CA2130212A1 - Process for working up thin acid - Google Patents
Process for working up thin acidInfo
- Publication number
- CA2130212A1 CA2130212A1 CA002130212A CA2130212A CA2130212A1 CA 2130212 A1 CA2130212 A1 CA 2130212A1 CA 002130212 A CA002130212 A CA 002130212A CA 2130212 A CA2130212 A CA 2130212A CA 2130212 A1 CA2130212 A1 CA 2130212A1
- Authority
- CA
- Canada
- Prior art keywords
- filtrate
- manganese
- solution
- magnesium
- soluble compounds
- 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.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
- C22B34/1254—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching using basic solutions or liquors
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/24—Sulfates of ammonium
- C01C1/242—Preparation from ammonia and sulfuric acid or sulfur trioxide
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Compounds Of Iron (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Fertilizers (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Removal Of Specific Substances (AREA)
Abstract
A PROCESS FOR WORKING UP THIN ACID
A b s t r a c t The invention relates to a process for working up thin acid from the production of titanium dioxide by the sulfate method.
A b s t r a c t The invention relates to a process for working up thin acid from the production of titanium dioxide by the sulfate method.
Description
;..1 ,~,~ ..1., A PROCESS FOR WORKING UP T~IN ACII) This invention relates to a process for working up thin acid from the production of titanium dioxide by the sulfate method.
Thin acid accumulates in the production of titanium dioxide by the sulfate method and, at the present time, is recycled after concentration in several stages.
According to US 3,016,286, ammonia is added to thin acid from the production of titanium dioxide at elevated temperature up to a pH value of about6. The solid formed (TiO(OH)2, VO(OH)2, Al(0H)3, Cr(OH)3) is filtered off.
The filtrate is oxidized with air at pH 7 to 8, resulting in the formation of an iron-pigment which is also filtered off. However, the filtrate still contains small quantities of impurities, magnesium and manganese in particular being troublesome in the concentration of the filtrate by evaporation to produce ammonium sulfate.
In JP 45/36 216, thin acid (waste acid) is neutralized with ammonia in the presence of magnetite nuclei to precipitate iron. Residues of iron are removed .-.
after oxidation with air. The solution obtained is laden with impurities so thatconcentration by evaporation to form ammonium sulfate is barely possible. In addition, the ammonium sulfate would also contain numerous impurities.
According to DE 2 443 942, iron ions are removed from acidic wastewaters by a combined oxidation and precipitation process in which a mixtureof air and ammonia is delivered to the wastewater. The problems caused by other metal ions which are normally present in the thin acid are not discussed in thisdocument.
According to DE 3 115 937, cations are removed from the thin acid by increasing the pH value in steps by addition of ammonia. The solution obtained can then be concentrated by evaporation. However, the concentration step is extremely difficult to control and the ammonium sulfate obtained contains magnesium as an impurity so that, for example, it cannot be stored.
Accordingly, the problem addressed by the present invention was to provide a process which would enable thin acid from the production of titanium Le A 29 587-FC
r..- :, " '". :~
.....
~,. - - ' 2 ~ 3 i 1 2 dioxide to be effectively worked up, i.e. above all simply and inexpensively, the useful materials present in the thin acid being converted into a suitable usefulform so that they may be put to further uses.
According to the invention, this problem has been solved by a process in which the sulfate present in the thin acid is converted into technically pure ammonium sulfate which may be used as a fertilizer.
The present invention relates to a continuous process for working up thin acid from the production of titanium dioxide by the sulfate method, characterized in that a) in a first step, the thin acid is partly neutralized with ammonia to pH
values of 4 to 6 at temperatures above 50C to the boiling point of the solution and preferably at temperatures of 70C to 110C, 15 b) the resulting poorly soluble compounds of the metals titanium, vanadium, chromium, aluminium and, partly, iron from a) are filtered off and the filter cake is optionally washed and further worked up, c) the filtrate and optionally the washing water from b) are neutralized with ammonia to pH values of around 7 and, at the same time, oxidized with air/ oxygen, d) the resulting poorly soluble compounds of the metals iron and, partly, manganese from c) are filtered off and the filter cake is optionally washed and further worked up, e) the filtrate and optionally the washing water f`rom d) are subjected to reactive extraction at temperatures of from 60-95C, especially of from 70-90C, to remove magnesium and manganese by Le A 29 587-FC 2 ,,, . , ~ ' ,;
' '~
.
, ~
:` :
2 ~
el) contacting an ammonium salt of a phosphoric acid derivative or phosphonic acid derivative in an organic solution with the filtrate in countercurrent, the ammonium ions passing into the filtrate and the magnesium and manganese ions passing into the organic solution, e2) freeing the organic solution from magnesium and manganese by addition of aqueous sulfuric acid solution to form an aqueous sulfuric acid solution containing magnesium sulfate and manganese sulfate, e3) adding ammonium hydroxide to the organic solution from e2) and reusing the solution in el), f) after removal of magnesium and manganese, the aqueous ammonium sulfate solution from e) is optionally subj ected to evaporative crystallization to form solid arnmonium sulfate.
The process variants are schematized in Figs. 1 to 3.
The filter cake from reaction step b) is preferably further worked up by a) oxidizing the filter cake with air/oxygen, simultaneously adding sodium hydroxide and heating to temperatures above 100C, the pH value being kept at >12, 25 b) filtering off the resulting poorly soluble compounds of the metals titanium and iron from a), c) cooling the filtrate from b), which contains the soluble compounds of the metals aluminium, vanadium and chromium, in the presence of nuclei or neutralizing it with CO2 to pH 7, Le A 29 587-FC 3 , ............ .. .
.... .
., .
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d) filtering off the resulting poorly soluble compounds of aluminium from c), e) optionally adjusting the filtrate from d) with sulfuric acid to a pH value around 2, f) filtering off the resulting poorly soluble compounds of vanadium from e) and g) precipitating the chromium from the filtrate from f) by addition of sodium 10 sulfite and sodium carbonate as chromium hydroxide at pH 5-6.
The working up of the filter cake frorn b) is illustrated in Fig. 4. ~ :
The aqueous magnesium- and manganese-containing sulfuric acid solution 15accumulating in the liquid/liquid extraction is preferably cooled and the .
magnesium ammonium sulfate/manganese sulfate forrned is separated off.
The extraction step may be principally replaced by low-temperature .
crystallization to remove magnesium and mangarlese from the filtrate and, optionally, the washing water from reaction step d) of the process according to the 20invention, however, this low-temperature crystallization has some disadvantages (e.g. less pure ammonium sulfate as product, high expense).
The invention is illustrated by the following Examples.
Examples ~ .
Example 1 A. Neutralization with N~I3 and oxidation with air (invention) 1,000 kg of thin acid (for composition, see Table 1) are continuously neutrali~ed to pH 5.0 with 99.95 kg of NH3 at a temperature of 70 to 80C. 19.1430kg of a precipitate are formed (36.31% TiO(OH)2 54.37% Al(OH)3, 6.21%
VO(OH)2 and 3.11% Cr(OH)3) (see Table l; solid 1). After filtration, 1,080.81 kg Le A 29 587-FC 4 .,.
. ~ ~
'; ' :
(. J J ~
of a solution remain behind (35.92% (NH4)2S04, 4.15% FeSO4, 0.08% MnSO4, 3.25% MgS04, 0.22% CaSO4 and 56.37% H2O), see Table 1; filtrate 1.
In a second stage, the clear liquid is oxidized with approximately 40 m3 of air and kept at pH 7.0 during oxidation with 10.16 kg of NH3. Under these 5 conditions, 22.8 kg of Fe3O4 (magnetite) (Table 1; solid 2) are formed. After filtration, 1,069.74 kg of ammonium sulfate solution remain behind (39.98%
(NH4)2SO4, 3.29% MgSO4, 0.08% MnSO4, 0.22% CaS04 and 56.43% H20), see Table l; filtrate 2.
10 Bl. Concentration by evaporation (prior art) When the solution accumulating in the preceding step is directly concentrated by evaporation, 427.72 kg of ammonium sulfate containing Mg(NH4)2(SO4)2 6H20, CaS04 and MnSO4 as impurities (see Table 2) crystallize out. This solid cannot be used as a fertilizer, for example because its nitrogen15 content (18.24%) is too low (required nitrogen content: 21%). Because of the hygroscopic character of the double salt, the product is not free-flowing and, accordingly, is difficult to handle. In addition, the solubility of Mg(N~4)2(SO4)2 6H20 is highly dependent on temperature, so that caking would occur in the event of subsequent concentration of ammonium sulfate by evapora-20 tion in crystallization towers.
