CA1050235A - Production of pharmaceutical barium sulphate - Google Patents
Production of pharmaceutical barium sulphateInfo
- Publication number
- CA1050235A CA1050235A CA228,890A CA228890A CA1050235A CA 1050235 A CA1050235 A CA 1050235A CA 228890 A CA228890 A CA 228890A CA 1050235 A CA1050235 A CA 1050235A
- Authority
- CA
- Canada
- Prior art keywords
- barium sulphate
- fraction
- magnetic
- ore
- pharmaceutical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
- C01F11/462—Sulfates of Sr or Ba
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
PRODUCTION OF PHARMACEUTICAL BARIUM SULPHATE
Abstract of the Disclosure A new simplified process is described for producing pharmaceutical barium sulphate in which the barium sulphate does not require dissolution for purification. The new process comprises grinding a naturally occurring barite ore containing individual crystals of substantially pure barium sulphate together with gangue minerals to form a finely divided particulate ore material, passing this finely divided ore through a high intensity wet magnetic separator to remove magnetic particles, leaving a non-magnetic fraction containing barium sulphate and low specific gravity minerals, subjecting the non-magnetic fraction to gravity separation to separate a substantially pure barium sulphate fraction, leaching the barium sulphate fraction with sulphuric acid to remove acid soluble impurities and washing the leached product.
Abstract of the Disclosure A new simplified process is described for producing pharmaceutical barium sulphate in which the barium sulphate does not require dissolution for purification. The new process comprises grinding a naturally occurring barite ore containing individual crystals of substantially pure barium sulphate together with gangue minerals to form a finely divided particulate ore material, passing this finely divided ore through a high intensity wet magnetic separator to remove magnetic particles, leaving a non-magnetic fraction containing barium sulphate and low specific gravity minerals, subjecting the non-magnetic fraction to gravity separation to separate a substantially pure barium sulphate fraction, leaching the barium sulphate fraction with sulphuric acid to remove acid soluble impurities and washing the leached product.
Description
lns(~ s Background of the Invention 1. Field of the Invention This invention relates to a process for producing a pharmaceutical grade of barium sulphate.
2. Description of the Prior Art Pharmaceutical barium sulphate is widely used as `~
a radiopaque medium in the gastrointesinal tract, It is a fine, white, odourless, tasteless bulky powder which is practically insoluble in water, in organic solvents and in solutions of acids and of alkalies. It does, however, exhibit some solubility in hot concentrated sulphuric acid.
; While this extremely inert quality of barium sulPhate makes -~
it ideal as a radiopaque mediu~it has also in the past created great problems in the production of barium sulphate of pharmaceutical purity.
s~ The chemical specifications of pharmaceutical ' barium sulPhate are precisely known. The USP specifications can be summarized as follows:
Test USP Specifications Heavy Metals (as Pb) 0.0010% maximum Sulphide To pass test , Arsenic 0.0001% maximum (As203) Acid Soluble Substance 0.3% maximum Soluble Barium Salts To pass test Phosphate To pass test Acid or Alkalinity To pass test The usual commercial procedure now being used is the Mallinckrodt process in which finely divided barite ore is taken into solution by means of an acid and then precipitating barium sulphate. Because of the inertness of barlum sulphate,this is a very difficult and expensive procedure.
Even the precipitate formed still contains many impurities and must be sub~ected to a number of additional purification steps including acid leaching.
It is the object of the present invention to provide a simpler and less expensive process for producing pharmaceutical barium sulphate.
Summary of the Invention In accordance with the present invention, it has surprisingly been found that a greatly simplified procedure for producing pharmaceutical barium sulphate is possible by commencing with a naturally occurring barite ore which contains individual crys~als of substantially pure barium sulphate.
In other words, the barium ~ulphate within the individual -crystals is of pharmaceutical purity.
