阅读说明：本技术 一种从低钼氨浸渣中回收钼的方法 (Method for recovering molybdenum from low-molybdenum ammonia leaching residue ) 是由 郭株辉 王贺 舒志斌 冯永山 于 2020-07-16 设计创作，主要内容包括：本发明属于湿法冶金领域,涉及一种从低钼氨浸渣中浸出回收钼的方法,该方法具体包括以下步骤：S1)将氨浸后的低钼氨浸渣进行脱水,在进行浆化,备用；S2)将浆化后的低钼氨加入反应釜中,加压,加热,进行保压反应,得到反应液与钼渣；S3)将反应液与钼渣分离,将反应液进行负压浓缩,浓缩液进行酸沉压滤形成钼酸滤饼；S4)滤饼重新返回钼酸铵生产工序,产出钼酸铵产品符合GB/T3460-2017MSA-1级别产品。本发明的有益效果是,由于采用上述技术方案,本发明的方法工艺简便易行,氨浸渣无需烘干,研磨,流程短,工艺稳定,生产成本低,浸出回收率不低于94.98％,整个工艺流程环保。(The invention belongs to the field of wet metallurgy, and relates to a method for leaching and recovering molybdenum from low-molybdenum ammonia leaching residue, which specifically comprises the following steps: s1) dehydrating the ammonia-leached low-molybdenum ammonia leaching residue, and slurrying for later use; s2) adding the slurried low-molybdenum ammonia into a reaction kettle, pressurizing, heating, and carrying out pressure-maintaining reaction to obtain reaction liquid and molybdenum slag; s3) separating the reaction liquid from the molybdenum slag, concentrating the reaction liquid under negative pressure, and performing acid precipitation and filter pressing on the concentrated liquid to form a molybdic acid filter cake; s4) returning the filter cake to the ammonium molybdate production process again, wherein the produced ammonium molybdate product meets GB/T3460-2017MSA-1 grade products. The method has the advantages that the method is simple and easy to implement due to the adoption of the technical scheme, ammonia leaching residues are not required to be dried and ground, the process is short, the process is stable, the production cost is low, the leaching recovery rate is not lower than 94.98%, and the whole process flow is environment-friendly.)

1. A method for leaching and recovering molybdenum from low-molybdenum ammonia leaching residue is characterized by comprising the following steps:

s1) dehydrating the ammonia-leached low-molybdenum ammonia leaching residue, and slurrying for later use;

s2) adding the slurried low-molybdenum ammonia into a reaction kettle, pressurizing, heating, and carrying out pressure-maintaining reaction to obtain reaction liquid and molybdenum slag;

s3) separating the reaction liquid from the molybdenum slag, concentrating the reaction liquid under negative pressure, and performing acid precipitation and filter pressing on the concentrated liquid to form a molybdic acid filter cake;

s4) returning the obtained filter cake to the ammonium molybdate production process again to produce an ammonium molybdate product.

2. The method as claimed in claim 1, wherein the specific steps of S1) are:

s1.1) dehydrating the low-molybdenum ammonia leaching residue after ammonia leaching to obtain low-molybdenum ammonia leaching residue with water content of 10-25%;

s1.2) adding sodium carbonate and water into the low-molybdenum ammonia leaching residue in a ratio of 1: 5-10, and stirring and slurrying.

3. The method as claimed in claim 2, wherein the specific steps of S2) are:

s2.1) adding the slurry obtained in the step S1.2) into a reaction kettle, heating to 95-100 ℃, and introducing oxygen to pressurize;

s2.2) continuously heating to 150-180 ℃, continuously stirring, keeping the pressure for reaction for 1-2 hours, and stirring at the speed of 120-200 r/min to obtain reaction liquid and molybdenum slag.

4. The method as claimed in claim 3, wherein the specific steps of S3) are as follows:

s3.1) separating the reaction liquid from the molybdenum slag, carrying out negative pressure concentration on the reaction liquid,

s3.2) carrying out nitric acid precipitation on the concentrated solution to generate molybdic acid, and carrying out filter pressing to form a molybdic acid filter cake.

5. The method according to claim 2, wherein the low molybdenum ammonia leaching residue in S1.1) is a low molybdenum ammonia leaching residue produced in pyro-metallurgy and wet-metallurgy fields of molybdenite concentrates, and the molybdenum content is 5-15%.

