equation 2MgSO4 q- C = 2MgO + 2502 + CO:,. Experi¬ments showed that, at least in part, reaction occurs according to

1 J. pr. Chem., 1920, 100. 115-158 ; J. CI'm. SOC., 1921, 2,
40-42.
2 Chem. Ind., 1881, 4, 350
.
the equation MgSO4 + C = MgO + SO2 + CO. Thus the solid residue always contained sulphur when less than one atomic proportion of carbon to magnesium was employed, the best results being obtained with the proportion t : 1 at 750-850` or 1 5 : I at 950'. Under these conditions, the sulphur was obtained almost entirely as sulphur dioxide, with a little free sulphur. Contrary to what might be expected, reduction was not complete when greater proportions of carbon were used, probably because the molten sulphide then produced surrounded the sulphate and protected it from further action.
IL Reduction of Gypsum and Anhydrite by Carbon (with Hans Feld).—The reaction between gypsum and carbon sets in below 5o0', but very slowly, and is fairly rapid from about 700° upwards. Under suitable conditions, pure calcium sul¬phi1L was obtained, approximately according to the equation CaSO„ + 3C = CaS + CO2 -h 2CO. Similarly, from strontium and barium sulphates, the sulphides were produced, the different behaviour of magnesium sulphate being accounted for by a consideration of the heats of reaction. The composition of the gaseous phase in the former cases is controlled by the C : CO : CO., equilibrium, but in the case of magnesium sulphate this is disturbed by the action of sulphur dioxide on carbon monoxide.

The Calcium .Sulphate- Carbonate Equilibrium (with (Fri.) Italiener and (Fri.) M. Hesse).—The equilibrium CaS + H2O + CO2i=>-CaCO2 -1- H2S cannot be utilised for the dis¬posal of calcium sulphide obtained by the above reduction, since at temperatures, for example 700°, at which it is suffi¬ciently rapidly attained, it favours the formation of calcium sulphide to a very considerable extent.

Reduction of Gypsum and Anhydrite by Gases (with Margarete Hesse).—Gypsum was reduced by methane accord¬ing to the equation CaSO, + CH4 = CaS + CO2 + 2 H2O. Below 800°, dehydration of the gypsum alone occurred, but at 800-1000° quantitative reduction appears possible if the action be sufficiently prolonged. Above I Too°, some calcium oxide was produced, probably as a result of the reaction CaS + H2O = CaO + H;2S. The deduction from this equation — that excess of steam would favour complete removal of sulphur—was confirmed by experiments at 1200° and 1300°.
thionates, and heating in open vessels ; e.g. a liquid containing too parts sodium tetrathionate, 77 sodium bisulphite, and 140 sodium sulphate. This remains at first clear when being heated to boiling, but suddenly a strong separation of sulphur takes place, whereupon the decomposition is quickiy completed, and the liquid now contains only sulphate. In order to avoid explosions, they prefer converting 2 mol. bisulphate and 1 mol. normal sulphite, by heating under pressure, into sulphate and sulphur, through the quantitatively occurring reaction,
2NaI1SO.,+ Na2SO3 = zNa2SO4+ S + H2O.

Hansen (U.S. P. 1101740) obtains free sulphur and sodium sulphate by heating a mixed solution of bisulphate and sulphite, in exactly the same manner.
III.
The Nurnberg Consortium fur clektroch. Industrie (Ger. P. 162913) obtains sulphur by treating alkaline earth sulphides with chlorine at high temperatures, until the chlorine contained in the distillate in the form of sulphuryl chloride suffices for chlorinating the polysulphide formed, whereupon this is decomposed by the sulphuryl chloride in aqueous solutions to chlorides and free sulphur.
Deutsch Petroleum-A.-G. (Ger. P. 339610 of 1918) pass steam at 1200° or above, over the sulphides, which may be mixed with carbon. The steam may be mixed in varying proportions with a reducing-gas such as methane or hydrogen.
IV.
E. H. Riesenfeld 1 gives a resume on the preparation of sulphur from sulphates :

I. Reduction of Kieserile by Carbon (with Alfred Faber).—A review of the literature on the utilisation of magnesium sulphate leads to preference being given to the proposal of Precht 2 to reduce kieserite by means of charcoal according to the equation 2MgSO4 q- C = 2MgO + 2502 + CO:,. Experi¬ments showed that, at least in part, reaction occurs according to
1 J. pr. Chem., 1920, 100. 115-158 ; J. CI'm. SOC., 1921, 2,
40-42.
2 Chem. Ind., 1881, 4, 350.

