WO2014047761A1

WO2014047761A1 - Method for producing high-purity nanometer zinc oxide from low-grade zinc oxide ore by ammonia process

Info

Publication number: WO2014047761A1
Application number: PCT/CN2012/081874
Authority: WO
Inventors: 陈尚全; 李时春; 李晓红
Original assignee: 陈尚全
Priority date: 2012-09-25
Filing date: 2012-09-25
Publication date: 2014-04-03

Abstract

Disclosed is a method for producing a high-purity nanometer zinc oxide from low-grade zinc oxide ore by an ammonia process. The method comprises: taking slaked lime of 3-5% mass of the low-grade zinc oxide ore for activation before leaching, then taking ammonia water-ammonium bicarbonate solution as a leaching agent, adding 0.3-0.5kg of sodium fluorosilicate to per cubic meter of the leaching agent for leaching, purifying for impurity removal, and refining. On one hand, efficient leaching of the low-grade zinc oxide ore is achieved, and the high-purity nanometer zinc oxide with a large specific surface area can be obtained at a low calcination temperature; and on the other hand, the treatment method is low in energy consumption, valuable and harmful heavy metals in the low-grade zinc oxide ore can be all leached out for use and cleaned with water, and accordingly economy, environment friendliness and reasonable utilization of renewable resources are achieved.

Description

Instructions:

Method for producing high-purity nano zinc oxide by using low-grade zinc oxide ore ammonia method

The present invention relates to a method for producing zinc oxide, and more particularly to a method for producing high-purity nano zinc oxide.

Background technique

At present, the production of zinc oxide products is generally calcined into zinc calcine as a raw material with a high zinc content, because the zinc content is high and the leaching is relatively easy. With years of mining, the number of high-grade ore sources has become less and less, and the grade has gradually decreased. People have begun to pay attention to the utilization of zinc oxide ore. However, zinc oxide ore usually has a low zinc content (the content of valuable elements is less than 30% Zn; Pb 0.15%; Cu 0. 008%; Mn 0. 06%), and the composition is complex, mostly in the zinc ore, zinc Iron spinel and heteropolar ore, the content of iron oxide, silicon oxide, calcium oxide and magnesium oxide in the ore of the ore is high (about Fe ₂ 0 _:! 4- 7%; Si0, 3-5%; Ca030- 32% ; Mg0 7- 8%). The comprehensive recycling value is not large, but the zinc ore dressing and acid leaching are difficult, and the high dressing cost is a major technical problem for long-term domestic and international mineral processing. In recent years, most of the methods for extracting zinc oxide ore at home and abroad are to leaching zinc oxide ore with a zinc sulfate solution containing a strong acid. Although the zinc leaching rate is improved, the amount of iron and silicon entering the solution is also high. Difficulties, the amount of reagents consumed is large, and the washing liquid takes away more zinc. Chinese public patents such as CN1477217 A have improved the above method by first performing a neutral leaching process using a solution containing zinc sulfate pH=3, followed by a low acid leaching process. However, zinc iron spinel and heteropolar mines decompose slowly under low acid conditions, and problems such as low leaching efficiency, high cost, and environmental pollution still exist. Many metallurgical workers at home and abroad believe that zinc oxide ore containing less than 20% zinc should not be treated by a wet leaching process alone.

The most ideal method is to carry out selective leaching of zinc to allow zinc to enter the solution, and zinc is valuable for recycling.

On the other hand, high-purity zinc oxide generally means that the mass fraction of zinc oxide is above 99.7%. High-purity zinc oxide is an indispensable high-tech raw material for modern industry. It is widely used, mainly for glass, feed and ceramics. Dozens of industries, such as dyes, paints, paper, rubber, pesticides, oil refining, galvanizing, special steel, alloys, defense technology, etc., whether it is glass, paper, rubber, oil refining, etc., have a large demand for zinc oxide. And the purity requirements are very high.

At present, the method for producing high-purity zinc oxide is mainly indirect method. Indirect method generally uses zinc ingot as raw material, through electrolytic reduction, or high-temperature gasification, air oxidation and condensation to obtain zinc oxide, different zinc ingots.

Replacement page (Article 26) The zinc oxide produced by the process is not the same. The process mainly produces 99.5% - 99.7% of zinc oxide. Nano-ZnO (ZnO) is a new type of high-performance fine inorganic product with a particle size between 100 nm and facing the 21st century. It exhibits many special properties such as non-migration, fluorescence, piezoelectricity, absorption. And the ability to scatter ultraviolet light, etc., using its wonderful properties in light, electricity, magnetism, sensitivity, etc., can manufacture gas sensors, phosphors, varistors, ultraviolet shielding materials, image recording materials, piezoelectric materials, varistor, high-efficiency catalysts. , magnetic materials and plastic films.

