Research Status and Development Trend of Preparation Methods of Metal Antimony

Bismuth is a "green" metals, silver and abundance in the earth's crust quite. The main antimony minerals are stibnite (Bi ₂ S ₃ ), bismuth (Bi ₂ O ₃ ) and bismuth ore (nBi ₂ O ₃ mH ₂ O). Metal ruthenium is generally recovered as a by-product in the smelting process of tungsten, molybdenum , lead , copper and tin . According to the data of the US Mining Bureau in 1991, the proven reserves of foreign cockroaches in 1990 were 89,500 tons, and the other é“‹ resources were 114,000 tons, totaling 203,500 tons, mainly distributed in China, Japan, Peru, Australia, Mexico. The United States, Canada, etc., formed a discontinuous circle in the Pacific Rim. The distribution of foreign resources is shown in Table 1.

Table 1 Distribution of foreign resources

China has abundant resources, with reserves totaling 500,000 to 600,000 tons, accounting for 70% of the world's total reserves. It is concentrated in Hunan, Guangdong, Jiangxi and Yunnan provinces. The reserves of non-ferrous metal ore in Hunan Zhuzhuyuan account for 74% of the country's total reserves, and its high grade and easy mining are the most important raw material bases in China. In recent years, many domestic research institutes have carried out a lot of work and developed various hydrometallurgical processes based on the different compositions of antimony ore, focusing on reducing production costs, solving environmental pollution, regeneration of FeCl ₃ and enrichment of valuable metals in solution. process, there are: 1) FeCl ₃ extract - iron powder displacement method, 2) FeCl ₃ leaching - diaphragm electrode method, ₃₎ FeCl 3 - hydrolysis Shen bismuth method 4) selective leaching of chlorine, 5) hydrochloric acid - nitrous Leaching method, 6) new chlorination hydrolysis method, 7) slurry electrolysis method, and the like. Most of these processes have been extensively tested or semi-industrial, industrial tests, in which slurry electrolysis has been used in industrial production.

I. Hydrometallurgical technology and process parameters of foreign antimony ore

The use of wet technology to treat strontium ore recovery metals abroad was first seen in 1958. Fester, etc., using 10% HNO ₃ to leach metal rhodium from tantalum-containing tungsten concentrate, the leaching temperature is 80 ° C; using 10% H ₂ SO ₄ +NaNO ₃ and H ₂ SO ₄ +KClO ₃ as the leaching agent, at the lower The leaching of hydrazine at temperature also gave satisfactory results. Table 2 shows the process parameters for processing low grade antimony ore abroad.

Table 2 Foreign Yankuang Wet Processing Technology and Process Parameters

Second, domestic hydrometallurgical technology and existing problems

(1) FeCl ₃ leaching-iron powder replacement method

The method can be divided into three main steps of ferric chloride, hydrochloric acid leaching, iron powder replacement and sponge smelting. The process flow is shown in Fig. 1.

Fig.1 Process flow of recovering metal ruthenium by FeCl ₃ leaching-iron powder replacement method

1. Leaching of ferric chloride + hydrochloric acid. The strontium sulfide ore is leached with a mixture of ferric chloride and hydrochloric acid, and Bi ₂ S ₃ in the ore is dissolved by FeCl _{3 to} form soluble antimony trichloride:

At the same time, a small amount of natural earthworms in the ore are also dissolved:

The cerium oxide in the ore is dissolved by hydrochloric acid:

The addition of hydrochloric acid to the leaching agent helps prevent the hydrolysis of BiCl3 to insoluble.

Sexual BiOCl precipitation.

2. Iron powder replacement. After the leaching of the ore in the ore is transferred to the solution, the iron powder can be substituted for the sponge:

3, the refining of the sponge. The displaced sponge enthalpy needs to be heated and melted to form a bismuth ingot, but direct melting causes severe oxidation reaction, so that it is industrially melted in molten sodium hydroxide (melting point 318.4 ° C, density 2.13 g/cm ³ ). It can prevent the oxidation of bismuth, and the molten liquid enthalpy (melting point 271 0C, isothermal liquid density is 10.064g ∕cm ³ ) is also easy to aggregate, and the cerium oxide and some impurities thereof can also be absorbed by NaOH. The liquid helium accumulated in the lower layer is cast by casting to form a certain size of antimony ingot, which still contains some impurities, which are coarse and must be further refined.

