阅读说明：本技术 一种转底炉高锌除尘灰制取碱式氯化锌的方法 (Method for preparing basic zinc chloride from blast furnace blast zinc dedusting ash of rotary hearth furnace ) 是由 田文杰 林�智 郭灵巧 郭秀键 于 2020-07-09 设计创作，主要内容包括：本发明属于冶金领域,涉及一种转底炉高锌除尘灰制取碱式氯化锌的方法,转底炉除尘灰用氨水+氯化铵浸取,过滤后得到一次滤液和滤渣,滤渣用净水冲洗,滤液与冲洗水再次浸取除尘灰,滤液中锌氨络合离子达到浓度后,用高锰酸钾及金属锌粉置换净化后过滤,净化渣与一次渣一起进入转底炉焙烧,净化液蒸氨,得到碱式氯化锌沉淀,洗涤后烘干后得到产品碱式氯化锌,滤液返回浸取除尘灰,二次滤液盐浓度富集到15％后外排至蒸发系统制取混合盐。(The invention belongs to the field of metallurgy, and relates to a method for preparing basic zinc chloride from rotary hearth furnace blast-zinc dedusting ash, wherein the rotary hearth furnace dedusting ash is leached by ammonia water and ammonium chloride, primary filtrate and filter residue are obtained after filtration, the filter residue is washed by purified water, the dedusting ash is leached again by the filtrate and the washing water, after the concentration of zinc-ammonia complex ions in the filtrate reaches the concentration, the filter is filtered after displacement purification by potassium permanganate and metal zinc powder, purified residue and primary residue enter a rotary hearth furnace to be roasted, ammonia evaporation is carried out on the purified solution to obtain basic zinc chloride precipitate, the basic zinc chloride product is obtained after washing and drying, the filtrate returns to the dedusting ash, the secondary filtrate is discharged to an evaporation system after the salt concentration is enriched to 15%, and mixed salt is prepared.)

1. A method for preparing basic zinc chloride from blast furnace zinc dedusting ash of a rotary hearth furnace is characterized by comprising the following steps:

s1, mixing the fly ash mixed ammonia water with ammonium chloride, stirring and leaching;

s2, dehydrating and filtering a plate frame, and circularly leaching the filtrate in the step S1 until the zinc-ammonia complex ions reach a certain concentration;

s3, purifying the filtrate with zinc-ammonia complex ions reaching a certain concentration in the step S2, and roasting the purified slag and the filter residue in the step S2 in a rotary hearth furnace;

s4, ammonia evaporation is carried out on the purified liquid in the step S3 to obtain basic zinc chloride sediment;

s5 dewatering, drying and washing the precipitate in the step S4, and the filtrate generated in the dewatering process circularly enters the step S1.

2. The method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as claimed in claim 1, characterized in that in step S1, ammonia water and ammonium chloride are added at a molar concentration ratio of 1: 1, the mass concentration of ammonia water is 8 percent.

3. The method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as recited in claim 1, characterized in that in step S2, leaching is carried out until the zinc ammine complex ion reaches 60 g/L.

4. The method for preparing basic zinc chloride from the blast furnace zinc dedusting ash of the rotary hearth furnace as claimed in claim 1, wherein in the step S1, the water-ash ratio is 5-10: 1.

5. the method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as claimed in claim 1, characterized in that the chemical reaction equation for leaching the zinc ammine complex ions is as follows:

ZnO+(n-1)NH₃+NH₄Cl＝(Zn(NH₃)_n)Cl₂+H₂O。

6. the method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as claimed in claim 1, characterized in that in step S3, after potassium permanganate is used for oxidation, zinc metal is used for replacement, and heavy metal ions in the filtrate are removed, and the chemical reaction formula is:

2Fe²⁺+MnO₄ ^-＝2Fe³⁺+MnO² ₂ ^-；

Fe³⁺+3OH^-＝Fe(OH)³↓；

3Mn²⁺+2MnO₄ ^-+2H₂O→5MnO₂↓+4H⁺；

M²⁺+Zn＝M↓+Zn²⁺(ii) a M is a replaced heavy metal.

