JP5521433B2 - Filtration method of slurry containing colloidal silica - Google Patents

Description

The present invention relates to a method for filtering a slurry containing colloidal silica, and more specifically, without using an organic polymer flocculant during solid-liquid separation of a slurry containing colloidal silica obtained by a wet copper smelting method. The present invention relates to a method for filtering a slurry containing colloidal silica that can be solid-liquid separated.

As a technique for obtaining a metal from a metal sulfide, a dry smelting method is generally employed. For example, in the dry copper smelting method, copper sulfide ore is pulverized and concentrated to obtain copper concentrate. The copper concentrate and solvent are mixed and charged into a smelting furnace and melted at 1300 to 1400 ° C. Copper is a mat made of CuS and FeS, impurities such as silicic acid and iron are smelting furnace slag, and sulfur content is sulfur dioxide. The mat is oxidized in the converter, copper in the mat is made into crude copper, impurities such as iron are converted into converter slag, and the sulfur content is sulfur dioxide. The crude copper is further refined in a refining furnace, cast on an anode, and subjected to electrolytic purification. Thus, copper is recovered as electrolytic copper.
On the other hand, since a lot of copper is suspended in the converter slag, it is repeatedly charged into the smelting furnace, or the minerals are collected by collecting ores, and the recovered valuables are charged into the smelting furnace. To do. Then, after the mat portion suspended in the slag is separated in the electric furnace, the smelting furnace slag is granulated and discharged out of the system as a building material or a landfill material. The separated mat is charged into a converter and copper is recovered.
Moreover, the waste gas containing sulfur dioxide discharged from the smelting furnace or converter is washed and dried, and then converted into sulfur trioxide using a catalyst and recovered as sulfuric acid. The waste gas after recovering sulfur trioxide is detoxified and released into the atmosphere.
Therefore, in the dry copper smelting method, it is indispensable to handle a high-temperature melt and to install a facility for recovering sulfur dioxide, and it is indispensable to consider the environment in terms of working environment and pollution prevention.

In recent years, in order to solve such problems, research on a wet copper smelting method in which copper is leached by bringing acid into contact with copper concentrate and copper in the obtained leachate has been studied.
For example, when wet copper smelting using copper concentrate, an aqueous halide solution such as chlorine gas or chloride or an acidic aqueous solution containing sulfate is used as the leachate, and copper concentrate is leached by pressurization if necessary. And obtaining a leaching solution containing copper, extracting copper from the obtained leaching solution by a solvent extraction method, back-extracting to obtain a back-extraction solution, and using this as an electrolytic solution, electrolytically collecting copper to obtain electrolytic copper There is technology.
Incidentally, since elemental sulfur and sulfide are present in the leaching residue obtained by such leaching method, after separation from the leaching solution, it is separated into sulfur concentrate and iron residue by flotation or specific gravity separation. The sulfur concentrate is heated and distilled to obtain sulfur as a distillate, and a copper residue as a distillation residue. The copper residue is heat-treated in a non-oxidizing atmosphere at about 550 ° C. in order to convert the contained sulfide into a leached sulfide form, and then dissolved in sulfuric acid to recover the copper content as copper sulfate in the liquid. . Since the undissolved part generated at this time contains noble metal, the undissolved part is sent to the noble metal recovery step. The iron residue is discarded after washing.
As shown above, when metal copper is obtained from a copper sulfide such as copper concentrate by a wet copper smelting method, some sulfur in the copper sulfide is oxidized to sulfuric acid at the time of leaching, Since the sulfur content is recovered as elemental sulfur, there is an advantage that waste gas containing sulfur dioxide is not generated and a high-temperature melt may not be handled.

  By the way, when copper concentrate is leached using an aqueous solution of halide such as chlorine gas or chloride or an acidic aqueous solution containing sulfate as a leaching solution, the obtained leaching slurry often contains colloidal silica. In such a case, the filterability of the leaching slurry is deteriorated and the productivity is deteriorated. Therefore, the filtration process is divided into two stages, and a slurry containing leaching residue and colloidal silica (hereinafter, this “slurry containing colloidal silica” may be simply referred to as “slurry” by using a centrifugal separation method as the first stage. And then the slurry is subjected to solid-liquid separation with a vacuum filter or a pressure filter to obtain a leachate.

