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순도시험
(1) 불소화물 : 이 품목 1g을 정밀히 달아 「구연산칼슘」의 순도시험 (8)에 따라 시험한다(50ppm 이하).
(2) 비소 : 이 품목을 비소시험법에 따라 시험할 때, 그 양은 4.0ppm 이하이어야 한다.
(3) 납 : 「메타인산나트륨」의 순도시험 (2)에 따라 시험한다(2.0ppm 이하).
(4) 수은 : 이 품목을 수은시험법에 따라 시험할 때, 그 양은 1.0ppm 이하이어야 한다.
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확인시험
(1) 이 품목 500mg을 2.7N 염산 10mL에 녹이고 여과한 다음 6N 수산화암모늄용액으로 리트머스시험지를 사용하여 중화한 액은 확인시험법 중 칼슘염의 반응을 나타낸다.
(2) 「규산마그네슘」의 확인시험 (2)에 따라 시험한다.
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정량법
(1) 이산화규소 : 이 품목 400mg을 정밀히 달아 비이커에 넣고 물 5mL와 과염소산 10mL를 가하여 과염소산이 날라 가서 진해지고 흰 연기가 날 때 까지 가열한다. 시계접시로 비이커를 닫고 15분간 더 가열한다. 여기에 물 30mL를 가하여 식힌 후 뜨거운 물로 잔류물을 3회 천천히 세척한다. 잔류물이 있는 여지를 백금도가니로 옮겨 탄화시킨 다음 30분간 강하게 강열하고 방냉한다. 이에 황산 적당량을 가하고 1,300℃에서 강열하고 방냉하여 평량한다. 황산 5방울을 가하여 적시고 불화수소산 15mL를 가하고 서서히 가열하여 산을 완전히 제거하고 1,000℃이상에서 항량이 될 때까지 가열한 다음, 데시케이터에서 식히고 칭량하여 감소된 양을 이산화규소의 양으로 한다.
(2) 산화칼슘 : 정량법 (1)의 여액에 1N 수산화나트륨을 가하여 중화하고 0.05M 이.디.티.에이.이나트륨용액 30mL를 가하고 1N 수산화나트륨 15mL와 히드록시나프톨블루시액 0.3g을 가한 다음 0.05M 이.디.티.에이.이나트륨용액으로 적정한다. 종말점은 청색이 된 점으로 한다.
0.05M 이.디.티.에이.이나트륨용액 1mL = 2.804mg CaO
히드록시나프톨블루시액 : 이 품목 0.3g을 물 100mL에 녹이고 1N 수산화나트륨 10mL과 염화칼슘용액(1→200) 1mL을 가한 다음 물을 가하여 165mL로 하고 0.05M 이.디.티.에이.이나트륨 1mL를 가한다.
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정의
이 품목은 CaO와 SiO2로 구성된 함수 또는 무수규산염이다.
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개요
Calcium Silicate is a hydrous or anhydrous silicate with varying proportions of calcium oxideand silica. many different calcium silicates occur in nature in mineral form (e.g.,wollastonite, afwillite, grammite). The stoichiometry of the hydrate in cement paste is variable and the state of the chemically and physically bound water in its structure is not clear. Thus, calcium silicate can be prepared by calcining the oxide with silica, SiO2, at an elevated temperature: CaO + SiO2+ heat→CaSiO3. Calcium orthosilicate is commonly used as a safe alternative to asbestos for high-temperature insulation materials. Industrial grade piping and equipment insulation are often fabricated from calcium orthosilicate.
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화학적 성질
Calcium silicate occurs as a crystalline or amorphous white or off white material, and often exists in different hydrate forms. It consists of different ratios of CaO and SiO4, including tricalcium silicate (3CaO.SiO2) and dicalcium silicate Ca2SiO4. It is insoluble in water and forms a gel with inorganic acids. The pH of 5% suspension is 8.4~10.2.
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용도
Calcium Silicate is an anticaking agent that exists in different forms,
which are insoluble in water. it is used in salt to enhance flowability
under extremely high humidity conditions. it is also used in baking
powder and fabricated chips to absorb water or other liquids.
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주요 응용
The main applications of calcium silicate relate to its anticaking properties, and it has therefore been used in dusting powders and a range of different cosmetic products (e.g. face powders, eye shadow). It is also used as anticaking agent in table salt, foods, pharmaceuticals, and agricultural pesticides; replacement for asbestos in thermal insulation; Constituent (produced in situ) of lime glass, portland cement; reinforcing filler in elastomers and plastics; absorbent for liquids, gases, vapors; as anti-caking agent, suspension agent, pigment and pigment extender; binder for refractory material; in chromatography; in road construction.
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제조 방법
Calcium silicate is a naturally occurring mineral, but for commercial applications it is usually prepared from lime and diatomaceous earth under carefully controlled conditions.
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생산 방법
Calcium silicate is made in various ways by reacting siliceous material (such as diatomaceous earth) and calcium compounds (such as calcium hydroxide (Ca (OH) 2).The refinement of wollastonite ore into high-grade wollastonite was originally done by manual selection at many mines. This process is now performed by screening and magnetic separators, sometimes in combination with flotation and vacuum filtration. Grinding and milling operations can produce variable mesh powders or aggregates.
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위험도
Irritating dust. Use in foods restricted to
5% in baking powder, 2% in table salt. Upper res-
piratory tract irritant. Questionable carcinogen.
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건강위험
The toxicity of calcium silicate
depends on particle size, aspect ratio, and
amount of silica and respirable fiber.1 Synthetic
nonfibrous calcium silicate is considered to be
a nuisance dust.
Skin irritation was reported in a worker
exposed to an atmosphere permeated with calcium silicate.1 A study of 104 wallastonite (a
naturally occurring calcium silicate mineral)
miners showed no relationship between the
prevalence of chronic bronchitis or airflow
obstruction with increasing exposure.1 In a
cohort mortality study of wollastonite quarry
workers the observed numbers of deaths from
all cancers combined and lung cancer were
lower than expected.
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Pharmaceutical Applications
Calcium silicate (Ca2SiO4) is used in the pharmaceutical industry as an anticaking agent. Anti-caking agents absorb moisture and allow products to flow freely during the manufacturing process. It is also used as a filler aid for oral pharmaceuticals. It has also been used in pharmaceutical preparations as an antacid.
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공업 용도
Calcium silicate compounds belong to a complicated class of silicates. Among their many industrial applications, calcium silicates are heavily used as a building material as they constitute the main ingredient in today’s cement clinker.
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Safety Profile
A nuisance dust
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Safety
GRAS listed. Included in the FDA Inactive Ingredients Database (oral dosage forms). Included in nonparenteral (oral, orodispersible, effervescent and enteric-coated tablets) formulations licensed in the UK.
calcium silicate is generally recognized as safe (GRAS) when used at levels not exceed 2% in table salt and 5% in baking powder.
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저장
Calcium silicate is chemically stable and nonflammable, but it
should be protected from moisture. Store in airtight containers in a
cool, dry place.
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비 호환성
None reported [Note: After prolonged contact with water, solution reverts to soluble calcium salts & amorphous silica.]
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Regulatory Status
Calcium silicate (E552) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized as “additives other than colours and sweeteners”. It is an approved ingredient in Australia and New Zealand with the code number 552.
