CN1153221A - Cobalt-bearing oxidized ore treatment by microwave-heat plasma - Google Patents

Abstract

A process for treating Co-containing oxidized ore with microwave and thermal plasma features that with the selective heating and catalysis of microwave on said ore and raising temp quickly, non-dressable Co-containing oxidized ore is converted into ore concentrate dressable conventionally and after smelting in thermal plasma furnace, Co-rich alloy is obtained. Its advantages are short treating period, low energy consumption, no environmental pollution and high recovery.

Description

Microwave-thermal plasma treatment of cobalt-containing oxidized ore

The invention relates to a method for processing cobalt-containing oxidized ore by using microwave-thermal plasma and recovering associated valuable metals, wherein cobalt is an important strategic substance and is associated with minerals such as nickel, copper, manganese, iron and the like in the minerals, the geological resource of the cobalt in China is insufficient, the grade is low, the average grade is only 0.02-0.034%, the geological grade of the cobalt-containing minerals in China is more than 50 times different from that of foreign minerals, so that the production difficulty of the cobalt in China is large, the minerals which exist in the form of the cobalt oxide in the minerals capable of providing the cobalt comprise ① copper oxide ores, including copper-enriched ores with high cobalt content and copper-poor ores with low cobalt content, ② cobalt soil ores, manganese and copper, and ③ laterite ores (nickel oxide ores) associated with nickel and iron in the form of oxides.

The traditional smelting method for producing cobalt comprises a combined process of a fire method and a wet method and a whole wet method. The former is that the raw material containing more than 3% Co is directly fed into blast furnace or electric furnace to make reduction or matte smelting, and the produced cobalt-iron alloy or cobalt matte is further enriched and separated, and then transferred into wet process to produce electric cobalt by electrodeposition. The method has the biggest defects that the enrichment ratio of cobalt in the smelting process is low, the cobalt content of the produced slag is high, and the recovery rate of cobalt is low; the latter is that cobalt ore containing cobalt less than 2% is directly treated by wet method, and its disadvantages are large production equipment, large floor area, long technological process, low metal recovery rate, large acid consumption, serious environmental pollution, low production efficiency and high product cost.

The invention aims to provide a method for treating cobalt-containing oxidized ore by microwave-thermal plasma, which converts non-selectable cobalt oxide and associated copper oxide or nickel oxide into ore phases capable of being subjected to ore dressing enrichment by a conventional flotation method or a magnetic separation method, and transfers the produced concentrate into plasma smelting so as to effectively extract metallic cobalt and other associated valuable metals.

The invention is such that, because the minerals for extracting cobaltmainly include copper oxide ore, cobalt soil ore and nickel oxide ore (laterite ore), the oxides of cobalt, nickel, iron, copper, manganese and the like in the three minerals have strong wave-absorbing performance in a microwave field, but other gangue is not wave-absorbing, therefore, the minerals can be selectively heated and catalyzed by microwave energy, and the temperature rise is very rapid, the minerals are selectively heated, the conventional ore dressing enrichment is carried out, most gangue is discarded, the obtained concentrate is continuously smelted by plasma, cobalt-rich high nickel matte, cobalt iron alloy, crude copper and the like are obtained, and then the concentrate is transferred to the conventional wet process to separate and extract valuable metals such as cobalt and the like.

The technical scheme of the invention is as follows: because the cobalt-containing oxidized ore has different chemical compositions, different process methods are necessary for treatment, and the method specifically comprises the following steps:

the first step is that the copper oxide ore containing cobalt (which is suitable for processing copper oxide ore without cobalt for extracting copper) and nickel oxide ore (laterite ore):

the method comprises the steps of grinding raw ores mixed with a vulcanizing agent (pyrite or sulfur) (firstly, grinding the raw ores and the vulcanizing agent respectively and then mixing the raw ores and the vulcanizing agent, entering a microwave energy heating reactor (system) to heat at the temperature of 150-250 ℃ for a vulcanization reaction, completing the reaction within 5-8 minutes (continuous operation can be realized), completely converting valuable metal oxidation phases into selectable vulcanization phases, and then transferring the sulfide phases into conventional flotation for beneficiation enrichment (the valuable metal enrichment ratio can reach 8-12 times).

The obtained sulfide concentrate is transferred into a microwave energy heating reaction system (device) and is introduced with H at the temperature of 450-500 DEG C₂And (3) performing reverse desulfurization on the O steam, and completing the reaction within 10-15 minutes (realizing continuous operation) to directly prepare the elemental sulfur (the elemental sulfur can be returned to the previous vulcanization process for recycling).

And (3) transferring the desulfurized calcine into a thermal plasma furnace if the calcine containing nickel and cobalt is nickel-cobalt, adding a flux and a slag depletion agent, continuously smelting at 1700-1800 ℃ (the temperature of the melt in the arc zone), directly preparing the cobalt-rich high nickel matte by taking inert gas as the carrier gas of the plasma, and obtaining the waste slag at one time. The cobalt-rich high nickel matte can be transferred to the next conventional process to separate valuable metals such as nickel, cobalt and the like; if the copper calcine is obtained, adding a fusing agent and a slag depletion agent into a thermal plasma furnace for continuous smelting (at the temperature of 1600-1700 ℃ of the melt temperature in an arc zone), directly preparing the blister copper and obtaining the waste slag once. The crude copper can be transferred to the next conventional process to separate copper and cobalt.

