Seven Questions of Ore Dressing Common Sense

Most people are likely unfamiliar with  mineral processing. The reason why I think so is that I have often encountered  many people asking me some very basic questions about it. As I’m a worker in  Yantai Mining Technology & Equipment Inc, sometimes my friends and relatives around  will habitually ask me some questions about mines and mineral processing which I  think are very simple and basic questions. I have roughly sort out the  questions at my leisure time and carefully chosen seven of them. I believe even  people who never expose themselves to mineral processing industry can have a  basic understanding through these seven questions.

First, what is mineral processing?

Mineral processing is a process during  which we make full use of the physical and chemical difference of minerals to separate  the valuable minerals with gangue minerals and achieve the relative enrichment  of valuable minerals by means of various beneficiation equipment. Three are several solutions of mineral process in Yantai Group.  

Second, why do we conduct mineral  processing?

The ores mined from the underground are  generally made up of valuable minerals and gangue minerals with a lower grade  that cannot be directly smelt. Therefore, it is necessary to process them preliminarily  by eliminating most gangues and harmful ingredients to enrich the minerals to concentrates  for the sake of further utilization. That’s why mineral processing comes.

Third, what are the common minerals?

Minerals are native elements or natural  compounds with fixed chemical constitution and physical and chemical properties  that formed after the physical, chemical and biologic functions under natural  environment factors in the crust. They are component part of rocks or ores.

Apart from few native elements like Au, Ag,  Cu, S, C and so on, the vast majority of minerals are natural compounds, such  as Fe3O4, SiO2, PbS, CuFeS2 and so on.

There are over 3500 types of the known  minerals. However, under the existing technical conditions, only 200 of them  can be used.

Four, what are the steps in the mineral  processing of dressing plants?

Only after the ores from quarries finishing  the whole beneficiation process, can the final concentrate accord with the  smelting requirements. The whole process is as shown in the figure below.

The beneficiation process mainly includes  three steps, namely, preparation operation that consist of ores’  crushing-screening and grinding-classification, separating operation that  consist of technologies like gravity separation, flotation and electrostatic  separation, and dewatering operation that consist of concentration, filtration,  drying, etc.

Five, what does the grade of ores mean?

The grade of ores refers to the content of  some metal or useful components the ores contain, usually described by  percentage. There are three kind of ores grade: grade of raw ore, grade of  concentrate and grade of tailings, which are respectively represented with α, β and θ. If there is  something wrong with the mineral processing production, analyses will generally  come first in these three kinds of grades.

Six, what are respectively concentrates, tailings  and middlings?

The concentrates are the final products of  concentration plants obtained after the ores’ separating operation by  eliminating most gangues and impurities to fulfill the enrichment of the  valuable minerals.

The tailings are the last products with few  useful contents remained after all kinds of extractions and screening  operations on the raw ores.

The middlings are the intermediate products  obtained during the separating process. Their valuable contents are higher than  those of concentrate but lower than tailings, so it’s necessary to return them  for another separating operation or further deal with them separately so that  they can be used efficiently.

Seven, what are the common mineral  processing methods in ore dressing plants?

The common mineral processing methods in  beneficiation plants are gravity separation, flotation technology, magnetic  separation and electrostatic separation.

The gravity separation is a separation  method that is used in separating minerals according to their difference in  relative density. The principle here is that the ore grains with different  density will implement the separation under the appropriate loose layering and  separating conditions caused by the effect that the fluid dynamics and various  mechanical forces have on the ore grains in moving mediums like water, air and  heavy fluid.

The flotation technology is a separation  method which accomplishes the separation purpose by selectively absorbing the valuable  minerals onto the foams with the help of flotation reagents in accordance with  the difference in physical and chemical properties of the minerals surface. And  flotation technology is usually adopted when processing the non-ferrous metals  like copper, lead and zinc.

The magnetic separation achieves separation  of minerals by making different minerals experience different forces in the  magnetic field of magnetic separators on the basis of their different  magnetism. This technology takes the lead in the separation of ferrous metal  ores like iron, manganese, chrome, etc.

The electrostatic separation is conducted  according to the various minerals conductivity. When minerals pass by the  high-voltage electric field of the electrostatic separators, the minerals will  separate because of the different electrostatic force arising from the diverse  conductivity. Electrostatic separation method is mainly used for separation and  concentration of mixed ores, including separation of wolframine and cassiterite  and the concentration of zirconite.