According to thè inventive prccess, this naturally occurring barite ore containing individual crystals of ~ sub~tantially pure barium sulphate,together with gangue minerals, :~ i9 first ground to form a finely divided particulate ore ~l material. This finely divided ore is then passed through a high intensity wet magnetic separator to remove magnetic particles, leaving a non-magnetic fraction containing barium -~ sulfate and low specific gravity minerals. The non-magnetic .. ,~ . .
~, fraction is subjected to gravity separation and from this gravity separation a substantially pure barium sulphate fraction i is obtained. This barium sulphate fraction is then subjected ,~ to leac~ing with sulphuric acid to remove any remaining acid sOluble impurities and is washed to form a final pharmaceutical ' barium sulphate.
f The barium sulphate obtained by this procedure ; 30 easily meets all of the USP specifications.
;
f S
DescriPtion of Preferred Embodimen~s Preparation of Ore The ore contains, in addition to the individual crystalls of substantially pure barium sulphate, many other gangue! minerals. These gangue minerals typically include iron carbonate, iron oxides, silica and iron silicates.
One example of a typical ore analysis is as follows:
BaS04 74.4%
FeC03 18.6%
SiO2 5.6% ;
Miscellaneous 1.4%
However, it will be appreciated that the gangue minerals and their proportions can vary greatly in relation to the barium sulphate and the main consideration is that the lower the amount of barium sulpbate present in the ore~ the greater amount of ore ; that will hsve to be prepared and processed through the wet I magnetic ~eparator to obtain a given amount of barium sulphate.
i The ore a~ obtained fxom the mine is preferably sub-jected to an initial primary grinding with care being taken to keep the production of fine particle~ to a minimum. This can conveniently be done, for instance, by means of a ~aw crusher followed by a gyratory crusher or other means to reduce the i particles to a convenient working size of, for instance, 1/2 inch.
These ore particles are then subjected to a secondary grinding, for instance in a ball mill, rod mill or hammer mill, to produce finely divided particles suitable for feeding to a high intensity wet magnetic separator. Preferably the separator feed has a particle size of -35 mesh ~U.S. sieve) with care being taken to avoid excessive fines.
The size of the particles can be varied depending on the n~tture of the ore deposits with the concept being to
a radiopaque medium in the gastrointesinal tract, It is a fine, white, odourless, tasteless bulky powder which is practically insoluble in water, in organic solvents and in solutions of acids and of alkalies. It does, however, exhibit some solubility in hot concentrated sulphuric acid.
; While this extremely inert quality of barium sulPhate makes -~
it ideal as a radiopaque mediu~it has also in the past created great problems in the production of barium sulphate of pharmaceutical purity.
s~ The chemical specifications of pharmaceutical ' barium sulPhate are precisely known. The USP specifications can be summarized as follows:
Test USP Specifications Heavy Metals (as Pb) 0.0010% maximum Sulphide To pass test , Arsenic 0.0001% maximum (As203) Acid Soluble Substance 0.3% maximum Soluble Barium Salts To pass test Phosphate To pass test Acid or Alkalinity To pass test The usual commercial procedure now being used is the Mallinckrodt process in which finely divided barite ore is taken into solution by means of an acid and then precipitating barium sulphate. Because of the inertness of barlum sulphate,this is a very difficult and expensive procedure.
Even the precipitate formed still contains many impurities and must be sub~ected to a number of additional purification steps including acid leaching.
It is the object of the present invention to provide a simpler and less expensive process for producing pharmaceutical barium sulphate.
Summary of the Invention In accordance with the present invention, it has surprisingly been found that a greatly simplified procedure for producing pharmaceutical barium sulphate is possible by commencing with a naturally occurring barite ore which contains individual crys~als of substantially pure barium sulphate.
In other words, the barium ~ulphate within the individual -crystals is of pharmaceutical purity.
According to thè inventive prccess, this naturally occurring barite ore containing individual crystals of ~ sub~tantially pure barium sulphate,together with gangue minerals, :~ i9 first ground to form a finely divided particulate ore ~l material. This finely divided ore is then passed through a high intensity wet magnetic separator to remove magnetic particles, leaving a non-magnetic fraction containing barium -~ sulfate and low specific gravity minerals. The non-magnetic .. ,~ . .
