JP5546289B2 - Method and system for processing fine powder containing lead component and calcium component - Google Patents

Description

  The present invention relates to a processing method and a processing system for fine powder containing lead components and calcium components such as molten fly ash and chlorine bypass dust.

Conventionally, various techniques for recovering useful components such as lead from fine powder such as molten fly ash are known.
For example, in a method for recovering gypsum from molten fly ash containing a calcium component, a chlorine component, and a valuable metal component, the molten fly ash is adjusted to pH 7 to 10 with a hydrochloric acid-containing aqueous solution and leached to obtain the molten fly ash. A leaching step of leaching the majority of the calcium component and the chlorine component from the ash to produce a leachate; and a balance of the calcium component and the valuable metal component in the molten fly ash from the leachate produced in the leaching step A first solid-liquid separation step for separating the contained solid content, and adding and reacting sulfuric acid to the leachate from which the solid content has been removed in the first solid-liquid separation step to precipitate gypsum, A reaction step of forming a hydrochloric acid-containing aqueous solution, a second solid-liquid separation step of separating the gypsum precipitated in the reaction step from the hydrochloric acid-containing aqueous solution, and the second solid-liquid separation Method for recovering gypsum some or all of the hydrochloric acid-containing aqueous solution in which the gypsum has been removed from the molten fly ash and a step back to the leaching step in extent has been proposed (Patent Document 1).

JP 2008-246398 A

Conventionally, when recovering useful components such as lead components from fine powder such as molten fly ash, as described in Patent Document 1 above, the fine powder, water and hydrochloric acid are mixed, After the calcium component, chlorine component, and the like are eluted, solid-liquid separation is performed to obtain a solid component containing a useful component such as a lead component and a liquid component containing a calcium component, a chlorine component, and the like.
However, in this case, it is difficult to contain all of the lead component in the solid component and all of the calcium component in the solution component. For example, part of the lead component does not remain in the solid content but elutes in the liquid content. Also, if the fine powder is a processing object comprises a sulfate component (SO _3), solids not only lead sulfate, including calcium sulfate.
Therefore, the present invention provides a processing method and a processing system for a fine powder containing a lead component and a calcium component, which has a high recovery rate of the lead component and can separate and recover the lead component and the calcium component. Objective.

As a result of intensive studies to solve the above problems, the present inventor has added a chemical in the order of a sulfiding agent and hydrochloric acid to a slurry containing fine powder that is a processing target, thereby improving the lead component recovery rate. The present invention has been completed by finding that it is high and that the lead component and calcium component can be separated and recovered.
That is, the present invention provides the following [1] to [4].
[1] (A) A lead sulfide generation step of obtaining a slurry containing lead sulfide by mixing fine powder containing a lead component and a calcium component, water, and a sulfiding agent, (B) the slurry, and hydrochloric acid And a calcium component elution step of eluting the calcium component in the fine powder to obtain a slurry containing the lead sulfide and the eluted calcium component. Fine powder processing method.
[2] (C) Hydrophobizing step of adding a hydrophobizing agent to the slurry obtained in step (B) to hydrophobize the lead sulfide to obtain a slurry for flotation, (D) Flotation A method for treating fine powder containing a lead component and a calcium component according to the above [1], comprising a flotation step of subjecting the slurry for flotation to a flotation step including a lead sulfide.
[3] A fine powder containing a lead component and a calcium component according to [1] or [2], wherein the fine powder is at least one selected from molten fly ash, incinerated fly ash, and chlorine bypass dust. Processing method.
[4] and fine powder containing lead component and calcium components, and water, a mixture of a sulfurizing agent, and mixing tank to obtain a slurry containing lead sulfide, and the slurry obtained in the mixing tank, hydrochloride mixed and, in addition the calcium component dissolution tank to obtain a slurry containing lead sulfide and eluted calcium component, a hydrophobic agent to the slurry obtained in the above calcium component dissolution tank, hydrophobic the lead sulfide A hydrophobization reaction tank for obtaining a flotation slurry, and a flotation machine for flotation treatment of the flotation slurry to obtain a flotation containing lead sulfide. System for processing fine powder containing lead component and calcium component.

