CN103060570B - A method for extracting valuable components from sludge - Google Patents

Abstract

The invention discloses a method for extracting valuable components from copper sludge. The method utilizes vacuum distillation technology, vacuum secondary distillation, high-temperature oxidation roasting, arsenic extraction and crude antimony refining to realize arsenic, arsenic oxides and other volatile components. Separation and extraction of non-toxic metals to achieve the recovery of valuable metals and the purpose of reducing the content of harmful components in the sludge. The process is simple and the investment in equipment is small. The purpose of reducing the content of harmful elements, thereby reducing the leaching toxicity or solidification cost of sludge.

Description

A method for extracting valuable components from sludge

technical field

The invention relates to a comprehensive utilization technology of metallurgical hazardous solid waste, which is a technology for extracting valuable components from copper sludge, and belongs to the field of comprehensive utilization of resources and harmless disposal of hazardous waste.

technical background

A large amount of acidic wastewater is produced in the process of copper pyrometallurgy. The treatment of this type of wastewater is usually carried out by lime neutralization and precipitation, so that heavy metals are precipitated in the form of hydroxides, and a large amount of mixed sludge containing Cu, Sn, Zn, and As is produced. . The main component of these sludges is gypsum, but it is rich in arsenic and other heavy metals. If it is allowed to pile up randomly, it will cause serious harm to the environment. Due to the complex composition of sludge and various toxic and harmful substances, long-term stacking will not only encroach on land, but also seriously pollute groundwater, soil and farmland, affecting human health and the ecological environment. The sludge contains a variety of toxic and harmful substances, which must be disposed of harmlessly to achieve the purpose of pollution prevention and control.

Since this type of copper sludge contains a large amount of valuable components, such as As, Zn, Cu, Ag, Sb, Se, etc., if the valuable components can be effectively recovered, not only the waste of resources can be avoided, but more importantly, the waste of resources can be reduced. The content of harmful components in the sludge can reduce the pollution to the environment.

Compared with traditional wet leaching, it does not need multiple solid-liquid separations, which reduces the sludge treatment process. Compared with the traditional direct high-temperature roasting, the yield of arsenic and other volatile elements is improved, and the cost is saved. Compared with the traditional sludge solidification technology, it improves the utilization rate of sludge, recovers valuable metals, saves costs, reduces the cost of sludge solidification and reduces the harm of sludge to the environment.

In view of the above reasons, the present invention proposes a new method for recovering arsenic and volatile valuable metals in copper sludge to realize comprehensive utilization of sludge.

Contents of the invention

This method proposes a method for extracting valuable components of copper sludge, using sludge produced by copper pyrometallurgy as the main raw material, and using vacuum technology to achieve the separation and extraction of arsenic, arsenic oxides and other volatile metals to reduce The purpose of reducing the content of harmful components in copper sludge, thereby reducing the leaching toxicity or solidification cost of copper sludge.

The invention comprises the following steps:

(1) Dehydration pretreatment is carried out on the sludge, which is dried at 100°C~150°C for 12 hours to remove the water in it. After pretreatment, the sample is ground to control the particle size of the material to be about 0.45~1.0mm;

(2) Fully mix the pretreated sample with a certain amount of reducing agent (coal powder, coke, etc.), and the amount of reducing agent added is controlled within the range of 5-10%; the fully mixed material is placed in a vacuum furnace evacuate the furnace at the same time; control the residual pressure of the vacuum furnace within the range of 6.67~26.7Pa, control the temperature within the range of (800~1200°C), and perform vacuum high temperature treatment for 20~60min;

(3) As the temperature and vacuum degree of the vacuum furnace increase, the volatile components such as As and Sb in the reaction sludge are volatilized by reduction or decomposition, and are collected in the form of condensation to obtain a rectification product. The distillation product is mainly a mixture of arsenic and antimony, containing a small amount of volatile impurities such as Pb and Zn, and dust generated by roasting. Put the primary distillation product containing arsenic and antimony back into the vacuum furnace for secondary distillation It can further increase the content of valuable components. The distillation temperature is 400-800°C, and the residual pressure of the vacuum furnace is 5.33-66.7Pa. %above;

(4) Use the conventional antimony refining method to recover arsenic and antimony from the above-mentioned collected As and Sb alloys. During the refining of arsenic and antimony alloys, arsenic is preferentially evaporated. The refining process is carried out at 500-700 °C and a residual pressure of 40 Pa for 30-60 minutes. , recover arsenic and antimony respectively, wherein a reducing agent is added in alloy refining, and the amount of reducing agent added is 5-10% of the mass of the material;

(5) Put the residual material from the first distillation together with the residual material from the second distillation, put it into the roaster, and pass _O2 into it for oxidation roasting, the roasting temperature is 500~850°C, and the roasting time is 60~120min , collect As ₂ O ₃ gas to prevent environmental pollution, and solidify the roasted material.

