阅读说明：本技术 一种粗锑精炼过程深度除镉的方法 (Method for deeply removing cadmium in crude antimony refining process ) 是由 周威 赵俊华 郝文斌 刘富金 于 2021-09-10 设计创作，主要内容包括：本发明涉及一种粗锑精炼过程深度除镉的方法,属于粗锑精炼技术领域。该方法包括粗锑熔炼、制备除杂剂、一次造渣、二次造渣、气洗和脱渣步骤,其中提供一种除杂剂,该除杂剂由锑水质量2％-8％的磷酸和0.5％-2％的五氧化二磷混合制成,在造渣时,除杂剂直接与铅反应生成磷酸铅类盐浮渣,磷酸受热脱水生成偏磷酸,其与锑水中的被氧化的镉生成偏磷酸类镉盐浮渣,脱出的高温水再与五氧化二磷生成磷酸,之后进一步脱水生成偏磷酸,持续与镉造渣,使得在除铅的同时对镉进行深度处理,经测试,采用本发明精炼出的锑锭铅含量为0.017％-0.024％,镉含量为0.0008％-0.0012％,达到精品锑产品级别。(The invention relates to a method for deeply removing cadmium in a crude antimony refining process, belonging to the technical field of crude antimony refining. The method comprises the steps of crude antimony smelting, impurity removing agent preparation, primary slagging, secondary slagging, gas washing and deslagging, wherein an impurity removing agent is provided, the impurity removing agent is prepared by mixing phosphoric acid with 2% -8% of antimony water by mass and phosphorus pentoxide with 0.5% -2% of antimony water by mass, during slagging, the impurity removing agent directly reacts with lead to generate lead phosphate salt scum, the phosphoric acid is heated and dehydrated to generate metaphosphoric acid, the metaphosphoric acid cadmium salt scum is generated with cadmium in antimony water by oxidation, the dehydrated high-temperature water and the phosphorus pentoxide generate phosphoric acid, then the metaphosphoric acid is further dehydrated to generate metaphosphoric acid, and cadmium is continuously slagging, so that cadmium is deeply treated while lead is removed, and tests show that the lead content of an antimony ingot refined by adopting the method is 0.017% -0.024%, the cadmium content is 0.0008% -0.0012%, and the grade of a fine antimony product is achieved.)

1. A method for deeply removing cadmium in a crude antimony refining process is characterized by comprising the following steps:

step S1: smelting crude antimony: adding crude antimony into a reflecting furnace, and heating to a molten state to obtain antimony water;

step S2: preparing an impurity removing agent: mixing phosphoric acid and phosphorus pentoxide to prepare an impurity removing agent;

step S3: primary slagging: blowing 70-75% of impurity removing agent and preheated air from the bottom of the antimony water for primary slagging;

step S4: secondary slagging: blowing the residual impurity removing agent and preheated air from the bottom of the antimony water for secondary slagging;

step S5: air washing: blowing preheated nitrogen from the bottom of the antimony water through a blowing pipe to bring scum in the antimony water to the surface layer of the antimony water;

step S6: deslagging: and (3) placing a blower above the antimony water to blow the surface scum to one side for separation.

2. The method as claimed in claim 1, wherein in step S1, the heating temperature of the crude antimony is 950-.

3. The method of claim 1, wherein in step S2, the amount of phosphoric acid used in the impurity removing agent is 2-8% of the weight of antimony water, and the amount of phosphorus pentoxide is 0.5-2% of the weight of antimony water.

4. The method as claimed in claim 1, wherein the step S2, before mixing phosphoric acid and phosphorus pentoxide, is performed with low temperature drying treatment.

5. The method as claimed in claim 1, wherein the temperature of the preheated air in steps S3 and S4 is 600-650 ℃.

6. The method for deeply removing cadmium in the refining process of crude antimony as claimed in claim 1, wherein in step S3, the flow rate of the preheated air is 20-30L/min, and the flow rate of the preheated air is 1.4-1.5 times of the volume of the antimony water.

7. The method for deeply removing cadmium in the refining process of crude antimony as claimed in claim 1, wherein in step S4, the flow rate of the preheated air is 8-12L/min, and the flow rate of the preheated air is 1-1.3 times of the volume of the antimony water.