The process is relatively mature, and the leaching rate of bismuth is high (94% to 94.5%), and the environmental pollution is small. The disadvantage is that the material consumption is high, each

Tons of sponge é“‹ consume 1.5 to 1.8 tons of hydrochloric acid, 0.4 to 0.5 tons of chlorine, and 0.5 to 0.6 tons of iron powder. Due to the use of iron powder replacement and chlorine regeneration technology, the accumulation of iron and chloride ions in the solution can not be ignored, the discharge of waste liquid is large, the ion concentration in the leachate is high, the viscosity of the solution is large, and the filtration and washing of the slag is difficult.

(B) FeCl ₃ leaching - diaphragm electrode method

The diaphragm electrode method is used to replace the iron powder replacement method, and the potential is appropriately controlled, and the crucible is reduced at the cathode:

Iron is oxidized at the anode:

The key to this method is the control of the electrode potential and the speed control of the solution through the membrane. In the cathode region, the main cations in the solution are Bi ^{3 +} , Fe ^{2 +} and H ⁺ , and in the anode region, the main cations in the solution are Bi ^{3 +} , Fe ^{3 +} and H ⁺ . In order to reduce the current efficiency of the ferric ions in the anode region without being discharged at the cathode, the cathode and cathode electrodes are separated by a suitable separator material, and the liquid level in the cathode region is higher than the liquid level in the anode region. The permeation rate of the electrolyte is controlled to be equivalent to the oxidation rate of the ferrous iron.

Compared with the ferric chloride leaching-iron powder replacement method, this process is shorter, but due to the high concentration of iron ions in the solution, trivalent iron inevitably passes through the separator at the cathode during electrodeposition, and thus the current efficiency is low (42%). ~50%), the electrical oxidation rate of divalent iron is not high.

(III) FeCl ₃ - Hydrolysis and sedimentation method

The ruthenium chloride concentrate is hydrolyzed in a weakly acidic solution by utilizing the property of easy hydrolysis of ruthenium chloride to form bismuth oxychloride.

In order to complete the hydrolysis, the pH of the solution is generally controlled between 1 and 2. The solution needs to be diluted several times, resulting in large consumption of water and reagents, low recovery of hydrazine, and large discharge of wastewater. The Shizhuyuan Plant used this method to produce chlorinated bismuth concentrate, which consumes 800kg of industrial hydrochloric acid per ton of concentrate, and the recovery rate of strontium is only 60%.

(4) Chlorine selective leaching method

Control the potential of the solution, selectively leaching the strontium sulfide ore with chlorine gas while suppressing the leaching of impurities:

This method eliminates the problem of circulation and accumulation of a large amount of iron ions in the process, improves the product quality, improves the filtration and washing performance of the slag, and has a high leaching rate, but the consumption of chlorine gas is large, and some elemental sulfur will further Oxidation to sulfate, chlorine pollution and corrosion are more serious, equipment materials and sealing requirements are higher. There is no obvious superiority compared to the ferric chloride leaching method.

(5) Hydrochloric acid-nitrous acid leaching method

The method has been carried out in a semi-industrial test to treat refractory strontium ore. The basic chemical reaction is:

The method of reagent consumption large number and amount, in addition to hydrochloric acid and sodium chloride, sodium nitrate needed, such as hydrogen peroxide and kerosene.

(6) Chlorination-hydrolysis method

The results of years of research at Central South University show that two-stage leaching is carried out at a temperature of 90-105 ° C using a high concentration of chloride ion solution.