B2. Extraction (invention) 500 kg of a 40% solution of di-(2-ethylhexyl)-phosphoric acid in Shellsol-K~ are mixed with 37 kg of a 30% NH3 solution. The ammonium salt is formed.
25 1,000 kg of the ammonium sulfate solution accumulating in the preceding step (approx. 0.7% Mg; free from Ti, Al, V, Cr and Fe) are extracted with this solution in four mixer-settlers (countercurrent operation). 1,000 kg of ammonium sulfate solution containing approx. 150 ppm Mg remain behind. All other metal ions are quantitatively removed.
In the re-extraction step, the organic phase is regenerated with 121 kg of 25% H2SO4 in two additional mixer-settlers (countercurrent operation). 153 kg of Le A 29 587-FC 5 , : :
- , .
- . , ~ - ' , -.
,, . , , , -.,. ~- , ~ .
,, . - .
,~ . . . . .
~ 1 J !3 ~ ,. 2 rafflnate (composition: 22.6% MgSO4, 0.63% MnSO4 and 0.44% CaSO4) are formed.
B3. Concentration by evaporation (invention) 1,000 kg of the ammonium sulfate solution from B2. are concentrated by ~ :evaporation in stages at 50C, 75C and 108C. 454.6 kg of ammonium sulfate containing 21.13% of nitrogen are formed.
C. Working up of the solid from the neutralization step (invention) 10 Separation of the titanium: ~ .
100 kg of washed filter cake are heated beyond 100C with 80 kg of 25%
NaOH and, at the same time, oxidized with air. 27.2 kg of NaTiO3 remain after filtration and may be reused, for example, in the titanium digestion step. The filtrate contains 65.2 kg of NaAI02, 8.6 kg of NaVO3 and 5.6 kg of Na2CrO4.
Separation of the aluminium:
The aluminium can be removed in two ways:
a) 100 kg of filtrate (Ti-free) are neutralized to pH 7.0 with CO2, 30 kg of Al2O3-3H2O crystallizing out. :~
20 b) 100 kg of filtrate (free from Ti) are cooled to 25C with recycling of hydrargillite nuclei. 25 kg of Al(OH)3 are formed.
Separation of the vanadium: -:
70 kg of filtrate (free from Ti and Al) are acidified to pH 2 with 33 kg of H2SO4 (80%) at 25C, 3.2 kg of V2Os precipitating.
Separation of the chromium:
100 kg of filtrate (free from Ti, Al and V) are reduced by addition of 2 kg of Na~SO3, the solution is partly neutralized to pH S and 1.8 kg of Cr(OH)3 are isolated.
Le A 29 587-FC 6 ,~ . , - - : :
, "~ ~,1 ," ~
Table I [all quantities in % by weight]
r _ Thin acid Solid I Filtrate I Solid 2 Filtrate 2 H2SO4 25.92 TiOSO4 1.14 <0.0001 Al2(SO4 2.28 <0.0001 I
VOSO4 0.19 <o.oO
Cr2(sO4)3 0.11 <0.0001 FeSO4 4.49 0.0010 4.15 <0.0010 MnSO4 0.08 0.0010 0.08 2.06 0.08 I
MgSO4 3.52 0.0010 3.25 3.29 CaSO4 0.24 0.22 0.22 H2O 62.03 56.37 56.43 ¦
I
(NH4)2SO4 35.92 39.98 TiO(OH)2 36.31 l l I
¦ Al(OH)3 54.37 VO(OH)2 6.21 Cr(OH)3 3.11 _ _ Fe34 97.94 Le A 29 587-FC 7 . . . . :
.
,: .: . - .- :
Table 2 __ Quantity [kg] [%] [% N]
~NIlI4)2SO4 427.72 86.02 18.21 MgSO4 35.16 7.07 CaSO4 2.38 0.48 MgSO4 0.82 0.16 I
II2O 31.13 6.26 Total 497.21 100 Le A 29 587-FC 8
Thin acid accumulates in the production of titanium dioxide by the sulfate method and, at the present time, is recycled after concentration in several stages.