According to the present invention, the lead component can be recovered at a high recovery rate (for example, 98% by mass or more) as a solid content at the time after adding the sulfurizing agent and hydrochloric acid.
In addition, according to the present invention, lead sulfide is contained as a float by performing, for example, a hydrophobization process and a flotation process on the solid content including the lead component recovered at such a high recovery rate. Solids can be recovered. This solid content has a high quality, contains lead component, and has a small content of calcium component. By this flotation process, the lead component can be recovered at a high recovery rate.

It is a flowchart which shows an example of the processing method of the fine powder of this invention. It is a figure which shows notionally an example of the processing system of the fine powder of this invention.

First, the processing method of the fine powder of this invention is demonstrated.
The fine powder processing method of the present invention comprises (A) mixing a fine powder (for example, molten fly ash) containing a lead component and a calcium component, water, and a sulfiding agent (for example, sodium hydrosulfide) to lead sulfide. A lead sulfide generation step for obtaining a slurry containing a product, (B) a slurry containing lead sulfide and the eluted calcium component by mixing the slurry and hydrochloric acid to elute the calcium component in the fine powder. And a calcium component elution step to be obtained.
In the method for treating fine powder of the present invention, in addition to the steps (A) and (B), a hydrophobizing agent (eg, xanthate) is added to the slurry obtained in (C) step (B). Hydrophobizing the lead sulfide to obtain a flotation slurry, and (D) a flotation process to obtain a flotation containing lead sulfide by flotation treatment of the flotation slurry. Can be included. FIG. 1 shows an example including steps (A) to (D).
Hereinafter, each step will be described in detail.

[Step (A); lead sulfide generation step]
Step (A) is a step of obtaining a slurry containing lead sulfide by mixing fine powder containing a lead component and a calcium component, water, and a sulfiding agent.
Examples of the fine powder to be treated in the present invention include molten fly ash, incinerated fly ash, and chlorine bypass dust.
Examples of the sulfiding agent include sodium hydrosulfide (NaSH), sodium sulfide (Na ₂ S), hydrogen sulfide gas (H ₂ S), and the like.
Examples of the lead sulfide generated in the slurry include lead sulfide (PbS).
The mass of the fine powder containing a lead component and a calcium component per liter of water is preferably 5 to 300 g / liter, more preferably 20 to 250 g / liter, and particularly preferably 50 to 200 g / liter. When the value is less than 5 g / liter, the amount of water per unit mass of the fine powder becomes large, and the treatment efficiency is lowered. When this value exceeds 300 g / liter, the separation performance of the lead component and other components (particularly calcium component) in the step (D) (floating beneficiation step) is lowered.
Although the pH of a slurry is not specifically limited, For example, it is 8 or more.

[Step (B); Calcium component elution step]
In the step (B), the slurry obtained in the step (B) is mixed with hydrochloric acid to elute the calcium component in the fine powder which is the object to be treated, and the slurry containing lead sulfide and the eluted calcium component It is the process of obtaining.
The amount of hydrochloric acid added is not particularly limited, but is preferably such an amount that the pH of the slurry is in the range of 2-7. If the pH is less than 2, the increase in the elution amount of calcium component, chlorine component, etc. will reach a peak, while the addition amount of hydrochloric acid will increase and the drug cost will increase. When the pH exceeds 7, elution of calcium component, chlorine component and the like becomes insufficient, and the separation performance of the lead component and other components (particularly calcium component) in the step (D) (floating flotation step) is lowered.
The ratio of the mass of the lead component contained in the solid content in the slurry obtained in the step (B) to the total amount (100 mass%) of the lead component contained in the fine powder that is the object to be treated is usually 98% by mass or more. It is.

