JP2018111615A - Slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slag having less elution of impurities while containing As and Pb as impurities.SOLUTION: In the slag according to the present invention that contains Fe and Si as main components and As and Pb as impurities, an average crystallite diameter of fayalite (FeSiO) constituting the crystal phases is 1000Å or more, and elution amount of As and Pb measured in accordance with JIS K 0058-2 is less than 150 mg/kg. Such a slag can be produced from a slag which is a by-product of a smelting process of nonferrous metals, by a water granulation treatment of the slag as raw material in which temperature of water is 80°C or higher and amount of water is 10 mor more and 100 mor less per 1 t of the slag as raw material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to slag, and more particularly, to slag in which elution of impurities from slag containing Fe and Si as main components and As and Pb as impurities is effectively suppressed.

  Conventionally, sand, river sand, gravel, etc. have been used as fine aggregates to be mixed with concrete, but these sands, which are natural resources, have been moving to reduce or ban their collection from the viewpoint of environmental protection. It has been strengthened.

  From such a background, because slag by-produced in nonferrous metal smelting, for example, dry smelting of copper, is standardized as JIS A5011-3 and can be stably supplied as a fine aggregate for concrete. Movements to replace natural resources from various types of sand are accelerating.

  However, in applying slag to fine aggregates, etc., the content test for hazardous substances specified in the Ministry of the Environment Notification No. 19 (JIS K0058-2: 2005) and the 1991 Environment Agency Notification No. Based on the results of the toxic substance elution test (JIS K0058-1: 2005) defined in No. 46, it is required to satisfy the standards for soil contamination. In particular, the standards based on the content test (JIS K0058-2: 2005) for hazardous substances stipulated in the Notification No. 19 of the Ministry of the Environment in 2003 have strengthened the regulations. As (arsenic), Pb (lead ) Is required to be reduced as much as possible.

  For example, in Patent Documents 1 and 2 and Non-Patent Document 1, stable slag that suppresses the leaching amount of As and Pb from the slag in both the above-mentioned harmful substance content test and harmful substance elution amount test. The manufacturing technology is shown.

  However, the techniques described in these documents involve heat treatment of slag at a temperature of 500 ° C. to 800 ° C. for 30 minutes or more. Therefore, considerable heat energy and time are required for processing a large amount of slag. . There is a large amount of slag generated from a copper smelting process and the like, and there is a need for a slag that can be obtained by a process that does not require excessive heat energy and that can suppress the elution amount of As and Pb.

JP 2014-51706 A Japanese Patent Application Laid-Open No. 2015-124095

Masayasu Kawahara and Shintaro Komori, “Elution of heavy metals from copper slag”, Journal of The Mining and Materials Processing Institute of Japan, Vol. 129 (2013) p192-196

  This invention is proposed in view of such a situation, and it aims at providing the slag which suppressed the elution of these impurities in the slag containing As and Pb as impurities.

This inventor repeated earnest examination in order to solve the subject mentioned above. As a result, if the average crystallite diameter of the firelite (Fe ₂ SiO ₄ ) constituting the slag is 1000 mm or more, the elution amount of As and Pb contained as impurities is effectively suppressed. The invention has been completed.

(1) The first invention of the present invention is a slag containing Fe and Si as main components and As and Pb as impurities, and an average crystallite of firelite (Fe ₂ SiO ₄ ) constituting a crystal phase A slag having a diameter of 1000 mm or more.

  (2) The second invention of the present invention is the slag according to the first invention, wherein the elution amounts of As and Pb measured according to JISK0058-2 are less than 150 mg / kg.

  (3) The third invention of the present invention is the first or second invention, wherein Pb as an impurity component is 0.01% by mass or more and 0.2% by mass or less, and As is 0.01% by mass or more and 0.0. It is slag contained at a ratio of 2% by mass or less.