According to US 3,016,286, ammonia is added to thin acid from the production of titanium dioxide at elevated temperature up to a pH value of about6. The solid formed (TiO(OH)2, VO(OH)2, Al(0H)3, Cr(OH)3) is filtered off.
The filtrate is oxidized with air at pH 7 to 8, resulting in the formation of an iron-pigment which is also filtered off. However, the filtrate still contains small quantities of impurities, magnesium and manganese in particular being troublesome in the concentration of the filtrate by evaporation to produce ammonium sulfate.
In JP 45/36 216, thin acid (waste acid) is neutralized with ammonia in the presence of magnetite nuclei to precipitate iron. Residues of iron are removed .-.
after oxidation with air. The solution obtained is laden with impurities so thatconcentration by evaporation to form ammonium sulfate is barely possible. In addition, the ammonium sulfate would also contain numerous impurities.
According to DE 2 443 942, iron ions are removed from acidic wastewaters by a combined oxidation and precipitation process in which a mixtureof air and ammonia is delivered to the wastewater. The problems caused by other metal ions which are normally present in the thin acid are not discussed in thisdocument.
According to DE 3 115 937, cations are removed from the thin acid by increasing the pH value in steps by addition of ammonia. The solution obtained can then be concentrated by evaporation. However, the concentration step is extremely difficult to control and the ammonium sulfate obtained contains magnesium as an impurity so that, for example, it cannot be stored.
Accordingly, the problem addressed by the present invention was to provide a process which would enable thin acid from the production of titanium Le A 29 587-FC
r..- :, " '". :~
.....
~,. - - ' 2 ~ 3 i 1 2 dioxide to be effectively worked up, i.e. above all simply and inexpensively, the useful materials present in the thin acid being converted into a suitable usefulform so that they may be put to further uses.
According to the invention, this problem has been solved by a process in which the sulfate present in the thin acid is converted into technically pure ammonium sulfate which may be used as a fertilizer.
The present invention relates to a continuous process for working up thin acid from the production of titanium dioxide by the sulfate method, characterized in that a) in a first step, the thin acid is partly neutralized with ammonia to pH
values of 4 to 6 at temperatures above 50C to the boiling point of the solution and preferably at temperatures of 70C to 110C, 15 b) the resulting poorly soluble compounds of the metals titanium, vanadium, chromium, aluminium and, partly, iron from a) are filtered off and the filter cake is optionally washed and further worked up, c) the filtrate and optionally the washing water from b) are neutralized with ammonia to pH values of around 7 and, at the same time, oxidized with air/ oxygen, d) the resulting poorly soluble compounds of the metals iron and, partly, manganese from c) are filtered off and the filter cake is optionally washed and further worked up, e) the filtrate and optionally the washing water f`rom d) are subjected to reactive extraction at temperatures of from 60-95C, especially of from 70-90C, to remove magnesium and manganese by Le A 29 587-FC 2 ,,, . , ~ ' ,;
' '~
.
, ~
:` :
2 ~
el) contacting an ammonium salt of a phosphoric acid derivative or phosphonic acid derivative in an organic solution with the filtrate in countercurrent, the ammonium ions passing into the filtrate and the magnesium and manganese ions passing into the organic solution, e2) freeing the organic solution from magnesium and manganese by addition of aqueous sulfuric acid solution to form an aqueous sulfuric acid solution containing magnesium sulfate and manganese sulfate, e3) adding ammonium hydroxide to the organic solution from e2) and reusing the solution in el), f) after removal of magnesium and manganese, the aqueous ammonium sulfate solution from e) is optionally subj ected to evaporative crystallization to form solid arnmonium sulfate.
The process variants are schematized in Figs. 1 to 3.
The filter cake from reaction step b) is preferably further worked up by a) oxidizing the filter cake with air/oxygen, simultaneously adding sodium hydroxide and heating to temperatures above 100C, the pH value being kept at >12, 25 b) filtering off the resulting poorly soluble compounds of the metals titanium and iron from a), c) cooling the filtrate from b), which contains the soluble compounds of the metals aluminium, vanadium and chromium, in the presence of nuclei or neutralizing it with CO2 to pH 7, Le A 29 587-FC 3 , ............ .. .