[Step (C); Hydrophobization step]
Step (C) is a step of adding a hydrophobizing agent to the slurry obtained in step (B) to hydrophobize lead sulfide in the slurry to obtain a slurry for flotation.
In the step (C) (hydrophobization step), as a pretreatment of the step (D) (floating beneficiation step), a hydrophobizing agent is added to hydrophobize the lead sulfide particles.
Flotation is the supply of gas into water containing particles having a hydrophobic surface and particles having a hydrophilic surface, and the particles having a hydrophobic surface are attached to the surface of the foam made of this gas. The bubbles to which the particles are attached are separated into particles having a hydrophilic surface that is a deposit and particles having a hydrophobic surface that is a float by lifting the bubbles by buoyancy in water. .
Usually, various chemical agents called collection agents are used in order to artificially adjust the hydrophobicity and hydrophilicity of the surface of the particles to enhance the separation performance. It is known that conventionally known individual collectors have different effects (propriety) depending on the type of particles.
In the step (C), in order to separate the lead sulfide from other components (such as calcium sulfate), a hydrophobizing agent that is a collection agent for increasing the hydrophobicity of the surface of the lead sulfide particles is used.
A preferred example of the hydrophobizing agent is xanthate. After the lead sulfide is made hydrophobic by xanthate, it adheres to the surface of the foam and floats in the water to become a float.

The xanthates, -OC (= S) -S ^- refers to xanthate having the chemical structure. Examples of xanthate include R—OC (═S) —S ^— M ⁺ (wherein R is an alkyl group having 1 to 20 carbon atoms (preferably 2 to 5), M is an alkali metal such as Na or K, or A compound represented by the general formula of NH _{4 and the} like).
The amount of xanthate used can be determined by estimating from the normal content of the lead component in the fine powder that is the object to be treated of the present invention, for example. Specifically, it is desirable to add xanthate in such an amount that the molar ratio of xanthate / Pb is preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.04 or more. When the value is less than 0.01, it is difficult to sufficiently float the lead sulfide as a float.
The upper limit of the amount of xanthate used is not particularly limited, but from the viewpoint of reducing drug costs, the xanthate / Pb molar ratio is preferably 1.0 or less, more preferably 0.5 or less, and even more preferably 0. It is desirable that the amount be 2 or less.

A foaming agent can also be added to the slurry. By using a foaming agent, it is possible to promote floating of the ore in the flotation. The foaming agent is usually added after hydrophobizing lead sulfide.
Examples of the foaming agent include methyl isobutyl carbinol (MIBC; 4-methyl-2-pentanol), methyl isobutyl ketone, pine oil, ethylene glycol, propylene glycol methyl ether, cresolic acid and the like. As the foaming agent, in addition to the above-mentioned examples, for example, a chain hydrocarbon group having 6 to 8 carbon atoms (such as an alkyl group) or a cyclic hydrocarbon group having 10 to 15 carbon atoms (aromatic group, cyclohexane) A compound having a hydrophobic group such as an alkyl group or the like and a hydrophilic group such as a hydroxyl group or a carboxyl group can also be used.
The amount of the foaming agent added is preferably 5 to 100 mg with respect to 1 liter of the slurry.
In addition, in this invention, addition of a foaming agent is not essential and is arbitrary.