However, as is well known, a slurry containing colloidal silica is extremely difficult to filter and has very poor filtration efficiency. In order to solve this problem, 0.3 to 1.0 g of bentonite is added to the slurry containing colloidal silica, and the colloidal silica is aggregated at a flocculant concentration of 5 to 20 ppm. Has been proposed (see Patent Document 1, page 2).
This technique involves wastewater treatment, where the agglomerated colloidal silica is precipitated with a thickener, concentrated and filtered. The resulting filtrate is discharged as waste water along with the thickener overflow.
According to this technology, “After adding water to a silica residue slurry and diluting the slurry concentration to about 20 g / l, it is added and dispersed with bentonite powder to a concentration of 0.5 g / l, and then dispersed. The nonionic flocculant with a concentration of 0.1% was added to a concentration of 10 ppm, stirred for 10 minutes, and allowed to stand for 1 hour to separate the precipitate and the supernatant, and the precipitate was filtered. However, a filtration rate of 3.1 l / min · m ² was obtained ”(see Patent Document 1, page 3).
Considering that the colloidal silica is normally negatively charged, adding bentonite with this technology is a so-called silica seed method that promotes the precipitation of silica gel using the silicate constituting the added bentonite as a seed crystal. Although it can be used as a so-called method, nothing is described about how much the filtration rate can be improved only by adding bentonite.

By the way, in the example of the above-mentioned wet copper smelting method, the leachate obtained by acid leaching of copper concentrate extracts and separates copper in the leachate by a solvent extraction method. Therefore, when solid-liquid separation of the slurry containing colloidal silica, the use of an organic polymer flocculant is not preferable. This is because when the organic polymer flocculant is present in the leachate, the organic polymer flocculant accumulates in the solvent, and there are known adverse effects such as preventing phase separation.
Therefore, when the filtration technique described in Patent Document 1 using an organic polymer flocculant is applied to a slurry containing colloidal silica that is the object of the present invention, the leachate is treated with activated carbon prior to copper extraction. Will need to be done, leading to increased costs.

In addition, it is not impossible to improve the filterability by adjusting the pH of the slurry so that the potential of the colloidal silica is the equipotential point and the silica is aggregated. However, even if the pH of the slurry can be adjusted to agglomerate the colloidal silica, there is a risk that some valuable metals dissolved in the slurry may precipitate as hydroxides. It is hard to be a technology that can be adopted in
Therefore, there is a need for a method for filtering a slurry containing colloidal silica that can be efficiently solid-liquid separated without using an organic polymer flocculant during solid-liquid separation of the slurry containing colloidal silica obtained by a wet copper smelting method. .

JP 2000-126510 A (see pages 2 and 3)

In view of the above-mentioned problems of the prior art, the object of the present invention is to efficiently perform solid-liquid separation without using an organic polymer flocculant for solid-liquid separation of a slurry containing colloidal silica obtained by a wet copper smelting method. It is to provide a method for filtering a slurry containing colloidal silica.

As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by adding activated clay to a slurry containing colloidal silica, and have reached the present invention.
That is, according to the first invention of the present invention, there is provided a method for filtering a slurry containing colloidal silica obtained by acid leaching of copper concentrate or copper sulfide ,
It was added activated clay to the slurry containing the colloidal silica, the after uniformly dispersing the activated clay mixed with stirring into the slurry, filtration methods of slurry containing colloidal silica, characterized in that filtering is provided The

  Further, according to the second invention of the present invention, in the first invention, the amount of activated clay added is 10 g or more with respect to 1 l of the slurry containing colloidal silica. A method for filtering a slurry containing is provided.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the stirring and mixing time after adding the activated clay is 0.5 to 1.5 hours. A method for filtering a slurry containing silica is provided.