8. The method as claimed in claim 1, wherein in step S5, the temperature of the preheated nitrogen is 700-.

Technical Field

The invention belongs to the technical field of crude antimony refining, and particularly relates to a method for deeply removing cadmium in a crude antimony refining process.

Background

The antimony and the antimony compound are widely applied to the fields of flame retardants, alloys, enamels, batteries, semiconductors, medicines, munitions and the like, and have the characteristics of low substitution degree, high munitions demand degree and single supply source.

In the prior art, an antimony hydrometallurgy process is usually adopted to treat antimony-containing complex multi-metal paragenetic ore, crude antimony produced by the process contains more lead and arsenic and a small amount of cadmium, the cadmium is a harmful element in a refined antimony product, the cadmium content in the refined antimony is required to be not more than 0.002%, in the prior art, an alkaline fire refining process is adopted to refine the crude antimony, the removal rate of the lead and the arsenic is high, but no mature refining method is provided for the cadmium at present, so that the cadmium content in a final finished product is unstable, and a large amount of antimony products containing excessive cadmium cannot be refined into standard refined antimony products.

Disclosure of Invention

The invention aims to provide a method for deeply removing cadmium in a crude antimony refining process, which solves the technical problem of poor cadmium removal effect in the crude antimony refining in the prior art.

The purpose of the invention can be realized by the following technical scheme:

a method for deeply removing cadmium in a crude antimony refining process comprises the following steps:

step S1: smelting crude antimony: adding the crude antimony into a reverberatory furnace, heating to 950-980 ℃ and keeping the temperature for 3.7-4.2min/t to completely melt the crude antimony to obtain antimony water;

step S2: preparing an impurity removing agent: adding the phosphoric acid and the phosphorus pentoxide subjected to low-temperature drying treatment into an anhydrous stirrer, and stirring to fully mix the phosphoric acid and the phosphorus pentoxide to prepare an impurity removing agent;

step S3: primary slagging: adding an impurity removing agent into a chemical box above an air blowing pipe, blowing preheated air and the impurity removing agent from the bottom of antimony water through the air blowing pipe, directly slagging a part of the impurity removing agent with lead in the antimony water to generate lead phosphate salt, floating the lead phosphate salt on the surface of the antimony water along with scum, oxidizing cadmium contained in the antimony water by oxygen in the air under a high-temperature environment to generate cadmium oxide, heating and dehydrating a part of phosphoric acid in the impurity removing agent to generate metaphosphoric acid, producing phosphoric acid by the dehydrated high-temperature water and phosphorus pentoxide, further dehydrating the phosphorus pentoxide to generate metaphosphoric acid, continuously carrying out slagging reaction with the cadmium oxide in the antimony water to generate metaphosphoric acid cadmium salt scum, and floating the cadmium salt scum on the surface of the antimony water;

step S4: secondary slagging: blowing preheated air and an impurity removing agent from the bottom of the antimony water through an air blowing pipe to carry out secondary slagging;

step S5: air washing: blowing preheated nitrogen from the bottom of the antimony water through an air blowing pipe, stirring the antimony water, and taking scum in the antimony water out of the surface layer of the antimony water;

step S6: deslagging: and (3) placing a blower above the antimony water to blow the surface scum to one side for separation.

Further, in step S2, the amount of phosphoric acid used is 2% -8% by weight of the antimony water, and the amount of phosphorus pentoxide used is 0.5% -2% by weight of the antimony water.

Further, in the step S3 and the step S4, the temperature of the preheated air is 600-.

Further, in step S3, the usage amount of the impurity removing agent is 70% -75% of the mass of the impurity removing agent, the inlet flow rate of the preheated air is 20-30L/min, the inlet flow rate of the preheated air is 1.4-1.5 times of the volume of the antimony water, the scum generated in the antimony water is rapidly taken out by one-time slagging with higher gas flow, and the deslagging efficiency is improved.

Further, in step S4, the amount of the impurity removing agent is the remaining impurity removing agent, the flow rate of the preheated air is 8-12L/min, the flow rate of the preheated air is 1-1.3 times of the volume of the antimony water, and the secondary slagging is performed at a lower flow rate, so that the impurity removing agent fully reacts with the lead and cadmium impurities with lower content, and the antimony water is prevented from being greatly stirred by the high-flow preheated air to affect slagging.

Further, in step S5, the temperature of the preheated nitrogen is 700-.