[Process (D): Flotation process]
Step (D) is a step of obtaining a floatation containing lead sulfide by subjecting the slurry for floatation ore obtained in step (C) to a floatation treatment.
As a means of flotation, the Fahrenwald type flotation machine (FW type flotation machine), MS type flotation machine, Fegergren type flotation machine, agitaya type flotation machine, Worman type flotation machine, etc. There is a selection machine.
Flotation can be separated from other components of the slurry (liquid content, sedimentation) by recovering the solid content present in the upper region (particularly near the liquid surface) of the slurry liquid.
Float has a high lead (Pb) distribution ratio (in other words, the mass ratio of Pb in the float in the total amount of Pb in the float and Pb in the deposit), and therefore contains lead and calcium components. Can be separated and recovered as a lead-containing substance derived from fine powder.
The number of times of the flotation process may be one or more, but from the viewpoint of increasing the recovery rate of the lead component from the fine powder that is the object to be processed, it is preferably two times or more, more preferably three times or more. It is. However, the number of times is preferably 5 times or less from the viewpoint of processing cost.
In addition, when Pb was contained abundantly in the fine powder which is a process target object, and the quantity of Ca was small (for example, when using fly ash D in the below-mentioned Example), it was obtained at the process (B). Only by solid-liquid separation of the slurry, a lead-containing solid content with high lead quality can be obtained, and the steps after the step (C) can be omitted.
When the flotation process is performed twice or more, it is desirable to add a hydrophobizing agent at a point before each time. That is, it is desirable to repeat a series of operations of the step (C) and the step (D).

The quality of the lead component in the float ore obtained by the step (D) (the ratio (%) of the Pb equivalent content of the lead component in the dry mass of the float ore) is, for example, when the number of times of the flotation treatment is 1st In the case of 35 mass% or more and the 2nd time, it is 25 mass% or more, for example.
The ratio of the mass of the lead component contained in the floatation (recovery rate of the lead component as the floatation) to the total amount (100% by mass) of the lead component contained in the solid content in the slurry at the time before the flotation treatment is When the number of times of the flotation process is the first time, for example, it is 30% by mass or more.

Next, an example of the fine powder processing system of the present invention will be described.
In FIG. 2, the processing system for fine powder of the present invention is a processing system corresponding to the processing method shown in FIG. 1, wherein the fine powder as a processing object, water, and a sulfiding agent are mixed to lead sulfide. Mixing tank 1 for obtaining a slurry containing substances, a slurry containing sulfide obtained in the mixing tank 1, and a calcium component elution tank for promoting the elution of chlorine components contained in fine powder by mixing hydrochloric acid 5 and a hydrophobizing reaction tank 8 for hydrophobizing lead sulfide in the slurry by adding a hydrophobizing agent to the slurry containing lead sulfide and the eluted calcium component, and obtained in the hydrophobizing reaction tank 8 In addition, a flotation machine 11 for carrying out the flotation process by introducing the slurry is provided.
In the case where the flotation process is performed twice or more, a plurality of flotation machines 11 are arranged in series. In this case, the hydrophobizing agent is supplied by the hydrophobizing agent supplying means similar to the hydrophobizing agent supplying means 9 at a point on the upstream side of each device after the flotation machine that performs the second flotation processing. .
The mixing tank 1, the calcium component elution tank 5, and the hydrophobization reaction tank 8 are each provided with a stirring blade for stirring the slurry.

The mixing tank 1 has a fine powder supply means 2 (for example, having a fine powder storage tank and a flow passage) for supplying fine powder as a processing object, and a water supply means 3 for supplying water. (For example, a water flow passage such as a water pipe) and a sulfiding agent supply means 4 (for example, having a sulfiding agent storage tank and a flow passage) for supplying a sulfiding agent are connected.
The calcium component elution tank 5 is connected to hydrochloric acid supply means 6 (for example, having a hydrochloric acid storage tank and a flow passage) for supplying hydrochloric acid.
The hydrophobizing reaction tank 8 is connected with a hydrophobizing agent supply means 9 (for example, having a hydrophobizing agent storage tank and a flow passage).
Each of the calcium component elution tank 5 and the hydrophobization reaction tank 8 is provided with pH measuring means (pH meters) 7 and 10. Both the pH measuring means 7 and the pH measuring means 10 are not necessarily provided, and only one of them may be provided.
Between the mixing tank 1, the calcium component elution tank 5, the hydrophobization reaction tank 8, and the flotation separator 11, each of the slurry is circulated in one direction from the mixing tank 1 to the flotation separator 11. Flow passages (eg, pumps and conduits) are provided.
The treatment system of the present invention is provided with a foaming agent supply means (not shown; for example, foaming agent) for supplying a foaming agent in the middle of the flow path from the hydrophobization reactor 8 to the flotation separator 11. A storage tank and a flow passage).
In the present invention, either a continuous processing system or a batch processing system may be adopted, but a continuous processing system is preferable from the viewpoint of processing efficiency.