In the present invention, activated clay is added to a slurry containing colloidal silica obtained by acid leaching of copper concentrate, and stirred and mixed to uniformly disperse the activated clay in the slurry, followed by filtration.
By carrying out like this, the filtration speed of 8 to 13 times when not using activated clay can be obtained. In addition, what is newly added to the slurry is activated clay, and since no organic polymer flocculant is added, a new process for subjecting the obtained leachate to activated carbon treatment, etc. prior to the next copper solvent extraction process Is never needed.
The present invention is effective not only for slurries containing colloidal silica obtained by acid leaching of copper concentrate, but also for slurries containing colloidal silica in general, and the industrial value of the present invention is high. .

It is the figure which graphed the result of the Example of this invention.

Hereinafter, the present invention will be described in detail for each item such as slurry, activated clay, and filtration method.
1. Slurry containing colloidal silica Generally, when copper concentrate or finely pulverized copper ore is leached with an acid, a leaching slurry containing colloidal silica is obtained. The size of the particles of the leaching residue contained in this leaching slurry is larger than that of colloidal silica and is an average of several tens of μm. Therefore, it is possible to separate the leach residue and the slurry containing colloidal silica with a centrifuge or a centrifugal decanter.
The slurry containing colloidal silica that is the subject of filtration of the present invention is a solid-liquid separation of the leaching slurry obtained by leaching such copper concentrate or finely pulverized copper ore with an acid, using a centrifuge or a centrifugal decanter, A slurry containing colloidal silica obtained as a filtrate.

2. Activated clay Activated clay is also called acid clay, and its properties have been further improved by performing activation treatment (acid treatment) on naturally adsorbed clay, mainly montmorillonite or montmorillonite or It is composed of clay minerals such as halloysite and colloidal silicic acid, and this is different from bentonite containing montmorillonite as the main constituent. Therefore, the SiO ₂ / Al ₂ O ₃ value of the activated clay is 6 to 8 and higher than the SiO ₂ / Al ₂ O ₃ value of 4 to 6 of bentonite, and the base exchange capacity of the activated clay is 50 m equivalent and 60 of bentonite. It is smaller than ~ 100m equivalent. The pH of the suspension is also 5 to 6 for activated clay and 7.5 to 8.5 for bentonite. Furthermore, the amount of moisture adsorbed on 1 g of powder is 2 to 3 g in activated clay, and 3 to 20 g in bentonite. Thus, it can be said that activated clay and bentonite are different substances.
The surface of the activated clay has fine pores because soluble substances in the structure are eluted by the activation treatment. The surface area is 150 to 300 m ² / g, and the average diameter of the pores is about 50 mm.
In addition, activated clay has a certain layer structure, and has cation exchange similar to that of ion exchange resin. Part of the cation is exchanged with hydrogen ions by the activation treatment, and has a replaceable hydrogen. Yes. This amount is generally 10-30 m. e. / 100 g, it is supposed to show chemical activity not found in other adsorbents.
Furthermore, the adsorption of substances on the surface of the activated clay is selective, and in the state where several kinds of substances coexist, selective adsorption ability for polar substances, unsaturated substances and aromatic substances is exhibited.
Because of these special surface properties, activated clay is used in many applications that cannot be replaced by other adsorbents. For example, it uses adsorption purification such as decolorization, dehydration, stability improvement and impurity removal of petroleum and fats and oils, refines raw materials, intermediate products and final products in petrochemical and related chemical industries, and uses the chemical activity of activated clay. For example, a contact reaction. In addition, the utilization to the slurry containing colloidal silica like this invention is not seen.

3. Filtration method The amount of activated clay added to the slurry depends on the slurry concentration. For example, when the slurry concentration is 700 to 1000 mg / l, the addition of 10 g or more per 1 liter of slurry is preferable, and the amount should be 10 to 40 g. Is more preferable. This is because when the amount is less than 10 g, the adsorption of colloidal silica is not sufficient, and a filtration rate of 8 times or more of the case of no addition cannot be obtained. If it exceeds 40 g, further improvement in the filtration rate cannot be expected, and only the amount of filtered starch increases. If it exceeds 300 g / l, the viscosity increases remarkably and mixing becomes difficult and operation becomes impossible.