At present, methods for producing nano zinc oxide include chemical precipitation method, sol-gel method, microemulsion method, and hydrothermal synthesis method. However, the raw materials used are zinc calcine or pure zinc salts containing more than 50% zinc.

The ammonia method is a common method for preparing zinc oxide. At present, the general steps of the ammonia method (ammonia-carbon ammonium combined leaching method for producing zinc oxide) include: preparing a zinc-ammonium solution by using ammonia-carbon ammonium combined leaching for a zinc-containing material. The liquid mixture, purified, evaporated ammonia, dried and calcined to obtain zinc oxide products, generally having a zinc oxide content of 95-98%.

This conventional ammonia method for the preparation of zinc oxide has not been applied to the treatment of low-grade zinc oxide ore, mainly because:

1. Because the mineral zinc content is low, the mud content is high, the zinc concentration of the leachate is low, the consumption of the leachant is large, and the cost is high, which the enterprise cannot bear.

2. Because of the complexity of the impurity components, the qualified rate of the products produced is low, and the product price is low and the economic benefits are poor.

3. When leaching by conventional means, the leaching rate of zinc ore is low and the waste is large, and the value of zinc ore is not utilized and manifested.

Nano-ZnO (ZnO) is a new type of high-performance fine inorganic product with a particle size between 1-100 nm and facing the 21st century. It exhibits many special properties such as non-migration, fluorescence, and piezoelectricity. Absorbing and scattering ultraviolet light, etc., using its wonderful properties in light, electricity, magnetism, sensitivity, etc., it can manufacture gas sensors, phosphors, varistors, UV shielding materials, image recording materials, piezoelectric materials, varistors, and high efficiency. Catalysts, magnetic materials and plastic films.

At present, methods for producing nano zinc oxide include chemical precipitation method, sol-gel method, microemulsion method, and hydrothermal synthesis method. However, all the raw materials used are zinc calcine or pure zinc salts containing more than 50% of zinc.

At present, the open ammonia leaching method for the production of nano zinc oxide technology is a low temperature hydrolysis method such as: Chinese Patent Application No. 92103230. 7 Reveals a modification to the traditional ammonia system for the production of zinc oxide.

Replacement page (Article 26) In the advancement technique, the purified zinc-ammonium complex solution is diluted with water to hydrolyze part of the zinc-ammonium complex solution to obtain basic zinc carbonate (the ratio of zinc hydroxide to zinc carbonate is 2:1), and then heating is continued until the zinc ammonia The complex solution is decomposed and calcined at a high temperature to obtain 30-ΙΟΟηη nano zinc oxide.

The following issues need to be addressed in this technology patent:

After hydrolysis, the undissociated zinc-ammonium complex solution will continue to grow on the surface of the original nucleus during the thermal decomposition process, which will promote the growth of the original hydrolyzed crystal, which will easily cause the size of the basic zinc carbonate crystal. Uneven, making the final product particle size difficult to control.

Increasing the amount of water by 4-10 times reduces the efficiency in the process of production, increases energy consumption, and increases the cost of back-end water treatment.

Chinese Patent Application No. 200610130477. 7 discloses an improved technique for the production of zinc oxide by conventional ammonia complexation. The zinc-ammonium complex solution is continuously mixed with 1: 2-20 hot water or hot mother liquor, and the mother liquor is heated. After the heat preservation, the solution is used for the hydrolysis of the zinc-ammonium complex liquid to obtain 10-50 rm of nano zinc oxide.

The following problems need to be solved in the technical patent - the ammonia cannot be completely separated after the mother liquor is hydrolyzed, and the repeated superposition does not achieve the hydrolysis effect, and finally the mixture of the zinc ammonia complex solution and the zinc ammonia complex solution.

The above two patents are essentially trying to obtain a part of the nanocrystals by hydrolyzing and crystallization by using a large amount of dilution of water at a low temperature to slightly change the pH of the solution. In fact, only a slight change in pH can only be obtained in the zinc concentration. Very little hydrolysis at high temperatures (as can be seen from zinc oxide in the ammonia solubility curve). In fact, the high concentration of zinc ammonia solution has high efficiency and low energy consumption. The low concentration of zinc and ammonia liquid is low in efficiency and high in energy consumption. It is technically feasible to artificially increase the proportion of water to produce nanometer zinc oxide. It may not be feasible in terms of economic benefits.

In addition, in the process of producing zinc oxide by ammonia leaching, the ammonia is crystallized out after the precipitation of ammonia, and the decomposition temperature is high (the initial decomposition of zinc hydroxide is about 125 温度, and the zinc carbonate is about 300 ° C), in order to obtain high For pure products, a sufficiently high decomposition temperature must be ensured. Generally, the temperature of 500 ° C or higher is controlled to completely decompose the basic zinc carbonate. For example, the Chinese patent application with the application number 200610130477. 7 has a calcination temperature of up to 550 'C. High temperature calcination seriously affects the specific surface area, dispersibility and fluidity of zinc oxide, which in turn affects its application.

