JP2008080271A - Ball milling method for copper smelting solvent - Google Patents

Abstract

PROBLEM TO BE SOLVED: Since the conventional ball mill pulverization method uses only pulverization heat, when the water content of silicate ore is increased, the pulverization heat alone cannot be sufficiently dried and dew condensation occurs in the ball mill pot. , The silicate ore, powder and balls that are the contents of the mill stick to the inner wall of the pot and become stuck, and the pulverization efficiency may decrease or the pulverization itself may become impossible. The purpose is to solve the problem.
SOLUTION: A silicate ore is supplied into an interior of a ball mill pot from an opening formed in one of the pot wall surfaces intersecting with a rotation axis of a horizontal ball mill, and crushed silicate ore is discharged from an opening on the opposite side. In a ball milling method of a copper smelting solvent, a ball milling of a copper smelting solvent that accelerates drying of the silicate ore by blowing hot air into the ball mill pot through any of the openings during rotation of the mill pot. Method.
[Selection] Figure 1

Description

  The present invention relates to a ball milling method for a copper smelting solvent. A flash smelting furnace for performing copper smelting is charged with a solvent mainly composed of silicate ore together with ore raw materials such as copper ore or copper concentrate.

  Roller mills, ball mills, and the like are mainly used for pulverizing ores, stones, earth and sand, cement clinker, solid fuel, solvents and the like. Ball mills are frequently used for pulverization because of their simple structure and high reliability.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-172339 relates to a ball mill that pulverizes a relatively small amount of contaminated soil or the like in kg, and the rotating mechanism of the mill pot rotates around its own central axis. Is a revolving / revolving type that revolves around the base rotation axis. That is, since the inside of the mill pot is filled with earth and sand and balls, the rotation mechanism is performed via rotary joints provided above and below the mill pot.
In this ball mill, it has been proposed to form a cooling water flow path penetrating the inside of the mill pot in order to prevent the heat generated due to the pulverization of the non-pulverized product from adversely affecting the non-pulverized product itself.

  Patent Document 2: Japanese Patent Application Laid-Open No. 2006-110474 also relates to a rotation / revolution ball mill, and includes a temperature sensor for measuring the temperature in the mill pot.

  Patent Document 3: Japanese Patent Laid-Open No. 5-15805 relates to a facility for two-stage pulverization of cement clinker, blast furnace slag, etc. In the primary pulverization apparatus, the raw material is transferred from the raw material storage bin to a vertical roller mill via a conveyor. Supply and pulverize, and finely pulverize with a ball mill as the secondary pulverization.

Silicate ore supplied to a copper smelting furnace such as a flash smelting furnace or a reflection furnace serves as a supply source of SiO ₂ combined with Fe in copper ore. Silicate ores are currently produced in Japan at the Kasuga Mine (Kagoshima Prefecture), the Koryu Mine (Hokkaido), the Tsuchata Takayama (Iwate Prefecture), and others. Silicate ores contain trace amounts of valuable metals such as gold and silver, and these are also recovered in the copper smelting process.

  Silicate ore is transported from the mountain to the copper smelter and ground by ball milling after field loading. A horizontal type suitable for continuous operation is used for the ball mill. Ball milling to prepare a copper smelting solvent requires particle size adjustment, drying and continuous feeding. In adjusting the particle size, it is necessary that the solvent is smoothly injected from the concentrate nozzle of the flash smelting furnace and melted in the smelting furnace to form slag. Also, if the silicate ore becomes too fine, valuable metals (gold, etc.) are lost as dust. In order to satisfy these conditions, pulverization is generally performed until the average particle size reaches about 20 mm.

Next, regarding moisture drying, moisture causes endothermic decomposition in the smelting furnace, lowering the temperature in the furnace and generating H ₂ S. Therefore, it is necessary to reduce moisture as much as possible. is there. For this purpose, pulverization heat generated by pulverization is used.

Finally, for continuous feed, it is necessary to continuously supply a predetermined amount of solvent along with the ore to a smelting furnace such as a flash furnace and a reflection furnace, so the silicate ore grinding speed must be kept almost constant. . For example, when the silicate ore is excessive with respect to the copper ore raw material, it is necessary to temporarily store the excess silicate ore in a stock bottle, and there is a risk of absorbing moisture during this period. On the other hand, when the silicate ore is insufficient with respect to the copper ore raw material, it is necessary to reduce the copper ore raw material put into the smelting furnace, and the productivity is lowered. By the way, although the water | moisture content etc. of the raw material thrown into a grinder change with storage conditions etc., since a grinding | pulverization speed cannot be changed according to this, the water | moisture content of the crushed silicate ore will change.
JP 2002-172339 A JP 2006-110474 A Japanese Patent Laid-Open No. 5-15805

  None of the above-mentioned prior art patent documents relates to the promotion of moisture evaporation of the object to be crushed. In addition, since the conventional ball mill pulverization method uses only the heat of pulverization, if the water content of the silicate ore is increased, it cannot be sufficiently dried only with the pulverization heat, and condensation occurs in the ball mill pot. The contents of the silicate ore, powder, balls and the like stick to the inner wall of the pot and cast, which may reduce the grinding efficiency or make the grinding itself impossible.