V.
the equation MgSO4 + C = MgO + SO2 + CO. Thus the solid residue always contained sulphur when less than one atomic proportion of carbon to magnesium was employed, the best results being obtained with the proportion t : 1 at 750-850` or 1 5 : I at 950'. Under these conditions, the sulphur was obtained almost entirely as sulphur dioxide, with a little free sulphur. Contrary to what might be expected, reduction was not complete when greater proportions of carbon were used, probably because the molten sulphide then produced surrounded the sulphate and protected it from further action.

IL Reduction of Gypsum and Anhydrite by Carbon (with Hans Feld).—The reaction between gypsum and carbon sets in below 5o0', but very slowly, and is fairly rapid from about 700° upwards. Under suitable conditions, pure calcium sul¬phi1L was obtained, approximately according to the equation CaSO„ + 3C = CaS + CO2 -h 2CO. Similarly, from strontium and barium sulphates, the sulphides were produced, the different behaviour of magnesium sulphate being accounted for by a consideration of the heats of reaction. The composition of the gaseous phase in the former cases is controlled by the C : CO : CO., equilibrium, but in the case of magnesium sulphate this is disturbed by the action of sulphur dioxide on carbon monoxide.
The Calcium .Sulphate- Carbonate Equilibrium (with (Fri.) Italiener and (Fri.) M. Hesse).—The equilibrium CaS + H2O + CO2i=>-CaCO2 -1- H2S cannot be utilised for the dis¬posal of calcium sulphide obtained by the above reduction, since at temperatures, for example 700°, at which it is suffi¬ciently rapidly attained, it favours the formation of calcium sulphide to a very considerable extent.

Reduction of Gypsum and Anhydrite by Gases (with Margarete Hesse).—Gypsum was reduced by methane accord¬ing to the equation CaSO, + CH4 = CaS + CO2 + 2 H2O. Below 800°, dehydration of the gypsum alone occurred, but at 800-1000° quantitative reduction appears possible if the action be sufficiently prolonged. Above I Too°, some calcium oxide was produced, probably as a result of the reaction CaS + H2O = CaO + H;2S. The deduction from this equation — that excess of steam would favour complete removal of sulphur—was confirmed by experiments at 1200° and 1300°. Partly

in consequence, however, of dissociation of hydrogen sulphide and partly by its reaction with water vapour,' the sulphur was obtained almost entirely as sulphur dioxide or elementary sulphur, the latter predominating when only a slight excess of water was employed.

VI. Decomposition of Calcium Sulphide by Steam and the Direct Conversion of Gyp•um and Anhydrite into Oxide (with Margarete IIesse).—Experiments on the action of steam on calcium sulphide justified the above assumption of its inter-mediate formation, the amounts of sulphur dioxide and ele¬mentary sulphur produced being in agreement with the previous results. It must therefore be possible to convert calcium sulphate directly into the oxide by treatment with carbon and steam, and experiment showed this to occur at 12000, but more than six times as rapidly at 1300'. Owing to the reducing action of carbon monoxide and hydrogen on sulphur dioxide, elementary sulphur predominated in the product, only 5o per cent. being obtained as the dioxide, even when 8 5o times the theoretical proportion of steam was employed.
VII.
Sulphur dioxide is produced from calcium sulphate by Chem. Fabr. vorm. Weiler-ter Meer, Ger. P. 307772. A mixture of calcium sulphate and calcium sulphide is heated above i000°, whereby sulphur dioxide is formed in accordance with the equation
3CaSO4 + CaS = 4CaO + 4SO2.