.... .
., .
!j,, ' . :
~,';''' ~
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~, . . .
d) filtering off the resulting poorly soluble compounds of aluminium from c), e) optionally adjusting the filtrate from d) with sulfuric acid to a pH value around 2, f) filtering off the resulting poorly soluble compounds of vanadium from e) and g) precipitating the chromium from the filtrate from f) by addition of sodium 10 sulfite and sodium carbonate as chromium hydroxide at pH 5-6.
The working up of the filter cake frorn b) is illustrated in Fig. 4. ~ :
The aqueous magnesium- and manganese-containing sulfuric acid solution 15accumulating in the liquid/liquid extraction is preferably cooled and the .
magnesium ammonium sulfate/manganese sulfate forrned is separated off.
The extraction step may be principally replaced by low-temperature .
crystallization to remove magnesium and mangarlese from the filtrate and, optionally, the washing water from reaction step d) of the process according to the 20invention, however, this low-temperature crystallization has some disadvantages (e.g. less pure ammonium sulfate as product, high expense).
The invention is illustrated by the following Examples.
Examples ~ .
Example 1 A. Neutralization with N~I3 and oxidation with air (invention) 1,000 kg of thin acid (for composition, see Table 1) are continuously neutrali~ed to pH 5.0 with 99.95 kg of NH3 at a temperature of 70 to 80C. 19.1430kg of a precipitate are formed (36.31% TiO(OH)2 54.37% Al(OH)3, 6.21%
VO(OH)2 and 3.11% Cr(OH)3) (see Table l; solid 1). After filtration, 1,080.81 kg Le A 29 587-FC 4 .,.
. ~ ~
'; ' :
(. J J ~
of a solution remain behind (35.92% (NH4)2S04, 4.15% FeSO4, 0.08% MnSO4, 3.25% MgS04, 0.22% CaSO4 and 56.37% H2O), see Table 1; filtrate 1.
In a second stage, the clear liquid is oxidized with approximately 40 m3 of air and kept at pH 7.0 during oxidation with 10.16 kg of NH3. Under these 5 conditions, 22.8 kg of Fe3O4 (magnetite) (Table 1; solid 2) are formed. After filtration, 1,069.74 kg of ammonium sulfate solution remain behind (39.98%
(NH4)2SO4, 3.29% MgSO4, 0.08% MnSO4, 0.22% CaS04 and 56.43% H20), see Table l; filtrate 2.
10 Bl. Concentration by evaporation (prior art) When the solution accumulating in the preceding step is directly concentrated by evaporation, 427.72 kg of ammonium sulfate containing Mg(NH4)2(SO4)2 6H20, CaS04 and MnSO4 as impurities (see Table 2) crystallize out. This solid cannot be used as a fertilizer, for example because its nitrogen15 content (18.24%) is too low (required nitrogen content: 21%). Because of the hygroscopic character of the double salt, the product is not free-flowing and, accordingly, is difficult to handle. In addition, the solubility of Mg(N~4)2(SO4)2 6H20 is highly dependent on temperature, so that caking would occur in the event of subsequent concentration of ammonium sulfate by evapora-20 tion in crystallization towers.
B2. Extraction (invention) 500 kg of a 40% solution of di-(2-ethylhexyl)-phosphoric acid in Shellsol-K~ are mixed with 37 kg of a 30% NH3 solution. The ammonium salt is formed.
25 1,000 kg of the ammonium sulfate solution accumulating in the preceding step (approx. 0.7% Mg; free from Ti, Al, V, Cr and Fe) are extracted with this solution in four mixer-settlers (countercurrent operation). 1,000 kg of ammonium sulfate solution containing approx. 150 ppm Mg remain behind. All other metal ions are quantitatively removed.
In the re-extraction step, the organic phase is regenerated with 121 kg of 25% H2SO4 in two additional mixer-settlers (countercurrent operation). 153 kg of Le A 29 587-FC 5 , : :
- , .
- . , ~ - ' , -.
,, . , , , -.,. ~- , ~ .
,, . - .
,~ . . . . .
~ 1 J !3 ~ ,. 2 rafflnate (composition: 22.6% MgSO4, 0.63% MnSO4 and 0.44% CaSO4) are formed.