Second, cobalt-earth ore, nickel oxide ore (laterite):

for cobalt-bearing ores and nickel oxide ores, the raw ores are ground and mixed with reducing agent carbon (gas phase CO and H can also be used)₂、C₂H₂Reducing, heating in a microwave energy heating reactor (system) at the temperature of 250-300 ℃ for reduction (the treatment method of nickel oxide ore can also be the sulfuration method), finishing the reaction within 5-8 minutes (continuous operation can be realized), forming magnetic solid solution after reduced cobalt ferrite, copper ferrite (or nickel oxide), manganese ferrite and ferrite are zero-valent metals, and then carrying out beneficiation and enrichment by conventional magnetic separation.

And transferring the magnetic concentrate obtained by magnetic separation into a thermal plasma furnace, adding a fusing agent and a slag depletion agent, continuously smelting at the temperature of 1700-1800 ℃ of the melt temperature in an arc zone, and taking inert gas as the carrier gas of the plasma to produce the cobalt alloy (one-time waste slag).

The cobalt alloy can be transferred to a conventional wet process to separate and extract valuable metals such as cobalt and the like.

The fusing agent used in the invention is SiO₂The slag barren agent is CaO. The dosage is calculated according to the ingredients of the raw materials.

The chemical reaction formula of each oxide and additive in microwave heating is as follows:

(1) nickel oxide ore (laterite)

Reduction reaction

Vulcanization reaction

(2) Copper oxide ore

$\mathrm{CuC}{O}_3.\mathrm{Cu}{\left(\mathrm{OH}\right)}_2+\mathrm{FeS}(\mathrm{<figure-callout\; id="2"\; label="Fe\; S"\; filenames="A9611257800111.png"\; state="\{\{state\}\}">Fe</figure-callout>}{S}_{}{}_2.S)=C{u}_{2}S+\mathrm{FeO}+C{O}_2+H_{2}O+\frac{1}{2}{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="A9611257800111.png"\; state="\{\{state\}\}">O</figure-callout>}}_2$

(3) Cobalt soil ore

Compared with the prior art, the invention has the following advantages and effects: the invention utilizes the selective heating and catalytic action of microwave energy on minerals and the characteristic of extremely rapid temperature rise, so that copper oxide ores, laterite ores, cobalt-soil ores and the like which cannot be beneficiated and enriched by a conventional beneficiation method are converted into mineral phases which can be beneficiated and enriched by conventional flotation or magnetic separation, most gangue is discarded, the obtained concentrate is transferred into a plasma furnace for smelting, and valuable metals and gangue are effectively separated. The treatment method provided by the invention can be completed in a short time, can realize continuous treatment, greatly saves comprehensive energy consumption, shortens the process flow, improves the metal recovery rate, reduces the metal content in slag, most effectively utilizes resources, and has no environmental pollution, thereby being the essence of a new generation of mineral separation and smelting technology.

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is another process flow diagram of the present invention;

FIG. 3 is a diagram of a microwave energy heating reaction system according to the present invention;

FIG. 4 is a diagram of a thermal plasma furnace melting system according to the present invention.

In FIG. 3, 1-continuous feed seal; 2-a monitoring device; 3-an exhaust device; 4-an exhaust chamber; 5-a microwave source; 6-a microwave heater; 7-feeding and discharging transmission device; 8-a continuous discharge device; 9-discharging and sealing the bin.

In FIG. 4, 10-plasma power supply; 11-a monitoring system; 12-continuous feed sealing device; 13-a cooling water circulation system; 14-a plasma torch lifting device; 15. 16, 17-plasma torch; 18-a plasma smelting tank; 19-metal outlet; 20-a slag outlet; 21-an exhaust gas discharge device; 22-carrier gas supply means; 23-furnace body cooling water circulating device

Example 1: (reduction-magnetic separation-plasma smelting method)

The process flow is shown in figure 1, and the chemical components of the nickel oxide ore to be treated are as follows: 0.8% of nickel (Ni), 0.04% of cobalt (Co), 14% of iron (Fe), and silicon dioxide (SiO)₂) 40% of aluminum oxide (AL)₂O₃)2.5 percent, 15 percent of magnesium oxide (MgO), 1.7 percent of calcium oxide (CaO) and 10 percent of crystal water.

Grinding nickel oxide ore with ball mill to particle size of 100% to 0.076mm, adding reducing agent carbon powder according to the calculated amount of raw materials, adding 0.5% (by weight) binder (preferably starch water) for granulation, (requiring average particle size no more than 5mm, maximum particle size no more than 8mm), drying (requiring water content ∠ 4%), adding into microwave energy heating furnace for pre-reductionRaw materials (reducing agent can be not added in advance during granulation, butGranulating, heating the reactor with microwave energy, and introducing reducing gas CO (or C)₂H₂、H₂Etc.), the apparent temperature of pre-reduction (i.e. the measured temperature of the material population) is controlled at 250 ℃ to 300 ℃ for about 5 minutes to complete the reduction reaction (the process can be continuous).

