nature (i.e. properties of sth)
Magnesium carbonate can be divided into light and heavy depending on the crystallization conditions, generally light. The light ones are: MgCO3-H2O, the heavy ones are: 5MgCO3-Mg(OH)2-3H2O, 5MgCO3-2Mg(OH)2-7H2O, 4MgCO3-Mg(OH)2 and 3Mg(OH)2-4H2O. trihydrate salt at room temperature.
Light magnesium carbonate is a white loose powder or friable lump. Odorless, relative density 2.2, melting point 350°C. Stable in air, heated to 700 ℃ to produce carbon dioxide, to produce magnesium oxide, almost insoluble in water, but in water to cause a slight alkaline reaction. Insoluble in ethanol, can be dissolved and bubbled by dilute acid.
(1)Magnesite (MgCO2) or dolomite (MgCO3-CaCO3) is treated and refined.
(2)It is refined from the precipitate obtained after the reaction of magnesium sulfate and sodium carbonate.
Take 0.2g of magnesium carbonate gradually add dilute hydrochloric acid solution (1+3) mL when dissolved and bubbling. Add ammonia solution (40mL ammonia with water into 100mL) to make it alkaline, this solution is magnesium salt reaction.
Magnesium salt reaction: when ammonium chloride solution (1+10) and ammonium carbonate solution (20g dissolved in 20mL ammonia solution and water added to 100mL) are added to the above solution, no precipitate appears, and when disodium hydrogen phosphate solution (1+8) is subsequently added, a white crystalline precipitate is produced, and the precipitate is insoluble when ammonia solution is added to the collected precipitate.
2. ADI is not required (FAO/WHO, 1994).
Use: Flour treatment agent, anti-caking agent, bulking agent.
1.Precautions for use This product has an acid-suppressive effect on the stomach (2g/L), and overdose may cause diarrhea.
2. Scope of use and amount of use
(1) China\’s \”Food Additive Use Hygiene Standard\” (GB2920-1996) stipulates: it can be used in wheat flour, the maximum dosage is 1.5g/kg.
(2) FAO/WHO (1983) stipulates: as an anti-caking agent can be used in milk powder and thin cream powder, the maximum amount of 10g/kg and 1g/kg respectively (used alone or with other anti-caking agents, only for other anti-caking agents and shall not have starch). It can also be used in chocolate, cocoa powder, etc.