Magnetic Separator For Silica Sand

Magnetic Separator For Silica Sand – High Gradient Magnetic Separator

High Gradient Magnetic Separator For Silica Sand

Silica Sand?

Silica Sand, also known as Quartz Sand, is a common non-metallic mineral raw material. The purified high-purity silica sand is widely used in optical glass, optical fiber communication, semiconductor, aerospace and other fields.

Silica sand is formed by rocks such as quartz sandstone, feldspar, and quartzite, which gradually wheathering and decompose under the influence of moisture and other external factors in nature.

Under normal circumstances, it mainly exists in the form of sea sand, river sand and weathered sand with Silicon Oxide (SiO2) as the main component. The content of SiO2 in quartz sand varies greatly from place to place. This is because quartz sand also contains other mineral impurities, such as , Clay, heavy minerals, rock debris and feldspar and other impurities.

The color of quartz sand is also different due to the different impurities contained. For example, because of the impurities such as titanium and iron, it is brownish red or light yellow. The Mohs hardness of quartz is generally 7, and the refractoriness is 1650~1770℃, specific gravity 2.65~2.66, refractive index 1.533~1.541. Usually the quartz we see is α-quartz (ie low temperature quartz).

Large pieces of quartz stone are processed, crushed and sieved into fine quartz particles, also known as silica sand. Quartz is a silicate mineral, which is characterized by stable chemical properties, hardness and wear resistance. There are currently four main forms of quartz sand we use for production: quartzite, quartz sandstone, natural quartz sand and vein quartz.

Why Use Magnetic Separator For Silica Sand?

Silica Sand usually contains some impurity minerals, including iron-containing impurity minerals: goethite, hematite, limonite, ilmenite, pyrrhotite, tourmaline, amphibole, biotite, etc. These iron-containing impurities may be embedded in quartz particles and attached to the quartz surface.

The presence of these iron-containing impurities greatly reduces the use value of quartz sand and affects the quality of the product. For example, in the production of glass, iron-containing impurities will cause greater harm to the production and quality of glass, especially the thermodynamic properties and the light transmittance of the glass product in glass melting process. Therefore, it is very important to improve the grade of silica sand and reduce the content of iron in the production process.

In actual production, the raw materials are washed with water first, and then mechanical scrubbing, magnetic separation, flotation, ultrasonic cleaning, acid leaching and other processes are used to remove the iron element in the quartz sand and improve the use value of the quartz sand. Therefore, the use of a magnetic separator is a very critical step in the purification process of silica sand.

Silica Sand Purification - Magnetic Separation

Magnetic Separators For Silica Sand

Wet Magnetic Separation Process
Plate Type High Gradient Magnetic Separator/ Belt Type High Gradient Magnetic Separator

GTEK belt type high gradient magnetic separator is mainly suitable for the separation of weak magnetic minerals with a particle size of less than 5mm.

It is suitable for iron removal of non-metallic minerals, such as: mica powder, quartz sand, potash feldspar, nepheline, fluorite, sillimanite, spodumene, kaolin,  pyrrhotite, roasted ore, hematite, limonite, siderite, chromite, wolframite, tantalum-niobite, red mud, etc.

Belt Type High Gradient Magnetic Separator - GTEKmagnet
Working Principle

The powerful permanent magnet is placed in the middle part of the belt, just below the feed inlet.

When feeding, the iron impurities in the product stream will be absorbed in the magnetic field area and transported upward through the belt, in the opposite direction of the non-magnetic material.

When the magnetic impurities are transported to the end of the magnetic field area, the magnetic impurities will stay at the end to gather into a cluster due to the action of the magnetic force, and then be pushed out of the magnetic field area by the rids on the belt. Eventually washed away by water and fall off the belt.

Dry Magnetic Separation Process
Dry High Intensity Magnetic Roller Separator/ Roll Magnetic Separator

GTEK high intensity magnetic roller separator uses ultra-strong magnetic rollers for multiple sorts, it is suitable for sorting minerals with weak magnetism, such as limonite, manganese ore, and after sorting it can be improved by 10 to 25 grades.

It is also suitable for Iron removal of non-metallic minerals, such as quartz, feldspar, nepheline, sillimanite, spodolite kaolin, etc.

Magnetic Roller Separator - Double Layers | GTEKmagnet
High Intensity Magnetic Head Pulley/ High Intensity Magnetic Roller

Magnetic Head Pulley is usually installed on the end of the conveyor belt and is suitable for the automatic separation of iron filings, iron pieces, iron blocks or other ferromagnetic materials from large quantities of dry materials such as ore, grains, sand, gravel, plastics, wood, broken glass, waste, etc.

Our high intensity series magnetic head pulley can reach 15000Gs, which can efficiently remove iron impurities in fine powder.

High Intensity Magnetic Head Pulley

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Is Magnetic Separation Effective For The Purification Of Silica Sand?

Yes. We reached this conclusion through experiments on 300 grams of a certain raw silica sand sample. After particle size analysis, the particle size distribution of the sample sand is as follows:

>0.50mm 0.1~0.5mm <0.1mm
0.40% 84.70% 14.90%

The smaller the particles of quartz sand, the larger the specific area, which is more conducive to the removal of impurities. However, the particle size that is too small will have an adverse effect on transportation and storage. On the whole, the quartz sand samples we selected meet the requirements for glass production.

After magnetic separation of the sample by using a strong neodymium iron boron magnet with a surface magnetic field strength of up to 3350Gs, some impurities adsorbed by the magnet are taken and analyzed by SEM-EDS. Take 7 representative particles and analyze the results, check them in the table below:

It can be seen from the data in the table that the common feature of samples 1-7 is that there are Fe impurities, but the content of Fe impurities carried by different particles is very different, and except for C, O, Al, Si and Fe impurities, they are common. The remaining K, Mn, Cl, Ti, Na, Ni and Ca impurities are not present in all particles, which shows that the magnetically separated impurities are not the same substance, but multiple magnetic substances.

After magnetic separation, the Fe content in the quartz sand sample decreased from 2661ppm to 637ppm, which shows that magnetic separation has a significant effect on the removal of Fe impurities. And through experimental comparison, the quartz sand that has been subjected to acid leaching after magnetic separation has a better and faster iron removal effect than the acid leaching without magnetic separation.

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