Iron ore decomposition method

Decomposition method

Decomposition of iron ore, in practical application, depending on the characteristics of the ore, where the analysis items requested and the separation of interfering elements and the like, usually used an acid decomposition and alkali melting.

The commonly used acid decomposition method is as follows:

(1) Hydrochloric acid decomposition Iron ore can generally be decomposed by heating with hydrochloric acid. The iron-containing silicate can be dissolved in hydrochloric acid, and a little hydrofluoric acid or ammonium fluoride can be added to decompose the sample completely. Magnetite is slow dissolution rate, can be added a few drops of stannous chloride solution, a decomposition speed.

(2) Sulfuric acid-hydrofluoric acid decomposition sample In platinum crucible and plastic crucible, add 10 drops of 1:1 sulfuric acid, 4-5 ml of hydrofluoric acid, heat at low temperature, and then emit sulfur trioxide white fumes, use hydrochloric acid extract.

(3) Sulfuric acid or sulfur- phosphorus mixed acid (1:2) should be heated until the water completely evaporates and sulfur trioxide is present, and it is heated for several minutes. However, the heating time should not be too long to prevent the formation of pyrophosphate. It is now more common to use alkaline melting to decompose samples. Commonly used fluxes are sodium carbonate, sodium peroxide, sodium hydroxide, potassium hydroxide and sodium peroxide-sodium carbonate (2:1) mixed flux.

Melting crucible may be made of silver, nickel crucible, an alumina crucible or a high graphite crucible. Sodium peroxide is also semi-fused in nickel crucible. Since iron ore contains a large amount of iron, the direct melting of sodium carbonate in the platinum crucible impairs the enthalpy, and platinum also affects the determination of iron, so it is rarely used. For iron ore containing sulfides and organics, the sample should be pre-fired at 500-600 ° C to remove sulfur and organic matter, then decomposed with hydrochloric acid, and a small amount of nitric acid is added to completely decompose the sample. The presence of nitric acid affects the determination of iron and can be removed by evaporation with hydrochloric acid.

Sodium Trimetaphosphate

Sodium trimetaphosphate is a white crystalline powder that is used in various industrial applications, including as a water softener, detergent builder, and food additive. It is a sodium salt of trimetaphosphoric acid, which is a cyclic phosphate with the chemical formula (PO3)3. Sodium trimetaphosphate is soluble in water and has a high melting point of 622°C. It is commonly used in the production of ceramics, as a dispersant in paints and coatings, and as a corrosion inhibitor in metalworking fluids. In the food industry, it is used as a sequestrant and emulsifier in processed meats, dairy products, and canned foods. However, excessive consumption of sodium trimetaphosphate can lead to adverse health effects, such as high blood pressure and kidney damage.