阅读说明：本技术 含钒钢渣中钙组元净化与回收的新工艺 (New process for purifying and recovering calcium components in vanadium-containing steel slag ) 是由 叶国华 陈子杨 谢禹 路璐 左琪 张豪 陶媛媛 唐悦 胡渝杰 于 2020-06-05 设计创作，主要内容包括：本发明公布了含钒钢渣中钙组元净化与回收的新工艺,其工艺步骤包括：无添加选择性浸钙：将含钒钢渣粉碎至-74μm占60％以上,置于简单再生后的沉钙液中,进行浸出脱钙；快速高效沉钙制备碳酸钙：向富钙浸出液中加入碳酸氢铵或碳酸铵,制备出高纯碳酸钙；沉钙液简单再生后无补加循环浸出：常温下沉钙液经简单再生处理后,返回至第一道工序无需补加浸出剂进行循环浸出。本发明的新工艺,适用性强,可有效实现含钒钢渣中钙组元的净化与回收；新工艺能耗相对较低,无需添加浸出剂,净化率高,选择性好,不损失钒并使钒得以富集,同时,可快速高效沉钙并制备出高纯碳酸钙,沉钙滤液经简单再生处理,可零补加循环浸出,具有节约环保效果。(The invention discloses a new process for purifying and recovering calcium components in vanadium-containing steel slag, which comprises the following process steps: selective calcium leaching without addition: crushing the vanadium-containing steel slag to-74 microns, wherein the-74 microns account for more than 60%, and placing the crushed vanadium-containing steel slag in a simply regenerated calcium precipitation solution for leaching and decalcification; preparing calcium carbonate by rapid and efficient calcium precipitation: adding ammonium bicarbonate or ammonium carbonate into the calcium-rich leaching solution to prepare high-purity calcium carbonate; the calcium precipitation solution is simply regenerated and then is leached circularly without being supplemented: after the normal-temperature calcium sinking solution is subjected to simple regeneration treatment, the solution returns to the first procedure and is subjected to circulating leaching without adding a leaching agent. The novel process has strong applicability, and can effectively realize the purification and recovery of calcium components in the vanadium-containing steel slag; the new process has relatively low energy consumption, no need of adding leaching agent, high purification rate, good selectivity, no loss of vanadium and enrichment of vanadium, and can simultaneously rapidly and efficiently precipitate calcium and prepare high-purity calcium carbonate, and the precipitated calcium filtrate can be subjected to simple regeneration treatment, zero-supplement circulating leaching, thereby having the effects of saving and protecting environment.)

1. The new process for purifying and recovering calcium components in vanadium-containing steel slag is characterized in that selective calcium leaching without addition, calcium carbonate preparation by rapid and efficient calcium precipitation and simple regeneration of calcium precipitation liquid without supplementary cyclic leaching are carried out, and the adopted process steps are as follows:

s1: selective calcium leaching without addition: crushing the vanadium-containing steel slag to the fineness of more than 60 percent in a mesh with the particle size of-74 mu m, and placing the crushed vanadium-containing steel slag in a simply regenerated calcium precipitation solution for selective leaching and decalcification without adding; obtaining calcium-rich leaching liquid and leaching slag; enriching vanadium in leaching slag without leaching, and enabling the leaching slag to enter a subsequent vanadium extraction process;

s2: preparing calcium carbonate by rapid and efficient calcium precipitation: adding ammonium bicarbonate or ammonium carbonate into the calcium-rich leaching solution, precipitating calcium instantly, quickly and efficiently, and performing solid-liquid separation to obtain high-purity calcium carbonate and a calcium precipitation solution;

s3: the calcium precipitation solution is simply regenerated and then is leached circularly without being supplemented: at normal temperature, the pH of the calcium precipitation solution is adjusted to be less than or equal to 4.2 by dilute hydrochloric acid to remove residual CO₃ ^2-、HCO₃ ^-Then, the pH value is adjusted back to be more than or equal to 6.0 by ammonia water, and the solution is simply regenerated and returned to the first procedure without adding a leaching agent for cyclic leaching.

2. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S1, the steel slag containing vanadium needs to be crushed to the fineness of-74 μm and accounts for more than 70%; the solution used for leaching is simply regenerated precipitated calcium, no leaching agent is added, the leaching time T is 4-5 h, the stirring speed r is 300-400 rpm, and the leaching temperature T is 80-85 ℃.

3. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S1, vanadium is not leached but enriched in the leaching slag, and the enrichment ratio is more than or equal to 1.2.

4. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: s1, the vanadium-containing steel slag is placed in the simply regenerated calcium precipitation liquid to be selectively leached and decalcified without adding, the process is carried out in a closed container, and the temperature in the closed container is controlled to be in a relatively low-temperature environment of 75-90 ℃.

5. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S2, the precipitant is ammonium bicarbonate or ammonium carbonate, and the usage amount is 30-60% of the vanadium-containing steel slag.

6. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S2, calcium precipitation and preparation of calcium carbonate are carried out in an instant, rapid and efficient process, the conversion rate of calcium precipitation is more than 99%, the purity of the prepared calcium carbonate is more than 99%, and ammonium salt decomposition and volatilization losses are basically avoided.

7. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S3, during simple regeneration, dilute hydrochloric acid is needed to adjust the pH of the calcium precipitation solution to be less than or equal to 4.2 at normal temperature to remove residual CO₃ ^2-、HCO₃ ^-Then, the pH value is adjusted back to be more than or equal to 6.0 by using ammonia water.

8. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: in S3, the precipitated calcium filtrate is simply regenerated and can be leached out in a zero-supplement circulation manner.

9. The new process for purifying and recovering calcium components in vanadium-containing steel slag as claimed in claim 1, which is characterized in that: the vanadium-containing steel slag can be high-calcium vanadium-containing steel slag with the CaO content reaching fifty percent or low-calcium vanadium-containing steel slag with the CaO content being only thirty percent, and can belong to calcium trisilicate slag or calcium disilicate slag.

Technical Field

The invention relates to a process method, namely purification and recovery of calcium components in steel slag, belongs to the fields of chemical mineral separation, hydrometallurgy and comprehensive utilization of solid waste resources, and particularly relates to a novel process for preparing calcium carbonate by non-additive selective calcium leaching-rapid high-efficiency calcium precipitation-simple regeneration of calcium precipitation liquid and non-complementary cyclic leaching, which is particularly suitable for vanadium-containing steel slag.

Background

The steel slag containing vanadium is produced from the steel-making process of vanadium titano-magnetite. Vanadium-titanium magnetite is the most main mineral resource of vanadium, and vanadium is mostly recovered from vanadium by an indirect method at present, namely vanadium-titanium magnetite is smelted into vanadium-containing molten iron firstly, and then vanadium is further extracted. The vanadium-containing molten iron is processed by a plurality of methods, including a vanadium slag blowing method, a vanadium-containing steel slag method, a sodium slag method and the like. The vanadium-containing steel slag method is that vanadium-containing molten iron is directly blown into steel, vanadium is blown into the steel slag as an impurity, and the high-calcium steel slag is obtained as a raw material for extracting the vanadium. The method can omit equipment for converting vanadium slag, can recover the pig iron lost in the process of converting the vanadium slag, and is a new generation of treatment method. In addition, no matter which method is adopted, a certain amount of residual vanadium is oxidized into slag to form the vanadium-containing steel slag.

For a long time, except that a small part of the steel slag is returned to be sintered and utilized, a large amount of vanadium-containing steel slag is always regarded as solid waste and is in a stacking state. Although it is not limited toThe vanadium content of the vanadium-containing steel slag is very low, and only V₂O₅1 to 4 percent, but still higher than 0.3 to 1.0 percent of the stone coal vanadium ore, is a valuable metallurgical secondary resource and can be used as an important raw material for extracting vanadium. If the vanadium can be extracted from the steel slag containing vanadium, remarkable economic, social and environmental benefits can be brought.

At present, the mainstream vanadium extraction process comprises two major types of sodium treatment/calcification roasting-leaching and roasting-free direct acid leaching. However, the content of calcium component in the vanadium-containing steel slag is very high, generally reaching 40-60 percent in terms of CaO, the individual content is low and also reaching more than 30 percent, the content of vanadium is very low, only 1-4 percent, and the large content difference is that the vanadium extraction is very difficult no matter which process is based on. In the roasting-leaching vanadium extraction process, calcium can be combined with vanadium in the roasting process to generate calcium vanadate with poor solubility, so that the leaching rate of vanadium is greatly reduced; and no matter which roasting method is adopted, the process inevitably produces smoke pollution, and the environmental protection cost is high. In order to overcome the defects of the roasting-leaching process, people further provide a roasting-free direct acid leaching process, namely, under the condition of strong acid, the roasting process is cancelled, and vanadium is directly leached and extracted by acid. The direct acid leaching is an advanced process method at present, does not need a roasting link, has simplified flow and good working environment, can obtain higher leaching rate, and is the development direction of vanadium extraction. However, the vanadium-containing steel slag is directly subjected to acid leaching to extract vanadium, and calcium reacts with a leaching agent in the acid leaching process to consume a large amount of acid, so that the acid consumption is overlarge, the cost is overhigh, the dissolution of vanadium is influenced, and the leaching of vanadium is hindered.