[Example 1]
Hereinafter, the present invention will be described with reference to examples and comparative examples. The following “%” is based on mass unless otherwise specified.
[Preparation of fine powder containing lead and calcium components]
Three types of molten fly ash (fly ash A to fly ash D) having the component composition shown in Table 1 below were prepared as fine powders containing a lead component and a calcium component, which are treatment objects. In Table 1, components included at a content of 3% by mass or less were omitted.

[Example 1]
130 g of “fly ash A” and 1300 ml of distilled water were put into a mixing tank and stirred to obtain a uniform slurry. An aqueous sodium hydrosulfide solution (concentration: 10%) having a molar ratio of sodium hydrosulfide / lead of 1.0 was added as a sulfiding agent to this slurry and stirred to obtain a slurry containing lead sulfide.
Next, hydrochloric acid (concentration: 36%) was added to the slurry and stirred to adjust the liquidity to pH 3.0. The slurry after pH adjustment was subjected to solid-liquid separation using a suction filter to obtain a solid component containing lead sulfide and a liquid component.
[Example 2]
An experiment was conducted in the same manner as in Example 1 except that “fly ash B” was used instead of “fly ash A”.
[Example 3]
An experiment was conducted in the same manner as in Example 1 except that “fly ash C” was used instead of “fly ash A”.
[Example 4]
An experiment was conducted in the same manner as in Example 1 except that “fly ash D” was used instead of “fly ash A”.

[Comparative Example 1]
130 g of “fly ash A” and 1300 ml of distilled water were put into a mixing tank and stirred to obtain a uniform slurry. Hydrochloric acid (concentration: 36%) was added to the slurry and stirred to adjust the liquidity to pH 3.0. The obtained slurry was subjected to solid-liquid separation using a suction filter to obtain a liquid component.
Next, a sodium hydrosulfide aqueous solution (concentration: 10%) having a molar ratio of sodium hydrosulfide / lead of 1.0 is added to this liquid as a sulfiding agent, and stirred to prepare a slurry containing lead sulfide. Obtained.
The obtained slurry was subjected to solid-liquid separation using a suction filter to obtain a solid component containing lead sulfide and a liquid component.
[Comparative Example 2]
An experiment was conducted in the same manner as in Comparative Example 1 except that “fly ash B” was used instead of “fly ash A”.
[Comparative Example 3]
An experiment was conducted in the same manner as in Comparative Example 1 except that “fly ash C” was used instead of “fly ash A”.
[Comparative Example 4]
An experiment was conducted in the same manner as in Comparative Example 1 except that “fly ash D” was used instead of “fly ash A”.

The amount of lead sulfide contained in each solid component obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was quantified, and the recovery rate of lead component from the total amount of lead component contained in fly ash (% )
The results are shown in Table 2. Table 2 shows that the recovery rate of the lead component in Examples 1 to 4 is 98.8% or more, which is very high. On the other hand, the recovery rate of the lead component in Comparative Examples 1 to 4 is 33.6% or less, which is lower than those in Examples 1 to 4.

