CN101967566B

CN101967566B - Process for preparing metal magnesium by normal pressure thermal reduction method

Info

Publication number: CN101967566B
Application number: CN2010105365066A
Authority: CN
Inventors: 夏德宏; 李一帆; 舒斌
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2010-11-04
Filing date: 2010-11-04
Publication date: 2011-11-16
Anticipated expiration: 2030-11-04
Also published as: CN101967566A

Abstract

The invention belongs to the field of non-ferrous metal metallurgy, and relates to a process for preparing metal magnesium from a serpentine mineral serving as a raw material by a normal pressure thermal reduction method. The method is characterized in that: the serpentine mineral is taken as the raw material, calcium carbide is taken as a reducing agent, calcium oxide is taken as an auxiliary agent, calcium fluoride is taken as a catalyst, and thermal reduction reaction is performed under normal pressure so as to obtain magnesium vapor. The method comprises the following processes of: firstly, calcining the serpentine mineral at the temperature of between 500 and 750 DEG C to remove crystal water; secondly, mixing calcinate, the calcium carbide and the calcium oxide in a weight ratio of 30-60:24-50:7-20, adding 5 to 10 weight percent of catalyst and pressing the mixed materials into pellets under the pressure of 50MPa; and finally, feeding the pellets into a reduction furnace, raising the temperature to 1,000 to 1,200 DEG C, reducing magnesium in the pellets to obtain the magnesium vapor and condensing into a magnesium crystal in a magnesium condenser. The process can be performed under normal pressure, decarburization is not needed in the whole reaction process, and the process is low-carbon and environmental-friendly.

Description

A kind of normal pressure hot reducing method prepares the technology of MAGNESIUM METAL

Technical field

The invention belongs to smelting field of nonferrous metal, relating to a kind of is raw material with the serpentine minerals, is reductive agent with carbide of calcium, and thermal reduction prepares the method for MAGNESIUM METAL under the condition of normal pressure.

Background technology

Magnesium is one of element distributed more widely in the earth's crust, has good physical properties, is widely used in fields such as aerospace, communications and transportation, microelectronics, is described as " 21 century tool potentiality to be exploited and the green engineering material of application prospect ".

The industrial production of magnesium mainly contains two kinds of electrolytic process and silicothermic process (Pidgeon process) at present: electrolytic process generally is raw material with the Magnesium Chloride Anhydrous, and metal alloy is an anode and cathode, feeds the direct current electrolysis under the magnesium chloride molten state, and negative electrode obtains MAGNESIUM METAL, and anode is emitted chlorine.Its technology shortcoming is a magnesium chloride hexahydrate dewatering process complexity, and the intractability of waste gas, waste water, waste residue is big, production unit seriously corroded, production cost height.Magnesium-smelting silicothermic process is widely used at present because of its flow process weak point, instant effect, raw material make things convenient for, production is flexible, be convenient to operation.It adopts ferrosilicon as reductive agent, and under certain vacuum degree and temperature, with the rhombspar reduction after the calcining, magnesium is reduced into and carries out condensation again behind the steam and obtain MAGNESIUM METAL.But every technico-economical comparison of magnesium-smelting silicothermic process is unsatisfactory, mainly has following subject matter: 1) taste to raw material requires height, can only adopt the rhombspar mineral aggregate at present, and its magnesium oxide and Mg content are far below serpentine; 2) higher as the ferrosilicon cost of reductive agent; 3) reduction reaction needs vacuum condition, is difficult to realize continuous production, and the industrial scale of magnesium factory is little; 4) reduction temperature height, reduction is short jar work-ing life, the production cost height; 5) energy dissipation and environmental pollution are serious, and the growth of magnesium output is a cost with sacrificialing environment and resource.

