Method and device for condensing magnesium vapor generated by evaporation and heat absorption of magnesium liquid and coproducing refined magnesium

Abstract

The invention relates to a method and a device for condensing magnesium vapor generated by evaporation and heat absorption of a magnesium liquid and coproducing refined magnesium and belongs to the technical field of extraction metallurgy or nonferrous magnesium metal. The method comprises the following steps: carrying out reverse phase change heat exchange on primary magnesium vapor in a first condensing section by taking evaporation and heat absorption of the magnesium liquid as a cooling manner, wherein the primary magnesium vapor is condensed to a liquid state; then evaporating the magnesium liquid to form higher-purity refined magnesium vapor due to the heat obtained by the magnesium liquid; then condensing the refined magnesium vapor to liquid refined magnesium; and continuously cooling and condensing residual vapor of the primary magnesium and refined magnesium in a second condensing section, wherein the primary magnesium and refined magnesium are condensed to solid crystal magnesium. According to the method and device provided by the invention, a magnesium liquid evaporator is used for condensing the primary magnesium vapor and further serves as a heat source for purifying the magnesium liquid. Parallel secondary cooling monomers are arranged in a secondary cooling section to realize alternate condensation and follow-up heating and re-melting. By adopting returned heating, heat demand on evaporation and remelting is realized by using heat energy of magnesium vapor condensation, so that high purity magnesium is coproduced and heat energy is fully utilized; the secondary cooling monomers are alternately condensed and remelted, so that the condensing rate is improved and the magnesium liquid is convenient to flow out and recycle.

Description

technical field [0001] The invention belongs to the technical field of extraction metallurgy of non-ferrous metal magnesium, in particular to a method for co-producing pure magnesium by condensation of magnesium vapor, and also to a device thereof. Background technique [0002] Magnesium and magnesium alloys are the lightest metal structural materials. They are used in transportation, electronic products, building materials, aerospace and other fields to bring energy-saving effects. They are known as "the third metal" and "the first metal of the 21st century Green Metallic Materials". Mineral resources of major metal materials such as steel and aluminum are gradually being exhausted, while metallic magnesium is very rich in mineral resources, and seawater contains even more abundant magnesium resources, which can be used by humans for thousands of years. [0003] The technology for extracting metal magnesium from natural minerals is divided into two categories: electrolysis...

AI Technical Summary

Problems solved by technology

[0014] 1. The reactant ferrosilicon and calcined white react chemically in the form of solid phase contact, the reaction rate is slow, and the reduction reaction cycle in a typical process is as long as 10 to 12 hours, which is inefficient;

[0015] 2. The flame is used for external heating, and the heat is gradually transferred from the outside of the reactor to the inside. The cycle is long, the heat energy loss is large, and the heat energy utilization rate is low. According to professional analysis, the heat energy utilization rate of a typical process is only about 20%;

[0016] 3. Due to the limitation of the reactor volume by the external heating method, the inner diameter of a typical horizontal tank is within 400 mm, generally 300-370 mm in diameter, and the amount of material charged at one time is small. The output of raw magnesium in a single tank is only 20-12 hours. 30 kg, covers a large area and is difficult to manage on-site, making it difficult to achieve large-scale production and mechanized operations;

[0017] 4. Ferrosilicon containing 75% silicon is used as the reducing agent. Generally, the consumption per ton of magnesium ferrosilicon is 1.05 to 1.20 tons, that is, silicon far exceeds the theoretical consumption value and causes waste, and at the same time all iron elements are wasted;

[0018] 5. Horizontal tanks generally use expensive heat-resistant steel containing nickel and chromium, which consumes quickly and costs high;

[0019] 6. The smoke pollution is serious, the working environment is harsh, and the negative impact on the surrounding ecological environment is great;

[0020] 7. It requires manual loading, slag removal, and cleaning of crystalline magnesium, which is labor-intensive and difficult to achieve automated operations

[0033] (2) The cooling water flow and consumption required for the condensation of the large-scale magnesium smelting process are huge

Due to the simple water-cooled condensation, the water required is huge and the water consumption is high

[0035] (3) The huge heat released by the condensation of magnesium vapor cannot be recovered

[0038] (4) Pidgeon process condenses into solid magnesium, which has many disadvantages and inconveniences

[0039] The Pidgeon method condenses magnesium vapor into a solid state, which has no fluidity and cannot be discharged in time, occupying the space of the condenser, and further refining, alloying, and even simple ingot casting must remelt solid crystalline magnesium, resulting in repeated heating and melting. Energy waste

[0040] (5) When the amount of magnesium vapor is large, it is easy to cause solid crystalline magnesium to block the condenser

[0041] Because the bulk density of metal magnesium vapor is very small when it condenses into a solid state, a large amount of magnesium vapor continuously produced in a large-scale magnesium smelting reactor will inevitably condense into a solid when condensing, which will easily lead to blockage of the condenser pipe and cause production stoppage

[0042] (6) Stirring the molten pool to condense requires a huge absorption molten pool

[0044] (7) High-temperature magnesium smelting leads to a decrease in the purity of magnesium vapor, and impurities are not removed during the condensation process

[0045] The Magnetherm and MTMP processes can be 300-500 degrees Celsius higher than the Pidgeon process, and part of the charge is in the liquid phase, thereby obtaining good kinetic contact conditions, but at the same time it also causes the purity of magnesium vapor to decrease and the impurity content to increase, as shown in Table 2

These impurities enter the liquid or solid magnesium after entering the condenser. In the existing technology and patented solutions, these impurities are not removed by condensation.

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