[Example 5]
Finally, a slurry whose liquidity was adjusted to pH 3.0 was obtained in the same manner as in Example 1 except that solid-liquid separation was not performed.
A xanthate aqueous solution (concentration: 5%) was added as a hydrophobizing agent to the slurry, and the mixture was stirred for 15 minutes. The amount of xanthate added was such that the xanthate / lead molar ratio was 0.04. Next, this slurry was guided to the first stage flotation beneficiator and subjected to flotation treatment for 20 minutes. After the treatment, the slurry portion containing the floatation and the slurry portion containing the sedimentation were recovered from the floatation machine. Among these, the amount of lead sulfide in the slurry portion containing floatation was quantified, and the recovery rate and quality of the lead component were calculated.
On the other hand, an aqueous xanthate solution (concentration: 5%) was added to the slurry portion containing the sediment recovered from the first stage of the floatation separator and stirred for 15 minutes. The amount of xanthate added was such that the xanthate / lead molar ratio was 0.04. Next, this slurry portion was guided to a second stage flotation machine and subjected to flotation treatment for 10 minutes. After the treatment, the slurry portion containing the floatation and the slurry portion containing the sedimentation were recovered from the floatation machine. Among these, the amount of lead sulfide in the slurry portion containing floatation was quantified, and the recovery rate and quality of the lead component were calculated.
On the other hand, an aqueous xanthate solution (concentration: 5%) was added to the slurry portion containing the sediment recovered from the second stage floatation separator, and stirred for 15 minutes. The amount of xanthate added was such that the xanthate / lead molar ratio was 0.04. Next, this slurry portion was guided to a third stage flotation machine and subjected to flotation treatment for 10 minutes. After the treatment, the slurry portion containing the floatation and the slurry portion containing the sedimentation were recovered from the floatation machine. Among these, the amount of lead sulfide in the slurry portion containing floatation was quantified, and the recovery rate and quality of the lead component were calculated.
[Examples 6 to 8]
An experiment was conducted in the same manner as in Example 5 except that the type of fly ash was changed to that shown in Table 3.
The above results are shown in Table 3. From Table 3, it can be seen that the lead component can be recovered at a recovery rate of 73% or more by performing the flotation three times. Moreover, it turns out that the quality of a lead component is 32% or more in all 1-3 times.

DESCRIPTION OF SYMBOLS 1 Mixing tank 2 Fine powder supply means 3 Water supply means 4 Sulfide supply means 5 Calcium component elution tank 6 Hydrochloric acid supply means 7 pH meter 8 Hydrophobization reaction tank 9 Hydrophobizing agent supply means 10 pH meter 11 Flotation beneficiator

Claims (4)

(A) a lead sulfide generation step of obtaining a slurry containing lead sulfide by mixing a fine powder containing a lead component and a calcium component, water, and a sulfiding agent;
(B) A calcium component elution step of mixing the slurry and hydrochloric acid to elute the calcium component in the fine powder to obtain a slurry containing lead sulfide and the eluted calcium component;
The processing method of the fine powder containing the lead component and calcium component characterized by including these. (C) A hydrophobizing step of adding a hydrophobizing agent to the slurry obtained in step (B) to hydrophobize the lead sulfide to obtain a slurry for flotation,
(D) Flotation process of obtaining the flotation containing lead sulfide by flotation treatment of the slurry for flotation,
The processing method of the fine powder containing the lead component and calcium component of Claim 1 containing this.   The method for processing a fine powder containing a lead component and a calcium component according to claim 1 or 2, wherein the fine powder is at least one selected from molten fly ash, incinerated fly ash, and chlorine bypass dust. A mixing tank for mixing a fine powder containing a lead component and a calcium component, water, and a sulfurizing agent to obtain a slurry containing lead sulfide;
Calcium component elution tank for obtaining slurry containing lead sulfide and eluted calcium component by mixing slurry obtained in the mixing tank and hydrochloric acid,
Adding hydrophobizing agent to the slurry obtained in the above calcium component dissolution tank, the lead sulfide is hydrophobic, and the hydrophobic reaction vessel to obtain a flotation slurry,
A flotation machine for obtaining a flotation containing lead sulfide by flotation treatment of the slurry for flotation;
A processing system for fine powder containing a lead component and a calcium component.

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