General beneficiation method of tin ore - gravity separation

 The density of cassiterite (SnO2) is 6800~7000 kg/m3, and it is often symbiotic with gangue minerals (such as quartz, feldspar, muscovite, etc.) with a density of about 3000 kg/m3.

Gravity beneficiation is the basic method of cassiterite separation. More than 85% of the world's tin concentrates come from gravity beneficiation operations. Gravity beneficiation can be used as cassiterite pre-enrichment means, and can also directly produce qualified cassiterite concentrate. In the Bronze Age, people began to use gravity beneficiation to enrich tin minerals. Since the 1960s, tin beneficiation has developed from a single gravity beneficiation to a combined process consisting of gravity beneficiation, flotation, magnetic separation, and electrical separation.

Grading desliming is a necessary preparation for the cassiterite gravity beneficiation process. The desliming equipment used mainly includes water guns, various washing machines, Bartley-Maudsley turning beds, cross-flow belt chutes and hydrocyclones. Medium concentrators and jigs mostly use dry coarse-grained and medium-grained cassiterite for pre-selection; screw concentrators use dry to effectively recover cassiterite with a particle size of 0.074~1 mm. The enrichment ratio of the shaker separation is high, which can not only select high-grade cassiterite concentrate, but also throw out the final tailings, which is the main equipment of the tin processing plant. Centrifugal concentrators are used to sort tin slime with a dry size of 0.037 mm.

Tin ore is divided into sand tin ore and vein tin ore. Sand tin ore is the main mining object, accounting for about 75% of the total mining volume. Sand tin ore generally adopts the gravity beneficiation process of stage grinding, stage separation, mud sand separation, and rich and poor separation. Vein tin ore has cassiterite-oxide mineral type, cassiterite-quartz type and cassiterite-sulfide mineral type.

The cassiterite-oxide mineral type mainly adopts a single gravity beneficiation process, mainly using a shaking table, and multi-grinding and multi-separation operations. Cassiterite-quartz type and cassiterite-sulfide mineral type are generally pre-selected by rich separation or heavy media separation, rough separation by jig and shaker, and finally by flotation, gravity beneficiation, magnetic separation, and electric separation. The process is selected to produce the final concentrate.

After the raw ore is ground to less than 1.5 mm in one stage, the middle 500 mm and middle 250 m hydrocyclones are used for two-stage classification, and the particles larger than 74 microns and 37~74 microns are still sorted and classified in a flat field shaker. After mixing with the secondary ore, Baiping uses a @125 high-meter hydraulic flow applicator to carry out late sludge, and discards the fine 19-micron or 1000-micron fine ore sludge with a very low tin content. Centrifugal concentrator, belt chute, shaker for sand settling.

Production of battery-grade lithium

 Lithium is currently produced from two main different deposit types: brine and hard rock. In mining brine deposits, brine, which is high in lithium, is pumped from below the surface. The lithium is concentrated by evaporation before the brine is sent to a processing facility for the production of lithium carbonate or lithium chloride. It can then be further processed to produce lithium hydroxide.

In hard rock operations, ore is typically extracted from pegmatite deposits using conventional mining techniques and then concentrated by crushing, heavy media separation and sometimes flotation to produce concentrates. The main lithium-bearing mineral in this ore is usually spodumene, so most of these mines produce spodumene concentrate as the final product.

Most of the world's battery-grade lithium is produced by:

Mining and acid leaching from i.e. LiAl(SiO3)2 produces a lithium sulfate solution, which is then electrochemically converted to battery-grade lithium carbonate or lithium hydroxide. Processed spodumene dominates production in Australia.

Lithium carbonate is concentrated and precipitated from brine by evaporation ponds. These resources tend to be of low hardness (eg, calcium, magnesium) and are located in areas with high evaporation rates, such as the high deserts of South America.

