CN101984100B - Method for eliminating hazards of elemental potassium and sodium generated during magnesium smelting by siliconthermic method - Google Patents

Abstract

The invention provides a method for eliminating hazards of elemental potassium and sodium generated during magnesium smelting by the siliconthermic method, which comprises the following steps: adhering metal oxide powder which can be reacted with the potassium and the sodium on a potassium and sodium catcher in advance, placing the potassium and sodium catcher in a reduction tank according to the conventional magnesium smelting process, leading the elemental potassium and the sodium generated during the reduction process to be reacted with metal oxides after entering into the catcher and be further converted to K2O and Na2O, avoiding burning when opening the tank, and further eliminating the hazards caused by burning of the elemental potassium and the sodium during the magnesium smelting.

Description

A method for eliminating the harm of elemental potassium and sodium generated in silicothermal magnesium smelting

technical field

The invention relates to the technology related to metal magnesium smelting in the non-ferrous metal smelting industry, in particular to a method for eliminating the hazards of elemental potassium and sodium generated in silithermal magnesium smelting.

Background technique

Silicon thermal method is one of the main methods of smelting magnesium at present. Its process is as follows: calcining dolomite, the raw material for smelting magnesium, mixing the obtained calcined white with ferrosilicon and fluorite in proportion, finely grinding, pressing balls, and pressing well. Put the pellets into the reduction tank, then seal and vacuum the reduction tank and heat it to above 1200°C, so that the ferrosilicon can be reduced to calcined white under vacuum and high temperature conditions to generate magnesium vapor. Under the action of the vacuum system, the generated magnesium vapor escapes to the mouth of the tank, and a cooling water jacket is installed near the mouth of the tank, where the magnesium vapor condenses to form crystalline magnesium. After the reduction is completed, the crystalline magnesium is taken out and refined, and finally metal magnesium is obtained.

In the process of magnesium smelting, in addition to the metal Mg being reduced, other substances are often reduced, the more obvious ones are elemental K and Na. Since the vapor pressure of K and Na is higher than that of Mg at the same temperature, K and Na will condense at the mouth of the tank with a lower temperature. When the reduction tank is opened, K and Na will burn when exposed to the air, producing a large amount of smoke, strong light, and a large amount of heat, which will deteriorate the environment of the reduction workshop, and the heat generated by the combustion will easily cause the combustion of crystalline magnesium. Cause a large loss of crystalline magnesium. The current solution is to place a potassium and sodium trap to separate the K and Na condensation zone from the Mg crystallization zone, and remove the potassium and sodium trap quickly after opening the tank to reduce the impact of K and Na combustion on crystalline magnesium.

When the content of K and Na in dolomite ore is low, placing potassium and sodium traps can effectively avoid the influence of K and Na combustion on Mg; when the content of K and Na is high, there will still be a large amount of crystallization using the above method Magnesium loss. Therefore, at present, when selecting dolomite for smelting magnesium, it is required that the mass percentages of K ₂ O and Na ₂ O in the mineral should be less than 0.005%. my country is rich in dolomite resources, which are distributed all over the country, and there are many dolomite that meet the requirements of magnesium smelting. However, for some areas, such as Chongqing, the local dolomite resources are abundant, and various quality indicators are relatively high, but the K and Na contents are relatively high. The impact, including the impact of high K and Na content, the production status is very unsatisfactory. To solve the local magnesium smelting problem, it is an important part to try to eliminate the influence of K and Na combustion.

Chongqing's major scientific and technological research project "Clean Energy Primary Magnesium Smelting Technology and Its Industrial Application" (CSTC009AA4002) and the Science and Technology Plan Project of Chongqing Municipal Bureau of Land Resources and Housing Administration "Research on Key Technologies for Magnesium Smelting to Improve the Utilization Rate of Chongqing Dolomite" Propose a project on the subject of this invention and provide corresponding financial support.

