water cooling electromagnetic separator for Quartz

PTMS MAGNETIC SEPARATOR

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Introduction to the whole process of mineral processing

Sampling and analysis

In order to obtain the information needed for the economic identification of ore and concentrate, the raw materials being processed are being routinely sampled and analyzed. In addition, the modern plant has a fully automated control system that allows in-process analysis of raw materials during raw material processing and adjustments at any stage to produce the most abundant concentrate at the lowest possible operating cost.

sampling

Sampling is the removal of a portion of a given large amount of material that represents the convenient size of the entire analysis. It can be done by hand or by machine. Manual sampling is often expensive, slow and inaccurate, so it is usually only suitable for places that are not suitable for machine sampling (such as slime) or when the machine is not available or the installation cost is too high.

Many different sampling devices can be used, including excavators, pipe samplers and automatic machine samplers. For these samplers to provide an accurate representation of the entire batch, the number of individual samples, the total number of samples, and the type of sample being sampled are of decisive importance. In order to achieve appropriate sampling standards, some mathematical sampling models have been designed.

analysis

After taking one or more samples from a quantity of ore through a material stream (such as a conveyor belt), the sample is reduced to an amount suitable for further analysis. Analytical methods include chemistry, mineralogy and particle size.

Chemical analysis

Even before the 16th century, it was known to use a comprehensive measurement method (measuring the value of ore) using a program that is not substantially different from the procedure used in modern times. Although traditional chemical analysis methods are now used to detect and estimate the amount of elements in ores and minerals, they are slow and not accurate enough, especially at low concentrations, and are well suited for process control. Therefore, in order to achieve higher efficiency, complex analytical instruments are increasingly being used.

In the emission spectrum, one establishes a discharge between a pair of electrodes, one of which is made of the material being analyzed. The discharge evaporates a portion of the sample and excites the elements in the sample to emit a characteristic spectrum. Detecting and measuring the wavelength and intensity of the emission spectrum reveals the identity and concentration of the elements in the sample.

In X-ray fluorescence spectroscopy, a sample bombarded with X-rays emits fluorescent X-rays having the characteristics of their elemental wavelengths. The amount of X radiation emitted is related to the concentration of each element in the sample. The sensitivity and accuracy of this method is low for the number of atoms of the element (ie, a few protons in the nucleus, such as boron and strontium), but most of the components of slag, ore, sinter, and pellets are at higher The atomic number range, as in the case of gold and lead, is usually appropriate.

Mineralogy analysis

A successful separation of a valuable mineral from its ore can be determined by determining a heavy liquid in which a single size of ore is suspended in a high specific gravity liquid. Particles that are less dense than liquid remain floating, while denser particles sink. Several different particle fractions of the same density (and therefore of similar composition) can be produced, and then valuable mineral constituents can be determined by chemical analysis or by microscopic analysis of the polished portion.

Size analysis

Crude grinding minerals can be classified by using special sieves or sieves that have been accepted by various national and international standards. An old standard (now obsolete) is the Tyler series, where the size of the wire mesh is measured in terms of wire or opening size per inch. Modern standards now classify screens based on the size of the aperture and measure in millimeters or micrometers (10 -6 meters).

Mineral particles smaller than 50 microns can be classified by different optical measurement methods using light or laser beams of various frequencies.

Crush

In order to separate the valuable components of the ore from the waste rock, the mineral must be liberated from the physical state by pulverization. Usually, the pulverization first pulverizes the ore to a certain size and then grinds into a powder, and the final fineness depends on the dispersion fineness of the desired mineral.

In the primitive era, the crushers were small manual mortars and mortars, and the grindstones were made by humans, horses or hydro-powered grindstones. Today, these processes are carried out in mechanized crushers and mills. Since the pulverization is carried out mainly under dry conditions, the mill can be both dry and wet, and wet milling is dominant.

broken

Some ore exists in nature as a mixture of discrete mineral particles, such as gold in gravel beds and streams, and diamonds in mines. These mixtures require little or no breakage because valuables can be recycled using other techniques, such as disintegrating sandpaper materials in a feller. However, most ore is composed of hard, hard rock that must be crushed before valuable minerals are released.

In order to produce a crushed material suitable for use as a mill feed (100% of the pieces must be less than 10 to 14 mm, or a diameter of 0.4 to 0.6 inches), the crushing is carried out in stages. In the initial stage, most of the equipment used was a jaw crusher with an opening of up to two meters. These ores are crushed to less than 150 mm, which is a suitable size and can be used as a feed for the secondary crushing stage. At this stage, the ore is crushed to less than 10 to 15 mm in a cone crusher. This material is the grinding of the feed.

grinding

At this stage of the process, the pulverized material can be further broken down into a. This is a cylindrical container which is a cylindrical container whose length to diameter ratio is variable, its axis is substantially horizontal, and partially Fill with a grated object (for example, flint, iron or steel balls) by the effect of gravity by rotating the container.

A special development is a self-generated or spontaneous semi-autogenous mill. The self-grinding mill operates without a grinding body; instead, the rougher portion of the ore simply grinds itself and the smaller portion. For semi-autogenous mills that have become commonplace, add 5-10% of the abrasive body (usually a metal sphere).

Crushing/grinding

Another development, combined with the process of comminution and grinding, is a roller crusher. This consists essentially of two cylinders mounted on a horizontal shaft and driven in opposite directions. The cylinders are pressed together under high pressure so that comminution occurs on the material bed between them.

concentration

Concentration involves the separation of valuable minerals from other raw materials received from the mill. In large-scale operations, this is achieved by exploiting the different properties of the mineral to be separated. These properties can be color (optical sorting), density (gravity separation), magnetic or electrical (magnetic and electrostatic separation), and physical chemistry (flotation separation).