Palaschowski (Russ. Ps. 5464 and 5477 of 1901 ; Chem. Zeit., 1902, p. 15) describes the following modifications of the process of Baranoff and Hildt for obtaining S and SO., from sulphates. Instead of simply mixing the sulphates with coke, he moulds them into briquettes by means of coal-tar, etc., which shortens the time of reduction. The sulphide is de-composed by CO2 at a pressure of 2 or 3 atmospheres. The H„S is best not passed at once through red-hot sulphates, but first through a solution of the sulphides, which forms Ca(SII), and NaHS. The former is converted by means of Na,SO4 into NaIIS, which with CO2 gives H2S and NaHCO3. Only this H2S is employed for being oxidised by sulphates to S and SO2.

Compare Randell and Bichowsky, J. Chem. Soc., 191 S, 2, 159.

The Verein Chemischer Fabriken Mannheim (B. P. 149662, 1919 states that sulphur dioxide is volatilised when sulphates of the alkaline earth and magnesium and iron sulphates are heated at a comparatively low temperature in the presence of certain reducing-agents. Preferably, the latter arc added only in sufficient quantities for the sulphates to be reduced to the sulphite stage ; the reduction being effected by means of metallic iron, other metals capable of being obtained by reduction with hydrogen, the lower oxides of these metals, or coal. Excess reducing-agent, or sufficient to form sulphides, may be employed, however, but the process is then performed in two stages. The reduction is first effected at about 600', and then the sulphur is volatilised as sulphur dioxide and sulphuric acid, at goo", in a current of steam and air. When excess is used, coal, water-gas, or other reducing-gas may partly replace the metals or their low oxides, and the latter may be produced during the actual process from higher oxides. The reduction may be carried out in an atmosphere of nitrogen or other inert gas, or in a vacuum, and the metal can be recovered from the residual mass by removal of the lime after reduction. In examples gypsum, hepatite, and magnesium sulphate are reduced by the methods given above by means of iron powder, and iron protoxide with evolution of sulphur dioxide.

Bambach (B. P. 3174, 1914 ; Ger. P. app'. P3o692 ; Fr. P. 470652) makes sulphurous acid from alkaline-earth sulphates by heating them to redness by contact with a burn¬ing mixture of gas and air, and further heating the residue, either by a flame containing an excess of air, or by the suc-cessive action 'of a reducing flame and oxygen (preferably as air). The process may be applied to sulphides, the heated material being decomposed by an oxidising flame or by air.

The preparation of sulphur from calcium sulphate was one of the German war-time chemical processes, and it is said that it is still being carried out with advantage because it yields a sulphur of 99.95 per cent. and at a cost smaller than the imported material.

The raw materials of the process are anhydrous calcium Chem. Trade", 1920, p. 652.
thionates, and heating in open vessels ; e.g. a liquid containing too parts sodium tetrathionate, 77 sodium bisulphite, and 140 sodium sulphate. This remains at first clear when being heated to boiling, but suddenly a strong separation of sulphur takes place, whereupon the decomposition is quickiy completed, and the liquid now contains only sulphate. In order to avoid explosions, they prefer converting 2 mol. bisulphate and 1 mol. normal sulphite, by heating under pressure, into sulphate and sulphur, through the quantitatively occurring reaction,
2NaI1SO.,+ Na2SO3 = zNa2SO4+ S + H2O.

Hansen (U.S. P. 1101740) obtains free sulphur and sodium sulphate by heating a mixed solution of bisulphate and sulphite, in exactly the same manner.

The Nurnberg Consortium fur clektroch. Industrie (Ger. P. 162913) obtains sulphur by treating alkaline earth sulphides with chlorine at high temperatures, until the chlorine contained in the distillate in the form of sulphuryl chloride suffices for chlorinating the polysulphide formed, whereupon this is decomposed by the sulphuryl chloride in aqueous solutions to chlorides and free sulphur.

Deutsch Petroleum-A.-G. (Ger. P. 339610 of 1918) pass steam at 1200° or above, over the sulphides, which may be mixed with carbon. The steam may be mixed in varying proportions with a reducing-gas such as methane or hydrogen.