The invention has the beneficial effects that:

1. the invention adopts the compounding of phosphoric acid and phosphorus pentoxide as an impurity removing agent, the phosphoric acid and phosphorus pentoxide can react with lead in antimony water to generate lead phosphate salt scum, the lead is effectively removed, the impurity removing agent takes preheated air as a carrier to be introduced from the bottom of the antimony water, oxygen in the air oxidizes cadmium, the phosphoric acid is heated and dehydrated to generate metaphosphoric acid, the metaphosphoric acid cadmium salt scum is generated with cadmium in the antimony water, the removed high-temperature water and the phosphorus pentoxide generate phosphoric acid, the metaphosphoric acid is further dehydrated to generate metaphosphoric acid, and the cadmium is continuously slagging.

2. The method adopts 600-plus 650-DEG C preheated air as a carrier of the impurity removing agent, the preheated air at the temperature is introduced from the bottom of the reverberatory furnace, the temperature of the preheated air is slowly reduced to antimony water, the reverberatory furnace compensates heat, the temperature of the antimony water is maintained at about 750 ℃ during the introduction of the preheated air, the fluidity of the antimony water is moderate, the impurity removing agent contained in the preheated air and the antimony water are fully reacted to form slag, the reaction speed of lead phosphate salt and metaphosphate cadmium salt is high at the temperature, the slag tapping efficiency is high, and meanwhile, the preheated air floats upwards to bring generated scum to the surface layer of the antimony water, so that the scum is favorably separated.

3. The invention adopts reasonable process design, carries out advanced treatment on cadmium while removing lead, has simple process and good impurity removal effect, and tests show that the lead content of the antimony ingot refined by the invention is 0.017-0.024 percent, the cadmium content is 0.0008-0.0012 percent, and the antimony ingot reaches the grade of a fine antimony product.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a process flow diagram of the method for deep removal of cadmium in the course of refining crude antimony.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention adopts crude antimony 6t produced by a wet antimony smelting process to carry out refining in three batches according to the method provided by the invention, and the specific implementation process is as the following embodiment.

Example 1

In this example, referring to fig. 1, the refining process of crude antimony is as follows:

smelting crude antimony: adding crude antimony into a reverberatory furnace, heating to 950 deg.C, maintaining for 8.4min to completely melt crude antimony to obtain antimony water, and synchronously measuring volume of the antimony water to 0.292m³；

Preparing an impurity removing agent: stirring phosphoric acid and phosphorus pentoxide, respectively, blowing dry with 40 deg.C dry nitrogen gas for 1h under stirring, then weighing 40kg phosphoric acid and 40kg phosphorus pentoxide, adding into a stirrer, and stirring at 240r/min for 30min to obtain impurity removing agent;

primary slagging: adding an impurity removing agent into a chemical box above an air blowing pipe, blowing preheated air and 70% of the impurity removing agent into the chemical box from the bottom of the antimony water through the air blowing pipe, controlling the temperature of the preheated air to be 600 ℃, leading in the flow of the preheated air to be 20L/min, leading in the amount of the preheated air to be 1.4 times of the volume of the antimony water, and carrying out primary slagging.

Secondary slagging: blowing preheated air and the residual impurity removing agent from the bottom of the antimony water through an air blowing pipe, carrying out secondary slagging, controlling the temperature of the preheated air to be 600 ℃, controlling the introduction flow of the preheated air to be 8L/min, and carrying out secondary slagging when the introduction amount of the preheated air is equal to the volume of the antimony water;

air washing: blowing preheated nitrogen from the bottom of the antimony water through an air blowing pipe, stirring the antimony water, taking scum out of the antimony water to the surface layer of the antimony water, controlling the temperature of the preheated nitrogen to be 700 ℃, introducing the preheated nitrogen at a flow rate of 4L/min, and performing air washing, wherein the introduction amount of the preheated nitrogen is 1.9 times of the volume of the antimony water;

step S6: deslagging: placing a blower above the antimony water, blowing for 30min, and taking out the scum at a lower air inlet.