7. The method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as claimed in claim 1, wherein in step S4, the chemical reaction formula of the ammonia distillation is as follows:

5(Zn(NH₃)₄)Cl₂+9H₂O＝Zn₅Cl₂(OH)₈.H₂O+12NH₃+8NH₄Cl。

8. the method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as set forth in claim 1, characterized in that in step S5, 10: and (3) performing serial cleaning with 1 water for 3 times, and then dehydrating.

9. The method for preparing basic zinc chloride from the blast furnace dust of the rotary hearth furnace as claimed in claim 1, wherein in the step S5, a rotary flash evaporation device is adopted for drying.

10. The method for preparing basic zinc chloride from the rotary hearth furnace blast zinc dedusting ash as claimed in claim 9, characterized in that in step S5, the air inlet temperature is 200 ℃ and the air outlet temperature is not lower than 80 ℃ during drying.

Technical Field

The invention belongs to the field of metallurgy, and relates to a method for preparing basic zinc chloride from blast furnace dust.

Background

Compared with other zinc-containing additives, the basic zinc chloride has the characteristics of no moisture absorption, convenient transportation, high animal absorption conversion rate and the like. The zinc-containing dust of the dezincification rotary hearth furnace in the steel mill contains high potassium salt and sodium salt, and does not meet the production requirement of feed-grade basic zinc chloride.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for preparing basic zinc chloride from blast furnace dust of a rotary hearth furnace, so as to prepare mixed salt meeting the production requirements of feed-grade basic zinc chloride.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for preparing basic zinc chloride from blast furnace zinc dedusting ash of a rotary hearth furnace comprises the following steps:

s1, mixing the fly ash mixed ammonia water with ammonium chloride, stirring and leaching;

s2, dehydrating and filtering a plate frame, and circularly leaching the filtrate in the step S1 until the zinc-ammonia complex ions reach a certain concentration;

s3, purifying the filtrate with zinc-ammonia complex ions reaching a certain concentration in the step S2, and roasting the purified slag and the filter residue in the step S2 in a rotary hearth furnace;

s4, ammonia evaporation is carried out on the purified liquid in the step S3 to obtain basic zinc chloride sediment;

s5 dewatering, drying and washing the precipitate in the step S4, and the filtrate generated in the dewatering process circularly enters the step S1.

Optionally, in step S1, the molar concentration ratio of ammonia to ammonium chloride in leaching is 1: 1, the mass concentration of ammonia water is 8 percent.

Optionally, in step S2, leaching is performed until the zinc-ammonia complex ion reaches 60 g/L.

Optionally, in step S1, the water-cement ratio is 5-10: 1.

optionally, the chemical reaction equation for leaching the zinc ammine complex ions is as follows: ZnO + (n-1) NH₃+NH₄Cl＝(Zn(NH₃)_n)Cl₂+H₂O。

Optionally, in step S3, after oxidizing with potassium permanganate, replacing with zinc metal, and removing heavy metal ions in the filtrate, the chemical reaction formula is:

2Fe²⁺+MnO₄ ^-＝2Fe³⁺+MnO² ₂ ^-；

Fe³⁺+3OH^-＝Fe(OH)³↓；

3Mn²⁺+2MnO₄ ^-+2H₂O→5MnO₂↓+4H⁺；

M²⁺+Zn＝M↓+Zn²⁺(ii) a M is a replaced heavy metal.

Optionally, in step S4, the chemical reaction formula of the ammonia distillation is: 5(Zn (NH)₃)₄)Cl₂+9H₂O＝Zn₅Cl₂(OH)₈.H₂O+12NH₃+8NH₄Cl。

Optionally, in step S5, the method comprises the following steps of 10: and (3) performing serial cleaning with 1 water for 3 times, and then dehydrating.

Optionally, in step S5, a spin flash apparatus is used during drying.