Contents of the invention

In view of the fact that the current use of potassium and sodium traps still cannot solve the problem of the combustion of elemental K and Na generated during reduction, the present invention proposes a method for eliminating the hazards of elemental K and Na generated during the reduction process: using the combination of elements and oxygen According to the law of strength and weakness, metal oxides are used to react with the elemental K and Na produced by reduction to convert them into oxides, and at the same time obtain non-combustible metal elements, so as to avoid burning when opening the tank, so as to completely eliminate silicon The combustion of K and Na reduced to elemental substances in thermal magnesium smelting and its harm. Wherein, the reaction between the elemental K and Na mentioned in the present invention and the metal oxide is as follows: 2K(Na)+MO=K ₂ O(Na ₂ O)+M (M in the reaction formula represents the above-mentioned metal oxide Metal element in), in order to realize the conversion of flammable metal elemental K and Na into stable and non-combustible K ₂ O and Na ₂ O.

The technical solution adopted in the present invention is: a method for eliminating the harm of elemental potassium and sodium generated in smelting magnesium by silicothermal method, which is characterized in that it includes the following steps: The metal oxide powder of the displacement reaction adheres to the surface of the potassium-sodium trap, and the potassium-sodium trap adhered to the oxide is placed in the magnesium smelting reduction tank according to the conventional process regulations, and the vacuum silicon thermal reduction production is carried out; the reduction is completed Finally, open the tank lid, take out the potassium and sodium trap and clean it up for use.

The metal oxide used for reacting with elemental K and Na mentioned in the present invention is selected from any one of FeO, Fe ₃ O ₄ and Fe ₂ O ₃ or a mixture of any combination. The adhesion method includes the following two methods: one: first coat the water glass liquid on the surface of the potassium-sodium trap, then evenly sprinkle the metal oxide powder on it, and then dry it to make the metal oxide powder stick Attached to the potassium-sodium trap; second: first fully mix the metal oxide powder and water glass liquid to make a mixed solution, and then evenly coat the mixed solution on the surface of the potassium-sodium trap, and then dry it to make the metal The oxide powder sticks to the potassium sodium trap.

By using the present invention, the elemental K and Na generated in the reduction process of silicothermal magnesium smelting can be converted into stable, non-combustible K and Na oxides before the can is opened, thereby completely eliminating the K and Na combustion. Hazards such as smoke, strong light, and loss of metal magnesium have improved the on-site working environment, and are conducive to increasing the actual yield of magnesium.

The present invention has better completed the major scientific and technological research project of Chongqing City "Clean Energy Raw Magnesium Smelting Technology and Its Industrial Application" (CSTC009AA4002) and the Science and Technology Plan Project of Chongqing Land Resources and Housing Administration Bureau "Increasing the Utilization Rate of Dolomite in Chongqing City" The project "Research on Key Technology of Magnesium Smelting" is established based on the project proposed by the present invention, which effectively eliminates the problem of burning hazards of elemental potassium and sodium produced in the reduction process of smelting magnesium by silicothermal method, and will be popularized and applied in actual production.

Description of drawings

none

Detailed ways

In the present invention, the commonly used metal oxides are preferred to be used as replacement substances, and the specific implementation method is: in the silicon thermal method of magnesium smelting, the metal oxide powder capable of replacement reaction with elemental K and Na is adhered to the surface of the potassium and sodium trap , place the potassium-sodium trap adhered to the oxide in the magnesium reduction tank according to the conventional process regulations and carry out vacuum silicon thermal reduction production; after the reduction, open the tank cover, take out the potassium-sodium trap and clean it up, use.

Comparative example 1:

In conventional silithermal magnesium production, the potassium and sodium traps that do not adhere to any substance are put into the reduction tank according to the conventional process operation rules and then carried out vacuum reduction production. After the reduction is completed, the lid of the reduction tank is opened, and the surface of the potassium and sodium trap generates violent combustion.

Comparative example 2:

In conventional silithermal magnesium production, only water glass liquid is coated on the surface of the potassium-sodium trap, and no metal oxide adheres to it, and it is dried, and the potassium-sodium trap is installed according to the conventional process operation rules. into the reduction tank and carry out vacuum reduction production. After the reduction is completed, the lid of the reduction tank is opened, and the surface of the potassium and sodium trap generates violent combustion.