(4) A fourth invention of the present invention is a slag manufacturing method according to any one of the first to third inventions, wherein the raw material contains Fe and Si as main components and As and Pb as impurities. slag, 80 ° C. above the water temperature, comprising the step of water granulated processed slag 1t per 10 m ³ or more 100 m ³ or less of the amount of water the raw material, a method for producing a slag.

  ADVANTAGE OF THE INVENTION According to this invention, in the slag containing As and Pb as impurities, the slag with little elution of the impurities can be provided.

It is a figure for demonstrating the manufacturing method of slag, and is a schematic diagram which shows the flow which performs a granulation process with respect to the molten slag obtained in the smelting furnace and discharged | emitted from the smelting furnace.

  Hereinafter, a specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention. In this specification, the notation “X to Y” (X and Y are arbitrary numerical values) means “X or more and Y or less”.

<1. Slag>
The slag according to the present embodiment is slag generated as a by-product in a nonferrous metal smelting process such as copper dry smelting. This slag is a slag containing Fe and Si as main components and further containing As and Pb as impurities while suppressing the elution amount of these As and Pb. In addition, a main component means that whose content rate in slag is 51 mass% or more. Further, in the slag mainly composed of Fe and Si, the content ratio of the main component refers to the total content ratio of Fe and Si.

Specifically, the slag according to the present embodiment is a slag containing Fe and Si as main components and As and Pb as impurities, and a firelite (Fe ₂ SiO ₄ : The average crystallite diameter of (Fayalite) is 1000 mm or more.

  Here, the average crystallite diameter of the firelite constituting the crystal phase can be obtained from the half width at the peak of the firelight in the diffraction pattern obtained by X-ray diffraction spectroscopy (XRD) using the Scherrer equation.

  In such slag, the elution amount of As and Pb contained as impurities is less than 150 mg / kg as the elution amount of As and Pb measured according to JISK0058-2, and the elution of these impurity components is effectively suppressed. Will be.

  This is because when the average crystallite diameter of the firelite is 1000 mm or more, the slag itself is not easily dissolved, and thus the elution of As and Pb due to the slag dissolution can be effectively suppressed. it is conceivable that. If the average crystallite diameter of the firelite is less than 1000 mm, the crystallinity is low, the slag itself is easily dissolved, and the elution of impurities cannot be effectively suppressed.

<2. Slag production method>
Next, the manufacturing method of the slag which has the characteristics mentioned above is demonstrated.

  The slag according to the present embodiment is, for example, slag produced as a by-product in a non-ferrous metal smelting process, and contains slag containing Fe and Si as main components and As and Pb as impurities. The raw material slag can be obtained through a step of subjecting the raw material slag to a water granulation treatment at a predetermined water temperature and amount.

(Raw slag)
As described above, the raw material slag is a slag containing Fe and Si as main components and further containing As and Pb. For example, as the composition of the raw material slag, the Fe content is 35 mass% to 45 mass%, the SiO ₂ content is 25 mass% to 40 mass%, and Pb is 0.01 mass% as an impurity component. -0.2 mass%, As is contained in the ratio of 0.01 mass%-0.2 mass%. Further, in this raw slag, the Cu 0.5 wt% to 3.0 wt%, the CaO 1.0 wt% to 6.0 wt%, and as other impurities as _Al 2 _{O 3} (alumina), MgO (magnesia) etc. may be included.

  Examples of such raw material slag include non-ferrous smelting slag, waste melting slag, etc. More specifically, copper slag (for example, self-melting) produced as a by-product in the copper smelting process. Furnace slag, smelting furnace slag).

(As and Pb elution suppression treatment)
In this manufacturing method of the slag for slag raw materials described above, 80 ° C. above the water temperature, is characterized in that water-granulated treated with water in the slag 1t per 10m ³ ~100m ^3. In this way, by subjecting the raw material slag to a water granulation treatment under predetermined conditions, the crystallite diameter of the firelite constituting the slag can be increased to 1000 mm or more, and the elution amount of As and Pb is reduced. Slag can be produced. Moreover, since slag can be rapidly cooled by a water granulation process, a slag composition can be made more uniform.

