Kaolin, as a kind of excellent domestic mineral, is widely used in ceramics, paper, rubber, plastics, building materials, paint, petrochemical and so on, especially in ceramics home. Kaolin can be used as ceramic billet and glaze.
No matter whether the ceramic household or other family parts, there is a certain requirement for the whiteness of kaolin. The natural whiteness of kaolin produced in nature is often affected by minerals containing some organic matter and iron, titanium, manganese and other elements. The iron impurity in kaolin not only affects the color of ceramic products after burning, but also seriously affects the electrical energy and chemical invariance of ceramic products. The physical mineral processing essentials of the recycling rule are not clear about the removal of pyrite and other weak magnetic minerals and fine particles containing iron impurities. The recovery of chemical iron removal method can effectively remove the iron impurity in this sector.
Today we will introduce a method of removing iron from kaolin and iron removal by oxidation.
When pyrite and organic matter are contained in kaolin, the minerals are often gray. These substances are difficult to be removed from the pickling and reduction methods, and the oxygen removal method should be recycled to hold bleaching.
Oxidizing iron removal is a strong oxidizing agent that oxidize the reductive pyrite in the water medium into ferrous ions soluble in water, and oxidize deep color organic matter to make it a colorless oxide that can be washed by water. The oxidants used in the oxidation process include sodium hypochlorite, hydrogen peroxide, Potassium Permanganate, chlorine and ozone.
The results of oxidation and iron removal are related to the pH value of the medium, and are also influenced by ore characteristics, temperature, dosage of the reagent, pulp concentration and bleaching time.
1. The influence of pH value. Hypochlorite is a weak acid salt, and its oxidation capacity varies at different pH values. It is more stable in alkaline medium than in acidic and neutral media, Silver powder, and is analytically fast to generate strong oxidant. Under the condition of weak acidity (Ph5 ~ 6), the activity is the largest and the oxidation capacity is the strongest. The two valence iron ion is relatively unchanged at this time.
2. The influence of temperature. With the increase of temperature, Boron carbide powder, the rate of hydrolysis of bleach is accelerated, the rate of bleaching is accelerated, and the bleaching time is shortened. However, when the temperature is too high, the consumption of heat will be great, and the speed of drug analysis is too fast, which will lead to waste and pollution. In actual operation, the expected results can be achieved by increasing the dosage of drugs, mediating the pH value and prolonging the bleaching time at normal temperature.
3. Influence of dosage of medicament. The optimum dosage is related to the properties of the raw ore, the level of oxidation, the temperature, the time and the pH value of the impurities. The excessive or too small dosage of the reagent affects the iron removal results.
4. The influence of the concentration of the pulp. When the dosage of medicament is on time and the concentration of pulp is low, the result of iron removal and bleaching decreases; if the concentration is too high, the product is not washed, and the excessive ion of the residual agent after the filtration will also affect the function of the product.
5. The effect of bleaching time. The longer the time is, the better the iron removal results, the faster the reverberation is at first, and then the slower, and the silicon powder, the fair and economic bleaching time needs to be determined by the test talent.