Grinding the material pre-reduced by microwave heating by a double-roller mill until the granularity is required to be less than 0.076mm, transferring the material to dry magnetic separation, wherein the magnetic substance is valuable metal concentrate such as cobalt, nickel and the like to be enriched (the enrichment ratio can reach more than 8 times), and the non-magnetic substance is gangue, and discarding. The obtained concentrate (magnetic material) is transferred into a thermal plasma furnace, a silicon oxide flux and a calcium oxide barren agent are calculated and added according to the alkalinity of the slag, continuous smelting is realized at the melt temperature of 1700-1800 ℃, the cobalt-rich alloy is directly prepared, the slag is obtained at one time, the enrichment ratio of cobalt in the alloy can reach 12 times in the smelting process, and the nickel enrichment ratio can reach 20 times.

The cobalt-rich alloy can be transferred to the next conventional wet process for separating and extracting the valuable metals such as cobalt, nickel and the like.

Example 2: (sulfurization-flotation-reverse desulfurization-plasma smelting method)

The process flow is shown in figure 2, and the typical chemical compositions of the processed copper oxide ore are as follows:

element(s)	Gu	Co	Au	Ag	CaCO3	MgCO3	SiO2
								Content (wt.) (％)	0.62	0.1	0.059g/T	5g/T	43.88	32.29	18.30

Element(s)	AL2O3	Fe2O3
			Content (wt.)	1.08	2.97

Adding pyrite or elemental sulfur into copper oxide ore according to a required calculation proportion, grinding until the grain size is 100% or less and 0.076mm, transferring into a microwave energy heating reactor for vulcanization, controlling the vulcanization temperature to be about 150 ℃ (apparent temperature), carrying out vulcanization for 5-8 minutes, grinding the vulcanization product to be 100% or less and 0.076mm, transferring into conventional flotation, enriching valuable metals into vulcanized concentrate, introducing most gangue into tailings, re-granulating the vulcanized concentrate, carrying out reverse desulfurization by heating with a microwave energy heater, introducing steam as a desulfurizing agent, controlling the desulfurization temperature to be 500 ℃ and 10-15 minutes, directly preparing the elemental sulfur, transferring the roasted sand into a thermal plasma furnace after adding flux silicon oxide and poor agent calcium oxide, and continuously smelting at the melt temperature of 1700 ℃ to prepare the cobalt-rich blister copper. And (5) transferring to the next conventional flow, and separating and extracting the valuable metals.

Claims (4)

1. A method for treating cobalt-containing oxidized ore by microwave-thermal plasma is characterized in that:

a. mixing raw ore with pyrite or sulfur serving as a vulcanizing agent, heating the raw ore in a microwave energy heating reactor at the temperature of 150 ℃ and 250 ℃ for a vulcanization reaction, completing the reaction within 5-8 minutes, transferring the reaction to conventional flotation for mineral separation and enrichment, and discarding most gangue;

b. feeding the sulfide concentrate obtained by ore dressing into a microwave energy heating reactor, introducing desulfurizer steam at the temperature of 450-500 ℃ for reverse desulfurization, and completing the reaction within 10-15 minutes;

c. transferring the desulfurized calcine into a thermal plasma furnace, adding flux silicon oxide and slag barrenner calcium oxide, continuously smelting at the temperature of 1600-1800 ℃ (arc zone melt temperature) to prepare cobalt-rich alloy, obtaining waste slag once, and transferring into a conventional wet process to separate and extract cobalt and other valuable metals.

2. A method for treating cobalt-containing oxidized ore by microwave-thermal plasma is characterized in that:

A. mixing raw ore with reducing agent carbon (or carbon monoxide or hydrogen), heating in a microwave energy heating reactor at the temperature of 250-300 ℃ for reduction reaction, completing the reaction within 5-8 minutes, transferring to conventional magnetic separation, and discarding most gangue;

B. and transferring the magnetic concentrate obtained by magnetic separation into a thermal plasma furnace, adding flux silicon oxide and slag barrenner calcium oxide, continuously smelting at the temperature of 1700-1800 ℃ (the temperature of the melt in the arc zone), preparing cobalt alloy, obtaining waste slag at one time, and transferring into a conventional wet process to separate and extract cobalt and other valuable metals.

3. The method according to claim 1 or 2, characterized in that the microwave energy heated reactor is mainly composed of a continuous feed sealing device (1), a monitoring device (2), an exhaust device (3), a microwave source (5), a microwave heater (6), a feed and discharge transmission device (7), a continuous discharge device (8) and the like.

4. The method according to claim 1 or 2, characterized in that the thermal plasma furnace is mainly composed of a plasma power supply (10), a monitoring system (11), a continuous feed and discharge sealing device (12), a cooling system (13), plasma torches (15), (16), (17), a plasma smelting bath (18), an exhaust gas discharge device (21), a gas supply device (22), a furnace body cooling device (23), and the like.

Images