阅读说明：本技术 一种利用硝酸介质综合处理红土镍矿的方法 (Method for comprehensively treating laterite-nickel ore by using nitric acid medium ) 是由 王成彦 马保中 赵林 陈永强 王鹏辉 但勇 金长浩 赵澎 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种利用硝酸介质综合处理红土镍矿的方法包括：步对红土镍矿的原矿矿石进行破碎与细磨,从而得到矿粉；再将硝酸溶液作为浸出剂加入所述矿粉中,进行选择性浸出,液固分离得到浸出渣和浸出液；再将得到的浸出液加入煅烧炉进行煅烧分解,得到混合干基金属氧化物,在煅烧过程中产出氮氧化物气体NO<Sub>x</Sub>；再将得到的浸出渣进入球团与烧结工序,生产铁精矿；对氮氧化物NO<Sub>x</Sub>进行吸收,制备浓硝酸,并配制硝酸溶液返回作浸出剂。该方法能实现铁与镍钴的有效分离,以及降低镍钴产物中铝镁等金属的含量,降低中和剂的使用,实现硝酸的可再生利用,大大提升红土镍矿的综合利用效率和经济价值。(The invention discloses a method for comprehensively treating laterite-nickel ore by using a nitric acid medium, which comprises the following steps: crushing and finely grinding raw ore of the laterite-nickel ore to obtain ore powder; adding a nitric acid solution serving as a leaching agent into the mineral powder for selective leaching, and performing liquid-solid separation to obtain leaching residues and a leaching solution; adding the obtained leachate into a calcining furnace for calciningDecomposing to obtain mixed dry-base metal oxide, and generating nitrogen oxide gas NO during calcining x (ii) a Then the obtained leaching slag enters a pelletizing and sintering process to produce iron ore concentrate; to nitrogen oxide NO x Absorbing to prepare concentrated nitric acid, and preparing nitric acid solution to be used as a leaching agent. The method can realize effective separation of iron and nickel and cobalt, reduce the content of aluminum, magnesium and other metals in the nickel and cobalt product, reduce the use of a neutralizing agent, realize the renewable utilization of nitric acid, and greatly improve the comprehensive utilization efficiency and economic value of the laterite-nickel ore.)

1. A method for comprehensively treating laterite-nickel ore by using a nitric acid medium is characterized by comprising the following steps:

step one, crushing and fine grinding: crushing and finely grinding raw ore of the laterite-nickel ore to obtain ore powder;

step two, selective leaching: adding a nitric acid solution serving as a leaching agent into the mineral powder, selectively leaching, and performing liquid-solid separation to obtain leaching residues and a leaching solution;

step three, one-step or multi-step calcination: adding the leachate obtained in the step two into a calcining furnace for calcining and decomposing to obtain mixed dry-base metal oxide, and producing nitrogen oxide gas NO in the calcining process_x；

Step four, pelletizing and sintering: the leaching slag obtained in the step two enters a pelletizing and sintering process to produce iron ore concentrate;

step five, preparing concentrated nitric acid: for nitrogen oxide NO generated in the third step_xAbsorbing to prepare concentrated nitric acid, and preparing nitric acid solution to be used as a leaching agent in the second step.

2. The method for comprehensively treating lateritic nickel ores by using nitric acid media according to claim 1, characterized in that the particle size of the ores in the step one is less than 74 μm.

3. The method for comprehensively treating lateritic nickel ores by using nitric acid medium according to claim 1, characterized in that the lateritic nickel ore raw ore contains the following elements by mass: the Fe accounts for 38-48%; ni is 0.6 to 2.0%.

4. The method for comprehensively treating lateritic nickel ores by using nitric acid medium according to claim 3, characterized in that the lateritic nickel ore raw ore further contains the following elements by mass: 0.05-0.20% of Co, 1-5% of Al and 0.05-0.30% of Mn.

5. The method for comprehensively treating the lateritic nickel ore by using the nitric acid medium according to the claims 1, 2, 3 or 4, characterized in that the concentration of the nitric acid solution in the second step is 150-300 g/L; the solid-liquid ratio of the mineral powder to the nitric acid solution is 1: 1-1: 5 g/mL;

control reaction conditions for selective leaching: the leaching temperature is 160-220 ℃, the leaching time is 0.5-2 h, and the stirring speed is 150-600 rpm.