The third method, direct lithium extraction, is gaining popularity, especially in North America and China:

Direct lithium extraction involves adsorption of lithium from a brine source onto ion-exchange-type materials or beads, followed by release by washing the material with hydrochloric acid. Generates dilute lithium chloride containing impurities. We prefer to be suitable for lithium resources with higher hardness, in areas that are not suitable for evaporation ponds.

Magnetite separation method

 According to the different types of iron-bearing minerals, magnetite ore can be divided into single magnetite and mixed ore.

Generally, single magnetite ore is often separated by weak magnetic separation method, while polymetallic magnetite ore and mixed ore are mostly separated by a combined process composed of a variety of beneficiation methods, including magnetic separation method, flotation method, gravity separation method, and magnetization roasting. Magnetic separation method, reduction roasting magnetic separation method, etc.

1. Single magnetite beneficiation method

Most of the iron minerals in single magnetite are magnetite. Because single magnetite has simple composition, strong magnetism, easy grinding and easy selection, weak magnetic separation method is often used for separation.

◆ When the grinding particle size is greater than 0.2mm, most iron ore magnetic separation plants often use a one-stage grinding-magnetic separation process;

◆ When the grinding particle size is less than 0.2mm, a two-stage grinding-magnetic separation process is adopted;

◆ If qualified tailings are separated in the rough grinding stage, the magnetite magnetic separation plant should adopt the stage grinding-magnetic separation process;

◆ For dry and water-deficient areas, the magnetite processing plant can consider adopting the dry grinding-dry magnetic separation process;

◆ For the enriched magnetite-rich ore or magnetite-lean ore, generally, the gangue can be removed by the dry magnetic separation process first, and after the massive rich ore is obtained, the concentrate can be obtained through the grinding-magnetic separation process.

In order to obtain high-grade concentrates, the magnetite concentrates can be treated by methods such as reverse flotation or high-frequency fine sieves. In addition, in order to further improve the recovery rate, processes such as tailings reselection can also be considered to further recover magnetic minerals.

2. Method for beneficiation of polymetallic magnetite

The polymetallic magnetite gangue often contains silicate or carbonate minerals, associated cobalt pyrite, chalcopyrite and apatite, etc. Generally, the combined process of weak magnetic separation and flotation is used, that is, the use of weak magnetic separation The process recovers iron, and then sulfides or apatite, etc. are recovered through a flotation process.

Generally, the combined weak magnetic separation-flotation process of polymetallic magnetite ore can be divided into weak magnetic separation-flotation and flotation-weak magnetic separation. The difference lies in the conjoined body of magnetite and sulfide. Going different.

For the weak magnetic separation-flotation process, the conjoined bodies mainly enter the iron concentrate; for the flotation-weak magnetic separation process, the conjoined bodies mainly enter the sulfide concentrate. Therefore, under the same grinding particle size, iron concentrate with lower sulfide content and sulfide concentrate with higher recovery rate can be obtained from the process of flotation first and then magnetization.

【Technology】Gold mining process

 1. Mining

Mining is the extraction of economically valuable minerals or other substances from the ground, and all mining sites are mineral-rich deposits. Mining techniques are basically divided into two forms: open pit mining and underground mining. After exploration and feasibility studies are completed, ore is mined from the surface or underground using machinery such as excavators, drills, explosives and trucks.

2. Crushing mining process

The ore mined is very large. At present, the maximum ore particle size of open pit mines is 1000mm1500mm, and the maximum ore particle size of underground mines is 300mm600mm. Due to the close symbiosis of useful minerals and gangue minerals, such large ores cannot be directly separated. To separate them from each other, the ore must be crushed to a certain particle size before the next beneficiation operation.

3. Transportation during mining

Typically, belt conveyors are used to feed bulk ore to primary and secondary crushers, and then feed the crushed ore to vibrating screens to obtain different sizes.

4. Screening of the mining process

The screening process also plays a different role in the gold mining process.

Pre-screening: Before the ore enters a certain stage of the crusher, pre-screening the qualified products that meet the requirements. This process not only prevents the ore from being over-crushed, increases the productivity of the crusher, but also prevents the crusher from clogging.