~, fraction is subjected to gravity separation and from this gravity separation a substantially pure barium sulphate fraction i is obtained. This barium sulphate fraction is then subjected ,~ to leac~ing with sulphuric acid to remove any remaining acid sOluble impurities and is washed to form a final pharmaceutical ' barium sulphate.
f The barium sulphate obtained by this procedure ; 30 easily meets all of the USP specifications.
;
f S
DescriPtion of Preferred Embodimen~s Preparation of Ore The ore contains, in addition to the individual crystalls of substantially pure barium sulphate, many other gangue! minerals. These gangue minerals typically include iron carbonate, iron oxides, silica and iron silicates.
One example of a typical ore analysis is as follows:
BaS04 74.4%
FeC03 18.6%
SiO2 5.6% ;
Miscellaneous 1.4%
However, it will be appreciated that the gangue minerals and their proportions can vary greatly in relation to the barium sulphate and the main consideration is that the lower the amount of barium sulpbate present in the ore~ the greater amount of ore ; that will hsve to be prepared and processed through the wet I magnetic ~eparator to obtain a given amount of barium sulphate.
i The ore a~ obtained fxom the mine is preferably sub-jected to an initial primary grinding with care being taken to keep the production of fine particle~ to a minimum. This can conveniently be done, for instance, by means of a ~aw crusher followed by a gyratory crusher or other means to reduce the i particles to a convenient working size of, for instance, 1/2 inch.
These ore particles are then subjected to a secondary grinding, for instance in a ball mill, rod mill or hammer mill, to produce finely divided particles suitable for feeding to a high intensity wet magnetic separator. Preferably the separator feed has a particle size of -35 mesh ~U.S. sieve) with care being taken to avoid excessive fines.
The size of the particles can be varied depending on the n~tture of the ore deposits with the concept being to
- 3 -form particles among which there will be a large number of individual particles of substantially pure barium sulphate, Magnetic Separation The suitably ground ore is subjected to high intensity wet 1nagnetic separation and a variety of high intensity wet magnetic separators are known. A particularly suitable machine is the Jones separator.
The ground ore can be passed through the separator one or more times to remove as much of the magnetic particles a~ posslble. The ore will contain particles of varying s degrees of magnetic susceptability and, for instance, there may be combined particles of iron carbonate and silica where the combined particle, due to its iron carbonate content, is sufficiently magnetic to remove the entire particle. It is also sometimes desirable to size the feed to the separator since better recults may be obtained if the feed does not contain particles of too greatly varying sizes. For instance, the ore feed to the separator could be divided into three different size ranges for feeding, e.g. -10 ~ 35; -35 + 65;
-65 + 100 mesh.
During the magnetic separation, the bulk of the magnetic minerals or combined particles that as a whole e~hibit some magnetic susceptability are removed. The non-magnetic fraction at this stage contains primarily barium --' sulfate and the lighter specific gravity minerals such as ~ quartz, as well as other contaminants such as lead, zinc, etc.
i Gravity Separation Much of the undesirable material remaining in the non-magnetic fraction obtained from the magnetic separator can be removed by gravity separation. A variety of gravity separators are known and a highly useful one for this purpose
The ground ore can be passed through the separator one or more times to remove as much of the magnetic particles a~ posslble. The ore will contain particles of varying s degrees of magnetic susceptability and, for instance, there may be combined particles of iron carbonate and silica where the combined particle, due to its iron carbonate content, is sufficiently magnetic to remove the entire particle. It is also sometimes desirable to size the feed to the separator since better recults may be obtained if the feed does not contain particles of too greatly varying sizes. For instance, the ore feed to the separator could be divided into three different size ranges for feeding, e.g. -10 ~ 35; -35 + 65;
-65 + 100 mesh.