Example 1:

FeO was chosen as the reactant substance. Select the same equipment and operating procedures as the comparative example, the difference is: after the potassium-sodium trap is coated with water glass, the metal oxide FeO powder is evenly sprinkled on it, and heated and solidified to make FeO adhere to the potassium-sodium on the trap. After the reduction is completed, open the lid of the reduction tank, and the potassium and sodium traps have no obvious burning phenomenon.

The comparison between Comparative Examples 1 and 2 and Example 1 proves that the selection of FeO powder and its operation method in the present invention can effectively solve the problem of K and Na combustion.

Example 2:

Fe ₃ O ₄ is selected as the reaction substance. Select the same equipment and operating procedures as the comparative example, the difference is: metal oxide Fe ₃ O ₄ powder is evenly sprinkled on it after coating water glass on the potassium sodium trap, and heat solidified to make Fe ₃ O ₄ Adhere to the Potassium-Nadium Trap. After the reduction is completed, open the lid of the reduction tank, and the potassium and sodium traps have no obvious burning phenomenon.

The comparison between Comparative Examples 1 and 2 and Example 2 proves that the selection of Fe ₃ O ₄ powder and its operation method in the present invention can effectively solve the problem of K and Na combustion.

Example 3:

Fe ₂ O ₃ is selected as the reaction substance. Select the same equipment and operating procedures as the comparative example, the difference is: on the potassium sodium trap, coat the mixed solution made by fully mixing the metal oxide Fe ₂ O ₃ powder with water glass, and heat and solidify, so that Fe ₂ O ₃ sticks to the Potassium-Nadium trap. After the reduction is completed, open the lid of the reduction tank, and the potassium and sodium traps have no obvious burning phenomenon.

The comparison between Comparative Examples 1 and 2 and Example 3 proves that the selection of Fe ₂ O ₃ powder and its operation method in the present invention can effectively solve the problem of K and Na combustion.

Example 4:

A mixture of FeO, Fe ₃ O ₄ and Fe ₂ O ₃ in a ratio of 1:1:1 is selected as the reaction substance. The difference is that the potassium-sodium trap is coated with a mixed liquid made by fully mixing the mixture powder of metal oxides FeO, Fe ₃ O ₄ and Fe ₂ O ₃ with water glass, and heated and solidified to make FeO, Fe 3 O 4 and Fe 2 O 3 _A mixture _{of Fe3O4} and _Fe2O3 powder adhered to the potassium-sodium trap. After the reduction is completed, open the lid of the reduction tank, and the potassium and sodium traps have no obvious burning phenomenon.

The comparison of Comparative Examples 1, 2 and Example 4 proves _that choosing the mixture of FeO, _Fe3O4 and _Fe2O3 in the present invention and its operation method can effectively solve the _problem of K and Na combustion.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions can be modified Or an equivalent replacement, for example, the metal oxide is selected from FeO, Fe ₃ O ₄ and Fe ₂ O ₃ , any one or more metal oxides that can react with K, Na or a mixture of any combination, and does not break away from The purpose and scope of the technical solution should be included in the scope of the present invention.

Claims (1)

1. a method for eliminating the harm of elemental potassium and sodium generated in silicothermal magnesium smelting, is characterized in that comprising the steps: 1) In the silicothermal magnesium smelting, water glass liquid is first coated on the surface of the potassium sodium trap, and then the mixture powder of any one or any combination of FeO, Fe ₃ O ₄ and Fe ₂ O ₃ is evenly sprinkled on it on, and then dried to make the powder adhere to the potassium sodium trap; or first mix the mixture powder of any one or any combination of FeO, Fe ₃ O ₄ and Fe ₂ O ₃ with water glass liquid to make it Mixed solution, then evenly coat the mixed solution on the surface of the potassium-sodium trap, and then dry to make the powder adhere to the potassium-sodium trap, 2) Then place the potassium and sodium trap in the magnesium reduction tank for vacuum silicothermal reduction production according to the conventional process regulations. 3) After the reduction, open the tank lid, take out the potassium and sodium trap and clean it up for use. the