Inspection and screening: After crushing, screening should be carried out to check the particle size of the crushed products, so that the unqualified extra-large ore particles can be sent back to the crushing operation to be crushed again.

5. Grinding during mining

Crushing is a continuation of the crushing process. Its purpose is to separate most of the useful mineral particles in the ore into monomers and classify them so that the particle size meets the requirements of the classification operation. In general, we support the principle of grinding more and grinding less to save costs.

6. Classification of mining processes

Classification: In the medium, substances are divided into different particle sizes according to different sedimentation rates.

The purpose of classification and screening is to separate the ore particles into different particle sizes, but their working principle and the particle size characteristics of the product are different.

The sieving should be strictly separated according to the sieving size;

Distinguish and classify materials according to the different settling velocities of materials in the medium.

In the grinding process, the qualified materials are usually separated in time by the method of classification, so as to avoid the excessive grinding of the ore and improve the grinding efficiency. Commonly used equipment are spiral classifiers and cyclones.

7. Gold mining process

The gold mining process mainly includes the following methods: cyanidation, flotation, gravity separation and mercury amalgamation.

8. Water treatment during mining

Coarse dewatering is relatively easy. Usually natural drainage is used, that is, natural drainage is drained by the gravity of the water itself. Dewatering of fines typically involves three operations: concentration, filtration and drying. Reclaimed water can be used for some parts of mineral processing operations, or it can be discharged after being treated to standards through a water treatment plant. 

9. Dry stacking of tailings

Concentrating hydrocyclone + high-efficiency deep cone thickener + high-efficiency multi-frequency dewatering screen, so that the final concentration can reach more than 85%, so as to achieve dry accumulation. The tailings are then used for paving, construction, etc.

【Phosphate ore flotation】Phosphate ore beneficiation and flotation reagents

Phosphorus is an important raw material for the production of phosphate fertilizer, yellow phosphorus, phosphoric acid, phosphide and other phosphate products, and is a non-renewable and alternative resource. The reserves of phosphate rock resources in my country are relatively large, but more than 70% of them are low-grade and lean ore, which cannot be industrialized only by the scrubbing process. At present, medium and low-grade phosphate rock resources are mainly used for enrichment, and the flotation effect of phosphate rock depends on the interaction between mineral particles and air bubbles in the water medium, among which flotation reagents are particularly important.

Commonly used flotation processes for phosphate ore beneficiation are: positive flotation, reverse flotation, first positive then reverse flotation, first reverse then positive flotation and double reverse flotation.

1. Positive flotation process of phosphate rock

The process is to grind the phosphate rock until the monomer is dissociated, add water to the slurry to adjust the concentration to a certain concentration, use a specific collector to enrich the useful phosphorus minerals in the foam product, and use a specific agent to inhibit the silicon in the phosphate rock. gangue minerals such as salts and carbonates. Commonly used flotation agents are "S", "L", "sulfonated phenol tar", "F" series of inhibitors.

The process is suitable for siliceous or calcium-siliceous phosphate rock, endogenous apatite, and sedimentary phosphate rock. The technological process is simple, the impurity removal effect is good, and the content of impurities such as Me and Fe can be effectively reduced. But the energy consumption is high and the beneficiation cost is high.

2. Phosphate rock reverse flotation process

In this process, inorganic acid is generally used to adjust the pH of the pulp to a certain range (pH=4.0 to 5.0), and a specific collector is used in a weakly acidic medium to enrich the dolomite into the foam product, and the phosphorus minerals remain in the tank. Commonly used flotation reagents are mainly inorganic acid regulators, modified fatty acid collectors, sulfate modification of fatty acids, or addition of auxiliary agents during their saponification process to improve their water solubility, temperature resistance, collection performance and Optional.

This process is generally suitable for the separation of phosphorus minerals and dolomite gangue minerals, and the exclusion rate of dolomite gangue minerals can reach 70% to 80%. The process does not require heating, and can be carried out at low temperature and normal temperature, which reduces energy consumption and saves costs.