During the magnetic separation, the bulk of the magnetic minerals or combined particles that as a whole e~hibit some magnetic susceptability are removed. The non-magnetic fraction at this stage contains primarily barium --' sulfate and the lighter specific gravity minerals such as ~ quartz, as well as other contaminants such as lead, zinc, etc.
i Gravity Separation Much of the undesirable material remaining in the non-magnetic fraction obtained from the magnetic separator can be removed by gravity separation. A variety of gravity separators are known and a highly useful one for this purpose
- 4 -~ iO;~35 is the wet shaking table. Once again, it may be desirable to brealc the non-magnetic fraction up into quite restricted `
size ranges by screening prior to the gravity separation.
This tends to give a better separation.
The "heavys" end of the table contains predominantly barium sulfate while the "lights" end contains the gangue.
There may be a fraction removed in between these that, on completion of the leaching process, does not meet pharmaceutical specifications, but it has been found that this fraction normally meets the requirements for a commercial product known as "Ground White Barite".
Leachin~
The purpose of the leaching step is to eliminate any remaining soluble impurities f such as soluble barium salt~ etc. which must be eliminated in order to pass the specified test. In order to obtain a product meeting USP
specifications, it has been found that the leaching must be conducted with sulphuric acid.
convenient technique for this is a counter-current three-stage leach starting with 25% commercial sulphuric acid ; ~ith commercial tap water and three washing steps. Of course, these steps can be greatly varied depending on the concentration of the acid used, economics, grade of water, etc.
The product obtained from the leaching step is 1 filtered and washed and can either be made up in plastic bags --in the ~orm of pre~Mixed dosage units or it may be dried screened and packaged as a dry powder.
EXAMP~E
An ore sample was obtained from a mine located at Brookfield, Nova Scotia, Canada. This ore had the following analysis.
lO~iOZ35 BaS04 FeC03 18.6%
SiO2 5.6%
Miscellaneous 1.4Z
The ore was reduced in size by means of a jaw crusher to form particles having a dimension of about 1/2 inch. These ~
particles were then passed through a hammer mill to produce a -flnely divided ore having particles of -35 mesh.
This finely divided ore was passed through a "Standard Laboratory Jones High Intensity Wet Magnetic Separator" with a maximum amperage to coils of 40 amperes to obtain 44% by weight of a magnetics fraction and 56% by weight of a non-magnetics fraction. The non-magnetic fraction was screened into the following ize fractions:
-35 + 60 mesh ! -60 + 150 mesh,~ -150 mesh Each of the above fractions was subjected to gravity separation on a wet table no. 11099 ava~lable from Deister Concentrating Company Inc. and three cuts were made of the heavys product. In other words, the heavys product was '1 removed from the wet table as three separate fractions. The weight distribution of these various fractions is shown in -3~
-~ Table 1 below:
~ TABLE 1 . _ ~; ~ Particle Size -35 + 60 -80 + 150 -150 1 __ , ~ Wet Table Cut C-l C-2 C-3 C-l C-2 C-3 C-l C~2 C-3 % Wt. BaS04 Based on 12.0 4.7 1.91.7 0.9 0.9 2.0 2.6 1.3 Orig. Feed ~ 30 Total BaS04 i (% Wt.) 28.0%
, - 6 -l~()Z35 The various fractions obtained were then subjected to leaching with 20~ sulphllric acid solutions using a coun~er current four stage procedure with analytical grade and commercial grade sulfuric acid and either tap water or distilled water.
~ach leaching stage was of 30 minutes duration and the leaching procedures used on the various fractions are set out in Table 2 below:
Product No.Source Relevant Process Differences 117 Analytical grade ~2S04 and 118 All C-l's distilled water wa~h. All 119 leaching on -150 mesh.
131 C-l, C-2, Analytical grade H2S04 and 132 C-3 tap water wash. Leaching on 133 (-35+60) finely ground.
; 134 C-l, C-2 Analytical grade H2S04 and 135 C-3 tap water wash. Leaching on 136 (-60+150) finely ground.
