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|Barium sulfate Chemical Properties|
|Barium sulfate Usage And Synthesis|
|Chemical Properties||Barium sulfate has its chemical formula BaSO4. It is colorless or white orthorhombic crystals with relative molecular mass of 233.4, the relative density of 4.5 (15 ℃), the melting point of 1580 ℃, and the Refractive index of 1.637. Upon being heated to 1149 ℃, it will become monoclinic crystalline when the refractive index is 1.649. It is almost insoluble in water with the solubility being 0.00022 at 18 ℃ and 0.0041 at 100 ℃. It is slightly soluble in concentrated sulfuric acid and soluble in carbonate alkali metal solution in which it is converted to barium carbonate; it is insoluble in other kinds of acid or base. In nature, it is existed in the barite mineral form. Upon co-heating with carbon (pulverized coal) to 800 ℃, it is reduced to soluble barium sulfide and carbon monoxide. It has a strong ability for absorbing X-rays with X-ray being impermeable to it. Therefore, it is medically used as the agent (barium meal) for X-rays on the gut and stomach. Barium sulfate is the only non-toxic barium salts. It can be used in analysis reagents, electronics, instrumentation, metallurgy and other industries. It can also be used as a white pigment and an administrated agent upon stomach X-ray angiography; it can also used as copper flux, drilling mud weight enlarging agent and the filling agent of rubber, paper, and plastic. It is produced from the reaction between sulfuric acid and barium chloride. |
I-type barium sulfate: it is white loose powder and is odorless and tasteless.
II-type barium sulfate: it is refined from barite sulfate type minerals: barium sulfate. Calculated from the dry goods, the barium sulfate content should not be less than 97%. It is white loose powder, and is odorless and tasteless. Barium sulfate (Ⅰ type and Ⅱ type) are both insoluble in water, organic solvent, acid o and sodium hydroxide. It contains 58.85% of barium.
Figure 1 is a white powder of barium sulfate.
The above information is edited by the Chemicalbook of Dai Xiongfeng.
|Imaging diagnostic agents||This product can’t be absorbed in the gastrointestinal tract and can be maintained at a high concentration which prevents X-rays from penetrating through with a clear developing. It is non-toxic to humans and thus is suitable for the imaging of esophagus and gastrointestinal tract. |
Barium salt can absorb a relatively large amount of X-ray. Upon entering into the gastrointestinal tract, it can form density contrast with surrounding structures in the X-ray image, thus showing the location of the cavity, the contour, shape, surface structure and functional activities. Fine and uniform type of barium is mostly synthetic barium with the particles being fine and uniform, and mostly circular with lighter weight, and slow and consistent settlement. It is suitable for the single, double contrast imaging examination of the esophagus, stomach, duodenum, small intestine and colon. Owing to the low optimal developing concentration for the thin and uniform barium concentration, it has a better performance on the display of fine structure of mucosal such as than uneven and thick type barium.
This product is not absorbed after oral administration or pouring into the gastrointestinal tract with its prototype being excreted from faeces. Its discharge time is roughly the same as the time for food to going through. It is non-irritating, non-toxic without substantially affecting the gastrointestinal tract and is an excellent X-ray contrast agent. Upon entering into the bronchial, it is mostly cough up with a small amount going into the alveoli and depositing in the alveolar wall, or being swallowed by phagocytes and further being transported to the pulmonary interstitial and lymphatic system. However, owing to the very low speed, it is not appropriate for bronchial angiography.
Barium sulfate suspension agent can be applied to the single, double contrast examination of esophagus, stomach, duodenum, small intestine, and colon; also be used for gastrointestinal double contrast examination.
Orally administration of its suspensions: apply thick version for esophagus contrast radiography and apply the dilute version to stomach and intestines examination, which is called as barium meal examination. Its dilute suspensions can also subject to rectal perfusion. The colonography is called barium enema. Barium sulfate agent for injection purpose can be applied to bronchial angiography and brain abscess angiography.
|Dosage||Dry suspension: before using, add water for making its suspension with proper concentration and temperature. Common introducing methods include oral administration, small intestine enema and colon enema. |
1. esophageal examination: oral administration (concentration 60% ~ 250%) for 15 ~ 60mL after which you are able to immediately observed esophageal motility situation; before taking barium agent, first take gas production drugs and this can be used for double contrast examination of the esophagus.