It is the aluminothermy for smelting magnesium method of raw material with magnesite and rhombspar that China's patent application 93115701.3 discloses a kind of, is reductive agent with the aluminium powder, under 1100～1170 ℃ and vacuum condition, generates MAGNESIUM METAL through 6～8 hours.It is the method that reductive agent prepares MAGNESIUM METAL with the silumin that China patent application 200410020666.X discloses a kind of, this method one rhombspar and magnesite are raw material, make reductive agent with silumin, under high temperature and vacuum condition, reduction calcined dolomite and magnesite, the preparation MAGNESIUM METAL.China patent application 200810058928.X discloses a kind of method of preparing magnesium metal by giobertite vacuum carbon thermal reduction, it with the coal reductive agent and to add Calcium Fluoride (Fluorspan) be catalyzer, control furnace pressure 20～700Pa, under 1300～1500 ℃ condition retailoring 40～60min, obtain reguline metal magnesium.China's patent application 200910084574.0 discloses a kind of method for preparing MAGNESIUM METAL and byproduct with the serpentine minerals vacuum carbothermal reduction, with the serpentine is raw material, allocate carbonaceous reducing agent into, through after the pressure ball drying under 10～500Pa and 1200～1500 ℃ of conditions reduction preparation MAGNESIUM METAL.

By above technical background as can be known, the technology of producing MAGNESIUM METAL of research needs to carry out under vacuum mostly at present, the purpose that be difficult to realize continuous production, enlarges scale, and prepare the MAGNESIUM METAL desired raw material at present and adopt magnesium oxide and mineral white marble or magnesite mostly, and the mineral high to another kind of Mg content---serpentine is studied seldom.Based on this situation, we further investigate serpentine minerals hot reducing method production MAGNESIUM METAL under non-vacuum condition, have invented the technology that the thermal reduction of serpentine minerals normal pressure prepares MAGNESIUM METAL.

Summary of the invention

The objective of the invention is defective at present smelting magnesium by thermal reduction process, seek a kind of simple, environmental protection and can be continuously, the method for mass preparation MAGNESIUM METAL.For achieving the above object, the invention provides a kind of is the technology that raw material thermal reduction under condition of normal pressure prepares MAGNESIUM METAL with the serpentine minerals, it is characterized in that with the serpentine fine ore be raw material, carbide of calcium is reductive agent, calcium oxide is an auxiliary agent, Calcium Fluoride (Fluorspan) is catalyzer, carries out reduction reaction under the condition of normal pressure and obtains magnesium vapor.Reaction equation is:

2MgO·SiO ₂+MgO·SiO ₂+3CaC ₂+CaO?→3Mg(g)+2(2CaO·SiO ₂)+6C

Concrete steps are:

(1) is raw material with the serpentine minerals, puts into stove and be warming up to 500～750 ℃ of calcinings with the temperature rise rate of 5～15 ℃/min and remove crystal water, obtain calcinate;

(2) according to calcinate, reductive agent and auxiliary agent weight ratio 30～60: 24～50: 7～20 batchings, and after adding catalyzer, mixture is pressed into pelletizing under 50Mpa;

(3) described pelletizing feed is added in the stove, be warming up to 1000～1200 ℃, carry out the magnesium in the reduction reaction reducting pellet with the temperature rise rate of 5～15 ℃/min;

(4) magnesium vapor that restores is condensed into crystallization magnesium on 200～600 ℃ magnesium condenser, the magnesium condenser is cooled to room temperature, collects to obtain the crystallization MAG block.

Wherein, reductive agent is a carbide of calcium, and auxiliary agent is a calcium oxide, and catalyzer is a Calcium Fluoride (Fluorspan).

Further, the described Calcium Fluoride (Fluorspan) addition 5～10wt% that is the mixing raw material amount.

Further, in the described step (2), the pelletizing granularity that mixing raw material is pressed into is about 30mm.

This reducing process has the following advantages:

1) selecting serpentine minerals for use is raw material, and domestic reserves are abundant, and its theoretical magnesium content can reach 26.3%, far above 13.2% of rhombspar, has very high utility value;

2) serpentine is a kind of Magnesium Silicate q-agent mineral, need not to carry out decarburization in the technical process, and this technology does not have CO ₂Discharging is a kind of technology of low-carbon environment-friendly;

3) magnesium reduction is reflected under the normal pressure and can finishes, and cooperates suitable material charging and discharging device can realize continuous production, expands the scale of production, and enhances productivity.