Therefore, the content of calcium components in the vanadium-containing steel slag is extremely high, and no matter what process is adopted to extract vanadium from the vanadium-containing steel slag, high-content calcium can cause a series of technical problems, thereby seriously influencing the index of vanadium extraction and increasing the cost of vanadium extraction. However, if the purification and recovery of calcium components in the steel slag containing vanadium can be realized, the problems can be solved naturally. Therefore, the purification and recovery of calcium components in the vanadium-containing steel slag before vanadium extraction are of great significance, which is a necessary vanadium extraction pretreatment means and is also a key to the success of vanadium extraction from the vanadium-containing steel slag.

Calcium is oneThe purification and recovery of the cheap metal components with low economic value do not arouse enough attention and related researches are not much, but relatively diversified technical methods, such as table concentrator reselection, wet leaching and other related technologies, also appear. Wherein, the table concentrator gravity concentration method has low purification rate and can lose a certain amount of vanadium in the purification decalcification process, and the calcium removed by purification can not be recycled. Some other technologies for treating calcium components in ordinary steel slag, such as steam treatment, steel slag carbon fixation, gasification desulfurization, etc., have certain applicability and can provide reference guidance, but it is not clear whether the calcium components can be transplanted into the steel slag containing vanadium to purify and recover, and the specific effect is. Compared with the prior art, wet leaching such as ammonium chloride leaching has good selectivity and high purification rate, does not cause vanadium loss, can enrich the purified calcium in the leaching solution, is favorable for comprehensive recovery of the calcium, and is a relatively promising process method; but the consumption of ammonium chloride is large during leaching by the conventional ammonium chloride leaching method; and for the recovery of calcium, the method is single, and the method adopts the steps of introducing CO into the leaching solution₂Adding Ca²⁺Carbonization and addition of ammonia to maintain an alkaline environment for the preparation of calcium carbonate, CO₂The action efficiency is low, the preparation speed of calcium carbonate is slow, and the decomposition and volatilization loss of ammonium chloride is large; in addition, the conventional ammonium chloride leaching method is difficult to realize circulating leaching, or even if the circulating leaching is realized by adopting low-efficiency high-consumption means such as heating and the like, a large amount of leaching agent is still required to be added during the circulating leaching.

In general, although the existing technical methods for purifying and recovering calcium components have various characteristics, the problems exist more or less, most of the problems still stay in the laboratory research stage, the popularization and application are limited, and the problem of high calcium during extracting vanadium from vanadium-containing steel slag does not make a critical and substantial breakthrough.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

In order to solve the problems of low purification rate, certain vanadium loss in the purification process, difficult recovery of purified calcium or single and low-efficiency recovery means, high consumption of leaching agents, difficult cyclic leaching and the like in the existing calcium component purification and recovery process method, the invention provides a novel process capable of effectively realizing the purification and recovery of calcium components in vanadium-containing steel slag, namely 'selective calcium leaching without addition-rapid high-efficiency calcium precipitation preparation of calcium carbonate-simple regeneration of calcium precipitation solution without supplement and cyclic leaching'. The new process has strong applicability, does not need to add a leaching agent, has high purification rate and good selectivity, does not lose vanadium and enrich the vanadium, can quickly precipitate calcium and prepare high-purity calcium carbonate, and realizes circulating leaching by simply regenerating the calcium precipitation filtrate without adding the leaching agent, thereby having the effects of saving and protecting the environment.

