Feldspar Beneficiation Process Magnetic & Flotation

Published time:25 June 2019

Feldspar Properties

Feldspar is a silicate mineral of K, NA, Ca composed of silicon-oxygen Tetrahedra. Its main components are SiO2, Al2O3, K2O, Na2o, CaO, and MgO, which are important raw materials for manufacturing, and widely used in chemical, abrasive, glass fiber, electrode, Enamel and filler industries.
The prevalence of top quality glass and ceramic products demands a growing supply of feldspar with high purity and low iron.
feldspar ore
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What’s the workflow of the feldspar stone processing plant?
Generally speaking, the feldspar concentrate rich in potassium and sodium is recovered by the combined mineral separation methods of gravity separation, electric separation, magnetic separation and flotation to remove associated minerals such as quartz and mica.
feldspar processing plant

Feldspar extraction processing plant

1. Crushing and grinding

The crushing and grinding of feldspar are not only to meet the grain size requirement of the final product, but also to meet the need of the impurity removal process. The coarse crushing of feldspar mostly adopts jaw crusher, and the particle size is about 10mm. There are many options for fine crushing and grinding machines of the feldspar processing plant, mainly roller crusher, impact crusher, sand making machine, hammer crusher, stone grinding, column mill, tower mill, Raymond mill, stirring mill, vibration mill, sanding mill, and airflow mill, etc.
At present, feldspar grinding can be divided into dry grinding and wet grinding, wet type grinding is more efficient than dry type.
ball mill

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From the point of view of the application industry, the processing of feldspar raw materials in the glass industry mostly adopts a steel rod medium grinding machine, which has high grinding efficiency and uniform particle size, but the introduction of iron pollution leads to the low quality of feldspar products. The ceramic industry has higher requirements for feldspar raw materials, so stone roll grinding or ceramic ball grinding is often used, which has low grinding efficiency and high energy consumption, and can not realize high efficiency and continuous process.

On the basis of ensuring the high quality of feldspar products, how to realizing high efficiency grinding process and continuous production is an important subject in the research of feldspar beneficiation and purification.

2. Ore washing and desliming

The washing process is suitable for feldspar produced from weathered granite or feldspar placer, which mainly to remove impurities such as clay, fine mud and mica. On the one hand, it can reduce the content of Fe2O3 in feldspar ore, on the other hand, it can increase the content of potassium and sodium in feldspar ore.
Common ore washing machines: Denver washer dryer, vibrating screen, log washer, mixing tank, and grinders.

Desliming is mainly used to remove the primary slime and the secondary slime produced by grinding, prevent a large amount of fine slime from affecting the separation effect of subsequent operations such as flotation and magnetic separation. Commonly used equipment desliming hopper, centrifuge concentrator, hydrocyclone, etc.

3. Magnetic separation

Due to the magnetic properties of iron minerals, mica and garnet in feldspar ore, it can be separated from feldspar mineral by the external magnetic field. In general, the magnetic properties of iron minerals and mica in feldspar are weak, only by using high-intensity magnetic separator can get a good result. The main magnetic separator equipment has a permanent magnetic roller type strong magnetic separator, permanent magnetic drum type medium strong magnetic separator, wet flat type strong magnetic separator and high gradient strong magnetic separator.
types of magnetic separator

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    • Permanent magnetic roller high-intensity magnetic separators
      Permanent magnetic roller high-intensity magnetic separators use rare earth permanent magnetic repulsion magnetic pole principle, magnetic roller surface magnetic induction up to 2.0 t. It is suitable for dry separation of weakly magnetic minerals, and has become the main magnetic separation equipment for dry iron removal from feldspar in recent years. Particle size lower limit of 0.12mm, good separation effect, low operation cost, and convenient operation.
    • Permanent magnetic drum type high-intensity magnetic separator
      The magnetic induction of a separate field is between 0.3 t and 0.8 t, has the dry type and wet type processing methods. Due to the weak magnetic field, it is difficult to get high-grade feldspar products.
    • Wet type horizontal ring high-intensity magnetic separator
      It is the common used strong electromagnetic separator both at home and abroad, its magnetic induction is 1.2 ~1.7t, great advantages of wide particle size and high capacity.
    • High gradient high-intensity magnetic separator
      The high gradient high-intensity magnetic separator is the most effective equipment for the purification of fine mineral, its magnetic induction can reach 2.0 t, even 5.0 t, and it can purify-74 m feldspar. It is definitely an effective machine for dressing high-grade feldspar products, but the equipment cost and operation cost are higher than that of other magnetic separators.