3. Phosphate ore first positive and then reverse flotation process

The process is to first use inorganic alkali to adjust the pulp to weak alkalinity, use a specific collector to enrich the useful phosphorus minerals in the foam product, and leave the silicate gangue minerals in the tank to remove, and the foam is positive flotation. Concentrate, then add inorganic acid to adjust the pulp to weak acidity, positive flotation concentrate (regrinding or non-grinding), and then use collector to enrich carbonate impurities, and leave useful phosphorus minerals in the tank to obtain Reverse flotation concentrate, the main purpose of reverse flotation is to remove MgO impurities in phosphate concentrate. Commonly used are inorganic bases and inorganic acid modifiers, XM-10, water glass and sulfur-phosphorus mixed acid inhibitors.

This process is suitable for the treatment of siliceous phosphate ore, and the grade of phosphate concentrate obtained is higher than that of single positive or reverse flotation, and the combination of positive and negative can effectively improve the processing performance of phosphate concentrate, but the cost of reagents is high, which is not suitable for concentrators. The recycling of water resources has caused great difficulties.

4. Phosphate ore reverse first and then positive flotation process

In this process, the carbonate gangue is first floated with a collector in an acidic medium to obtain an anti-floating concentrate, and then the second-stage grinding is performed until the siliceous gangue is decomposed, and the phosphate rock is floated in an alkaline medium. material to obtain positive floating concentrate.

This process is suitable for low-grade silicon-calcareous collophanites. The process does not require heating and has low energy consumption, but the circulating water needs to be treated separately, which has a great impact on production.

5. Double reverse flotation process of phosphate rock

In this process, inorganic acid is generally used to adjust the pulp to weak acidity, and a part of dolomite gangue is enriched by fatty acid collectors, and then quartz minerals are enriched by fatty amine collectors. Phosphorus minerals in the tank are the final concentrate. Commonly used flotation reagents are inorganic acid modifiers, fatty acid and fatty amine collectors.

This process is mainly suitable for the treatment of mixed phosphate rock with low content of siliceous gangue and carbonate. Especially for the separation of dolomite and quartz-like gangue minerals. It can realize low and normal temperature flotation, with simple process, low energy consumption, simple pharmaceutical system and few types of pharmaceuticals. However, the amine collectors used in this process are cationic collectors, which will produce viscous foam, poor selectivity, and are more sensitive to ore slime. This makes the process more complicated.

List of quartz sand beneficiation equipment

 At present, the common quartz ore beneficiation process is to remove the mineral impurities in the quartz ore by scrubbing, magnetic separation, chute gravity separation, flotation, pickling or a combination of several methods to obtain the particle size and impurities of the quartz ore. The content meets the requirements of high-purity quartz ore. In this process, the commonly used quartz mineral processing equipment mainly includes rod mill, magnetic separator, flotation machine, hindered settler, XCIII hydrocyclone, high-frequency and high-efficiency dewatering screen, inclined plate concentrator, washing tower, desliming Buckets, slurry pumps, etc.

In this article, we will mainly introduce rod mills, magnetic separators, flotation machines, hindered settlers and XCIII hydrocyclones.

01 Rod Mill

In the processing of quartz ore, rod mills are mostly used as grinding equipment, which has good grinding effect, controllable discharge particle size and certain scrubbing function.

◆ Quartz ore grinding discharge particle size is generally between 40-120 mesh. The steel rod of the rod mill is in contact with the material surface, and it is not easy to over-grind. At the same time, it is guaranteed to grind qualified products and exclude unqualified products.

◆ Use rod mill to process quartz ore, which can scrub to a certain extent and help to remove some impurities.

◆ The steel rods and steel rods of the quartz ore rod mill have a certain screening effect on the quartz ore during the movement, so that the large particles can be lifted to the top position of each layer and concentrated to the place with strong crushing force. crushing ability.

02 Magnetic separator

Magnetic separation is one of the effective methods to remove iron-containing impurities in quartz ore, so as to remove weak magnetic impurity minerals such as hematite, limonite, and biotite including conjoined particles as much as possible.