Moreover, in order to adsorb | suck colloidal silica reliably to activated clay, it is necessary to disperse | distribute activated clay uniformly in a slurry, Therefore After adding activated clay to a slurry, 0.5-1. It is preferable to stir for 5 hours. If the time is less than 0.5 hours, the adsorption of the colloidal silica on the activated clay becomes insufficient, and even if the mixture is stirred for 1.5 hours or more, further increase in the effect cannot be expected.
The slurry added with activated clay and uniformly mixed is then subjected to vacuum filter such as drum filter and belt filter, and pressure filter such as filter press to separate the solid and liquid, and the obtained filtrate is used as leachate in the next step. Sent to.

The reason why the activated clay is effective for the filtration of the slurry containing colloidal silica is that, as described above, it is desired to stir and mix for a predetermined time after adding the activated clay to sufficiently obtain the effect of the present invention. I think as follows.
The major function of the activated clay is to adsorb the colloidal silica to the active silica contained in the activated clay, and a clear leachate can be obtained by filtering the activated clay that has adsorbed the colloidal silica. Therefore, the role of activated clay as a filter aid is small.

  The slurry filtration method of the present invention is effective not only for a slurry obtained from an acid leaching solution of copper sulfide but also for a slurry containing colloidal silica.

The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples. The analysis of Si in the aqueous solution was performed using ICP emission analysis. The activated clay used was the product name Galeon Earth manufactured by Mizusawa Chemical Co., Ltd.
Example 1
a) Preparation of slurry (original solution) containing colloidal silica Add sulfuric acid solution with a concentration of 90 g / l to copper concentrate with a composition of 27% copper, 29% iron, 30% sulfur and 6% silicon and an average particle size of 30 μm The slurry was mixed so that the slurry concentration became 200 g / l, charged into a titanium pressure vessel equipped with a stirrer, heated to 160 ° C., and kept at 160 ° C. for 2.5 hours while stirring. Thereafter, the slurry was taken out from the pressurized container and rotated at 1000 rpm for 10 minutes using a centrifuge with a basket radius of 150 mm to separate the slurry containing colloidal silica and the leach residue. This operation was repeated to obtain 2 l of a slurry containing colloidal silica. The Si concentration of this slurry was 690 mg / l, and the pH of the original solution was 0.35.
The following filtration treatment was performed using the obtained slurry containing colloidal silica as a base solution.
b) Filtration treatment 50 ml of the original solution was taken, 0.5 g of activated clay was added thereto, and a slurry with a concentration of 10 g / l was obtained. The slurry was stirred with a stirrer for 1 hour, and then suction filtered with a Nutsche using 5C filter paper having a diameter of 47 mm. Table 1 shows the amount of activated clay added per liter of slurry, the obtained filtration rate, and the Si concentration in the filtrate.

(Example 2)
A filtration test was conducted in the same manner as in Example 1 except that the amount of activated clay added to 50 ml of the original solution was changed to 1.0 g. The obtained results are shown in Table 1.

(Example 3)
A filtration test was conducted in the same manner as in Example 1 except that the amount of activated clay added to 50 ml of the original solution was changed to 1.5 g. The obtained results are shown in Table 1.

Example 4
A filtration test was conducted in the same manner as in Example 1 except that the amount of activated clay added to 50 ml of the original solution was 2.0 g. The obtained results are shown in Table 1.

(Example 5)
A filtration test was conducted in the same manner as in Example 1 except that the amount of activated clay added to 50 ml of the original solution was changed to 2.5 g. The obtained results are shown in Table 1.

(Comparative Example 1)
A filtration test was conducted in the same manner as in Example 1 except that nothing was added to 50 ml of the original solution. The obtained results are shown in Table 1.

(Comparative Example 2)
A filtration test was conducted in the same manner as in Example 1 except that the activated clay added to 50 ml of the original solution was changed to 0.25 g. The obtained results are shown in Table 1.

(Comparative Example 3)
A filtration test was conducted in the same manner as in Example 1 except that activated clay was not added to 50 ml of the original solution, and a polymer flocculant (trade name C510H, manufactured by Aron Flock Co., Ltd.) was added to a concentration of 20 mg / l. It was. The obtained results are shown in Table 1.

(Comparative Example 4)
A filtration test was conducted in the same manner as in Comparative Example 3 except that a polymer flocculant (trade name C510H, manufactured by Aron Flock Co., Ltd.) was added to 50 ml of the original solution so as to have a concentration of 50 mg / l. The obtained results are shown in Table 1.