In summary, for the treatment of low-grade zinc oxide ore, how to effectively extract zinc from minerals with low zinc content, and obtain high-purity nano zinc oxide, while overcoming the shortcomings of traditional methods, become the industry.

Replacement page (Article 26) Technical problems to be solved. Summary of the invention

One of the objects of the present invention is to provide a method for efficiently recovering zinc in low-grade zinc oxide ore and preparing high-purity nano zinc oxide in view of the above problems.

The technical solution adopted by the present invention is as follows: A method for producing high-purity nano zinc oxide by low-grade zinc oxide ore leaching method, comprising the following steps:

Leaching low-grade zinc oxide ore to obtain leaching mother liquor, pre-steaming ammonia, purification and impurity removal, refining treatment, vaporized ammonia crystallization and dry calcination, wherein

Before leaching the low-grade zinc oxide ore, adding slaked lime to the low-grade zinc oxide ore to be treated to obtain a mixture, and mixing and activating, the amount of slaked lime added is low-grade zinc oxide by weight ratio. 3-5% of the ore, the mass percentage of water in the mixture is controlled at 8-10%;

The mixed activated low-grade zinc oxide ore is leached with the ammonia-carbon ammonium solution as a leaching agent; wherein, the leaching agent, wherein c (NH ₃ ) = 5. 5 - 7 mol / L, c (CO ^{:, 2 -) = 0. 95-} 1. 2 mol / L, sodium fluoride was added at 0. 3-0 5kg per cubic meter leaching agent;.

After purifying and removing impurities, the refining treatment is carried out by: adding ammonium phosphate and a surfactant to the liquid after purifying and removing the impurities, and adding the amount of l-3 kg of phosphoric acid hinge in the liquid after purification and impurity removal treatment per cubic meter, 10- 50g surfactant;

The purification and impurity removal, the steaming ammonia crystallization and the drying and calcining steps all adopt the current process parameters of preparing zinc oxide by the common ammonia method.

The invention firstly applies the existing ammonia method for preparing zinc oxide to the treatment of low-grade zinc oxide ore, and at the same time, on the basis of the existing ammonia method, pretreatment is added before the ammonia leaching step. That is, the slaked lime is added to the low-grade zinc oxide ore for mixing and activation, and an appropriate amount of sodium fluorosilicate is added to the leaching solution. In addition, after purification and impurity removal, the liquid refining treatment step is increased.

First of all, in order to obtain high-purity zinc oxide, it is first necessary to ensure that the zinc in the low-grade zinc oxide ore can be leached as much as possible, so that on the one hand, the recovery rate of zinc can be improved, and on the other hand, the zinc concentration in the leachate is larger. The smaller the relative proportion of impurity concentration, the higher the purity of zinc oxide can be obtained under the same process conditions.

Since the gangue component of the low-grade zinc oxide ore has a high content of calcium oxide and magnesium, it cannot be leached by an acid method, and not only the acid consumption is large, but also a large amount of calcium and magnesium are eluted, and purification is difficult. Therefore, the present invention is leached by ammonia method, and the ash powder of the shale plays a loose and puffing effect on the mineral, and the ultrafine particles of the gangue in the ore also play a certain role in the leaching agent.

Replacement page (Article 26) In order to solve this problem, the inventors of the present application have obtained through a large number of experiments: Appropriate amount of sodium fluorosilicate can break the effect of ultrafine particles on the inclusion of zinc particles, and realize the stratification of ultrafine particles to expose zinc. Allow it to be completely immersed in the leachate.

Secondly, in order to obtain nano-scale zinc oxide, it is necessary to suppress the growth of crystal particles. The size and size distribution of nano-zinc oxide produced by the existing ammonia method are not satisfactory, and the most important reason is in the process. The crystals continue to grow, especially for low-grade zinc oxide ore, which is a low-zinc raw material. In order to solve the above problems, the inventors of the present application have increased the liquid refining treatment step after purifying and removing impurities by a large number of experiments, adding an appropriate amount of ammonium phosphate and a surfactant to the refining liquid, and effectively inhibiting the growth of crystals under high-speed stirring. .

among them:

The chemical reaction during the mixed activation process is:

Ca(OH) ₂ +ZnC0,+ →CaC0, \ + Zn(0H)

Fe ^ft +30H— →Fe (OH), i

The chemical reaction equation for the leaching step is:

ZnO+nNH:, +H ₂ 0→ [Zn(NH ₃ )n] ²⁺ +201f

ZnFe.O,, +nNH ₃ +4H ₂ 0→ [Zn(NH.,)n] ²⁺ +2Fe(0H), \ +20H"