  The water used in the water granulation process is referred to as “granulated water”. The “water temperature” is the temperature of the granulated water just before contacting the raw material slag.

  In general, as a method of suppressing the leaching amount of impurities and As and Pb contained in trace amounts in slag mainly composed of Fe and Si obtained as a by-product such as non-ferrous smelting, a method of promoting crystallization is considered. However, when slag is obtained by water granulation with normal temperature granulated water, it is difficult to promote crystallization in this water granulation treatment step.

In contrast, the present inventors have, 80 ° C. above the water temperature, and by performing water granulated processed slag 1t per 10 m ³ or more 100 m ³ or less of water, of less than 80 ° C. water temperature, or water with a large amount of water It has been found that a slow cooling effect can be obtained as compared with the case of crushing, and the crystallinity can be effectively increased. Thus, it is thought that crystallization of the firelite which comprises the crystal phase of a slag is accelerated | stimulated, and a crystallite diameter becomes effective effectively by cooling slag by the water granulation process of a predetermined condition.

  When the temperature condition of the granulated water in the granulation treatment is less than 80 ° C., the crystallization of slag becomes insufficient, and the effect of suppressing elution of As and Pb as impurities becomes small. In addition, although it does not specifically limit as an upper limit of water temperature, From a viewpoint of suppressing the energy which heats granulated water, it is preferable to set it as 95 degrees C or less, and it is more preferable to set it as 90 degrees C or less.

Also, the water volume of water砕水in granulated processing, it is impossible to guide the crystallization tendency due to rapid cooling to be 100 m ³ greater per slag 1t. The particle size of the slag obtained by water granulation process is less than slag 1t per 10 m ³ is increased.

  Hereinafter, the method for producing slag in the copper refining process will be described more specifically.

  For example, as shown in FIG. 1, in the copper refining process, copper raw material other than copper concentrate and copper concentrate and silicate ore as flux were charged as a raw material into a smelting furnace such as the self-smelting furnace 1. After that, it is melted at a high temperature of about 1300 ° C., and is separated into a mat 2 having a relatively large specific gravity and a slag 3 having a relatively small specific gravity. The obtained mat 2 is sent to the converter in the next step, where Fe and S are removed, and the resulting copper becomes crude copper with a Cu quality of 98%. On the other hand, the slag 3 in which most of the impurities are distributed is sent to the smelting furnace 5 through the self-melting furnace 4, and the Cu content that cannot be separated is separated in the smelting furnace 5.

  The slag from which the Cu content has been separated in the smelting furnace 5 is discharged from the slag trough 7 as a molten slag 6 having a temperature of about 1300 ° C. At this time, the molten slag 6 supplied to the granulated slag 8 is crushed by the crushed water flowing in the granulated slag 8 so that it is rapidly cooled to 100 ° C. or less and crushed into fine particles. It becomes slag.

At this time, in the present embodiment, the water temperature of the water砕水supplied from granulated nozzle 9 into water砕樋8 and 80 ° C. or more, further the amount of water is adjusted to 100 m ³ or less 10 m ³ or more per slag 1t Granulate.

  Here, in the granulation treatment, the treated granulated water may be circulated in the system and repeatedly used. In the granulation process, the granulated water comes into contact with the molten slag 6 at about 1300 ° C., so that part of it evaporates and part of the temperature rises to 80 ° C. or higher. For this reason, efficient reuse of heat becomes possible by reusing the evaporated water having a water temperature of 80 ° C. or higher.

  In the water granulation treatment, the amount of the molten slag 6 and the amount of water from the water granulation nozzle 9 are set so that the molten slag 6 does not sink into the water flow in order to prevent the occurrence of clogging phenomenon in the steam explosion or the water slag 8. It is preferable to maintain the adjustment. In particular, by using a method using high-pressure water (for example, a pressure of 0.5 MPa to 5 MPa) ejected from the water granulating nozzle 9 or a method using a water granulating device described in Japanese Patent Application Laid-Open No. 2000-34528, steam explosion It is possible to effectively prevent the occurrence of clogging.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

<Preparation of raw material slag>
Slag having a composition as shown in Table 1 was used as raw material slag. As shown in FIG. 1, this raw material slag is a by-product molten slag 6 produced in a smelting furnace 5 in a copper refining process.