6. The method for comprehensively treating lateritic nickel ores by using nitric acid medium according to the claims 1, 2, 3 or 4, characterized in that the third step includes one-step calcination or multiple-step calcination:

calcining at one step, wherein the temperature of the calcining furnace is controlled to be 500-550 ℃; producing dry mixed oxide containing nickel, cobalt, manganese and aluminum, magnesium and iron;

two-step calcining, namely firstly, controlling the temperature of a calcining furnace to be 230-330 ℃ to produce dry-based oxides of nickel, cobalt and manganese, which contain a small amount of iron, magnesium and aluminum impurities; and controlling the temperature of the calcining furnace to rise to 500-550 ℃ to produce the dry-based oxide of the aluminum, magnesium and manganese.

Calcining in multiple steps, namely firstly, controlling the temperature of a calcining furnace to be 180-210 ℃, producing iron dry-based oxide mixed with a very small amount of cobalt and manganese, and separating all iron; controlling the temperature of the calcining furnace to rise to 260-290 ℃, and producing pure nickel-cobalt-manganese dry-based oxide; and continuously heating, controlling the temperature of the calcining furnace to be 500-550 ℃, and producing the aluminum-magnesium-manganese dry-based oxide containing a very small amount of nickel and cobalt.

7. The method for comprehensively treating lateritic nickel ores by using nitric acid media according to claim 6, characterized in that the dry oxides containing nickel, cobalt and manganese are purified and then used for preparing ternary materials; the pure nickel-cobalt-manganese dry oxide is used for preparing ternary materials.

8. The method for comprehensively treating lateritic nickel ores by using a nitric acid medium according to claim 6, wherein the leachate is added into the calciner in a spraying manner.

9. The method for comprehensively treating lateritic nickel ores by using a nitric acid medium according to claims 1, 2, 3 or 4, characterized in that iron ore concentrate with 50-65% of iron content is obtained after the four-pellet and sintering treatment.

Technical Field

The invention relates to the technical field of nonferrous metal metallurgy and mineral resource comprehensive utilization, in particular to a method for comprehensively treating laterite-nickel ore by using a nitric acid medium, which is used for efficiently separating valuable metals.

Background

The mineral resources of nickel mainly include nickel sulfide ore and nickel oxide ore (also called laterite-nickel ore). The nickel produced by the nickel industry in the world in the past years is mainly from nickel sulfide ore resources, and the current statistical data show that: the nickel sulfide ore accounts for over 70 percent, and the nickel yield is about 50 percent. Along with the continuous increase of the market demand on nickel and cobalt and the gradual depletion of nickel sulfide ore resources, the laterite-nickel ore with rich reserves draws attention of people, and the efficient and economic treatment of the laterite-nickel ore has important significance.

At present, the hydrometallurgical method for processing the laterite-nickel ore mainly comprises a reduction roasting-ammonia leaching method, a high-pressure acid leaching method, a normal-pressure acid leaching method and the like. The reduction roasting-ammonia leaching method reduces nickel silicate and nickel oxide in the minerals into metal to the maximum extent through reduction roasting, and simultaneously controls the reduction conditions to reduce iron into ferroferric oxide. Leaching the roasted nickel and cobalt by adopting an ammoniacal solution, and recovering iron in leaching residues through magnetic separation. Although the process adopts normal pressure leaching, the equipment cost and the management cost are reduced, but the defects that the reducing atmosphere is difficult to control, the fluctuation of the leaching rate of nickel is large, the leaching rate of cobalt is low, ammonia is easy to volatilize, the enrichment rate of iron magnetic separation is low and the like exist. The high-pressure acid leaching method is suitable for treating the laterite-nickel ore, and has the greatest advantage that the leaching rate of nickel and cobalt can reach more than 90 percent. But the leaching method has harsher conditions and lower utilization rate of laterite resources. The normal pressure acid leaching method is one of attractive smelting methods for the laterite-nickel ore due to small equipment investment, mild reaction conditions, small technical risk and stronger universality of ore species. However, the acid consumption is large in the normal-pressure acid leaching process, and Fe and Ni in the leaching solution are difficult to separate.