Intensive magnetic separation usually adopts wet strong magnetic separator or high gradient magnetic separator. Generally speaking, for quartz whose impurities are mainly weak magnetic impurity minerals such as limonite, hematite, biotite, etc., it can be selected by a wet high-magnetic machine above 10000GS; for impurities mainly containing magnetite, for strong magnetic minerals, It is best to use a weak magnetic machine or a medium magnetic machine for sorting. In order to further remove a small amount of other weak magnetic minerals (such as amphibole, pyroxene, the combination of magnetic minerals and quartz), a high-gradient magnetic separator with a magnetic field strength greater than 12,000 Gauss can be used for secondary magnetic separation.

03 Flotation machine

Flotation is also a beneficiation method widely used in quartz ore processing plants, mainly to remove non-magnetic associated impurities such as feldspar and mica in quartz sand. The quartz sand beneficiation equipment used in this process is various suction mechanical stirring flotation machines (SF type flotation machine, BF type flotation machine, JJF type flotation machine) and air-filled mechanical stirring flotation machine (KYF type flotation machine). machine, XCF flotation machine)).

04 Obstructed settler

The hindered settler is a disturbance settling equipment, which is mainly composed of a cylinder, a bracket, a feed port, an overflow tank, a retaining ring, a support seat, a pressure detector, an electric valve and an automatic control system. . Special equipment especially effective for non-metals such as ores. The material is affected by the rising water flow in the cylinder to achieve the purpose of particle size classification and specific gravity separation, with high production efficiency and low energy consumption. It can be equipped with an automatic control system, and the adjustment of operating parameters is simple, convenient and easy to control. The water tank at the bottom of the cylinder can be equipped with a special rubber nozzle device. When the water stops, the rising water hole automatically closes,

In the quartz ore dressing plant, the hindered settler can strictly classify the coarse and fine particles, completely replacing the fine screen for particle size control.

05 XCⅢ Hydrocyclone

The XCIII hydrocyclone has a specially designed fish tail device in the grit chamber and a specially designed siphon device on the top of the overflow tank, so it has excellent characteristics that other hydrocyclones cannot match. Through the adjustment of the siphon device, a higher underflow concentration and a lower overflow concentration can be obtained. For the silica (quartz) industry, the overflow can be adjusted to almost release water and the underflow concentration can be as high as 85%. In addition, the specially designed fish tail device can keep the discharge concentration and overflow fineness of the swirl cone bottom flow constant when the ore feeding amount, ore feeding concentration and ore feeding pressure fluctuate within a certain range.

06 Summary

In the actual beneficiation process, the selection of quartz ore beneficiation technology and equipment is often determined according to various factors such as the nature of the quartz ore, the conditions of the beneficiation plant, and the investment budget. We need to comprehensively consider factors such as the actual situation and investment of the concentrator to determine the beneficiation plan, and customize the quartz ore beneficiation equipment to achieve an ideal return on investment.

Selection of spodumene flotation reagents

At present, the beneficiation methods of spodumene mainly include: manual separation, thermal disintegration, magnetic separation, resuspension method, flotation method and combined beneficiation method. Among them, the flotation method of spodumene is the most studied in the laboratory and the most widely used mineral processing method in industry.

1. Cationic collectors

The cationic collectors used in the flotation of spodumene ore are mainly amine collectors, which flotate gangue minerals such as quartz, feldspar and mica under acidic conditions, and leave the spodumene at the bottom of the tank. This method is often used in the roughing of spodumene, and cannot directly obtain spodumene concentrate with higher purity, and needs to be used in conjunction with other sorting methods.

In production practice, Yan Gengsheng used the process of flotation of spodumene with mixed soap and diesel oil under alkaline conditions after flotation of mica with phylloylamine under acidic conditions for a certain pegmatite spodumene ore. Mica concentrate and spodumene concentrate were obtained, and good economic benefits were obtained. In terms of single minerals, Yin Wanzhong and Sun Chuanyao studied the flotation of spodumene with the cationic collector dodecylamine without adding any activator and inhibitor, and obtained the result that the spodumene in the dodecylamine system The stone has better buoyancy conclusions.