B3. Concentration by evaporation (invention) 1,000 kg of the ammonium sulfate solution from B2. are concentrated by ~ :evaporation in stages at 50C, 75C and 108C. 454.6 kg of ammonium sulfate containing 21.13% of nitrogen are formed.
C. Working up of the solid from the neutralization step (invention) 10 Separation of the titanium: ~ .
100 kg of washed filter cake are heated beyond 100C with 80 kg of 25%
NaOH and, at the same time, oxidized with air. 27.2 kg of NaTiO3 remain after filtration and may be reused, for example, in the titanium digestion step. The filtrate contains 65.2 kg of NaAI02, 8.6 kg of NaVO3 and 5.6 kg of Na2CrO4.
Separation of the aluminium:
The aluminium can be removed in two ways:
a) 100 kg of filtrate (Ti-free) are neutralized to pH 7.0 with CO2, 30 kg of Al2O3-3H2O crystallizing out. :~
20 b) 100 kg of filtrate (free from Ti) are cooled to 25C with recycling of hydrargillite nuclei. 25 kg of Al(OH)3 are formed.
Separation of the vanadium: -:
70 kg of filtrate (free from Ti and Al) are acidified to pH 2 with 33 kg of H2SO4 (80%) at 25C, 3.2 kg of V2Os precipitating.
Separation of the chromium:
100 kg of filtrate (free from Ti, Al and V) are reduced by addition of 2 kg of Na~SO3, the solution is partly neutralized to pH S and 1.8 kg of Cr(OH)3 are isolated.
Le A 29 587-FC 6 ,~ . , - - : :
, "~ ~,1 ," ~
Table I [all quantities in % by weight]
r _ Thin acid Solid I Filtrate I Solid 2 Filtrate 2 H2SO4 25.92 TiOSO4 1.14 <0.0001 Al2(SO4 2.28 <0.0001 I
VOSO4 0.19 <o.oO
Cr2(sO4)3 0.11 <0.0001 FeSO4 4.49 0.0010 4.15 <0.0010 MnSO4 0.08 0.0010 0.08 2.06 0.08 I
MgSO4 3.52 0.0010 3.25 3.29 CaSO4 0.24 0.22 0.22 H2O 62.03 56.37 56.43 ¦
I
(NH4)2SO4 35.92 39.98 TiO(OH)2 36.31 l l I
¦ Al(OH)3 54.37 VO(OH)2 6.21 Cr(OH)3 3.11 _ _ Fe34 97.94 Le A 29 587-FC 7 . . . . :
.
,: .: . - .- :
Table 2 __ Quantity [kg] [%] [% N]
~NIlI4)2SO4 427.72 86.02 18.21 MgSO4 35.16 7.07 CaSO4 2.38 0.48 MgSO4 0.82 0.16 I
II2O 31.13 6.26 Total 497.21 100 Le A 29 587-FC 8
Claims (3)
1. A continuous process for working up thin acid from the production of titanium dioxide by the sulfate, characterized in that a) in a first step, the thin acid is partly neutralized with ammonia to pH values of 4 to 6 at temperatures above 50°C to the boiling point of the solution and preferably at temperatures of 70°C to 110°C, b) the resulting poorly soluble compounds of the metals titanium, vanadium, chromium, aluminium and, partly, iron from a) are filtered off and the filter cake is optionally washed and further worked up, c) the filtrate and optionally the washing water from b) are neutralized with ammonia to pH values of around 7 and, at the same time, oxidized with air/
oxygen, d) the resulting poorly soluble compounds of the metals iron and, partly, manganese from c) are filtered off and the filter cake is optionally washed and further worked up, e) the filtrate and optionally the washing water from d) are subjected to reactive extraction at temperatures of from 60-95%, especially of from 70 to 90°C to remove magnesium and manganese by e1) contacting an ammonium salt of a phosphoric acid derivative or phosphonic acid derivative in an organic solution with the filtrate in countercurrent, the ammonium ions passing into the filtrate and the magnesium and manganese ions passing into the organic solution, e2) freeing the organic solution from magnesium and manganese by addition of aqueous sulfuric acid solution to form an aqueous sulfuric acid solution containing magnesium sulfate and manganese sulfate, e3) adding ammonium hydroxide to the organic solution from e2) and reusing the solution in e1), f) after removal of magnesium and manganese, the aqueous ammonium sulfate solution from e) is optionally subjected to evaporative crystallization to form solid ammonium sulfate.