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

the new process for purifying and recovering calcium components in the vanadium-containing steel slag comprises three procedures of selective calcium leaching without addition, rapid and efficient calcium precipitation for preparing high-purity calcium carbonate, simple regeneration of calcium precipitation liquid and no supplement and circulating leaching, and comprises the following specific steps:

s1: selective calcium leaching without addition: crushing the vanadium-containing steel slag to the fineness of more than 60 percent of minus 200 meshes, placing the crushed vanadium-containing steel slag in a simply regenerated calcium precipitation solution for selective leaching and decalcification, and carrying out solid-liquid separation to obtain leaching slag and a calcium-enriched leaching solution. The vanadium is not leached but enriched in the leaching slag, the enrichment ratio is more than or equal to 1.2, and the leaching slag enters the subsequent vanadium extraction process. The conditions are controlled as follows: the solution used for leaching is simply regenerated precipitated calcium, no leaching agent is added, the leaching time T is 3-6 h, the stirring speed r is 250-500 rpm, and the leaching temperature T is 75-90 ℃.

S2: preparing calcium carbonate by rapid and efficient calcium precipitation: adding ammonium bicarbonate or ammonium carbonate into the calcium-rich leaching solution, precipitating calcium instantly, quickly and efficiently, and performing solid-liquid separation to obtain precipitated high-purity calcium carbonate and a precipitated calcium solution. The conditions are controlled as follows: the precipitator is ammonium bicarbonate or ammonium carbonate, and the dosage of the precipitator is 30-60 percent of the mass of the vanadium-containing steel slag. The method is an instant, rapid and efficient process, the conversion rate of calcium precipitation is more than 99%, the purity of the prepared calcium carbonate is more than 99%, and the prepared calcium carbonate basically has no decomposition and volatilization loss of ammonium salt.

S3: the calcium precipitation solution is simply regenerated and then is leached circularly without being supplemented: at normal temperature, the calcium precipitation liquid is treated with dilute saltAdjusting pH to 4.2 or less with acid to remove residual CO₃ ^2-、HCO₃ ^-Then, the pH value is adjusted back to be more than or equal to 6.0 by ammonia water, and the solution is simply regenerated and returned to the first procedure without adding a leaching agent for cyclic leaching.

In the invention, in S1, the steel slag containing vanadium needs to be crushed to the fineness of more than 70 percent when the fineness is-74 mu m; the solution used for leaching is simply regenerated precipitated calcium, no leaching agent is added, the leaching time T is 4-5 h, the stirring speed r is 300-400 rpm, and the leaching temperature T is 80-85 ℃.

In the invention, in S1, vanadium is not leached but enriched in the leaching slag, and the enrichment ratio is more than or equal to 1.2.

In the invention, in S1, the vanadium-containing steel slag is placed in the simply regenerated calcium precipitation liquid to be subjected to selective leaching decalcification without adding, the process is carried out in a closed container, the temperature in the closed container is controlled to be in a relatively low-temperature environment of 75-90 ℃, the heat loss can be reduced, and the pyrolysis volatilization of ammonium salt is avoided.

In the invention, in S2, the precipitator used is ammonium bicarbonate or ammonium carbonate, and the usage amount is 30-60% of the vanadium-containing steel slag.

In the invention, in S2, calcium precipitation and preparation of calcium carbonate are immediate, rapid and efficient processes, the conversion rate of calcium precipitation is more than 99%, the purity of the prepared calcium carbonate is more than 99%, and ammonium salt decomposition and volatilization losses are basically avoided.

In the invention, in S3, during simple regeneration, dilute hydrochloric acid is needed to adjust the pH of the calcium precipitation solution to be less than or equal to 4.2 at normal temperature so as to remove residual CO₃ ^2-、HCO₃ ^-Then, the pH value is adjusted back to be more than or equal to 6.0 by using ammonia water.

In the invention, in S3, the precipitated calcium filtrate can be subjected to zero-supplement circulating leaching through simple regeneration treatment.

In the invention, the vanadium-containing steel slag can be high-calcium vanadium-containing steel slag with the CaO content reaching fifty percent or sixty percent, or low-calcium vanadium-containing steel slag with the CaO content being only thirty percent, and can belong to calcium trisilicate slag or calcium disilicate slag.

After the technical scheme is adopted, compared with the prior art, the invention has the following beneficial effects.