2. Anionic collectors

The traditional spodumene anion collectors are mainly fatty acids and their soaps, namely oleic acid, oxidized paraffin soap, naphthenic acid soap, tar oil and sodium oleate, etc., alkyl sulfates and sulfonates, etc. However, due to the difference in ore properties, the increasingly complex ore composition and the comprehensive utilization of low-grade spodumene ore, the use of collectors has developed from a single drug to a mixed drug.

    Ren Wenbin used oximic acid to replace the original oxidized paraffin soap as a collector for the recyclability of spodumene tailings in Cocoto Sea, and the grade of spodumene concentrate was increased from 2.3% to 5.8%.

In terms of mixed drug use, in response to the problem of low recovery rate of high-grade spodumene of a granite pegmatite type in Jiangxi, Zhao Yun used oxidized paraffin soap and tall oil as a collector to obtain better indicators and solved the problem. The problem of low recovery rate.

Sun Wei and Ye Qiang used oxidized paraffin soap and naphthenic acid soap as collectors to conduct a flotation test on pegmatite-type spodumene (Li2O grade 1.42%) in a certain place in Sichuan, and finally obtained a concentrate with a Li2O grade of 6.04. %, a good indicator of the recovery rate of 85.88%. Liu Ningjiang conducted a flotation experiment on V26 and V38 spodumene of rare ore bodies in Keketuohai, Xinjiang, using strong stirring and scrubbing to remove sludge, and using cationic collectors and foaming agents to flotate mica under neutral and weak alkaline conditions. , and then mixed with sodium carbonate and sodium hydroxide to adjust the size, so that the pH value is 10.5 to 11.5, and the flotation process of using oxidized paraffin soap and naphthenic acid soap as collectors, obtained 5.65% to 6.37% of the flotation process. Spodumene concentrate, a good indicator of recovery of 80.77%.

3. New collectors

    In the research of spodumene collector selectivity, Wang Yuhua used a new type of chelating collector to replace the traditional oxidized paraffin soap, and realized the flotation separation of spodumene from quartz and feldspar, which not only can significantly reduce the cost of chemicals, And can greatly improve the separation between spodumene and quartz and feldspar, thereby improving the spodumene beneficiation index. At the same time, for the spodumene (Li2O grade 0.46%) and beryl in a granite pegmatite mineral, using the chelating collector YZB-17 can improve the grade and recovery rate of the mixed concentrate of spodumene and beryl. , and can realize the separation of spodumene and beryl.

    In the research on the collection performance of spodumene collector, Wang Yuhua studied sodium oleate, C7-9 hydroxamic acid, sodium dodecyl sulfonate and a new amphoteric collector YOA- The collection performance of 15 pairs of spodumene, the research results show that: the new amphoteric collector YOA-15 has a higher ability to collect spodumene than that of sodium oleate, C7-9 carboxyxamic acid and sodium dodecylsulfonate. Strong collecting ability. For the No. 3 vein spodumene ore and tailings in the tailings pond, the Cocoto Sea Concentration Plant used the new amphoteric collector YOA-15 to carry out flotation tests under different water quality, all of which showed strong collection capacity. With the foaming ability, a rough concentration of Li2O grade of 5.62% and a recovery rate of 83.3% can be achieved in one roughing.

    According to the research of many scholars, it is not difficult to find that there is less research on the reverse flotation process of spodumene, which may be related to the low content and grade of spodumene in the raw ore; in the positive flotation of anionic collectors, the traditional single It is difficult to meet the flotation separation of spodumene by the spodumene, and the combination drug is a new development direction; in terms of new collectors, it mainly focuses on multi-group chelating collectors and amphoteric collectors, but it is necessary to realize industrial production, there is still a long way to go.