oxygen, d) the resulting poorly soluble compounds of the metals iron and, partly, manganese from c) are filtered off and the filter cake is optionally washed and further worked up, e) the filtrate and optionally the washing water from d) are subjected to reactive extraction at temperatures of from 60-95%, especially of from 70 to 90°C to remove magnesium and manganese by e1) contacting an ammonium salt of a phosphoric acid derivative or phosphonic acid derivative in an organic solution with the filtrate in countercurrent, the ammonium ions passing into the filtrate and the magnesium and manganese ions passing into the organic solution, e2) freeing the organic solution from magnesium and manganese by addition of aqueous sulfuric acid solution to form an aqueous sulfuric acid solution containing magnesium sulfate and manganese sulfate, e3) adding ammonium hydroxide to the organic solution from e2) and reusing the solution in e1), f) after removal of magnesium and manganese, the aqueous ammonium sulfate solution from e) is optionally subjected to evaporative crystallization to form solid ammonium sulfate.
2. A process as claimed in claim 1, characterized in that the filter cake of theresulting poorly soluble compounds of the metals titanium, vanadium, chromium, aluminium and, partly, iron from b) is further worked up by a) oxidizing the filter cake with air/oxygen, simultaneously adding sodium hydroxide and heating to temperatures above 100°C, the pH value being kept at >12, b) filtering off the resulting poorly soluble compounds of the metals titanium and iron from a), c) cooling the filtrate from b), which contains the soluble compounds of the metals aluminium, vanadium and chromium, in the presence of nuclei or neutralizing it with CO2 to pH 7, d) filtering off the resulting poorly soluble compounds of aluminium from c), e) optionally adjusting the filtrate from d) with sulfuric acid to a pH value around 2, f) filtering off the resulting poorly soluble compounds of vanadium from e) and g) precipitating the chromium from the filtrate from f) by addition of sodium sulfite and sodium carbonate as chromium hydroxide at pH 5-6.
3. A process as claimed in claim 1, characterized in that the magnesium- and manganese-containing solution from e2) is cooled so that the magnesium ammonium sulfate/ manganese sulfate is precipitated and removed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4327025 | 1993-08-12 | ||
| DEP4327025.5 | 1993-08-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2130212A1 true CA2130212A1 (en) | 1995-02-13 |
Family
ID=6494984
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002130212A Abandoned CA2130212A1 (en) | 1993-08-12 | 1994-08-09 | Process for working up thin acid |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0638515B1 (en) |
| JP (1) | JPH082905A (en) |
| AU (1) | AU668313B2 (en) |
| CA (1) | CA2130212A1 (en) |
| DE (1) | DE59409261D1 (en) |
| ES (1) | ES2146628T3 (en) |
| FI (1) | FI943702A (en) |
| NO (1) | NO942973L (en) |
| PL (1) | PL178525B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6416723B1 (en) | 1998-03-20 | 2002-07-09 | Bayer Aktiengesellschaft | Method for reprocessing waste acid to form gypsum and iron oxide |
| WO2008034921A1 (en) | 2006-09-18 | 2008-03-27 | Fertinagro Nutrientes, S.L. | Process for obtaining fertilizers from tio2 subproducts, and products obtained in this manner |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19812261A1 (en) * | 1998-03-20 | 1999-09-23 | Bayer Ag | Production of gypsum and iron oxide pigments from dilute acid formed in the manufacture of titanium dioxide |
| DE19812260A1 (en) * | 1998-03-20 | 1999-09-23 | Bayer Ag | Production of iron oxide pigments from dilute acid formed in manufacture of titanium dioxide |