Compared with the prior art, the invention has the advantages that:

1. the solution used in leaching is simply regenerated calcium precipitation solution, and the component of the solution is NH₄ ⁺、Cl^-Equivalent to the existence of ammonium chloride, the calcium leaching agent still has good calcium leaching performance: nCaO SiO₂+2nNH₄Cl→nCaCl₂+2nNH₃+SiO₂·nH₂O, calcium component in steel slag is mainly calcium silicate nCaO. SiO₂The form exists, so that no leaching agent is required to be added during leaching, and the leaching cost is low; meanwhile, the purification removal rate/leaching rate of calcium is high and can reach more than 60%, the selectivity is good, and vanadium and other components are not leached only by leaching calcium, so that the loss of vanadium is not caused; the selective leaching is actually a process of continuously dissolving calcium components and continuously reducing the quality of steel slag, since vanadium is not leached but the quality of the steel slag is reduced, the grade of the vanadium is naturally improved, and the leached vanadium slag can be enriched by 1.2 times or more.

2. The leaching process is carried out in a closed container, the temperature in the closed container is controlled to be in a relatively low-temperature environment, the conventional calcium chloride leaching method is boiling water bath leaching, the temperature is more than or equal to 95 ℃, the leaching temperature is only 75-90 ℃, the energy consumption is relatively low, the heat loss can be reduced, and the pyrolysis volatilization of ammonium salt is avoided.

3. The existing process method has single means for recovering calcium in the calcium-rich leaching solution, and adopts the steps of introducing CO into the leaching solution₂Gas to remove Ca²⁺Carbonization and ammonia water addition to maintain alkaline environment to prepare calcium carbonate ": CO 2₂+CaCl₂+2NH₃+H₂O→CaCO₃↓+2NH₄Cl，CO₂Low action efficiency, slow preparation speed of calcium carbonate and large decomposition and volatilization loss of ammonium chloride. The invention uses ammonium carbonate and ammonium bicarbonate as precipitant to precipitate calcium in time, quickly and efficiently and prepare high-calciumPure calcium carbonate by-product: CaCl₂+2NH₄HCO₃→CaCO₃↓+2NH₄Cl+CO₂+H₂O、(NH₄)₂CO₃+CaCl₂→CaCO₃↓+2NH₄Cl is instantly and quickly finished, so that decomposition and volatilization of ammonium salt are basically avoided, and the method has the advantages of high action efficiency and high preparation speed, the conversion rate of calcium precipitation is more than 99 percent, and the purity of calcium carbonate is more than 99 percent.

4. The existing process method rarely considers the problem of circular leaching; although some documents mention that the precipitated calcium solution is heated on an electric furnace to fully volatilize the ammonia water in the filtrate, and the leaching agent ammonium chloride can be recycled, for this method, the electric furnace heating is not referred to for a moment, and is an inefficient and high-consumption means, not only the ammonia water is easy to volatilize, but also the ammonium chloride is easy to volatilize and lose in the heating process: NH (NH)₄Cl→NH₃And ↓ + HCl ↓, then, a large amount of leaching agent ammonium chloride is necessarily required to be supplemented again during the circulating leaching, and the heating volatilization products are gases with pungent smell and serious environmental pollution. In the invention, the pH of the calcium precipitation solution is adjusted to be less than or equal to 4.2 by dilute hydrochloric acid at normal temperature to remove residual CO₃ ^2-、HCO₃ ^-Then, the pH value is adjusted to be more than or equal to 6.0 by ammonia water for simple regeneration treatment, and the component is NH₄ ⁺、Cl^-The loss of pyrolysis and volatilization is basically avoided, the good calcium leaching performance is still maintained, and the zero-addition circulating leaching can be realized without adding a leaching agent. The invention is a closed cycle process from selective leaching to rapid and efficient calcium precipitation and then to simple regeneration, and has the effects of saving and environmental protection.

5. Based on the aspects, the novel process can effectively realize the purification and recovery of calcium components in the vanadium-containing steel slag, thereby solving the problem of high calcium in the vanadium extraction of the vanadium-containing steel slag. The new process has relatively low energy consumption, no need of adding a leaching agent, high purification rate, good selectivity, no loss of vanadium and enrichment of vanadium; the calcium can be rapidly and efficiently precipitated, the high-purity calcium carbonate can be prepared, the pyrolysis volatilization loss of ammonium salt is basically avoided, and the method has the advantages of high action efficiency and high preparation speed; the precipitated calcium filtrate can be subjected to zero-supplement circulating leaching through simple regeneration treatment, and has the effects of saving and environmental protection. The new process has strong applicability, and satisfactory effects can be obtained no matter the high-calcium vanadium-containing steel slag with the CaO content reaching fifty-six percent or the low-calcium vanadium-containing steel slag with the CaO content being only thirty percent.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention to its proper form. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

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

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.