6. The method according to claim 4, wherein specific process parameters of the negative pressure concentration in S3.1) are as follows: the pressure is 0.05-0.08 Mpa, and the temperature is 80-93 ℃.

7. The method of claim 3, wherein the pressure value is between 0.3MPa and 0.5 MPa.

8. The method according to claim 3, wherein the stirring rate in S2.2) is 120-200 r/min.

9. The method as claimed in claim 4, characterized in that the concentration of molybdenum in S3.1) is 45-75 g/L.

10. The method according to any one of claims 1 to 9, wherein the leaching rate of molybdenum in the low-molybdenum ammonia leaching residue treated by the method is not lower than 94.98%.

Technical Field

The invention belongs to the field of wet metallurgy, and relates to a method for recovering molybdenum from low-molybdenum ammonia leaching residue.

Technical Field

With the production of ammonium molybdate by the traditional oxidizing roasting-ammonia leaching process, molybdenum concentrate is oxidized, roasted and desulfurized by a rotary kiln to be converted into molybdenum oxide, then alkali metal, alkaline earth metal, part of heavy metal impurities such as copper, iron and the like are removed by nitric acid pretreatment, and the pretreated filter cake is subjected to ammonia leaching to obtain ammonium molybdate solution low-molybdenum ammonia leaching residue. The yield of the low-molybdenum ammonia leaching residue is about 10-20% of the molybdenum oxide calcine, and the yield of the low-molybdenum ammonia leaching residue is about 5-15% of molybdenum and is 2-5% of the total amount of molybdenum metal. At present, the hydrochloric acid treatment process is adopted to recover molybdenum, so that the operation environment is poor, the equipment corrosion is serious, and a large amount of acidic high-chlorine wastewater containing heavy metals such as iron, copper and the like is produced, which becomes a problem to be solved urgently in molybdenum concentrate processing.

For the recovery of molybdenum in the ammonia leaching residue, a soda sintering method is available at present, an acid decomposition method is used for decomposing the ammonia leaching residue by hydrochloric acid, and ammonium molybdate, sodium molybdate and other products are produced by ammonia leaching and other processes, so that the molybdenum content in the ammonia leaching residue is reduced to below 2% and the leaching recovery rate of molybdenum is up to above 80%. The soda roasting sintering method is to roast ammonia leaching residue with sodium carbonate and then to prepare ammonium molybdate, ammonium molybdate and other products by an alkali leaching method. The two methods have the disadvantages of complicated process, high labor intensity, low yield, serious pollution, high raw material consumption, low economic benefit and high cost.

Disclosure of Invention

The invention aims to provide a method with short flow, little pollution, simple requirement on equipment and high leaching recovery rate aiming at the defects in the existing process of recovering molybdenum from ammonia leaching residues.

The purpose of the invention is realized by the following technical scheme: a method for leaching and recovering molybdenum from low-molybdenum ammonia leaching residue specifically comprises the following steps:

s1) dehydrating the ammonia-leached low-molybdenum ammonia leaching residue, and slurrying for later use;

s2) adding the slurried low-molybdenum ammonia into a reaction kettle, pressurizing, heating, and carrying out pressure-maintaining reaction to obtain reaction liquid and molybdenum slag;

s3) separating the reaction liquid from the molybdenum slag, concentrating the reaction liquid under negative pressure, and performing acid precipitation and filter pressing on the concentrated liquid to form a molybdic acid filter cake;

s4) returning the filter cake to the ammonium molybdate production process again, wherein the produced ammonium molybdate product meets GB/T3460-2017MSA-1 grade products.

Further, the specific steps of S1) are:

s1.1) dehydrating the low-molybdenum ammonia leaching residue after ammonia leaching to obtain the low-molybdenum ammonia leaching residue with the water content of 10-25% by mass;

s1.2) adding sodium carbonate and water into the low-molybdenum ammonia leaching residue in a ratio of 1: 5-10, and stirring and slurrying.

Further, the specific steps of S2) are:

s2.1) adding the slurry obtained in the step S1.2) into a reaction kettle, heating to 95-100 ℃, and introducing oxygen to pressurize;

s2.2) continuously heating to 150-180 ℃, continuously stirring, keeping the pressure for reaction for 1-2 hours, and stirring at the speed of 120-200 r/min to obtain reaction liquid and molybdenum slag.