Description of drawings

Fig. 1 be the present invention reduce the preparation MAGNESIUM METAL process flow sheet.

Embodiment

Embodiment 1: adopting MgO content is that 43.6% serpentine minerals is a raw material, and it is added in stove, is warming up to 500 ℃ and removes crystal water, obtains calcinate.According to calcinate, reductive agent and 30: 24: 7 batchings of auxiliary agent weight ratio, and mix behind the Calcium Fluoride (Fluorspan) of interpolation 5wt%, press down at 50Mpa and make the pelletizing that granularity is about 30mm.Pelletizing is packed in the stove, be warming up to 1100 ℃, reduction obtains magnesium vapor, and magnesium vapor condenses and collects on 200 ℃ magnesium condenser and obtains MAGNESIUM METAL.

Embodiment 2: adopting MgO content is that 43.6% serpentine minerals is a raw material, and it is added in stove, is warming up to 600 ℃ and removes crystal water, obtains calcinate.According to calcinate, reductive agent and 30: 35: 15 batchings of auxiliary agent weight ratio, and mix behind the Calcium Fluoride (Fluorspan) of interpolation 8wt%, press down at 50Mpa and make the pelletizing that granularity is about 30mm.Pelletizing is packed in the stove, be warming up to 1150 ℃, reduction obtains magnesium vapor, and magnesium vapor condenses and collects on 300 ℃ magnesium condenser and obtains MAGNESIUM METAL.

Embodiment 3: adopting MgO content is that 43.6% serpentine minerals is a raw material, and it is added in stove, is warming up to 750 ℃ and removes crystal water, obtains calcinate.According to calcinate, reductive agent and 30: 50: 20 batchings of auxiliary agent weight ratio, and mix behind the Calcium Fluoride (Fluorspan) of interpolation 10wt%, press down at 50Mpa and make the pelletizing that granularity is about 30mm.Pelletizing is packed in the stove, be warming up to 1200 ℃, reduction obtains magnesium vapor, and magnesium vapor condenses and collects on 500 ℃ magnesium condenser and obtains MAGNESIUM METAL.

Embodiment 4: adopting MgO content is that 43.6% serpentine minerals is a raw material, and it is added in stove, is warming up to 750 ℃ and removes crystal water, obtains calcinate.According to calcinate, reductive agent and 60: 35: 15 batchings of auxiliary agent weight ratio, and mix behind the Calcium Fluoride (Fluorspan) of interpolation 10wt%, press down at 50Mpa and make the pelletizing that granularity is about 30mm.Pelletizing is packed in the stove, be warming up to 1200 ℃, reduction obtains magnesium vapor, and magnesium vapor condenses and collects on 600 ℃ magnesium condenser and obtains MAGNESIUM METAL.

Claims

1. a normal pressure hot reducing method prepares the technology of MAGNESIUM METAL, it is characterized in that, finishes according to following steps:

1.1 with the serpentine minerals is raw material, puts into stove and is warming up to 500～750 ℃ of calcinings with the temperature rise rate of 5～15 ℃/min and removes crystal water, obtains calcinate;

1.2 according to calcinate, reductive agent and auxiliary agent weight ratio 30～60: 24～50: 7～20 batchings, and after adding catalyzer, mixture is pressed into pelletizing under 50Mpa;

1.3 described pelletizing feed is added in the stove, be warming up to 1000～1200 ℃ with the temperature rise rate of 5～15 ℃/min, carry out the magnesium in the reduction reaction reducting pellet;

1.4 the magnesium vapor that restores is condensed into crystallization magnesium on 200～600 ℃ magnesium condenser, the magnesium condenser is cooled to room temperature, collects to obtain the crystallization MAG block;

In the described step 1.2, reductive agent is a carbide of calcium, and auxiliary agent is a calcium oxide, and catalyzer is a Calcium Fluoride (Fluorspan), and described Calcium Fluoride (Fluorspan) addition is 5～10wt% of mixing raw material amount, and the pelletizing granularity that mixing raw material is pressed into is 30mm.