The reducing agent in the present invention is coal powder and coke.

The sludge treated in the present invention is the waste water produced by using flue gas to make acid during the copper pyrometallurgy process, and the sludge containing high arsenic and other heavy metals produced after the waste water passes through the waste water treatment station is generally referred to as copper sludge.

The solidification treatment in the present invention is a process of using conventional methods to blend the roasted sludge into a dense inert base material by using physical-chemical methods to stabilize it; or to use the roasted sludge The process by which an inert material is contained. The treated sludge contains a large amount of heavy metal elements. In order to prevent the heavy metal elements from causing secondary pollution to the environment, the sludge must be solidified.

Advantages of the present invention:

Compared with the traditional direct solidification treatment of sludge, it can effectively recover valuable elements such as As and Sb, improve the utilization rate of resources, and prevent harmful elements such as arsenic from entering the atmosphere and polluting the surrounding environment.

Compared with the previous method of directly roasting sludge for arsenic removal, the present invention can better ensure the recovery effect of arsenic and antimony through primary distillation and secondary distillation, and can prevent additional slaked lime from being added to calcined sludge. leaching of arsenic.

Compared with wet leaching, the present invention does not need to perform multiple solid-liquid separations, reduces operation links and saves costs.

Due to the adoption of the above process method, the present invention has simple process, less equipment input, low cost, no pollution in the extraction process, and is a new process for treating sludge.

Through the method of the invention, the recovery rate of arsenic and antimony in the valuable components can be increased to over 98%, and the recovery rate of antimony can be increased to over 95%.

Description of drawings

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

Detailed ways

Embodiment 1: the extraction method of this sludge valuable component, specific content is as follows:

What this embodiment used was the sludge produced after the copper smelter wastewater treatment, and its components are shown in Table 1:

Table 1: Sludge composition after wastewater treatment in a copper smelter

element As Sb Zn C o Ca Pb content% 16 6.5 4 5.5 twenty four 42 2

1. Perform dehydration pretreatment on 20g of sludge, dry it at 100°C for 15 hours, grind the sample after drying, and the particle size of the material after grinding is 1.0mm;

2. Mix the pretreated material with the reducing agent pulverized coal, add 5% coal pulverized by the mass of the material, put the material into a vacuum furnace after mixing, the residual pressure of the vacuum furnace is 6.67Pa, and carry out vacuum high-temperature rectification at 800°C Treat for 60 minutes, then collect the volatile components volatilized in the reaction sludge in a condensed manner, and obtain 6 g of a mixture containing As and Sb in the primary distillation product;

3. Put the primary distillation product containing As and Sb into a vacuum furnace for vacuum redistillation, the distillation temperature is 400°C, and the residual pressure of the vacuum furnace is 40Pa for 40 minutes, and the volatile components are collected by condensation to obtain an alloy containing As and Sb 4.46g;

4. Perform antimony refining on the alloys of As and Sb collected by condensation above to recover arsenic and antimony. Arsenic evaporates preferentially during the distillation of arsenic and antimony alloys. The antimony refining process evaporates at 500°C for 30 minutes under a residual pressure of 40 Pa, and respectively recovers arsenic 3.15 g, antimony 1.24g; the recovery rate of arsenic is 98.4%, and the recovery rate of antimony is 95.4%;

5. Collect the residual material produced by the first rectification and the residual material of the second rectification together, put it into the roaster, pass _O2 to carry out oxidation roasting, the roasting temperature is 500 ° C, the roasting time is 120min, by changing The structure of the material makes it loose and porous, and at the same time, the residual arsenic is volatilized from the sludge in the form of volatile oxide As ₂ O ₃ , and As ₂ O ₃ gas is collected, thereby reducing the leaching toxicity or solidification cost of the sludge, and roasting The final material is cured by conventional methods (see Figure 1).

Embodiment 2: the extraction method of this sludge valuable component, specific content is as follows:

What used in the present embodiment is the sludge after the wastewater treatment of a certain copper smelter, and its composition is as follows:

Table 2: Sludge composition after wastewater treatment in a copper smelter

element As Sb Zn C o Ca Pb content% 18.5 7.5 3.5 6 22.5 40 2

1. Perform dehydration pretreatment on 20g of sludge, dry it at 120°C for 12 hours, grind the sample after drying, and the particle size of the material after grinding is 0.8mm;

2. Mix the pretreated material with the reducing agent coal powder, add coal powder with 10% of the material mass, and put the material into a vacuum furnace after mixing. After 40 minutes of treatment, the volatile components volatilized in the reaction sludge were collected in a condensed manner to obtain 6.5 g of a mixture containing As and Sb in the primary distillation product;

3. Put the primary distillation product containing As and Sb into a vacuum furnace for vacuum redistillation, the distillation temperature is 800°C, and the residual pressure of the vacuum furnace is 66.7Pa for 30 minutes to obtain 5.14g of condensate containing As and Sb;