137 C-l, C-2, Analytical grade H2S04 and ~i 138 C-3 tap water wash. Leaching on 139 (-150) finely ground.
145 C-l Commercial grade acid and tap 146 (-35+60) water. Leaching on -150 mesh.
147 C-l Three stage commercial grade.
148 (-35+60) Last stage analytical with top water wash. Leaching on -150 mesh.
The above samples were submitted to an independent testing laboratory for the prescribed tests required under the USP specifications. The results of these tests are given in Table 3 below:
:
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size ranges by screening prior to the gravity separation.
This tends to give a better separation.
The "heavys" end of the table contains predominantly barium sulfate while the "lights" end contains the gangue.
There may be a fraction removed in between these that, on completion of the leaching process, does not meet pharmaceutical specifications, but it has been found that this fraction normally meets the requirements for a commercial product known as "Ground White Barite".
Leachin~
The purpose of the leaching step is to eliminate any remaining soluble impurities f such as soluble barium salt~ etc. which must be eliminated in order to pass the specified test. In order to obtain a product meeting USP
specifications, it has been found that the leaching must be conducted with sulphuric acid.
convenient technique for this is a counter-current three-stage leach starting with 25% commercial sulphuric acid ; ~ith commercial tap water and three washing steps. Of course, these steps can be greatly varied depending on the concentration of the acid used, economics, grade of water, etc.
The product obtained from the leaching step is 1 filtered and washed and can either be made up in plastic bags --in the ~orm of pre~Mixed dosage units or it may be dried screened and packaged as a dry powder.
EXAMP~E
An ore sample was obtained from a mine located at Brookfield, Nova Scotia, Canada. This ore had the following analysis.
lO~iOZ35 BaS04 FeC03 18.6%
SiO2 5.6%
Miscellaneous 1.4Z
The ore was reduced in size by means of a jaw crusher to form particles having a dimension of about 1/2 inch. These ~
particles were then passed through a hammer mill to produce a -flnely divided ore having particles of -35 mesh.
This finely divided ore was passed through a "Standard Laboratory Jones High Intensity Wet Magnetic Separator" with a maximum amperage to coils of 40 amperes to obtain 44% by weight of a magnetics fraction and 56% by weight of a non-magnetics fraction. The non-magnetic fraction was screened into the following ize fractions:
-35 + 60 mesh ! -60 + 150 mesh,~ -150 mesh Each of the above fractions was subjected to gravity separation on a wet table no. 11099 ava~lable from Deister Concentrating Company Inc. and three cuts were made of the heavys product. In other words, the heavys product was '1 removed from the wet table as three separate fractions. The weight distribution of these various fractions is shown in -3~
-~ Table 1 below:
~ TABLE 1 . _ ~; ~ Particle Size -35 + 60 -80 + 150 -150 1 __ , ~ Wet Table Cut C-l C-2 C-3 C-l C-2 C-3 C-l C~2 C-3 % Wt. BaS04 Based on 12.0 4.7 1.91.7 0.9 0.9 2.0 2.6 1.3 Orig. Feed ~ 30 Total BaS04 i (% Wt.) 28.0%
, - 6 -l~()Z35 The various fractions obtained were then subjected to leaching with 20~ sulphllric acid solutions using a coun~er current four stage procedure with analytical grade and commercial grade sulfuric acid and either tap water or distilled water.
~ach leaching stage was of 30 minutes duration and the leaching procedures used on the various fractions are set out in Table 2 below:
Product No.Source Relevant Process Differences 117 Analytical grade ~2S04 and 118 All C-l's distilled water wa~h. All 119 leaching on -150 mesh.
131 C-l, C-2, Analytical grade H2S04 and 132 C-3 tap water wash. Leaching on 133 (-35+60) finely ground.
; 134 C-l, C-2 Analytical grade H2S04 and 135 C-3 tap water wash. Leaching on 136 (-60+150) finely ground.