2. gastroduodenal double contrast examination: fast for 6 h above, orally administer gas production drugs until the stomach produces CO2 gas of about 300~500mL, then first oral administer barium for 70 ~ 100 mL (concentration 200% ~ 250%), then ask the patient to flip for a few laps so that the barium agent can be uniformly subject to coating on the stomach mucosa; if necessary, the patients can take an additional 150mL of barium agent; if at 20 min before angiography, have the patient be subject to a hypotonic drugs (such as injection of anisodamine or oral administration of atropine, etc.), and oral administration of gastric clearing enzyme for washing gastric juice before double contrast examination, the gastric mucosal surface structure can be more clearly displayed.
3. Single contrast gastrointestinal examinations: fast for over 6 h, after orally administration of 240 ~ 480 mL (concentration of 40% to 120%), you can immediately observe the morphology and motility of the stomach and duodenum; after 15 ~ 30 min, you can observe the morphology and motility situation of small intestine; one and half hours later, you can observe the morphology and motility of all part of the small intestine; after 2 ~ 6 h, you can observe ileocecal region and right colon.
4. small bowel enema: fast for 8 ~ 12h; directly introduce 800 to 2400 mL of barium agent (concentration of 30% to 80%) through a special catheter into the duodenum or proximal jejunum, perform examination of small intestine pieces by pieces; if necessary, directly conduct double contrast examination instead of single contrast examination.
5. colon enema: 1 ~ 3 d before checking, take liquid or semi-liquid diet, if necessary, apply an appropriate amount of laxatives and perform intestinal tract cleansing 1 to 2 h before the test; apply cannula into the colon through the anus; injecting contrast agent for filling the entire colon for angiography; conduct radiography and fluoroscopy after injection of barium agent as single-contrast; then drained out most of the barium agent, and then inject the gas into it for filling the colon as a double contrast; upon direct double contrast angiography for colon, first introduce 150 to 300 mL of barium agent (concentration of 60% to 80%) through catheter; rotate the position and inject into gas so that barium agent and gas fill the entire colon for double contrast radiography; in order to achieve good results, the patients can first subject to intramuscular or intravenous injection of glucagon or hypotonic drugs like anisodamine before injection of contrast agent.
|Adverse reactions||Although this product has no toxicity, but improper use can still cause nausea, constipation, diarrhea and other symptoms; improper use may also result in intestinal perforation, and subsequent peritonitis, adhesions and granulomas with severe cases being fatal. It is thus contraindicated in cases of esophageal bleeding, esophageal fistula, esophageal atresia, acute gastric perforation, acute gastroenteritis, gastrointestinal bleeding, and intestinal obstruction. |
The large amount of barium upon being poured into the lungs can cause mechanical irritation and inflammation which causes the infiltration of foreign body giant cells, epithelioid cells and mononuclear cell during early stage, and further causes fibrosis occurring surrounding the deposited barium, leading to barium nodule formation.
Fast for 6 to 12 hours before oral barium examination.
|Precautions||1. Patients of acute gastrointestinal perforation, gastrointestinal bleeding, colon infarction, acute gastroenteritis, and corrosive esophagitis should be disabled. Patients of congenital diseases such as tracheal fistula and esophageal atresia are not allowed for using this agent for examination. Instead, the patient can apply iodized oil or water-soluble contrast agent. |
2. The barium sulfate must comply with the purity stated in Chinese Pharmacopeia without containing soluble barium salt. Avoid by all means mixing it with barium chloride (highly toxic) to avoid poisoning after absorption.
3. Fast for 6 to 12 hours before oral administration of barium agent; usually take this agent for examination during empty stomach in the morning. At 1 to 2 hours before barium enema, the patients must first subject to cleansing enema; the patients are not allowed for taking laxative at 1 day before the examination.
4. For patients with pyloric obstruction symptoms, apply gastric lavage for at least twice at the day before the test.
5. within 3 days before the examination, the patients are disabled for administering drugs with higher atomic weight such as bismuth, calcium preparations. At 1 day before the test, disable the using of drugs which affect stomach and intestine such as atropine, calcium, bismuth, laxatives, etc., it recommended to take low-residue food and fast after dinner.
6. The fineness and purity of barium sulfate powder should reach the standard comply of the codex. For self-production of the paste or suspension of this product, you can choose suitable dispersing agent and flavoring agent to prepare a suitable preparation with suitable consistency.
|Solubility in water (g / 100ml)||Solubility per 100 ml of water in grams:
2.448 × 10-4 / 20 ℃
|Chemical Properties||It is colorless orthorhombic crystals or a white amorphous powder. It is almost insoluble in water, ethanol and acid but soluble in hot concentrated sulfuric acid.
|Uses||1. It can be used for powder coatings, paints, inks, paints, rubber, batteries, plastics and coated paper industries. |
2. It can be used medically as the contrast agent of the digestive system.
3. It can be used as the raw material of barium salt as well as rubber fillers, etc.
4. It can be used as the surface coating agents of making paper and coated paper, sizing agent in the textile industry, glass clarifying agent, and the filter of paint, ink, plastics, and rubber.