| US6726891B2 (en) | 2000-07-31 | 2004-04-27 | Sumitomo Chemical Company, Limited | Titanium oxide production process |
| DE10332530A1 (en) † | 2003-07-17 | 2005-02-10 | Kerr-Mcgee Pigments Gmbh | Process for reducing the soluble chromate content in cement and a preparation of cement and water-soluble metal sulphates |
| CN103572058B (en) * | 2012-07-31 | 2016-01-20 | 有研稀土新材料股份有限公司 | A kind of method of enrichment rare earth rare elements and the white gypsum of preparation from sulfate process titanium dioxide waste liquid |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3016286A (en) * | 1960-02-29 | 1962-01-09 | Ishihara Sangyo Kaisha | Method for the treatment of waste acid resulting from titanium dioxide production |
| JPS6012283B2 (en) * | 1975-05-31 | 1985-04-01 | 東ソー株式会社 | Method for recovering valuable components from ferrous ammonium sulfate |
| US4207295A (en) * | 1979-02-13 | 1980-06-10 | Union Carbide Corporation | Processing of chromium ore |
| SU923949A1 (en) * | 1979-12-07 | 1982-04-30 | Proizv Ob Polimir Im 50 Letiya | Process for producing ammonium sulphate |
| DE3115937A1 (en) * | 1981-04-22 | 1982-11-18 | Vajna, Sandor, Dipl.-Ing.Chem. Dr.techn. | Process for producing virtually pure solutions of alkali metal sulphates or ammonium sulphates or of sulphuric acid from effluents |
| DE3123361C2 (en) * | 1981-06-12 | 1983-10-06 | Bayer Ag, 5090 Leverkusen | Process for working up solutions containing chromium (VI) |
| DE3524053A1 (en) * | 1985-07-05 | 1987-01-08 | Bayer Antwerpen Nv | METHOD FOR PRODUCING HIGH QUALITY TITANIUM DIOXIDE BY THE SULFATE METHOD |
| CN1023107C (en) * | 1990-11-24 | 1993-12-15 | 侯相林 | Process for recovery of chromium from waste solution for electroplating chromium |
| FR2683217B3 (en) * | 1991-11-06 | 1994-02-11 | Papailhau Jean Louis | PROCESS FOR THE TREATMENT OF ACID EFFLUENTS FROM THE MANUFACTURE OF TITANIUM OXIDE PIGMENTS ACCORDING TO A SULFURIC PROCESS. |
| JP2968877B2 (en) * | 1991-11-08 | 1999-11-02 | 日鉄鉱業株式会社 | Method for recovering sulfuric acid from waste sulfuric acid containing metal sulfate |
-
1994
- 1994-08-01 DE DE59409261T patent/DE59409261D1/en not_active Expired - Fee Related
- 1994-08-01 ES ES94111966T patent/ES2146628T3/en not_active Expired - Lifetime
- 1994-08-01 EP EP94111966A patent/EP0638515B1/en not_active Expired - Lifetime
- 1994-08-05 AU AU68938/94A patent/AU668313B2/en not_active Ceased
- 1994-08-09 CA CA002130212A patent/CA2130212A1/en not_active Abandoned
- 1994-08-09 JP JP6206086A patent/JPH082905A/en active Pending
- 1994-08-10 PL PL94304612A patent/PL178525B1/en not_active IP Right Cessation
- 1994-08-10 FI FI943702A patent/FI943702A/en unknown
- 1994-08-11 NO NO942973A patent/NO942973L/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6416723B1 (en) | 1998-03-20 | 2002-07-09 | Bayer Aktiengesellschaft | Method for reprocessing waste acid to form gypsum and iron oxide |
| WO2008034921A1 (en) | 2006-09-18 | 2008-03-27 | Fertinagro Nutrientes, S.L. | Process for obtaining fertilizers from tio2 subproducts, and products obtained in this manner |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59409261D1 (en) | 2000-05-11 |
| AU668313B2 (en) | 1996-04-26 |
| JPH082905A (en) | 1996-01-09 |
| EP0638515A3 (en) | 1995-09-27 |
| FI943702A0 (en) | 1994-08-10 |
| PL178525B1 (en) | 2000-05-31 |
| AU6893894A (en) | 1995-02-23 |
| ES2146628T3 (en) | 2000-08-16 |
| PL304612A1 (en) | 1995-02-20 |
| NO942973D0 (en) | 1994-08-11 |
| NO942973L (en) | 1995-02-13 |
| FI943702A (en) | 1995-02-13 |
| EP0638515B1 (en) | 2000-04-05 |
| EP0638515A2 (en) | 1995-02-15 |
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