137 C-l, C-2, Analytical grade H2S04 and ~i 138 C-3 tap water wash. Leaching on 139 (-150) finely ground.
145 C-l Commercial grade acid and tap 146 (-35+60) water. Leaching on -150 mesh.
147 C-l Three stage commercial grade.
148 (-35+60) Last stage analytical with top water wash. Leaching on -150 mesh.
The above samples were submitted to an independent testing laboratory for the prescribed tests required under the USP specifications. The results of these tests are given in Table 3 below:
:
.~.
' 30 , . , .
1~13~5 ~ ~
O cr~ co CQ 0 CO
a) td ~I U~
U~ ~
Fq ..
000000000 ~n 00000 tq S 0 0 0 0 0 GO 0 0 0 0 0 0 ~0 0 0 ~O
~ ~ 0 ~ ~ ~
o ~ p~ ~ ~ ~ ~ p~ ~ ~ p~ p~ ~ ~ ~ ~ ~ :
s , oooooooooooooooo 'C ~ VVVVVVVVVVVVVVVV
E~ ~ :'' ~ 00000000,1 0000000 S 0 ~q 0 0 ~ 0 ~n 0 ~ 0 0 0 0 0 0 0 ~ ~ ~ 0 ~
U~
iP~! ;~ i~ æ~ ~ i~ i~ i~ ~ K ~ ;P~ K i~
~1 ~1 ~J ~ O C`~ O O O O ~1 ~1 ~ ~1 ~1 ~1 t~l ..............
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U~ V V V
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cd~ VVVVVVVVVVVVVVVV
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Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing pharmaceutical barium sul-phate which comprises grinding a naturally occurring barite ore containing individual crystals of substantially pure barium sulphate together with gangue minerals to form a finely divided particulate ore material having a particle size of -35 mesh and a minimal amount of fines, passing this finely divided ore through a high intensity wet magnetic separator to remove magnetic particles, leaving a non-magnetic fraction containing barium sulphate and low specific gravity minerals, subjecting the non-magnetic fraction to gravity separation to separate a substantially pure barium sulphate fraction, leaching the barium sulphate fraction with sulphuric acid to remove acid soluble impurities and washing the leached product.
2. A process according to claim 1 wherein the gravity separation is conducted on a wet shaking table.
3. A process according to claim 2 wherein the non-magnetic fraction separated from the magnetic fraction is divided into two or more separate fractions based on particle size range and these fractions are separately subjected to the gravity separation.
4. A process according to claim 1 wherein the ore contains a major proportion of barium sulphate together with minor proportions of gangue materials selected from iron carbonates, iron oxides, silica and iron silicates.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA228,890A CA1050235A (en) | 1975-06-09 | 1975-06-09 | Production of pharmaceutical barium sulphate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA228,890A CA1050235A (en) | 1975-06-09 | 1975-06-09 | Production of pharmaceutical barium sulphate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1050235A true CA1050235A (en) | 1979-03-13 |
Family
ID=4103289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA228,890A Expired CA1050235A (en) | 1975-06-09 | 1975-06-09 | Production of pharmaceutical barium sulphate |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1050235A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4588574A (en) * | 1983-08-04 | 1986-05-13 | Bracco Industria Chimica S.P.A. | Process for the preparation of barium sulfate of increased flowability and density, suitable as a radio-opaque component in radiographic contrast agents, product obtained according to this process and the radiographic contrast agent produced therefrom |
| CN114226049A (en) * | 2022-01-21 | 2022-03-25 | 集美精化科技(广西)有限公司 | Barium sulfate impurity removal device and method |
-
1975
- 1975-06-09 CA CA228,890A patent/CA1050235A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4588574A (en) * | 1983-08-04 | 1986-05-13 | Bracco Industria Chimica S.P.A. | Process for the preparation of barium sulfate of increased flowability and density, suitable as a radio-opaque component in radiographic contrast agents, product obtained according to this process and the radiographic contrast agent produced therefrom |
| CN114226049A (en) * | 2022-01-21 | 2022-03-25 | 集美精化科技(广西)有限公司 | Barium sulfate impurity removal device and method |
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