The existing pressure acid leaching process is that under high temperature and high pressure, sulfuric acid is used as a leaching agent, leaching conditions are controlled, most of iron, aluminum, silicon and the like are hydrolyzed and enter slag, nickel and cobalt enter a solution to realize selective leaching, and then the leaching solution is neutralized and impurities (Fe and Al) are removed to obtain a high-quality nickel and cobalt solution. The process has the biggest advantages of good leaching selectivity and high leaching rate of nickel and cobalt, but has the defects of complex process technology, high equipment requirement, large investment, high operation cost, serious scabbing of a pressurized kettle, incapability of realizing comprehensive utilization of leached slag due to low sulfur and high iron content, and the like.

In view of the above-mentioned shortcomings of the conventional hydrometallurgical process of laterite-nickel ore, people have been studying new technology with more competitive advantages suitable for laterite-nickel ore in recent years.

Patent CN200910180397 discloses an alkali-acid dual cycle process for treating laterite-nickel ore, which adopts the technical scheme that valuable metals such as aluminum, chromium and the like in the laterite-nickel ore are promoted to be leached through an alkali fusion reaction, and then nickel and cobalt are leached through an acid leaching pressurization process. The method can realize comprehensive utilization of toxic substances, thereby greatly reducing the cost and reducing the pollution to the environment, but the process cost is greatly improved for the laterite-nickel ore with low chromium content, and meanwhile, the filter cake has certain entrainment phenomenon after multiple times of filtration, thereby causing the loss of valuable metals.

Patent CN201110327198 discloses a method for processing laterite-nickel ore, which provides a method for recycling valuable elements of iron, nickel and cobalt in laterite-nickel ore which is used as a raw material by adopting a new process of raw ore curing, selective atmospheric pressure leaching, magnetizing roasting and magnetic separation. The process adopts sulfuric acid for selective leaching, and because a certain amount of calcium and magnesium is still contained in the laterite-nickel ore, serious scabbing phenomenon can be caused after a long time.

Patent CN1676634 discloses a pressure oxidation leaching method of nickel cobalt oxide ore, which does not directly use sulfuric acid as leaching agent, but adds sulfur powder slurry or sulfide ore concentrate slurry into autoclave, and reacts with introduced oxygen to generate sulfuric acid required for leaching, thereby leaching nickel cobalt in the ore. Although the patent avoids the problem of insufficient addition of sulfuric acid in the traditional method, the reaction temperature and pressure are still high, the requirements on industrial equipment and conditions are severe, and the implementation difficulty is high.

Patent CN103757261 discloses a clean production method of laterite-nickel ore, which comprises laterite-nickel ore hydrochloric acid atmospheric pressure leaching, serpentine type laterite-nickel ore selective leaching in acid leaching solution, hydrolysis coupling reaction, separation and purification of oxides containing Fe and Si to prepare iron powder and SiO2 for building materials.

The main inventor of this patent has disclosed in patents CN200810115191.0 and CN201810816384.2 a process for leaching lateritic nickel ore by using a nitric acid medium, but for the treatment of the leachate, the leachate is neutralized by adding alkaline substances (such as calcium oxide, calcium carbonate, magnesium oxide) to obtain metal hydroxides. Although the two technologies can avoid the defects of the traditional process, the problems that the slag generated in the neutralization and precipitation process carries serious valuable metals such as nickel and cobalt and the liquid-solid separation is difficult to solve all the time are solved.

In conclusion, the improvement of the process for refining the laterite-nickel ore in the prior art still has the defects of high production cost, harsh process conditions, serious impurity inclusion, difficult separation and purification and the like, and the serious scab phenomenon can occur when the sulfuric acid is used as a leaching agent.