Optical separation

This process is used by the naked eye for particle colors with very different concentrations (best contrast is black and white). In addition, electro-optical detectors collect data on mineral response when exposed to infrared, visible and ultraviolet light. Call the same principle and use only gamma radiation to separate the radiation.

Gravity separation

The gravity method uses the difference in mineral density as a concentrate.

In heavy medium separation (also known as uplift separation), the medium used is a suspension of finely divided heavy minerals (such as magnetite or arsenopyrite) or technical products (such as ferrosilicon) in water. This suspension can simulate fluids that are denser than water. When the ground ore enters the suspension, the gangue particles having a lower density tend to float and the tailings are removed, while the particles with higher density of valuable minerals sink and are removed. Magnetite or ferrosilicon can be removed from the tailings by magnetic separation and recycled.

Diving during the call, the water stream is pulsed or moved up and down by the piston through the material bed. Under the influence of this oscillatory motion, the bed is divided into layers of different densities, the heaviest concentrate forms the lowest layer, and the lightest product is the highest. It is important for this process to thoroughly classify the feed because particles smaller than 1 mm cannot be separated by jigging.

Finer particles (from 1 mm to 50 microns) can be effectively separated in a flowing water stream on a horizontal or inclined plane. Most systems use extra force, such as a spiral or impact force to shake the table. The spiral consists of a vertical spiral channel with an elliptical cross section. As the pulp flows from the top to the bottom of the channel, the heavier particles concentrate on the inside of the stream where they can be removed through special openings. Due to its low energy cost and simple operation, the use of spirals has increased rapidly. They are particularly effective when concentrating heavy ore and gold.

The gravity on the inclined plane is concentrated on the vibrating table, and the vibrating table can be smoothed or grooved and vibrated back and forth at right angles to the water flow. When the pulp flows down the slope, the floor material is layered into a heavy and light layer in the water; in addition, the particles are separated in the direction of impact under the influence of vibration. Shakers are typically used to concentrate finely grained tin, tungsten, tantalum and niobium ore.

Flotation separation

Flotation is the most widely used method for fine mineral concentration. It takes advantage of the different physicochemical surface properties of minerals - especially their wettability, which can be natural or artificially altered by chemical agents. By changing the hydrophobic (hydrophobic) or hydrophilic (absorbent) conditions of their surface, it is possible to induce the mineral particles suspended in the water to adhere to the bubbles passing through the flotation cell or to remain in the pulp. The bubbles are passed to the upper surface of the pulp and form a foam which is removed along with the attached hydrophobic mineral. The tailings containing hydrophilic minerals can be removed from the bottom of the cell.

Flotation makes it possible to process complex symbiotic ores containing copper, lead, zinc and pyrite into separate concentrates and tailings, an impossible task using gravity, magnetic or electrical separation methods. In the past, these metals were only recovered using expensive metallurgical processes.

magnetic separation

Magnetic separation is based on the different attractive forces of magnetic fields to various minerals. Successfully required feed pellets to fall within a specific size range (0.1 to 1 mm). If a low-intensity magnetic separator is used, strong magnetic minerals such as magnetite, zinc-rich iron ore and pyrrhotite can be removed from the gangue mineral. High-strength equipment can separate iron oxide ore, such as limonite and siderite, and iron-bearing manganese ore, titanium ore, tungsten ore and iron-containing silicates.

Electrostatic separation

Electrostatic methods separate particles of different charges and, where possible, separate particles of different sizes. When particles of different polarities enter the electric field, they follow different motion trajectories and can be captured separately. All plants that process heavy mineral sands containing zircon, rutile and monazite use electrostatic separation. In addition, the cleaning of special iron ore and cassiterite concentrates and the separation of cassiterite-scheelite are carried out by electrostatic methods.

Dehydration

The concentrate and tailings produced by the above process must be dewatered to convert the pulp into a transportable state. In addition, water can be recycled to the existing water circuit of the processing plant, greatly reducing the need for expensive fresh water.

filter

Filtration is carried out by separating the suspension into a solid filter cake and a liquid filtrate by passing the suspension through a permeable filter material. Important factors in the process are the nature of the suspension (eg, size distribution, concentration), the nature of the filter material (eg, the width and shape of the pores), and the force applied to the suspension. Filtration is carried out in a gravity filter (screen, dewatering tank), a centrifugal filter (screen centrifuge), a vacuum filter (tympanic filter, disc filter) or a pressure filter (filter press). This device can produce a filter cake with a moisture content of 8% to 15%.

Thicken

During thickening (also known as settling), the solids in the suspension settle in the tank under gravity and form a thick slurry. This pulp and the clear liquid at the top of the tank can be taken out continuously or intermittently. Thickening has the advantage of lower operating costs compared to filtration; on the other hand, it has the disadvantage of leaving a higher water content in the pulp. For this reason, the dewatering of pulp containing fine particles typically involves a combination of thickening and filtration. The use of flocculants usually aids in the thickening of the fines.

drying

The removal of water from solid materials by thermal drying plays an important role in modern mineral processing. There are a large number of dryer types to choose from. The most common is a convection dryer that uses a stream of hot combustion gases to remove moisture from the pulp stream. This type belongs to rotary drums, conveyors and fluidized bed dryers.