4. Flotation

Flotation is an effective way to remove impurities in feldspar. On the one hand, the impurity elements such as iron and titanium can be removed from feldspar, the combination of chemical agents depends on the existing components of impurity; on the other hand, the feldspar can be separated out the quartz, thus increase the content of K, Na.
At present, there are many studies on the separation of feldspar and quartz, as well as the selective separation of potassium feldspar and albite.
flotation machine

  • Flotation of Ti-bearing minerals
    The results show that titanium mainly exists in rutile (or Anatase) and a small amount of sphene. Using fatty acids as collectors, rutile (or Anatase) is easy to be flotation out in the pH4-6, but its floatability decreases in the following order: oleic, linoleic acid, linolenic acid.
    Using Petroleum sulfonate or aliphatic primary amine acetate, rutile (or anatase) can also be floated at Ph 2.5. At present, only a few pieces of literature have described the floatation performance of sphene.
  • Flotation of iron-bearing gangue minerals
    In general, iron in feldspar minerals occurs mainly in mica, pyrite, a small amount of hematite and iron-bearing alkali silicates (such as garnet, tourmaline and amphibole). In general, mica can be floated by amine cation collector at PH 2.5 ~ 3.5; sulfide minerals such as pyrite can be floated by xanthate collector at PH 5 ~ 6; Iron-bearing silicates can be obtained by flotation with sulphonate collectors at Ph 3 ~ 4.
  • Quartz-feldspar flotation separation
    The trading flotation separation method of quartz-feldspar is the HF acid method. consider of the environment protection, most mineral workers prefer to free-fluorine acid method.
  • Flotation separation of potash feldspar and albite
    The separation of potash feldspar (orthoclase and microcline) and albite is a challenging issue because they are mostly mixed in feldspar deposits and these minerals have similar chemical structures and similar physical chemistry properties.

What is the development trend of feldspar processing?

At present, it is easy to obtain high-grade concentrate in the combined process, and it is economical and effective to pretreat feldspar ore with high iron content by acid leaching and stripping.

1. Leaching

It is difficult to remove the iron-bearing minerals in ultrafine feldspar particles by traditional methods, but leaching can achieve better results. The feldspar leaching reagent is not only beneficial to the decomposition of feldspar, but also can effectively remove the interlayer iron minerals on the surface of feldspar.
Biological leaching has the advantages of simple operation and low environmental pollution.

2. Combination

For some very difficult separating feldspar, of which iron content is high, some iron minerals are permeated in the feldspar cleavage, only single separation process does not meet the requirements of concentrate, the combination of multistage is introduced at the right moment.

(1) Magnetic-floating combined flow
Most of the iron minerals were removed by magnetic separation, and then the fine iron minerals and iron-stained Potassium Feldspar were removed by flotation. Dry magnetic separation followed by flotation can get the best separation effect, but the dry magnetic separation need dehydration and drying process, the cost is higher, so wet magnetic separation followed by flotation process is more widely used.
(2) Stripping-strong magnetic separation process combined flow
If the feldspar ore is soft, easy crushing, put them into the grinding mill machine to peel off the iron material in the mica group minerals. The result shows that the stripping-strong magnetic separation process has a significant improvement, besides, its cost is lower than that of the magnetic – flotation combined flow.
JXSC focuses on help customers to solve mineral processing problems occurs in the feldspar mining plant, including provides mining machines, design mineral processing workflow, etc.

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