Further, the specific steps of S3) are:

s3.1) separating the reaction liquid from the molybdenum slag, carrying out negative pressure concentration on the reaction liquid,

s3.2) carrying out nitric acid precipitation on the concentrated solution to generate molybdic acid, and carrying out filter pressing to form a molybdic acid filter cake.

Further, the low molybdenum ammonia leaching residue is produced in the fields of pyro-metallurgy and wet-metallurgy of molybdenite concentrates, and the molybdenum content is 5-15 wt%.

Further, the specific process parameters of the negative pressure concentration in the step S3.1) are as follows: the pressure is 0.05-0.08 Mpa, and the temperature is 80-93 ℃.

Further, the pressure value is 0.3MPa to 0.5 MPa.

Further, the stirring speed in the S2.2) is 120-200 r/min.

Further, the concentration of the molybdenum in the S3.1) after concentration reaches 45 g/L-75 g/L.

Further, the leaching rate of molybdenum in the low-molybdenum ammonia leaching residue treated by the method is not lower than 94.98%.

The method has the beneficial effects that by adopting the technical scheme, the method mainly aims at the treatment method of the low-molybdenum ammonia leaching residue generated in the field of pyro-metallurgy and wet-metallurgy of molybdenite concentrate, the content of molybdenum in the low-molybdenum ammonia leaching residue is low, the contents of impurities such as molybdenum disulfide, molybdenum dioxide, iron, copper, phosphorus and the like are high, and the common leaching method cannot achieve the ideal effect. The method has the advantages of simple and easy process, no need of drying and grinding the ammonia leaching residue, short flow, stable process, low production cost, leaching recovery rate of not less than 95 percent and environmental protection of the whole process flow.

Drawings

FIG. 1 is a flow chart of a method for leaching and recovering molybdenum from low-molybdenum ammonia leaching residue according to the invention.

Detailed Description

The technical solution of the present invention is further described with reference to the following specific embodiments.

As shown in fig. 1, the method for leaching and recovering molybdenum from low-molybdenum ammonia leaching residue of the invention specifically comprises the following steps:

s1) dehydrating the ammonia-leached low-molybdenum ammonia leaching residue, and slurrying for later use;

s2) adding the slurried low-molybdenum ammonia into a reaction kettle, pressurizing, heating, and carrying out pressure-maintaining reaction to obtain reaction liquid and molybdenum slag;

s3) separating the reaction liquid from the molybdenum slag, concentrating the reaction liquid under negative pressure, and performing acid precipitation and filter pressing on the concentrated liquid to form a molybdic acid filter cake;

s4) returning the filter cake to the ammonium molybdate production process again, wherein the produced ammonium molybdate product meets GB/T3460-2017MSA-1 grade products.

The S1) comprises the following specific steps:

s1.1) dehydrating the low-molybdenum ammonia leaching residue after ammonia leaching to obtain low-molybdenum ammonia residue with water content of 10-25%;

s1.2) adding sodium carbonate and water into the low-molybdenum ammonia slag in a ratio of 1: 5-10, and stirring and slurrying.

The S2) comprises the following specific steps:

s2.1) adding the slurry obtained in the step S1.2) into a reaction kettle, heating to 95-100 ℃, and introducing oxygen to pressurize;

s2.2) continuously heating to 150-180 ℃, continuously stirring, keeping the pressure for reaction for 1-2 hours, and stirring at the speed of 120-200 r/min to obtain reaction liquid and molybdenum slag.

The S3) comprises the following specific steps:

s3.1) separating the reaction liquid from the molybdenum slag, carrying out negative pressure concentration on the reaction liquid,

s3.2) carrying out nitric acid precipitation on the concentrated solution to generate molybdic acid, and carrying out filter pressing to form a molybdic acid filter cake.

The low-molybdenum ammonia leaching residue is produced in the fields of pyro-metallurgy and wet-metallurgy of molybdenite concentrates, and the molybdenum content is 5-15%.

The specific process parameters of the negative pressure concentration in the S3.1) are as follows: the pressure is 0.05-0.08 Mpa, and the temperature is 80-93 ℃.

The pressure value is 0.3MPa to 0.5 MPa.

And the stirring speed in the S2.2) is 120-200 r/min.

The concentration of the molybdenum in the S3.1) reaches 45 g/L-75 g/L after concentration.

The leaching rate of molybdenum in the low-molybdenum ammonia leaching residue treated by the method is not lower than 94.98%.