Method for light roasting of magnesium oxide by using low-grade magnesite

Abstract

The invention relates to the technical field of mineral resource processing, in particular to a method for light roasting of magnesium oxide by using low-grade magnesite. The method comprises the following steps: 1) taking low-grade magnesite as a raw material, firstly cleaning to remove impurities dissolved in water, and then drying the magnesite; (2) feeding the dried raw materials into crushing equipment, and crushing to obtain 3-5mm materials; (3) putting the crushed material into a rotary kiln, carrying out low-temperature calcination for 25-35 minutes, and then cooling to room temperature; 4) performing magnetic separation on the material obtained in the step 3); 5) grinding the material subjected to magnetic separation in the step 4) to obtain 200-mesh powder; and (6) the powder is fed into calcining equipment to be calcined, the calcining temperature ranges from 600 DEG C to 700 DEG C, and the calcining time ranges from 50 min to 80 min. The process of low-temperature calcination, crushing, magnetic separation and secondary calcination is adopted, the grade of obtained magnesium oxide is high, low-grade magnesite is fully utilized, and the resource utilization rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral resource processing, and particularly to a method for lightly burning magnesium oxide using low-grade magnesite. Background Art

[0002] Magnesite is the main source of magnesium and has a wide range of industrial applications. It can be used as refractory materials and is the first choice for the lining and furnace wall materials of kilns such as steelmaking, cement, and non-ferrous metal smelting.

[0003] China is rich in magnesite resources, with a wide distribution, high quality, and large reserves. However, since magnesite is a non-renewable resource, the high-grade magnesite is mined year by year, and its reserves will become less and less. Low-grade magnesite cannot be directly used as the production raw material for calcined magnesium oxide. Therefore, the development of low-grade magnesite ore, tailings, and mineral processing waste to realize the comprehensive utilization of magnesite resources has become an inevitable direction for the industry to develop. Summary of the Invention

[0004] To overcome the defects of the prior art, the technical problem solved by the present invention is to provide a method for lightly burning magnesium oxide using low-grade magnesite. The present invention adopts the process of first low-temperature calcination - crushing - magnetic separation - re-calcination, obtaining high-grade magnesium oxide, making full use of low-grade magnesite, and improving the resource utilization rate.

[0005] To achieve the above purpose, the present invention is realized by adopting the following technical solutions:

[0006] A method for lightly burning magnesium oxide using low-grade magnesite, comprising the following steps:

[0007] 1) Using low-grade magnesite as raw material, first carry out cleaning to remove impurities soluble in water, and then dry the magnesite ore;

[0008] 2) Feed the dried raw material into a crushing device for crushing to obtain a material with a particle size of 3 - 5 mm;

[0009] 3) Feed the crushed material into a rotary kiln for low-temperature calcination for 25 - 35 min, and then cool it to room temperature;

[0010] 4) Carry out magnetic separation on the material obtained in step 3);

[0011] 5) Grind the material after magnetic separation in step 4) to obtain a 200-mesh powder;

[0012] 6) Feed the powder into a calcination device for calcination, the calcination temperature is 600 - 700 °C, and the calcination time is 50 - 80 min.

[0013] The mass content of MgO in the low-grade magnesite is ≤ 41%.

[0014] The drying temperature is 80 to 100 °C, and the drying time is 8 to 12 h.

[0015] The low-temperature calcination temperature is 550 to 650 °C.

[0016] The crushing equipment is a jaw crusher or a cone crusher.

[0017] The magnetic separation intensity is 2 to 3 T.

[0018] The calcination equipment is one of a muffle furnace, a rotary furnace, a calcination furnace or a fluidized bed furnace.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The present invention adopts a process of low-temperature calcination - crushing - magnetic separation - re-calcination to obtain high-quality magnesium oxide, which can realize the utilization of low-grade magnesite resources. Moreover, the process adopted by the present invention is simple, easy to operate, and environmentally friendly.

