Due to the existence of iron impurity greatly reduces the use value of quartz sand, affect the quality of the product, therefore, in the process of production to improve the grade of the quartz sand to reduce iron content is very important.In the real production elution mud,the raw material for water first to adopt mechanical scrubbing, ultrasonic cleaning, acid leaching, magnetic separation, flotation process to remove iron in quartz sand, such as increase the use value of the quartz sand.
Mechanical scrubbing to dislodge iron
Mechanical scrubbing is remove the film on the surface of the quartz sand iron and adhesion on the surface of the quartz sand, iron content by external mechanical forces and sand collision and friction.
Compared with other iron process it has the following features:
- It can achieve float glass products are of good quality, the quality requirements of high quality silica sand.
- High production.Now a small-scale production and processing enterprises to use this method in addition to iron, because it is low cost operation is simple, but the iron removal rate is relatively low.
Magnetic to dislodge iron
Main mineral in quartz sand, quartz,which is the magnetic materials,also is cannot be magnetized in the magnetic field.The impurities of iron in quartz sand mineral, hematite, limonite, magnetite, goethite, etc., most of them are in the magnetic material in magnetic field can be magnetized. On the magnetic separation process is the use of this property differences, through the magnetic separation to remove these mineral of iron impurities of quartz sand.
Magnetic separation can be divided into dry and wet. Wet magnetic separation have the disadvantage of magnetic separation machine power consumption is big, medium easy to wear,great water consumption of production, operation and maintenance cost higher defect.Dry magnetic separation process is easy to operate, low operating and maintenance cost of specific humidity type.
Ultrasonic to dislodge iron
In the process of transmission,Ultrasonic will interact with the medium, produce mechanical effect, thermal effect and cavitation effect. In the process of cavitation, the liquid inside the pressure mutations, which accompanied by shock wave.The pressure can amount to several thousand to tens of thousands of atmospheric pressure.Under the action of shock waves, adhesion in iron impurities on the surface of the particles from the particle surface off into the liquid phase, so as to achieve the aim of iron.
Ultrasonic to dislodge iron not only can eliminate impurities, and can remove particles of cleavage cracks in material.Thus, the iron removal effect is better. Ultrasonic to dislodge iron is the cheap resources for silica sand, it is appear more expensive, in large concentrator application will still be difficult.But for those who require high purity, less dosage of production is possible.
Flotation to dislodge iron
Flotation process is mainly used to separate the feldspar quartz sand and can also be used to remove the mica clay minerals such as quartz sand and iron flotation method can be divided into three kinds:
- Fluoride acid method. This method widely used because of its flotation effect is good, easy to control, stable. But the fluoride ion for land erosion and for weeks with the destruction of the ecological environment is very large.
- No fluoride method.The biggest advantage of this method is to avoid using fluorine ion has destructive effect to the environment, production index is stable, but the acid corrosion action on the equipment of mineral nots allow to ignore. The flotation equipment have higher requirements.
- Fluorine-free acid method. Under the condition of natural pH, through to the ion collector, create a unique high concentration slurry flotation environment and achieve the goal of preferential flotation impurity minerals.
Pickling to dislodge iron
Insoluble in acid pickling iron is the use the theory of quartz is not minerals containing but the iron impurities can be dissolved in the acid.Thereby realization the purpose of dislodging ore minerals from quartz sand. Acid leaching of ore minerals not only can be removed from quartz sand,but also has good removal effect om the non-metallic impurities of quartz mineral.Acid leaching is often use the acid such as sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid.After dealing with the acid leaching,can obtaine high purity quartz sand with SiO2 purity of 99.99% and iron content < 235 PPM.
Biological to dislodge iron
It is a newly developed a kind of iron removal technology with microbial leaching to dislodge iron oron on the surface of the silica sand.Now at the stage of research laboratory and pilot test. According to the foreign study results show that it have achieve good results to dislodge the ferric oxide on the surface of a quartz by the aspergillus and penicillium, pear-shaped, false form afterbirth fungus bacteria, bacillus, more stick of bacillus coli, lactic acid small aureus microbes.