<Water granulation treatment>
Next, the raw material slag is supplied from the smelting furnace 5 to the water granulation mill 8 and subjected to a water granulation treatment with high-pressure water granulated water having a pressure of 1 MPa discharged from the water granulation nozzle 9 according to the conditions shown in Table 2 below. did.

  After the water granulation treatment, the obtained slag was measured with an X-ray diffractometer. As a result, it was confirmed that firelite having an average crystallite size shown in Table 2 was formed in the crystal phase.

<Evaluation of slag obtained after heat treatment>
(2003 Ministry of the Environment Notification No. 19 (Content Test))
According to JIS K0058-2, the obtained slag is pulverized to obtain a sample, and then the sample is used according to the section “Preparation of a test solution for substances other than hexavalent chromium compounds and cyanide compounds”. Prepared. And the density | concentration of Pb and As was measured by ICP-AES (luminescence spectroscopy analysis) according to JISK0102: 2008 using the obtained test solution. The measurement results are shown in Table 2 below.

As shown in Table 2 results, 80 ° C. above the water temperature, in Examples 1 and 2 was subjected to a water granulated processed slag 1t per 10 m ³ or more 100 m ³ or less of water, the average crystallite size of fayalite at least 1000Å The elution amounts of As and Pb measured according to JIS K0058-2 were less than the standard value of 150 mg / kg, and the elution could be effectively suppressed.

  On the other hand, in Comparative Examples 1, 2, and 3 where the water temperature of the water granulation treatment is low or the amount of water is large, the average crystallite diameter of the firelite is less than 1000 mm, and the elution amount of As and Pb is 150 mg / kg as the standard value. The value exceeded.

<Reference example>
As a reference example, as shown in Patent Document 2, after slag was subjected to water granulation treatment, heat treatment was performed under the conditions shown in Table 3 under atmospheric pressure to prepare slag. About the slag obtained through such heat treatment, the average crystallite diameter of the firelite constituting the crystal phase and the elution amounts of As and Pb from the slag were measured. The measurement results are also shown in Table 3 below.

  As shown in the results of Table 3, in the slag obtained by heat treatment at 600 ° C. for 1 hour under atmospheric pressure, the average crystallite size of firelite was less than 1000 mm. The elution amounts of As and Pb measured in conformity were less than the standard value of 150 mg / kg, and the elution was effectively suppressed. However, in the treatment of this reference example, it is necessary to heat the slag at a temperature of 500 ° C. to 800 ° C., and considerable heat energy and time are required to process a large amount of slag. Have.

DESCRIPTION OF SYMBOLS 1 Self-melting furnace 2 Mat 3 Slag 4 Self-smelting furnace 5 Smelting furnace 6 Melting slag 7 Slag tank 8 Granulation tank 9 Granulation nozzle

Claims (4)

A slag containing Fe and Si as main components and As and Pb as impurities,
Slag whose average crystallite diameter of firelite (Fe ₂ SiO ₄ ) constituting the crystal phase is 1000 mm or more.   The slag of Claim 1 whose elution amount of As and Pb measured according to JISK0058-2 is less than 150 mg / kg.   The slag according to claim 1 or 2, comprising Pb as an impurity component in a proportion of 0.01% by mass to 0.2% by mass and As in a proportion of 0.01% by mass to 0.2% by mass. It is a manufacturing method of the slag in any one of Claims 1 thru | or 3, Comprising:
Fe and Si as main components, a slag material containing As and Pb as impurities, including 80 ° C. above the water temperature, the raw material of slag 1t per 10 m ³ or more 100 m ³ process water granulated treated in the following water, A method for producing slag.

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