ZnFe.O,, +nNH, +H _z 0→ [Zn(NH _:) )n] ² '+F 0 ₃ 1 +20H—

Zn ₂ SiO, _l +2nNH, → 2 [Zn(N3⁄4)n] ²⁺ + SiO

ZnSiO _:, + nNH _{: 1} + 2NH ₄ HC0:, → [Zn(N )n] C0:, + Si0 ₂ · 0+(N ) ₂ C0 ₃

ΖηίΟΙΟ, +ηΝΗ, ― [Zn(NH _; ,)n] ²⁺ +20H"

ZnC0 ₃ + nN ― [Zn (NH,)n] CO:,

Where n=l~4;

The reaction formula of pre-steamed ammonia:

NH ₃ · H ₂ 0 + NHHC0:, - 2NH ₃ † +C0, t +2H ₂ 0

(NH ₄ ) , 'Si0 ₄ - Si0 ₂ I + 2N t + 2H ₂ 0

Purify the reaction that occurs during the impurity removal process:

SA ² — ⁴ - Mn ²⁺ + 2NH _:1 · 0 + 0— Mn 0 (OH) ₂ i + 2NH/+2S0 + 2H ⁺

S ₂ 0 ₈ ² '+2Fe' ^† +6IW -2S0 + 2Fe (OH):, I + 6H ⁺

AsO, wide + Fe ^:i —— FeAsO,, I

Replacement page (Article 26) AsO— +SA ² '+H ₂ 0 — 2S 0 ₄ ² — +AsO— +2H ⁺

2H _: , As0 ₃ +8Fe (OH) ₃ → (Fe ₂ 0 _;! ) ₄ AsA · 5H ₂ 0 i +10H ₂ 0

M ²⁺ + S ² — MS IM stands for Cu ²⁺ , Pb ^2t , Ccf , Ni ⁺ Hg ²⁺ plasma

As ³⁺ + S ² "→As ₂ S _:1 1

+ Zn→Zn ²⁺ + Y where Y represents: Cu ²⁺ , Pb ⁺ , Ccf , Ni ²⁺ plasma; Reactive liquid treatment:

3 [Zn (NH _:! ) n] ²⁺ + 2 (N3⁄4 ) ₃ P0 ₄ + 60H—— [Zn (NH _{: t} ) n] :, (P0 ₄ ) ₂ + 6N · H ₂ 0

The reaction equation for the ammonia distillation step:

[Ζη (ΝΗ _: ,) ²⁺ +20H— = Zn (OH) ₂ I + iNH _:! ti =1~4

[Zn (NH ₃ ) ,] C0 _:! + 0— ZnC0 ₃ · 2Zn (0H) ₂ · 3⁄40 I +16NH, t

Dry calcination chemical reaction equation:

Zn (0H) ₂ →Zn0 + H ₂ 0†

ZnC0 ₃ * 2Zn (0H) · H ₂ 0 → 3Zn0 +3 0† +C3⁄4†

约为03.10kg的 surfactant (such as SDS) is added to each of the cubic meters of ammonia-carbon ammonium chloride leaching agent.

The surfactant reduces the surface energy and cooperates with sodium fluorosilicate to break the coating effect of the ultrafine particles to improve the penetration ability of the leaching agent and further improve the recovery rate of zinc.

Preferably, 0.5-lkg of dicyandiamide is further added per cubic meter of ammonia-carbon mash. As an ammonia stabilizer, bis-diamine can reduce the evaporation of ammonia during the leaching process, improve the leaching working environment, and reduce the loss of ammonia.

Preferably: leaching with a wet ball mill while leaching the low grade zinc oxide ore to be treated.

By wet ball milling, the original lattice structure can be destroyed and leached while being activated, thereby improving the leaching efficiency.

Preferably, it is ensured that the leaching time in the ball mill is 50 to 60 minutes, and the ball mill outlet material is all passed through a 140 mesh sieve.

The ball leaching wet leaching destroys the ore lattice structure (mechanical activation) in combination with the chemical activation of the surfactant and the ash powder to achieve higher leaching speed and leaching rate. A higher leaching rate is obtained by pre-activation of the raw materials and mechanical activation of the ball milling and the addition of the active agent (sodium fluorosilicate, SDS, etc.).

Preferably, the leaching solution obtained after leaching is heated to 95-105 Torr for ammonia precipitation (pre-vaporized ammonia), straight To the leachate c (NH _{: i} ) 3ra ₀ l / L (to achieve a near-saturated solution of zinc-ammonium complex, but not to precipitate zinc), then add ammonium persulfate at 2-4kg / m ^{: i} and stir for oxidation complete. The heating method uses indirect heating. When _C (NH ₃ ) 3. 5mol/L, the zinc-ammonium complex liquid is close to saturation, and zinc is not precipitated. When the ammonia is crystallized, the temperature is controlled within 105, and the speed of the ammonia-gas container is 600-900r/min.

Increasing the pre-steaming step, on the one hand, removing excess free ammonia, reducing the complexing ability of ammonia, and at the same time, because the temperature is raised, the silicate colloid and its impurities are suspected to be precipitated, so that the impurity ions can be removed, which is beneficial to the removal of the impurity ions. Purification is one of the reasons for the production of high-purity products; on the other hand, a large amount of carbonate ions in the solution can be removed, and the next step of the dehydration crystallization process of the complex liquid is favorable for hydrolysis to obtain zinc hydroxide crystal nuclei and reduce zinc carbonate. The composition can be one of the reasons for producing a large specific surface area; after pre-steaming, ammonium persulfate is added as an oxidizing agent to remove impurities such as iron and manganese.

Preferably, during the crystallization of the ammoniated ammonia, the zinc concentration of the solution in the ammoniated container is detected at any time. When the zinc content is 1-1.5%, the sodium hydroxide solution is added to the container, and the amount of the solution is added per cubic meter of the solution. 30% sodium hydroxide solution 35 liters, when the zinc content in the solution is less than 0.3%, the end of the ammonia distillation (the end of the ammonia distillation, the mountain contains a portion of the sulfate in the solution, forming a stable ammonium salt, continue Steaming ammonia has no meaning, and it will produce zinc sulfate bismuth double salt precipitation, which affects the quality of nano zinc oxide products).

In the late stage of ammonia distillation, when the concentration of zinc in the complex solution is low, by adding sodium hydroxide to increase the pH value of the liquid, NH / ions can be converted into NH ₃ molecules to achieve rapid ammonia evolution and rapid crystallization to form nano zinc hydroxide crystals. Nuclear effect.

Preferably, the ammoniated solution is added to a 5% by mass sodium stearate solution of 3-5 L per cubic meter. Sodium stearate is added during the process of steaming, so that the resulting nanocrystals are encapsulated and no longer grow.

Preferably, the low-grade zinc oxide ore is a mixed ore of one or more of a zinc-zinc ore, a zinc-iron-tip stone or a heteropolar ore having a zinc content of 8% to 30%.

The method of the invention can be applied to various low-grade zinc oxide ore, and has wide application range.

A second object of the present invention is to provide a high-purity and highly active nano zinc oxide by using a technique of drying calcination at a temperature of 150 to 300 °C.

According to the technical solution of the present invention, after the crystallization step of the ammonia distillation, the main result is zinc hydroxide, and the decomposition temperature of the zinc hydroxide is lower than that of the basic zinc carbonate, and the purity is obtained by calcining at a temperature of 150 to 300 ° C. Zinc oxide at 99.7% or more, because the crystal nucleus of zinc hydroxide is smaller than basic zinc carbonate, so the final

Replacement page (Article 26) A high-quality nano zinc oxide powder having a uniform particle diameter of 10 to 30 nm and a specific surface area of 100 m 7 g or more can be obtained.

In summary, using the above technical solution, the ammonia method is applied to the treatment of low-grade zinc oxide ore, and the existing ammonia method is technically improved, the activation step is added before the leaching and added during the leaching. Sodium fluorosilicate, surfactant and dicyandiamide, on the one hand, high-grade leaching of low-grade zinc oxide ore, addition of pre-steamed ammonia in the subsequent process, and addition of a resisting agent in the process of ammonia evaporation to inhibit crystal growth, obtaining particles The nano-zinc oxide precursor having a small diameter and a narrow distribution; on the other hand, the present invention preferably uses a lower calcination temperature to obtain a high-purity nano-zinc oxide having a large specific surface area (purity can reach 99.7%), High practical value and economic price; In addition, the treatment method of the invention has low energy consumption and high efficiency. The valuable and harmful heavy gold in the low-grade zinc oxide ore is leached and used, and washed with water to achieve economical environmental protection and rational utilization of renewable resources.

The innovations of the present invention mainly include: U) increasing the pre-steaming treatment, first removing too much free ammonia, and achieving the purpose of rapid product formation when steaming ammonia; (2) during the process of steaming ammonia, when the zinc-ammonia complex solution When the ammonia concentration is low, the liquid enthalpy is increased by adding sodium hydroxide to achieve the purpose of rapid ammonia evolution; (3) adding a surfactant (such as SDS), strontium phosphate, and the solution in the zinc ammonia complex solution. Some ammonium sulfate can effectively control the growth of the nano zinc oxide crystal nucleus; (4) The idle stirring is realized by the power of steam to control the crystal of the nano zinc oxide; DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. In order to make the objects, the technical solutions and the advantages of the present invention more comprehensible, the present invention will be described in detail below with reference to the embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

Starting material: zinc oxide in Yunnan Province ^# 1, having a composition of:..... Znl5 48 % Fel8 20% Si027 94%, zinc carbonate, zinc phase component was 9.49%, 2.12% zinc silicate vulcanization. Zinc 0.73 3%, iron-zinc tip stone 3.14%.

Method for preparing high purity nano zinc oxide:

U) activation: taking 500 g of zinc oxide ore, adding 15 g of slaked lime to obtain a mixture, and performing mixed activation, the mass percentage of water in the mixture is controlled at 8%, and the mixing activation time is 36 hours;

Replacement page (Article 26) (2) Leaching: The mixed activated low-grade zinc oxide ore 1 ^{# is} leached with 1500 ml of ammonia-carbon ammonium solution as a leaching agent, wherein the leaching agent exhibits a molar concentration c ( NH ₃ )=5.5mol/L, CO/—molar concentration c(C0 — ) = 1.2 raol/L, 0.3kg of sodium fluorosilicate added per cubic meter of leachant: fluorine added to the leachant Sodium silicate; total leaching time is 3 hours, temperature is 25-40. C _; after solid-liquid separation, the obtained zinc ammonia complex solution is 69.7 g of zinc; the zinc oxide zinc zinc leaching rate is 90.1%;

To remove impurities: Add 2. lg potassium permanganate to the leach solution after leaching for 0.5 h, add a small amount of polyacrylamide solution (1⁄2g / L) to filter, the filtrate is required to precipitate Cu, Cd, Pb Sodium sulfide theoretical 1.2 times added sodium sulfide, temperature, 70V, stirring time 2h, filtration, filtrate added ΚΜηΟ, the amount is 2.7 times the amount of Fe, temperature 80 ° C, stirring lh (test Fe, Mn qualified), filtered The filtrate is added to the zinc powder 2.5 times of the theoretical zinc powder required to replace Cu, Cd, Pb, stirred for 30 minutes, and the temperature is 60 ° C, and filtered to obtain a refined liquid;

(d) In the liquid treatment, the ammonium phosphate and the surfactant are added to the liquid after the decontamination treatment, and 1 kg of ammonium phosphate and 50 g of the surfactant SDS are added to the liquid after the cubic cleaning and impurity removal treatment, to the binding liquid;

(5) Steaming and finishing: The obtained binding liquid is placed in an ammonia evaporator for steaming ammonia, the vapor pressure inlet is 0.5 Pa/cm, and the solution temperature is 105 Torr until the [Zn ²⁺ ] = 1.5 g/L stops the ammonia distillation. , the obtained emulsion is separated by liquid separation, the filter cake is washed according to liquid-solid ratio 5: i water, washing time lh, and then separated by filtration to obtain a filter cake;

(6) Dry calcination: The filter cake was dried at 105 Torr to obtain a powder, which was calcined in a 300 Ό muffle furnace for 50 min, and sampled and detected to a pure skin Ζηϋ =99.76%; a bulk density of 0.26 g/m ² and an average particle diameter of 14.2 nm (XRD line) Wide method), high purity nano zinc oxide powder with a surface area of 102 inVg. Example

The raw material of the chemical, the composition of which is: Zn9.67%. Fel9.33%. Si026. 63%, Ca028.34% The zinc phase composition is 12.28% zinc carbonate, zinc silicate 2.37%. 0. 8 2%, iron-zinc spinel 3. 2U%o

Chuan f system ^ high purity 3⁄4 zinc method:

(ί): Take 500g 3⁄4 zinc mine 2 ^# , add 25g slaked lime to get the mixture, and mix

Replacement page (Article 26) Combined activation, the mass percentage of water in the mixture is controlled at 9%, and the mixing activation time is 36 hours;

(2) Leaching: The mixed activated zinc oxide ore 2 ^{# is} leached with 1500 ml of ammonia-carbon ammonium solution as a leaching agent; wherein, the molar concentration of N in the leaching agent is c(NH ₃ )=7 mol /L, C0 ₃ ² - molar concentration c (CO / ") = 1.2 raol / L, respectively, add 0.5 kg of sodium fluorosilicate per 0.05 m of leaching agent, 0.05 kg of surfactant SilS, 0.5 kg of two Cyanide diamine; during leaching, ball milling is used, and the leaching time in the ball mill is 60 minutes. The ball mill outlet material is all passed through a 140 mesh sieve. The total leaching time is 3 hours and the temperature is 25 Ό. The obtained zinc ammonia complex solution Medium zinc 44.28 grams; zinc oxide zinc leaching rate 91.58%;

(3) Pre-steamed ammonia: The leaching solution obtained after leaching is heated to 95 ° C for ammonia precipitation until c. (N ) = 2.8 mol / L in the leaching solution, and then leached per cubic meter 4 kg of persulfate hinge was added to the liquid and stirred;

; Removal of impurities: Add 1.33g of potassium permanganate to the leachate obtained after 3⁄4

0.5h, a small amount of polyacrylamide solution (4mg / L) was added to filter, the filtrate was added to the sodium sulfide of 1.2 times of the theoretical S of sodium sulfide required for precipitation of Cu, Cd, Pb, temperature, 70 ° C, stirring time 2h, filtration, The filtrate was added to 1 1 (3⁄4 with 蛩 for 3.5 times of the amount of 1, the temperature of 80 ° C, stirring for 1 h (test Fe, Mn qualified), after ^, the filtrate was added 2.5 times the theoretical zinc powder required for Cu, Cd, Pb Zinc powder, stirring

30min, 60°C, filtration, 3⁄4 liquid;

Process, purify and remove the mixed liquid, add ammonium phosphate and surfactant, add 3 kg of phosphoric acid hinge and 10 g of surfactant in the liquid after purification of methane

((;) steamed 3⁄4 knot: The obtained 3⁄4 liquid is placed in the ammonia machine for steaming ammonia, steam pressure inlet

0.6Μ13⁄4/(^, solution temperature i08°C, during the crystallization of distilled ammonia, 3L of sodium stearate solution with a mass fraction of 5% is added to each cubic meter of ammonia liquid, and the liquid zinc content in the ammonia plant is detected at any time. When the zinc content is in [%ί ', the sodium hydroxide solution is added to the ammonia plant, and the amount is added to the ammonia liquid per cubic meter. ^: 1'" contains id: 30% of the sodium solution of 3% sodium solution When the zinc content is less than 0.3%, the knot is 3⁄43⁄4, and the emulsion is subjected to solid-liquid separation. The filter cake is washed with liquid-solid ratio of 5:1 water, washed i'nj Hi, and then separated by filtration. Filter cake

(7) Bu-baking calcination: the filter cake is dried to obtain a powder, which is calcined in a muffle furnace at 150 ° C for 70 min, and the sample is found to have a pure skin Zn0%=99.89%; a bulk density of 0.21 g/m ² , an average particle diameter of 12.5 nm (XRD line width method), 'Compared with 115in7g of high-purity zinc oxide powder.

Replacement page (Article 26) Example 3

Raw material: zinc oxide ore 3 ^# , its composition is: Znl3.6%. Fel8.67%. Si027.83%, Ca029.92% Its zinc phase composition is zinc carbonate 7.%%, zinc silicate 2. 21 %. Zinc sulfide 0.76%, iron-zinc spinel 2.67%

Chuan Yu's method of producing high-purity zinc oxide:

(1) 3⁄4: Take U zinc oxide ore 3", add 40kg of slaked lime to obtain a mixture, and carry out mixing and activation, the mass percentage of water in the mixture is controlled at 10%, and the mixing activation time is 42 hours;

(2) Leaching: The mixed activated zinc oxide ore 3 ^# is immersed with 3000 L of ammonia-carbon ammonium solution as a leaching agent; wherein, the molar concentration of cerium in the leaching agent c (NH ₃ ) = 5.6 mol /L, CO molar concentration c (CO ) \ .05 IHOI / L, respectively, add 0.4kg of sodium fluorosilicate, 0. lkg of table per cubic meter of leachate and live '!:. SDS, 1kg of two ^Diamine; After leaching, using ball milling, and ensuring that the leaching time in the ball mill is 80 minutes, the ball mill outlet materials all pass through the 140 mesh sieve, the total leaching time is 3.5 hours, the temperature is 25 i (TC; the zinc 3⁄43⁄4 The liquid zinc is 124.86 kg, and the zinc leaching rate of low-grade zinc oxide is 91.8%;

(;n - : The liquid obtained after taking 3⁄4 ί is heated to 105 Γ for ammonia precipitation until it is in the leaching solution

! /[„ Then add 2kg of ammonium persulfate per cubic meter of leachate and stir;

(4) ; Decontamination: Add 3.75kg of potassium permanganate to the leachate obtained after confiscation and stir for 0.8h, : I enter less iiL poly-W enamide solution (4mg / L), the filtrate is precipitated Cu, Cd, Pb 3⁄4 讷讷 3 ϋ ϋ ϋ . 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化硫化Detect Fe, Mn qualified), filter, add 2.5 times of the theoretical zinc powder required for Cu, OJ, Pb, add zinc powder, stir for 30min, i30. C, Ηΰίί, sticking solution;

(ο ^ Processing, adding the phosphoric acid hinge and surfactant to the liquid after the decontamination treatment, adding lkg ammonium phosphate, 50 g of surfactant SDS, i'i ϋ^ in the liquid after the quaternization treatment ύΚ only;

( ; : Put the ^3⁄4 liquid into the ammonia machine for ammonia distillation, steam pressure inlet

0.8MPa/cn; , 3⁄4 liquid skin 108Ό, in the steaming process, every cubic meter of ammonia liquid is added

Replacement page (Article 26) 5L of sodium stearate solution with a mass fraction of 5%, the liquid zinc content in the ammonia plant is detected at any time. When the zinc content is 1.5%, sodium hydroxide solution is added to the ammonia plant, and the amount is added per cubic meter. The ammoniated liquid is added to 5 liters of a 30% sodium hydroxide solution, and the zinc content is lower than that.

0. 3%, the ammonia is finished, the obtained emulsion is subjected to solid-liquid separation, the filter cake is washed with a liquid-solid ratio of 5:1 water, and the mixture is washed for 1 hour, and then separated by filtration to obtain a filter cake;

(7) Drying calcination: filter cake 1 () 5 ° C drying, the powder is obtained, after calcination in a 22 CTC muffle furnace 70rain, the purity of Zn0% = 9. 83%; bulk density of 0. 26g / m ² , average Particle size 12. 9nra (XRD line width method), specific surface 枳! 06mVg pure nano zinc oxide powder.

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Claims

Claims:

1. A method for producing high-purity nano-zinc oxide using the ammonia method of low-grade zinc oxide ore, including the following steps: leaching low-grade zinc oxide ore, purifying and removing impurities, evaporating ammonia to crystallize and drying and calcining, which is characterized by: leaching Before the step of extracting low-grade zinc oxide ore, add hydrated lime to the low-grade zinc oxide ore to be processed to obtain a mixture, and perform mixing and activation. The amount of hydrated lime added, in terms of weight ratio, is that of low-grade zinc oxide ore. 3-5%, the mass percentage of water in the mixture is controlled at 8-10%;

The mixed activated low-grade zinc oxide ore is leached using ammonia water-ammonium bicarbonate liquid as the leaching agent; wherein, in the leaching agent, c (NH:,) =5. 5-7mol/L, c (C0 — ) = 0. 95-1. 2 mol/L, add 0. 3-0. 5kg sodium fluorosilicate to each cubic meter of leaching agent;

After purification and impurity removal, refining treatment is carried out. The method is: Add cymbal phosphate and surfactant to the liquid after purification and impurity removal. The amount added is 1-3kg ammonium phosphate, 10 - 50g surfactant.

2. A method for producing high-purity nano-zinc oxide using ammonia method of low-grade zinc oxide ore according to claim 1, characterized in that: when leaching the low-grade zinc oxide ore to be treated, the ammonia water per cubic meter - 03-0. 05kg surfactant is also added to the ammonium bicarbonate liquid.

3. A method for producing high-purity nano-zinc oxide using a low-grade zinc oxide ore ammonia method according to claim 2, characterized in that: 0.5-1kg is added to each cubic meter of ammonia water-ammonium bicarbonate liquid. of dicyandiamine.

4. A method for producing high-purity nano-zinc oxide using ammonia method of low-grade zinc oxide ore according to claim 1, characterized in that: when leaching the low-grade zinc oxide ore to be treated, wet ball milling is used for leaching. .

5. A method for producing high-purity nano-zinc oxide using a low-grade zinc oxide ore ammonia method according to claim 4, characterized in that: the leaching time in the ball mill is guaranteed to be 50 to 60 minutes, and all materials at the outlet of the ball mill pass through a 140-mesh sieve. .

6. A method for producing high-purity nano-zinc oxide by utilizing low-grade zinc oxide ore ammonia method according to claim 1, characterized in that: heating the leach solution obtained after leaching to 95-105°C for ammonia evolution , until c (N) 3.5mol/L in the leaching solution, then add 2 kg of ammonium persulfate per cubic meter of leaching solution and stir to complete the oxidation.

7. A method for producing high-purity nano-zinc oxide using low-grade zinc oxide ore ammonia method according to claim 1, characterized in that: during the ammonia evaporation crystallization process, the zinc content in the ammonia evaporation equipment is detected at any time. When the zinc content At 1-1.5%, add sodium hydroxide solution into the ammonia evaporation equipment, the amount added is per cubic meter of evaporated ammonia liquid.

Replacement Page (Rule 26) Add 3-5 liters of sodium hydroxide solution with a mass percentage of 30%. When the zinc mass content is lower than 0.3%, the ammonia evaporation is completed.

8. A method for producing high-purity nano-zinc oxide using a low-grade zinc oxide ore ammonia method according to claim 7, characterized in that: 5% sodium stearate with a mass fraction of 5% is added to each cubic meter of evaporated ammonia liquid. Solution 3-5L.

9. A method for producing high-purity nano-zinc oxide using ammonia method of low-grade zinc oxide ore according to claim 1, characterized in that: the temperature of the drying and calcining is 150-300Ό.

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