When barite is used in different fillers, its product requirements are different. For example, when used on coatings, the whiteness of barite is not less than 90, and the rubber filler is not allowed to contain impurity such as MnCU, Pb and so on. To this end, today sinoke for everyone to introduce the barite impurity whitening technology in detail.
1.The method of whitening by flotation.
For sedimentary barite ore and hydrothermal barite ore associated with fluorite sulphide ore, the size of inlay is very small, and the physical impurity removal effect is not good. There are two kinds of flotation reagents: one is anionic collector with alkyl sulfonate fatty acid sulfate, the other is cationic collector with high amine salt in barite flotation. Because of the diversity of associated minerals, the use of a single flotation reagents is often unable to achieve the desired goal. Therefore, combination reagents are often used to promote each other and achieve better flotation results. Fluorite, calcite and barite belong to calcium ionomer compounds. The energy is between 417~519kJ/mol and the floatability is similar, which determines that the complex barite ore is difficult to separate.
The mixed collector sodium dodecyl sulfate oleate sodium oleate 96g / t 24g / t sodium silicate, a mixed inhibitor, can also be used to flotation the tailings of Pingshui Copper Mine for barite recovery. A better index was obtained than the single collector inhibitor: the concentrate grade of 95.2 and the recovery rate of 83.1 and 2.67 were increased by 3.52 and 83.1 respectively.
In addition, barite can be fine ground and dissociated from quartz monomer. Oleic acid plus oxidized paraffin soap or sodium dodecyl sulfonate plus oxidized paraffin soap can be used as collector, and sodium carbonate as adjuster and gangue inhibitor. The flotation effect is good. The BaSO4 of concentrate grade is greater than 98 and Sio 2 is less than 1, which reaches the expected target.
2.Method of calcining and whitening
During the formation of barite, some colored organic compounds will inevitably be mixed, which will make barite grey and green and black, thus reducing the whiteness of barite and affecting the application of barite in white coatings. Due to the explosion of endothermic materials at high temperature, hydrothermal barites volatilize the chromogenic organic matter distributed in the crystal or gap of barite. The whiteness of barite powder calcined at 850 ℃ for 2 h can be increased from 88.19% to 90.64%, and 93.5% after calcined at 950 ℃ for 2 h.
3.The method of removing impurities and whitening by leaching
Pure barite shows white luster, due to the characteristics and quantity of the mixture, will appear light gray, light blue, yellow, pink, brown, light brown and so on.
The surface chemical properties of barite and associated minerals are different from those of barite, and the carbon, iron, manganese, magnesium, nickel and other impurities in the ore are removed by acid (or alkali) leaching and redox. Acid (alkali) leaching is the reaction of hydrochloric acid sulfate and other metal compounds (or Sio _ 2) associated with barite to form compounds soluble in water or dilute acid (silicate) which are then washed and filtered and separated from soluble matter. The oxidants such as hydrogen peroxide, sodium hypochlorite or concentrated sulfuric acid are used to dissolve the associated metal compounds in the mineral and oxidize the chromophore organic compounds in the barite. Then the Fe3 is added to the reduction agent. Reduction to Fe2, leaching iron in a short time, to achieve the purpose of removing impurities and whitening to improve the grade of minerals.
The barite mineral content was increased from 95.60% before purification to 97.29%, and the main chromophore Fe3 was completely removed. After flotation of low grade barite ore, barite powder with 96.12% whiteness and 89% whiteness of BaSO4 can be obtained by using aluminum powder as reducing agent under acid pickling condition of sulfuric acid.