Example 2

In this example, referring to fig. 1, the refining process of crude antimony is as follows:

smelting crude antimony: adding crude antimony into a reverberatory furnace, heating to 970 deg.C, maintaining for 8min to completely melt crude antimony to obtain antimony solution, and synchronously measuring volume of the antimony solution to be 0.302m³；

Preparing an impurity removing agent: stirring phosphoric acid and phosphorus pentoxide, respectively, blowing dry with 40 deg.C dry nitrogen gas for 1h under stirring, then weighing 160kg phosphoric acid and 10kg phosphorus pentoxide, adding into a stirrer, and stirring at 660r/min for 10min to obtain impurity removing agent;

primary slagging: adding an impurity removing agent into a chemical box above an air blowing pipe, blowing preheated air and 72% of the impurity removing agent into the chemical box from the bottom of the antimony water through the air blowing pipe, controlling the temperature of the preheated air to be 650 ℃, leading in the flow of the preheated air to be 25L/min, leading in the amount of the preheated air to be 1.5 times of the volume of the antimony water, and carrying out primary slagging.

Secondary slagging: blowing preheated air and the residual impurity removing agent from the bottom of the antimony water through an air blowing pipe, carrying out secondary slagging, controlling the temperature of the preheated air to be 650 ℃, controlling the introduction flow of the preheated air to be 10L/min, and controlling the introduction amount of the preheated air to be 1.2 times of the volume of the antimony water, and carrying out secondary slagging;

air washing: blowing preheated nitrogen from the bottom of the antimony water through an air blowing pipe, stirring the antimony water, taking scum out of the antimony water to the surface layer of the antimony water, controlling the temperature of the preheated nitrogen to be 750 ℃, introducing the preheated nitrogen at a flow rate of 5L/min, and performing air washing, wherein the introduction amount of the preheated nitrogen is 2 times of the volume of the antimony water;

step S6: deslagging: placing a blower above the antimony water, blowing for 30min, and taking out the scum at a lower air inlet.

Example 3

In this example, referring to fig. 1, the refining process of crude antimony is as follows:

smelting crude antimony: adding crude antimony into a reverberatory furnace, heating to 980 deg.C, maintaining for 7.4min to completely melt crude antimony to obtain antimony water, and synchronously measuring volume of the antimony water to 0.305m³；

Preparing an impurity removing agent: stirring phosphoric acid and phosphorus pentoxide, respectively, blowing dry with 40 deg.C dry nitrogen gas for 1h under stirring, then weighing 100kg phosphoric acid and 26kg phosphorus pentoxide, adding into a stirrer, and stirring at 360r/min for 20min to obtain impurity removing agent;

primary slagging: adding an impurity removing agent into a chemical box above an air blowing pipe, blowing preheated air and 75% of the impurity removing agent into the chemical box from the bottom of the antimony water through the air blowing pipe, controlling the temperature of the preheated air to be 650 ℃, controlling the introduction flow of the preheated air to be 30L/min, and carrying out primary slagging, wherein the introduction amount of the preheated air is 1.5 times of the volume of the antimony water.

Secondary slagging: blowing preheated air and the residual impurity removing agent from the bottom of the antimony water through an air blowing pipe, carrying out secondary slagging, controlling the temperature of the preheated air to be 650 ℃, controlling the introduction flow of the preheated air to be 12L/min, and controlling the introduction amount of the preheated air to be 1.3 times of the volume of the antimony water, and carrying out secondary slagging;

air washing: blowing preheated nitrogen from the bottom of the antimony water through an air blowing pipe, stirring the antimony water, taking scum out of the antimony water to the surface layer of the antimony water, controlling the temperature of the preheated nitrogen to be 800 ℃, introducing the preheated nitrogen at a flow rate of 7L/min, and performing air washing, wherein the introduction amount of the preheated nitrogen is 2.1 times of the volume of the antimony water;

step S6: deslagging: placing a blower above the antimony water, blowing for 30min, and taking out the scum at a lower air inlet.

The antimony water treated in the embodiment 1-3 is naturally cooled and formed to obtain antimony ingots, the antimony ingots are respectively sampled, the content of lead and cadmium in the antimony ingots is measured according to GB/T1599-:

TABLE 1

As can be seen from Table 1, the lead content of the refined lead by the treatment method provided by the invention is 0.017% -0.024%, the cadmium content is 0.0006% -0.0008%, and the lead and the cadmium are effectively and deeply treated.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is merely exemplary and illustrative of the principles of the present invention and various modifications, additions and substitutions of the specific embodiments described herein may be made by those skilled in the art without departing from the principles of the present invention or exceeding the scope of the claims set forth herein.