The strontium sulfide ore has a leaching rate of more than 94%, and the process flow is shown in Figure 2. The chlorination-hydrolysis method leaches out the strontium sulfide ore, solves the problem of a large amount of iron circulation in the solution and the oxidative regeneration of the leaching agent, and the concentration of the valuable metal in the leaching solution is relatively high. However, the temperature required for leaching is high, the oxidation of elemental sulfur is severe, and the leaching rate of impurity elements such as As is also high, so the consumption of oxidant is large, and there are problems such as corrosion of equipment and large discharge of waste liquid.

Figure 2 Process for the extraction of metal ruthenium by chlorination-hydrolysis

(7) Slurry Electrolysis

The slurry electrolysis method is the result of more than 20 years of research by the Beijing Research Institute of Mining and Metallurgy and is a new hydrometallurgical process. Simultaneously complete the oxidative leaching of bismuth ore and the electrowinning reduction of bismuth in a device, organically combine the traditional leaching, solid-liquid separation, solution purification, electrowinning and other processes, and change the oxygen consumption during the leaching of bismuth ore. The unreasonable situation of anodizing energy consumption during simplification simplifies the hydrometallurgical process, and the metal recovery rate is high, and the energy consumption is reduced, which is conducive to environmental protection.

The slurry electrolysis process is carried out at a medium temperature (50 to 60 ° C) and an acidic chloride salt system. The pulped antimony concentrate is directly added to the anode region of the slurry electrolysis cell for direct electrolysis. While the antimony concentrate is oxidized and leached, the metal antimony is reduced and precipitated at the cathode, thereby achieving one-step extraction of the metal antimony. The leaching reaction of the antimony concentrate occurring in the anode region is:

Reduction of metal ions in the cathode region:

The process flow is shown in Figure 3.

Figure 3 Process of processing bismuth concentrate by slurry electrolysis

The slurry electrolysis method not only retains the advantages of the traditional hydrometallurgical process, but also has the following characteristics:

1. One-step production of metal, elemental sulfur, arsenic , iron and gangue minerals into the leaching slag, the process is simple, the ion concentration in the solution is low, and the leaching slag is easy to be filtered and washed.

2. Operating at normal pressure and close to normal temperature, the equipment can be made of low-cost anti-oxidation materials such as FRP and polypropylene.

3. The ore-electrolyte-anode-air bubble system has a very strong depolarization capability. The required cell voltage during electrolysis is very low. Since the reduction oxidation of the anode and cathode is fully utilized, the power consumption is small.

4. The reagent consumption is small, and the whole process is basically free of reagent consumption.

5, flexible operation, suitable for large-scale continuous operations,

Mechanization and automated production can also be produced on a small scale and intermittent basis, and even in the mine can be “pit smelting”.

6, the comprehensive recovery effect is good. In addition to the treatment of antimony concentrate, it is also particularly suitable for the treatment of low-grade complex refractory copper, lead, zinc , antimony and silver mixed sulfide ore.

Third, the conclusion

Although the metal leaching process research is more in-depth and perfect, both conventional stirring leaching method and slurry electrolysis method require higher temperature or electric energy, large investment, high cost, and easy to pollute the environment. At present, the research on leaching metal ruthenium from low-grade antimony ore at room temperature is still a blank. The main reason is that the grade of antimony ore is low, the composition is complicated, and the conditions are difficult to select.

In addition, a large amount of waste residue and waste water are generated in the hydrometallurgical process, which is extremely harmful and requires comprehensive treatment. Therefore, in future research, it is necessary to continuously develop new high-efficiency, pollution-free, low-cost, low-energy, and comprehensive utilization. Process flow.

Oil Seal is a mechanical components that used to seal oil (oil is the most common transmission system liquid material), It`s isolated the lubricated components with other components, not let the lubricate oil leakage. 

Oil Seal is generally divided into single-type and assembly type, assembly type is the skeleton and lip material can be free combination, generally used for special oil seals.

Oil seal can have different names, customary general rotary axis lip seal called oil seal, the static seal and dynamic seal (general reciprocating motion) was called seal parts.

The representative form of oil seal is TC type, is a double lips oil seal with a fully rubber coated and garter spring, generally speaking oil seal refers to TC skeleton oil seal, skeleton oil seal diagram see Figure: