阅读说明：本技术 一种生产锌酸钙的方法 (Method for producing calcium zincate ) 是由 岳辉伟 李世川 龙忠祥 蒋涛 刘权锋 于 2019-05-08 设计创作，主要内容包括：提供一种生产锌酸钙的方法。该方法包括：浸提步骤：将磨细后的含锌原料与浸提剂混合搅拌,过滤,得到浸出液,其中,浸提剂为氨与NH<Sub>4</Sub>HCO<Sub>3</Sub>和/或(NH<Sub>4</Sub>)<Sub>2</Sub>CO<Sub>3</Sub>的混合水溶液；任选地,对浸出液进行净化；脱碳步骤：向浸出液中加入氧化钙和/或氢氧化钙,搅拌,过滤,得到第一固体和第一滤液；锌酸钙合成步骤：向第一滤液中加入氢氧化钙和/或氧化钙,搅拌进行反应,过滤得到第二固体和第二滤液；任选地,用水漂洗第二固体；干燥步骤：将第二固体干燥,得到锌酸钙终产品。(A method for producing calcium zincate is provided. The method comprises the following steps: leaching: mixing the ground zinc-containing raw material with lixiviant, stirring, and filtering to obtain lixivium, wherein the lixiviant is ammonia and NH 4 HCO 3 And/or (NH) 4 ) 2 CO 3 The mixed aqueous solution of (1); optionally, purifying the leachate; a decarburization step: adding calcium oxide and/or calcium hydroxide into the leaching solution, stirring and filtering to obtain a first solid and a first filtrate; calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide into the first filtrate, stirring for reaction, and filtering to obtain a second solid and a second filtrate; optionally, rinsing the second solid with water; and (3) drying: and drying the second solid to obtain a final calcium zincate product.)

1. A method for producing calcium zincate, comprising the steps of:

leaching: mixing and stirring the ground zinc-containing raw material and a leaching agent, and then filtering to obtain a leaching solution, wherein the leaching agent is a mixed aqueous solution of ammonia and ammonium bicarbonate, or a mixed aqueous solution of ammonia and ammonium carbonate, or a mixed aqueous solution of ammonia, ammonium bicarbonate and ammonium carbonate;

optionally, purifying the leachate obtained in the leaching step;

a decarburization step: adding calcium oxide and/or calcium hydroxide into the leachate, stirring, and then filtering to obtain a first solid and a first filtrate;

calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide into the first filtrate, stirring for reaction, and filtering to obtain a second solid and a second filtrate;

optionally, rinsing the second solid with water;

and (3) drying: and drying the second solid to obtain a final calcium zincate product.

2. The process for producing calcium zincate according to claim 1,

in the calcium zincate synthesis step, an active agent is added into the first filtrate before calcium hydroxide and/or calcium oxide is added into the first filtrate;

the average particle size of the final calcium zincate product is 10-100 nm.

3. The process for producing calcium zincate according to claim 1 or 2,

the mass concentration of total ammonia in the leaching agent is 5% -15%, and the molar concentration of available carbonate in the leaching agent is as follows:

C_{lixiviant carbonate radical}＝(n_{Total zinc of raw material}-n_{Raw material of zinc carbonate})×a/V_Lixiviant

Wherein the content of the first and second substances,

C_{lixiviant carbonate radical}Is the molar concentration of available carbonate in the leaching agent,

n_{total zinc of raw material}Is the amount of the material containing zinc element in the zinc-containing raw material,

n_{raw material of zinc carbonate}Is the zinc carbonate in the zinc-containing raw materialThe amount of the substance(s) to be,

V_lixiviantIs the volume of the leaching agent,

the value range of a is 100-600%, preferably 150-250%.

4. The method for producing calcium zincate according to any one of claims 1 to 3, wherein the concentration of the zinc ammine complex ion (in terms of the mass of the zinc element) in the leachate obtained in the leaching step is 10 to 25 g/L.

5. The process for the production of calcium zincate according to any one of claims 1 to 4, wherein the amount of the substance of calcium oxide and/or calcium hydroxide added in the decarbonation step is 100 to 130%, preferably 100 to 110% of the amount of the substance of available carbonate in the leachate.

6. The method for producing calcium zincate according to any one of claims 1 to 5, wherein in the calcium zincate synthesis step, the ratio of the amount of the substance of calcium hydroxide and/or calcium oxide to the amount of the substance of zinc ammine complex ion in the first filtrate is 1 to 1.2:2, preferably 1 to 1.1: 2.

7. The process for producing calcium zincate according to any one of claims 1 to 6, wherein carbon dioxide is introduced into the second filtrate obtained in the calcium zincate synthesis step, and the second filtrate introduced with carbon dioxide is recycled for leaching of the zinc-containing raw material as a leaching agent.

8. The process for producing calcium zincate according to any one of claims 1 to 7, wherein the reaction temperature of the calcium zincate synthesis step is 15 to 90 ℃, preferably 30 to 60 ℃, or preferably 15 to 25 ℃.

9. The method for producing calcium zincate according to claim 2, wherein the stirring reaction time of the calcium zincate synthesis step is 15 to 30 minutes.

10. The method for producing calcium zincate according to claim 2, wherein the active agent is one or more selected from sodium hexametaphosphate and sodium dodecylbenzenesulfonate.

Technical Field

The invention belongs to the technical field of inorganic chemical industry, relates to a production method of calcium zincate, and particularly relates to a method for producing calcium zincate by using low-grade zinc oxide raw ore.

Background

Calcium zincate has a wide range of uses. The application of calcium zincate to the negative electrode material of the alkaline secondary zinc electrode is a new direction developed in recent years and is continuously mature and industrialized; compared with the traditional zinc oxide desulfurizer, the calcium zincate is a normal-temperature desulfurizer with desulfurization active components, and the sulfur capacity is greatly increased; the calcium zincate as the feed additive is not only beneficial to the absorption of animals, but also beneficial to the reduction of environmental pollution. The calcium zincate can also be widely used for glaze, paint, coating additives and the like.

Disclosure of Invention

Problems to be solved by the invention

Detailed Description

Various exemplary embodiments, features and aspects of the disclosure are described in detail below. The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. In some instances, methods, means, reagents and devices well known to those skilled in the art are not described in detail, but those skilled in the art can implement the technical solutions of the present disclosure based on the general knowledge in the art.

The application range of the method disclosed by the invention is not particularly limited, and the method can be widely applied to the utilization of various zinc-containing raw materials. The advantages of the process disclosed herein are particularly pronounced when low grade zinc oxide raw ore is used as a production feedstock. For example, the low-grade zinc-containing raw ore can be zinc-containing raw ore with the zinc content of 3-15%; particularly, before the method, a large amount of zinc-containing raw ores (lean ores and mill tailings) with the zinc content of 3% -6% are stockpiled, the existing various processes cannot utilize the economic value of the zinc-containing raw ores, and great processing pressure is caused.

In the present disclosure, the form of the presence of the zinc component in the zinc-containing raw ore is not particularly limited, for example, the zinc component may be present in one or more forms including, but not limited to, zinc oxide, zinc carbonate, zinc silicate, and the like.

Noun interpretation

As used herein, unless otherwise specified, "zinc ammine carbonate" is a generic term for compounds formed from zinc ammine complex ions and carbonate ions, and includes [ Zn (NH)₃)₄]CO₃(Zinc tetraammine carbonate), [ Zn (NH)₃)₃]CO₃(Triammine Zinc carbonate), [ Zn (NH)₃)₂]CO₃(Diaminozinc carbonate), [ Zn (NH)₃)]CO₃(zinc monoammonium carbonate), and the like.

In this context, unless otherwise stated, "zinc ammine complex ion" is a generic term for each level of ammine zinc complex ion, and includes [ Zn (NH)₃)₄]²⁺(Zinc tetraammine ion), [ Zn (NH)₃)₃]²⁺(Triammine Zinc ion), [ Zn (NH)₃)₂]²⁺(Diaminato zinc ion), [ Zn (NH)₃)]²⁺(zinc ion ammine), and the like.

As used herein, unless otherwise indicated, "carbonate" in a solution (including but not limited to various liquors such as lixiviants, leachate, and the like) refers to the sum of carbonate and bicarbonate in the solution.

"optional" or "optionally" means that the subsequently described step may or may not be performed, and that the expression includes instances where the subsequently described step is performed and instances where the subsequently described step is not performed.

Chemical reaction formula

1. Leaching

a. Zinc oxide leaching

Extracting agent of ammonia and ammonium bicarbonate

ZnO+(i-1)NH₃+NH₄HCO₃＝[Zn(NH₃)_i]CO₃+H₂O (i is an integer of 1 to 4)

Ammonia and ammonium carbonate as leaching agents

ZnO+(i-2)NH₃+(NH₄)₂CO₃＝[Zn(NH₃)_i]CO₃+H₂O (i is an integer of 2 to 4)

b. Leaching of zinc hydroxide

Extracting agent of ammonia and ammonium bicarbonate

Zn(OH)₂+(i-1)NH₃+NH₄HCO₃＝[Zn(NH₃)_i]CO₃+2H₂O

(i is an integer of 1 to 4)

Ammonia and ammonium carbonate as leaching agents

Zn(OH)₂+(i-2)NH₃+(NH₄)₂CO₃＝[Zn(NH₃)_i]CO₃+2H₂O

(i is an integer of 2 to 4)

c. Zinc carbonate (calamine) leaching

ZnCO₃+iNH₃＝[Zn(NH₃)_i]CO₃(i is an integer of 1 to 4)

d. Zinc silicate leaching

Extracting agent of ammonia and ammonium bicarbonate

ZnSiO₃+(i-1)NH₃+NH₄HCO₃＝[Zn(NH₃)_i]CO₃+H₂O+SiO₂

(i is an integer of 1 to 4)

Ammonia and ammonium carbonate as leaching agents

ZnSiO₃+(i-2)NH₃+(NH₄)₂CO₃＝[Zn(NH₃)_i]CO₃+H₂O+SiO₂

(i is an integer of 2 to 4)

2. Decarburization of carbon

Reaction of lime with water

CaO+H₂O＝Ca(OH)₂

Precipitation of

Ca(OH)₂+(NH₄)₂CO₃＝CaCO₃↓+2NH₃·H₂O

Ca(OH)₂+NH₄HCO₃＝CaCO₃↓+NH₃+2H₂O

[Zn(NH₃)_i]CO₃+Ca(OH)₂＝[Zn(NH₃)_i](OH)₂+CaCO₃↓

(i is an integer of 1 to 4)

Possible side reactions:

Ca(OH)₂+[Zn(NH₃)_i]CO₃＝CaCO₃↓+Zn(OH)₂↓+iNH₃

(i is an integer of 1 to 4)

3. Calcium zincate synthesis

2[Zn(NH₃)_i](OH)₂+Ca(OH)₂+2H₂O＝Ca(OH)₂·2Zn(OH)₂·2H₂O+2iNH₃

(i is an integer of 1 to 4)

The concrete process steps

Step 1 extraction

The finely ground zinc-containing raw material is mixed with the prepared leaching agent according to a certain proportion for agitation leaching. The leaching agent may be selected from: a mixed aqueous solution of ammonia and ammonium bicarbonate; a mixed aqueous solution of ammonia and ammonium carbonate; a mixed aqueous solution of ammonia, ammonium bicarbonate and ammonium carbonate. The zinc-containing raw material is not particularly limited, and may be, for example, a zinc-containing raw ore, particularly a low-grade zinc-containing raw ore.

The concentration of total ammonia and the concentration of available carbonate in the leaching agent are not particularly limited, and those skilled in the art can select the concentration according to the factors such as raw material components and grade and the like and the actual requirements.

In the preferred scheme, the mass concentration of the total ammonia in the leaching agent is 5-15%, more preferably 6-8%, and the preferred concentration range can achieve sufficient leaching effect and avoid the problems of waste and environmental protection caused by excessive ammonia.

In a preferred scheme, the amount of available carbonate in the leaching agent is increased by 0-500% on the basis of the difference obtained by subtracting the amount of carbonate introduced by zinc carbonate in the raw material from the theoretical consumption of carbonate in complexed zinc, and more preferably, the amount of available carbonate in the leaching agent is increased by 50% -150% on the basis of the difference obtained by subtracting the amount of carbonate introduced by zinc carbonate in the raw material from the theoretical consumption of carbonate in complexed zinc. The consumption of carbonate in the theory of complex zinc is the carbonate consumed by completely converting the zinc element in the raw material into the zinc ammonium carbonate. Thus, the molar concentration of available carbonate in the lixiviant can be calculated as follows:

C_{lixiviant carbonate radical}＝(n_{Total zinc of raw material}-n_{Raw material of zinc carbonate})×a/V_Lixiviant

Wherein, C_{Lixiviant carbonate radical}Is the molar concentration of available carbonate in the lixiviant, n_{Total zinc of raw material}Is the amount of material containing zinc element in the zinc-containing raw material, n_{Raw material of zinc carbonate}Is the amount of zinc carbonate material in the zinc-containing raw material, V_LixiviantIs the volume of the leaching agent, a is a coefficient, and the value of a is 100 to 600 percent, preferably 150 to 250 percent. The mass concentration of carbonate in the lixiviant can be converted according to the molar concentration.

The optimized effective carbonate concentration of the leaching agent can ensure that zinc in the raw material is completely leached, can realize the circulation of carbonate in the process, and can avoid the pressure of excessive carbonate on the subsequent process treatment.

The weight ratio of the leaching agent to the zinc-containing raw material (e.g., raw ore powder containing zinc) is not particularly limited as long as the zinc component can be leached. Preferably, the weight ratio of the leaching agent to the zinc-containing raw material is 3:1 to 5:1, so that not only can a satisfactory leaching effect be obtained, but also the waste of the leaching agent is avoided.

The temperature of the leaching is not particularly limited as long as the zinc component in the zinc-containing raw material (e.g., zinc-containing raw ore powder) is leached. Preferably leaching is carried out at normal temperature, for example leaching is carried out at 15-30 ℃; the leaching may also be carried out at slightly elevated temperatures (e.g., 30-55 ℃). The temperature can be selected according to actual conditions.

The zinc-containing raw material (for example, zinc-containing raw ore powder) is mixed with the leaching agent and stirred for a time period not particularly limited as long as the zinc component in the raw material is leached, and the stirring time period is preferably 1 to 4 hours, and more preferably 1 to 2 hours.

In the leaching process, zinc element in the raw material is converted into zinc ammine complex ions (mainly zinc ammine complex ions at each stage) and enters a liquid phase. And filtering after leaching to obtain a leaching solution containing zinc ammonia complex ions. The leachate can be used in the subsequent decarburization process. The concentration of the zinc ammine complex ions in the leachate is not particularly limited, but the concentration of the zinc ammine complex ions (calculated by the mass of the zinc element) in the leachate is preferably 10-25 g/L, so that the treatment efficiency of the process is optimal, good yield and purity are obtained in the subsequent calcium zincate synthesis step, and the comprehensive economic benefit is optimal. If the concentration of the zinc ammine complex ions in the original leached liquid is not in the preferred range, optionally concentrating or diluting the leached liquid, and adjusting the concentration of the zinc ammine complex ions in the leachate to be in the preferred range of 10-25 g/L.

Step 2 purification

Step 2 is an optional step, and step 2 is optionally performed, if necessary. Purifying the leachate by a known method to remove impurity elements such as iron, manganese, lead, copper and the like. An exemplary purification method is to add zinc powder for displacement and then filtering to remove heavy metal contaminants, but various other known purification methods may be used. The purification step helps to increase the purity of the final product.

Step 3 decarburization

In the decarbonization step, calcium hydroxide and/or calcium oxide is added into the leachate containing the zinc-ammonia complex ions, and carbonate/bicarbonate radicals in the leachate are converted into calcium carbonate. If the concentration of the zinc ammine complex ions in the leachate is too high, equilibrium shift of zinc ammine complex ions-zinc hydroxide in the leachate may occur at the same time, and a very small portion of the zinc component may be co-precipitated with calcium carbonate in the form of zinc hydroxide.

In the decarbonising step, the amount of calcium hydroxide and/or calcium oxide added substantially matches the amount of available carbonate in the leach solution, for example, the amount of calcium hydroxide and/or calcium oxide species added in the decarbonising step is 100% to 130%, more preferably 100% to 110% of the amount of available carbonate species in the leach solution. Proper addition of calcium hydroxide and/or calcium oxide is helpful for controlling the process cost and improving the purity and quality of the finished zinc product.

In the decarbonization step, calcium hydroxide and/or calcium oxide are added into the leaching solution, and the mixture is stirred for reaction to generate solid precipitate. The reaction temperature is not particularly limited, and particularly, the reaction is preferably carried out at normal temperature (for example, 15 to 25 ℃), so that on one hand, energy is saved, and on the other hand, environmental pollution caused by ammonia volatilization is reduced. The stirring time is not particularly limited as long as a precipitate is obtained, and stirring is preferably performed for 1 to 2 hours.

And filtering after stirring to obtain a first solid and a first filtrate. The primary component of the first solid is calcium carbonate, and if the concentration of zinc ammine ions in the leach solution is high, some zinc hydroxide co-precipitated with the calcium carbonate may also be present in the first solid. The first solid can be calcined into calcium oxide and carbon dioxide for recycling. The first filtrate continues to be used for the subsequent calcium zincate synthesis.

Step 4 calcium zincate Synthesis

And adding calcium hydroxide and/or calcium oxide into the first filtrate, and stirring for reaction. The ratio of the amount of the calcium hydroxide and/or calcium oxide to the amount of the zinc ammine complex ion in the first filtrate is preferably 1 to 1.2:2, more preferably 1 to 1.1: 2. The reaction temperature is not particularly limited, and may be, for example, 15 to 90 ℃, preferably 20 to 90 ℃, and more preferably 30 to 60 ℃; or the reaction temperature at normal temperature (15-25 ℃) is also preferred, and the temperature range has the advantages of no need of heating, energy conservation and reduction of environmental pollution caused by ammonia volatilization. Preferably, the filtration is carried out after the reaction is carried out for 0.5 to 2 hours (more preferably 0.5 to 1 hour), and a long-time reaction and aging process is not required. Filtering to obtain a second solid and a second filtrate. The main component of the second solid is calcium zincate, and generally, the calcium zincate component may account for 95% or more of the total mass of the second solid. Carbon dioxide may additionally be passed to the second filtrate and then recycled for leaching of the zinc containing material.

In particular, if it is desired to control the particle size of the product calcium zincate, this step may be carried out by adding the activator to the first filtrate, then adding the calcium hydroxide and/or calcium oxide, and stirring to effect the reaction. The active agent is preferably sodium hexametaphosphate or sodium dodecyl benzene sulfonate, and the dosage is preferably 0.01-0.05 percent of the estimated quality of the final product. The reaction temperature is particularly preferably normal temperature (15-25 ℃), and the lower temperature is more favorable for controlling the crystal grain size. Another optional mode for controlling the crystal grain size is to perform filtration after stirring reaction for 15-30 minutes without long-time reaction and aging processes.

Step 5 rinsing

This step is an optional step, and a rinsing step is performed if necessary. And rinsing the second solid with water, wherein the liquid-solid ratio is 5-10: 1, and the rinsing times are 1-2.

Step 6 drying

Drying the second solid at a temperature not higher than 125 deg.C to obtain final product containing calcium zincate as main ingredient. If one or more measures such as adding an active agent, reacting at normal temperature and controlling the stirring reaction time are adopted in the calcium zincate synthesis step, a final product with nano calcium zincate as a main component can be obtained, and the average particle size of the final product is 10-100 nm.

Embodiments of the present disclosure will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present disclosure and should not be construed as limiting the scope of the present disclosure. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.