Disclosure of Invention

The invention aims to provide a method for comprehensively treating laterite-nickel ore by using a nitric acid medium, which can realize effective separation of iron and nickel and cobalt, reduce the content of aluminum, magnesium and other metals in a nickel-cobalt product, reduce the use of a neutralizer, realize the renewable utilization of nitric acid and greatly improve the comprehensive utilization efficiency and economic value of laterite-nickel ore.

The purpose of the invention is realized by the following technical scheme:

a method for comprehensively treating laterite-nickel ore by using a nitric acid medium comprises the following steps:

step one, crushing and fine grinding: crushing and finely grinding raw ore of the laterite-nickel ore to obtain ore powder;

step two, selective leaching: adding a nitric acid solution serving as a leaching agent into the mineral powder, selectively leaching, and performing liquid-solid separation to obtain leaching residues and a leaching solution;

step three, one-step or multi-step calcination: adding the leachate obtained in the step two into a calcining furnace for calcining and decomposing to obtain mixed dry-base metal oxide, and producing nitrogen oxide gas NO in the calcining process_x；

Step four, pelletizing and sintering: the leaching slag obtained in the step two enters a pelletizing and sintering process to produce iron ore concentrate;

step five, preparing concentrated nitric acid: for nitrogen oxide NO generated in the third step_xAbsorbing to prepare concentrated nitric acid, and preparing nitric acid solution to be used as a leaching agent in the second step.

The granularity of the mineral powder in the first step is less than 74 microns.

The laterite-nickel ore raw ore comprises the following elements in percentage by mass: the Fe accounts for 38-48%; ni is 0.6 to 2.0%.

The laterite-nickel ore raw ore also comprises the following elements in percentage by mass: 0.05-0.20% of Co, 1-5% of Al and 0.05-0.30% of Mn.

The concentration of the nitric acid solution in the second step is 150-300 g/L; the solid-liquid ratio of the mineral powder to the nitric acid solution is 1: 1-1: 5 g/mL;

control reaction conditions for selective leaching: the leaching temperature is 160-220 ℃, the leaching time is 0.5-2 h, and the stirring speed is 150-600 rpm.

The third step comprises one-step calcination or multiple-step calcination:

calcining at one step, wherein the temperature of the calcining furnace is controlled to be 500-550 ℃; producing dry mixed oxide containing nickel, cobalt, manganese and aluminum, magnesium and iron;

two-step calcining, namely firstly, controlling the temperature of a calcining furnace to be 230-330 ℃ to produce dry-based oxides of nickel, cobalt and manganese, which contain a small amount of iron, magnesium and aluminum impurities; and controlling the temperature of the calcining furnace to rise to 500-550 ℃ to produce the dry-based oxide of the aluminum, magnesium and manganese.

Calcining in multiple steps, namely firstly, controlling the temperature of a calcining furnace to be 180-210 ℃, producing iron dry-based oxide mixed with a very small amount of cobalt and manganese, and separating all iron; controlling the temperature of the calcining furnace to rise to 260-290 ℃, and producing pure nickel-cobalt-manganese dry-based oxide; and continuously heating, controlling the temperature of the calcining furnace to be 500-550 ℃, and producing the aluminum-magnesium-manganese dry-based oxide containing a very small amount of nickel and cobalt.

The leachate is added into the calcining furnace in a spraying mode.

And performing pelletizing and sintering treatment to obtain iron concentrate with the iron content of 50-65%.

According to the technical scheme provided by the invention, the method for comprehensively treating the laterite-nickel ore by using the nitric acid medium provided by the embodiment of the invention has the advantages of short flow and easiness in operation, can well realize the efficient purification and separation of nickel, cobalt, manganese, iron, aluminum and magnesium, and improves the overall recovery rate of valuable metals. The method does not use a neutralizer in the whole process, avoids the introduction of impurities of the neutralizer and reduces the production cost. The method can realize the renewable utilization of nitric acid, reduce the environmental pressure, and compared with sulfate and chloride, the nitrate is easier to decompose and NO generated by decomposition₂And NO more closely approaches the main acid making process. The nitric acid is adopted as a leaching agent, so that the problem of serious equipment scabbing in the industry is solved well.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for comprehensively treating laterite-nickel ore by using a nitric acid medium, which is provided by the embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.