[0021] The two-stage calcination at different temperatures in the present invention is beneficial to gradually remove impurities in the raw materials and improve the purity and performance of the magnesium oxide product. Specific Embodiments

[0022] The following further describes the specific embodiments of the present invention:

[0023] Example 1

[0024] The present invention provides a method for calcining light magnesium oxide from low-grade magnesite, comprising the following steps:

[0025] 1) Using low-grade magnesite as the raw material, first cleaning to remove impurities soluble in water, and then drying the magnesite ore;

[0026] 2) Feeding the dried raw material into the crushing equipment for crushing to obtain a material with a particle size of 3 to 5 mm;

[0027] 3) Feeding the crushed material into a rotary kiln for low-temperature calcination for 25 min, and then cooling to room temperature;

[0028] 4) Performing magnetic separation on the material obtained in step 3);

[0029] 5) Grinding the magnetically separated material obtained in step 4) to obtain a 200-mesh powder;

[0030] 6) Feeding the powder into the calcination equipment for calcination at a temperature of 650 °C for 60 min.

[0031] The mass content of MgO in the low-grade magnesite is ≤ 41%.

[0032] The drying temperature is 90 °C and the drying time is 10 h.

[0033] The temperature of the low-temperature calcination is 550 °C.

[0034] The crushing equipment is a jaw crusher.

[0035] The magnetic separation intensity is 2 T.

[0036] The calcination equipment is a rotary kiln.

[0037] Example 2

[0038] The present invention provides a method for lightly calcining magnesia using low-grade magnesite, comprising the following steps:

[0039] 1) Using low-grade magnesite as the raw material, first perform cleaning to remove impurities soluble in water, and then dry the magnesite ore.

[0040] 2) Feed the dried raw material into the crushing equipment for crushing to obtain a material with a particle size of 3-5 mm.

[0041] 3) Feed the crushed material into a rotary kiln for low-temperature calcination for 30 min, and then cool it to room temperature.

[0042] 4) Perform magnetic separation on the material obtained in step 3).

[0043] 5) Grind the material after magnetic separation in step 4) to obtain a 200-mesh powder.

[0044] 6) Feed the powder into the calcination equipment for calcination at a calcination temperature of 700 °C and a calcination time of 60 min.

[0045] The mass content of MgO in the low-grade magnesite is ≤ 41%.

[0046] The drying temperature is 80 °C and the drying time is 12 h.

[0047] The temperature of the low-temperature calcination is 650 °C.

[0048] The crushing equipment is a cone crusher.

[0049] The magnetic separation intensity is 3 T.

[0050] The calcination equipment is a muffle furnace.

[0051] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention. Additionally, it should be noted that, among the various specific technical features described in the above specific embodiments, without conflict, they can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. Furthermore, any arbitrary combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for lightly burning magnesia using low-grade magnesite, characterized in that, It includes the following steps: 1) Using low-grade magnesite as raw material, first wash to remove impurities soluble in water, and then dry the magnesite ore; 2) Feed the dried raw material into a crushing device for crushing to obtain materials with a size of 3 - 5 mm; 3) Feed the crushed materials into a rotary kiln for low-temperature calcination for 25 - 35 min, and then cool to room temperature; 4) Perform magnetic separation on the materials obtained in step 3); 5) Grind the materials after magnetic separation in step 4) to obtain 200-mesh powder; 6) Feed the powder into a calcination device for calcination, with a calcination temperature of 600 - 700 °C and a calcination time of 50 - 80 min.

2. A method for lightly burning magnesia using low-grade magnesite according to claim 1, characterized in that, The mass content of MgO in the low-grade magnesite is ≤ 41%.

3. A method for lightly burning magnesia using low-grade magnesite according to claim 1, characterized in that, The drying temperature is 80 - 100 °C, and the drying time is 8 - 12 h.

4. A method for lightly burning magnesia using low-grade magnesite according to claim 1, wherein The low-temperature calcination temperature is 550 - 650 °C.

5. A method for lightly burning magnesia using low-grade magnesite according to claim 1, characterized in that, The crushing device is a jaw crusher or a cone crusher.

6. A method for lightly burning magnesia using low-grade magnesite according to claim 1, characterized in that, The magnetic separation intensity is 2 - 3 T.

7. A method for lightly burning magnesia using low-grade magnesite according to claim 1, characterized in that The calcination device is one of a muffle furnace, a rotary furnace, a calciner or a fluidized bed furnace.