5. It can be used for high-grade plastics, rubber, paint, powder coating, etc.
6. It can be used as the raw material of barium salt, the mud weighting agent in the oil industry, mud weighting agent, rubber filler, sizing agents of textile industry, pigments and coatings.
7. It can be not only used as analysis reagents but also for the pharmaceutical industry.
8. It is used as the raw material or filling agents in paints, inks, plastics, rubber and electrical storage tank, surface coating agents of money-type paper money and coated paper, and sizing agents used in the textile industry. In glass products, it is used as a clarifying agent and can play the role of anti-foaming and increasing gloss. It can be used as anti-radiation protective wall material. It can also used in industries of ceramics, enamel, spices and pigments. It can also be used as the expanders of the cathode plate and X-ray contrast agent of digestive tract as well as the raw material for producing other barium salts.
9. It is mainly used as the weighting agent of drilling mud of petroleum and natural gas and is also an important kind of mineral raw material for extracting metals barium and preparation of various kinds of barium compounds. The most important industrial compounds are barium carbonate, barium sulfate, inlay, barium nitrate, barium hydroxide, barium oxide, barium peroxide, barium chromate, barium manganate, barium chlorate, lithopone, and polysulfide barium. Barium compound has very extensive applications such as being used for rubber, plastics, pigment, paint, paper, textile, oil paint, ink, and the raw material and welding filler of covered electrode; it can be used as barium-based grease, for oil refining, sugar manufacturing from beet, and as the raw material for making artificial silk; it can be used as insecticide, sterilizing agent, rodenticide, explosives, green fireworks, signal flares, tracer, and the indicator of medical X-light, etc.
10. It can also be used in sectors of glass, ceramics, leather, electronic, building materials, and metallurgy. Metal barium can be used as the getter and binder of television and vacuum. The alloys made formed between barium and aluminum, magnesium, lead, and silver can be used for the manufacture of bearings.
|Production method||Mirabilite-black ash: mix the raw material of barium sulfide (refer to preparation of barium sulfide) with mirabilite which has calcium, magnesium being removed and carry out the reaction at 90 °C to generate the barium sulfate precipitate. The precipitate further undergoes filtration, washing with water and acid and adjusted with sulfuric acid to pH 5-6; again go through filtration, drying and pulverization to obtain the precipitated barium sulfate products. After addition of surface treatment agent or dispersant during the production process of precipitated barium sulfate, we can obtain modified superfine precipitated barium sulfate; the reaction is as below: |
BaSO4 + 4C → BaS + 4CO ↑
BaS + Na2SO4 → BaSO4 ↓ + Na2S
Bittern utilization method applies yellow barium halide for reaction with mirabilite; then it further goes through acid cooking, washing with water, separation, dehydration drying to obtain the finished product of barium sulfate. The reaction is as below:
BaCl2 + Na2SO4 → BaSO4 ↓ + 2NaCl
|Toxicity grading||low toxic
|Chemical Properties||white powder|
|Usage||Finepowder Barium Sulphate is widely used in chemical industrypaint, plastics, rubber,glass, paper, medicine,ceramics, storage battery and other areas;Fine powder Barium Sulphate is widely used in chemical industry|
|Acute toxicity||the insoluble body portion has low toxicity; dissolved impurities is toxic; trachea- mouse LD50: > 600 mL / kg
|Explosives and hazardous properties||heating together with aluminum, phosphorus causing explosion
|Flammability and hazard characteristics||thermal decomposition releases toxic fumes of sulfur oxides
|Storage Characteristics||ventilation, low-temperature and drying; stored separately from aluminum and potassium
|Professional standards||TWA 0.5 mg / m³; STEL 1.5 mg / m3|
|General Description||White or yellowish odorless powder or small crystals. Mp: 1580°C (with decomposition). Density: 4.25 -4.5 g cm-3. Insoluble in water, dilute acids, alcohol. Soluble in hot concentrated sulfuric acid. Used as a weighting mud in oil-drilling, in paints, paper coatings, linoleum, textiles, rubber. Administered internally (barium cocktail) as a radio-opaque diagnostic aid.|
|Reactivity Profile||Barium sulfate is non-combustible and non-toxic. Emits toxic sulfur oxides when heated to decomposition. Can act as an oxidizing agent, but usually does not. Reacts with reducing agents such as potassium, phosphorus or aluminum (heating with aluminum can cause an explosion).|
|Barium sulfate Preparation Products And Raw materials|