Optionally, in step S5, the inlet air temperature is 200 ℃ and the outlet air temperature is not lower than 80 ℃ during drying.

The invention has the beneficial effects that:

the invention obtains high-concentration zinc-ammonia complex ions by circular leaching, and then removes heavy metal ions by potassium permanganate oxidation and metal zinc powder replacement; obtaining basic zinc chloride precipitate by an ammonia evaporation method, and obtaining a product by spin flash evaporation, dehydration and drying. Compared with other zinc-containing additives, the basic zinc chloride has the characteristics of no moisture absorption, convenient transportation, high animal absorption conversion rate and the like, zinc-containing dust of a dezincification rotary hearth furnace of a steel mill contains high potassium salt and sodium salt, and qualified feed-grade basic zinc chloride can be produced at lower cost through the scheme.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

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

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

Referring to fig. 1, the invention discloses a method for preparing basic zinc chloride from rotary hearth furnace blast zinc dedusting ash, leaching the rotary hearth furnace dedusting ash with ammonia water and ammonium chloride, filtering to obtain primary filtrate and filter residue, washing the filter residue with purified water, leaching the dedusting ash again with the filtrate and the washing water, performing displacement purification on zinc ammonia complex ions in the filtrate after the concentration of the zinc ammonia complex ions reaches a certain concentration, filtering, roasting the purified residue and the primary residue in a rotary hearth furnace, evaporating ammonia in a purification solution to obtain basic zinc chloride precipitate, washing, drying to obtain a product of basic zinc chloride, returning the filtrate to the dedusting ash, enriching the salt concentration of the secondary filtrate to 15%, and discharging to an evaporation system to prepare mixed salt.

The process steps of the invention comprise mixing and stirring of the dedusting ash, dehydration, washing, purification of filtrate, ammonia evaporation, washing and drying of a plate frame to obtain the basic zinc chloride of the feed additive. Adding ammonia water and ammonium chloride in a molar concentration ratio of 1: 1, ammonia water mass concentration of 8%, water-cement ratio of 5-10: 1, when the circulation leaching is carried out, the concentration of the ammonia ions reaches 60g/L for filtration. The main chemical formula is as follows: ZnO + (n-1) NH₃+NH₄Cl＝(Zn(NH₃)_n)Cl₂+H₂O。

During purification, potassium permanganate is used for oxidation, and then zinc metal is used for replacement, and heavy metal ions in the filtrate are removed. The main chemical reaction equation of the oxidation method for impurity removal is as follows:

2Fe²⁺+MnO₄ ^-＝2Fe³⁺+MnO² ₂ ^-；

Fe³⁺+3OH^-＝Fe(OH)³↓；

3Mn²⁺+2MnO₄ ^-+2H₂O→5MnO₂↓+4H⁺。

the main chemical reaction equation for impurity removal by the displacement method is as follows:

M²⁺+Zn＝M↓+Zn²⁺(ii) a M comprises: pb²⁺、Cu²⁺、Cd²⁺、Ni²⁺、Hg²⁺And (3) plasma.

The main chemical reaction equation during ammonia distillation:

5(Zn(NH₃)₄)Cl₂+9H₂O＝Zn₅Cl₂(OH)₈.H₂O+12NH₃+8NH₄Cl。

filtering the obtained filter residue after ammonia evaporation, and filtering the obtained filter residue by using a filter residue mixing device 10: 1, performing water cascade cleaning for 3 times, then dehydrating, wherein a rotary flash evaporation device is required to be adopted during drying, the air inlet temperature is 200 ℃, and the air outlet temperature is not lower than 80 ℃.

Taking 3000t/a zinc-containing dust of a certain steel mill as an example. 20 percent of ZnO, 3.80 percent of TFe and 80 percent of ZnO leaching rate

The TFe leaching rate is 20%, KMnO 435 t, zinc powder 5t, NH4Cl 700t and 8% ammonia 2750t are needed, and Zn5Cl2(OH)8.H2O 650t can be produced.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.