4. The above-mentioned condensed collected As and Sb alloys are subjected to antimony refining to recover arsenic and antimony. During the distillation of arsenic, antimony and alloys, arsenic is preferentially evaporated. Antimony refining is performed at 700°C and evaporated at a residual pressure of 40 Pa for 60 minutes, and arsenic is recovered separately. 3.66g, antimony 1.46g; the recovery rate of arsenic is 98.9%, and the recovery rate of antimony is 97.3%;

5. Collect the residual material produced by the first rectification and the residual material of the second rectification together, put it into the roaster, and pass _O2 to carry out oxidation roasting. The roasting temperature is 850 ° C, and the roasting time is 60 minutes. As ₂ O ₃ gas, the calcined material is solidified by conventional methods.

Embodiment 3: the extraction method of this sludge valuable component, specific content is as follows:

What used in the present embodiment is the sludge after the wastewater treatment of a certain copper smelter, and its composition is as follows:

Table 3: Sludge composition after wastewater treatment in a copper smelter

element As Sb Zn C o Ca Pb content% 17 6.5 3.5 8 twenty one 41 3

1. Perform dehydration pretreatment on 20g of sludge, dry it at 120°C for 12 hours, grind the sample after drying, and the particle size of the material after grinding is 0.45mm;

2. Mix the pretreated material with the reducing agent coal powder, add coke with a mass of 18% of the material, put the material into a vacuum furnace after mixing, the residual pressure of the vacuum furnace is 7Pa, and carry out vacuum high-temperature rectification treatment at 1200 ° C for 20 minutes , and then the volatile components volatilized in the reaction sludge are collected in a condensed manner to obtain 5.8 g of a mixture containing As and Sb in the primary distillation product;

3. Put the primary distillation product containing As and Sb into a vacuum furnace for vacuum redistillation, the distillation temperature is 650°C, and the residual pressure of the vacuum furnace is 6Pa for 50 minutes to obtain 4.67g of condensate containing As and Sb;

4. Collect As and Sb alloys from the above-mentioned condensation for antimony refining to recover arsenic and antimony. Arsenic evaporates preferentially during the distillation of arsenic and antimony alloys. The antimony refining process evaporates for 40 minutes under a residual pressure of 40 Pa at 500°C, and recovers 3.38 g of arsenic respectively. , antimony 1.26g; the recovery rate of arsenic is 99.4%, and the recovery rate of antimony is 96.9%;

5. Collect the residual material produced by the first rectification and the residual material of the second rectification together, put it into the roaster, pass _O2 to carry out oxidation roasting, the roasting temperature is 600°C, the roasting time is 100min, and collect at the same time As ₂ O ₃ gas, the calcined material is solidified by conventional methods.

Claims (2)

1. an extracting method for copper mud valuable constituent, is characterized in that carrying out as follows:

(1) pre-treatment of mud: to the pre-treatment of dewatering of copper mud, drying and processing is 12 hours at 100 ~ 150 ℃, dry after sample grind, after grinding, raw meal particle size is 0.45 ~ 1.0mm;

(2) material after pre-treatment is mixed with reductive agent, mix rear material and put into vacuum oven, vacuum oven residual voltage is 6.67 ~ 26.7Pa, at 800 ~ 1200 ℃, carry out vacuum high-temperature rectification process 20 ~ 60min, then the easy volatile composition evaporating in reaction mud is collected in the mode of condensation, obtain rectifying product one time, to contain arsenic, a rectifying product of antimony is put into vacuum oven again and is carried out vacuum vapor enrichment, distillation temperature is 400 ~ 800 ℃, under vacuum oven residual voltage 5.33 ~ 66.7Pa, distill 30 ~ 50min, fugitive constituent is collected in condensation, obtain containing arsenic, the alloy of antimony, wherein the addition of reductive agent be after pre-treatment quality of material 5 ~ 10%,

(3) arsenic of collection, antimony alloy are adopted conventional antimony method of refining carry out the recovery of arsenic and antimony, antimony refining is to process 30 ~ 60min under 500 ~ 700 ℃, residual voltage 40Pa, obtain respectively arsenic and antimony, wherein in refining and modifying, add reductive agent, the addition of reductive agent is for containing 5 ~ 10% of arsenic, antimony alloy quality of material;

(4) residual material rectifying for the first time being produced is collected together with the residual material of rectifying for the second time, puts into stoving oven, passes into O ₂carry out oxidizing roasting, maturing temperature is 500 ~ 850 ℃, and roasting time 60 ~ 120min collects As simultaneously ₂o ₃gas, is cured processing by the material after roasting;

Wherein said copper mud be in copper pyrometallurgy process with the waste water producing after flue gas acid preparing, waste water after waste water processing station, produce containing high arsenic and other heavy metal sewage sludge.

2. the extracting method of copper mud valuable constituent according to claim 1, is characterized in that: reductive agent is coal dust, coke.

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