8. Sulphur from Sulphates of the Alkaline Earths.
E. H. Riesenfeld 1 gives a resume on the preparation of sulphur from sulphates :
I. Reduction of Kieserile by Carbon (with Alfred Faber).—A review of the literature on the utilisation of magnesium sulphate leads to preference being given to the proposal of Precht 2 to reduce kieserite by means of charcoal according to the equation 2MgSO4 q- C = 2MgO + 2502 + CO:,. Experi¬ments showed that, at least in part, reaction occurs according to
1 J. pr. Chem., 1920, 100. 115-158 ; J. CI'm. SOC., 1921, 2,
40-42.
2 Chem. Ind., 1881, 4, 350.

the equation MgSO4 + C = MgO + SO2 + CO. Thus the solid residue always contained sulphur when less than one atomic proportion of carbon to magnesium was employed, the best results being obtained with the proportion t : 1 at 750-850` or 1 5 : I at 950'. Under these conditions, the sulphur was obtained almost entirely as sulphur dioxide, with a little free sulphur. Contrary to what might be expected, reduction was not complete when greater proportions of carbon were used, probably because the molten sulphide then produced surrounded the sulphate and protected it from further action.

IL Reduction of Gypsum and Anhydrite by Carbon (with Hans Feld).—The reaction between gypsum and carbon sets in below 5o0', but very slowly, and is fairly rapid from about 700° upwards. Under suitable conditions, pure calcium sul¬phi1L was obtained, approximately according to the equation CaSO„ + 3C = CaS + CO2 -h 2CO. Similarly, from strontium and barium sulphates, the sulphides were produced, the different behaviour of magnesium sulphate being accounted for by a consideration of the heats of reaction. The composition of the gaseous phase in the former cases is controlled by the C : CO : CO., equilibrium, but in the case of magnesium sulphate this is disturbed by the action of sulphur dioxide on carbon monoxide.

III. The Calcium .Sulphate- Carbonate Equilibrium (with (Fri.) Italiener and (Fri.) M. Hesse).—The equilibrium CaS + H2O + CO2i=>-CaCO2 -1- H2S cannot be utilised for the dis¬posal of calcium sulphide obtained by the above reduction, since at temperatures, for example 700°, at which it is suffi¬ciently rapidly attained, it favours the formation of calcium sulphide to a very considerable extent.

IV. Reduction of Gypsum and Anhydrite by Gases (with Margarete Hesse).—Gypsum was reduced by methane accord¬ing to the equation CaSO, + CH4 = CaS + CO2 + 2 H2O. Below 800°, dehydration of the gypsum alone occurred, but at 800-1000° quantitative reduction appears possible if the action be sufficiently prolonged. Above I Too°, some calcium oxide was produced, probably as a result of the reaction CaS + H2O = CaO + H;2S. The deduction from this equation — that excess of steam would favour complete removal of sulphur—was confirmed by experiments at 1200° and 1300°. Partly in consequence, however, of dissociation of hydrogen sulphide and partly by its reaction with water vapour,' the sulphur was obtained almost entirely as sulphur dioxide or elementary sulphur, the latter predominating when only a slight excess of water was employed.

V. Decomposition of Calcium Sulphide by Steam and the Direct Conversion of Gyp•um and Anhydrite into Oxide (with Margarete IIesse).—Experiments on the action of steam on calcium sulphide justified the above assumption of its inter-mediate formation, the amounts of sulphur dioxide and ele¬mentary sulphur produced being in agreement with the previous results. It must therefore be possible to convert calcium sulphate directly into the oxide by treatment with carbon and steam, and experiment showed this to occur at 12000, but more than six times as rapidly at 1300'. Owing to the reducing action of carbon monoxide and hydrogen on sulphur dioxide, elementary sulphur predominated in the product, only 5o per cent. being obtained as the dioxide, even when 8 5o times the theoretical proportion of steam was employed.

Sulphur dioxide is produced from calcium sulphate by Chem. Fabr. vorm. Weiler-ter Meer, Ger. P. 307772. A mixture of calcium sulphate and calcium sulphide is heated above i000°, whereby sulphur dioxide is formed in accordance with the equation
3CaSO4 + CaS = 4CaO + 4SO2.