(Comparative Example 5)
A filtration test was conducted in the same manner as in Comparative Example 3 except that a polymer flocculant (trade name C510H, manufactured by Aron Flock Co., Ltd.) was added to 50 ml of the original solution so as to have a concentration of 80 mg / l. The obtained results are shown in Table 1.

(Comparative Example 6)
The filtrate (leachate) obtained in Example 1, Comparative Example 4 and Comparative Example 5, and 30% by volume of Cognis brand name LIX860I-NC as an extractant for copper were used. ) Extracted organic and 50ml using the brand name Teklin N20 manufactured by the company were placed in a separatory funnel, respectively shaken for 1 minute, and then allowed to stand to confirm the separability. The separation of Example 4 was poorer than the separation of Example 1 separated within 1 minute, and separation did not occur even when it took 10 minutes.

以上の結果をまとめると、本発明の方法に従う実施例１〜５では、何も添加しない場合、即ち比較例１のろ過速度の８〜１３倍のろ過速度が得られることがわかった。なお、実施例５では実施例４と比較してろ過速度はわずかに低下しており、これ以上添加量を増加しても更なるろ過速度の改善は見られないことがわかった。また、ろ過澱物量が、当然のことながら増加しており、これ以上添加量を増加させるとろ過機への負担を大きくすることもわかった。
また、実施例１〜５で添加するものは活性白土のみであり、有機高分子凝集剤は使用しない。したがって、ろ過して得られる浸出液中に有機物は含まれておらず、次工程で銅を溶媒抽出して回収する際に、予め活性炭処理等の必要は生じない。
比較例２は、活性白土の添加量を本発明の範囲より少なくした例であるが、量が足りないことによりろ過速度の改良は得られていない。また、高分子凝集剤を用いてろ過性を改善するためには、５０ｍｇ／ｌ以上の濃度としなければならず、量が多いことばかりか、比較例６に見られるように、次工程への影響も無視できないものとなっている。

Summarizing the above results, it was found that in Examples 1 to 5 according to the method of the present invention, a filtration rate of 8 to 13 times the filtration rate of Comparative Example 1 was obtained when nothing was added. In Example 5, the filtration rate was slightly decreased as compared with Example 4, and it was found that further improvement in the filtration rate was not observed even when the addition amount was further increased. It was also found that the amount of filtered starch naturally increased, and increasing the amount added further increased the burden on the filter.
Moreover, what is added in Examples 1-5 is only activated clay, and an organic polymer flocculant is not used. Therefore, the organic matter is not contained in the leachate obtained by filtration, and there is no need for an activated carbon treatment or the like in advance when copper is extracted by solvent extraction in the next step.
Comparative Example 2 is an example in which the amount of activated clay added is less than the range of the present invention, but the filtration rate is not improved due to the lack of the amount. Moreover, in order to improve the filterability using the polymer flocculant, the concentration must be 50 mg / l or more, and not only the amount is large, but as seen in Comparative Example 6, The impact is not negligible.

According to the method of the present invention, by adding a specific amount of activated clay to a slurry containing colloidal silica obtained by leaching copper concentrate, the filtration rate is 8 to 13 times that when no activated clay is added. Can be obtained. In addition, since only activated clay is added and no organic polymer flocculant is used, there is no burden on the copper solvent extraction process, which is the next process.
The present invention is effective not only for slurries containing colloidal silica obtained by leaching copper concentrate, but also for slurries containing colloidal silica in general, and the industrial value of the present invention is high.

Claims (3)

A method for filtering a slurry containing colloidal silica obtained by acid leaching of copper concentrate or copper sulfide ,
A method for filtering a slurry containing colloidal silica, comprising adding active clay to the slurry containing colloidal silica, stirring and mixing to uniformly disperse the active clay in the slurry, and then filtering.   The method for filtering a slurry containing colloidal silica according to claim 1, wherein the amount of the activated clay added is 10 g or more per 1 l of the slurry containing colloidal silica.   The method for filtering a slurry containing colloidal silica according to claim 1 or 2, wherein the stirring and mixing time is 0.5 to 1.5 hours.

Images