Palaschowski (Russ. Ps. 5464 and 5477 of 1901 ; Chem. Zeit., 1902, p. 15) describes the following modifications of the process of Baranoff and Hildt for obtaining S and SO., from sulphates. Instead of simply mixing the sulphates with coke, he moulds them into briquettes by means of coal-tar, etc., which shortens the time of reduction. The sulphide is de-composed by CO2 at a pressure of 2 or 3 atmospheres. The H„S is best not passed at once through red-hot sulphates, but first through a solution of the sulphides, which forms Ca(SII), and NaHS. The former is converted by means of Na,SO4 into NaIIS, which with CO2 gives H2S and NaHCO3. Only this H2S is employed for being oxidised by sulphates to S and SO2.
Compare Randell and Bichowsky, J. Chem. Soc., 191 S, 2, 159.

The Verein Chemischer Fabriken Mannheim (B. P. 149662, 1919) states that sulphur dioxide is volatilised when sulphates of the alkaline earth and magnesium and iron sulphates are heated at a comparatively low temperature in the presence of certain reducing-agents. Preferably, the latter arc added only in sufficient quantities for the sulphates to be reduced to the sulphite stage ; the reduction being effected by means of metallic iron, other metals capable of being obtained by reduction with hydrogen, the lower oxides of these metals, or coal. Excess reducing-agent, or sufficient to form sulphides, may be employed, however, but the process is then performed in two stages. The reduction is first effected at about 600', and then the sulphur is volatilised as sulphur dioxide and sulphuric acid, at goo", in a current of steam and air. When excess is used, coal, water-gas, or other reducing-gas may partly replace the metals or their low oxides, and the latter may be produced during the actual process from higher oxides. The reduction may be carried out in an atmosphere of nitrogen or other inert gas, or in a vacuum, and the metal can be recovered from the residual mass by removal of the lime after reduction. In examples gypsum, hepatite, and magnesium sulphate are reduced by the methods given above by means of iron powder, and iron protoxide with evolution of sulphur dioxide.

Bambach (B. P. 3174, 1914 ; Ger. P. app'. P3o692 ; Fr. P. 470652) makes sulphurous acid from alkaline-earth sulphates by heating them to redness by contact with a burn¬ing mixture of gas and air, and further heating the residue, either by a flame containing an excess of air, or by the suc¬cessive action 'of a reducing flame and oxygen (preferably as air). The process may be applied to sulphides, the heated material being decomposed by an oxidising flame or by air.

The preparation of sulphur from calcium sulphate was one of the German war-time chemical processes, and it is said that it is still being carried out with advantage because it yields a sulphur of 99.95 per cent. and at a cost smaller than the imported material.

The raw materials of the process are anhydrous calcium Chen'. Trade", 1920, p. 652.

sulphate and magnesium chloride, both occurring in the potash salt deposits.

The sulphate is mixed with coal and heated in revolving furnaces to 1100o ; the resulting calcium sulphide is ground up and treated with a solution of magnesium chloride and live steam ; the sulphuretted hydrogen passes through Claus furnaces (bauxite being used as a catalyser), and the sulphur is deposited there and in the subliming chambers.

The Badische Anilin- and Soda-Fabrik Ger. Ps. (A) 301682, (B) 302471, 18.11.16, (C) 306312, 24.12.16, are for the production of sulphur from calcium sulphate.

(A) The gases containing sulphur dioxide derived from the decomposition of calcium sulphate are mixed with carbon monoxide, or gases containing carbon monoxide, in presence of red-hot coal or coke.
(.R) Instead of, or in addition to, carbon monoxide, oxygen or air may be introduced in such excess that the gases, after leaving the combustion zone and on entering the reduction-chamber, contain an appreciable proportion of oxygen.

(C) When gypsum is employed for the production of the gases, it may be first dehydrated, the air introduced into the process being also completely dried. The yield of sulphur is practically doubled by this means.

Reducing Sulphur to Fine Powder.