According to the present invention, in order to solve the above-mentioned problems, the following ball milling method for a copper smelting solvent is provided.
(1) Silicic acid ore fed into the inside of the mill pot from an opening formed on one of the pot wall surfaces intersecting the rotation axis of the horizontal ball mill, and crushed from the opening formed on the opposite pot wall surface In a ball mill pulverizing method of a copper smelting solvent for discharging ore, a method of promoting drying of silicate ore by blowing hot air into the mill pot through any of the openings during rotation of the mill pot .
(2) A chute for supplying silicate ore is plunged into the cylinder attached to the opening so as to enable rotation of the mill pot so that the tip faces the mill pot, and the cylinder The method according to item (1), wherein hot air is blown through
(3) The method according to (2), wherein hot air in the mill pot is sucked by a suction fan provided on the pulverized ore discharge side of the ball mill.
(4) The method according to (2), wherein hot air is pumped into the ball mill by a pushing fan provided in the cylindrical body.
(5) the SO ₃ which is converted from the SO ₂ to SO ₃ by the converter of contact sulfuric acid production unit, the manufacturing method of the contact type sulfuric acid method which leads to the absorption tower through a heat exchanger, said from the heat exchanger A flow control valve and SO ₃ cooler are placed in parallel from the gas passage to the absorption tower to the bypass gas passage, and the gas flow rate is adjusted so that the gas temperature in the SO ₃ cooler placed in parallel is 160 ° C or higher. The method according to any one of (1) to (4), wherein the gas recovered by the SO ₃ cooler is used as the hot air.
(6) Any one of items (1) to (5), characterized in that air is fed into a gas flow path between the ball mill and a dust collector provided on the discharge side to reduce the temperature of the exhaust gas. The method according to claim 1.
The present invention will be described in detail below.

  The ball mill pot for grinding silicate ore is generally rotating at about 10 to 100 rpm. An opening is formed on any surface that intersects the rotation axis of the mill pot, and a silicate ore charging chute enters the opening, and the crushed silicate ore is discharged from the opening on the opposite side. These openings are formed symmetrically with respect to the rotation axis so that their positions do not change during the rotation of the ball mill, and are formed so that the ore chute and the wall surface of the mill pot do not interfere with each other during the rotation.

In the present invention, hot air is blown from one of the above-described openings while the ball mill is rotating, thereby compensating for the amount of heat that is insufficient for water evaporation with only the heat of grinding of the solvent.
Hot air may be blown from either the ore supply side or the discharge side, but it is preferable to blow from the ore supply side because no pulverization heat is generated and the cooled silicate ore can be dried.

  The heat of grinding of the solvent depends on the processing capacity of the ball mill, but the amount of heat that raises the silicate ore to 50-100 ° C in the mill with a grinding speed of about 20-30 t / h used in the applicant's smelter It corresponds to. Therefore, in the method of the present invention, it is necessary to compensate for the heat of drying by blowing hot air at a temperature equal to or higher than the temperature provided by the pulverization heat. According to the method of the present invention, various supply means such as a pipe, a hose, and a nozzle can be adopted as a method for blowing hot air. There may be a gap between the pipe and the opening, but it can be configured as described below.

According to the embodiment of the present invention, the chute for silicic acid mining is plunged into the cylinder attached to the opening so as to enable rotation of the ball mill pot, and the cylinder is inserted through the cylinder. And blow hot air.
Since the above-mentioned cylinder is airtightly inserted into the ball mill through an appropriate seal, hot air does not escape from the opening to the outside air, so that the drying efficiency can be improved and the working environment can be kept comfortable. it can.

According to the embodiment of the present invention, the ore powder is prevented from being blown up from the silicate ore charging chute by the blown hot air by sucking the inside of the mill pot by the fan provided on the pulverized ore discharge side of the ball mill. At the same time, the hot air is made to flow uniformly in the mill pot. When the intake fan is installed downstream of the dust collector, the gas excluding the dust is once sucked, so that the fan is hardly worn by the dust.
FIG. 1 illustrates a preferred embodiment of claim 3 characterized in that a differential pressure gauge is provided on the feed side, wherein the pressure in the feed chute is negative to the outside air, preferably −30 mm, aq. The air in the ball mill is sucked by the fan through the bag filter so that the pressure is reached. The stock bottle is a container for temporarily storing the crushed silicate ore.
Subsequently, a preferred hot air generation source will be described in the following paragraphs 0017 to 0020 with reference to Japanese Patent Application No. 2006-093752 filed on March 31, 2006 by the present applicant.

A conventional converter group flow sheet in the applicant's smelter is shown in FIG.
The equipment of the sulfuric acid converter group is the SO ₂ gas tank (T), the converter (Cv) that oxidizes sulfurous acid (SO ₂ ) gas to sulfuric acid (SO ₃ ) gas, and heat exchange with the raw material gas to achieve the predetermined reaction temperature Heat exchanger (1HE), absorption tower (Abt) for absorbing SO ₃ gas, and heat exchanger (2HE, 3HE, 4HE) for adjusting the temperature of gas from each layer of the converter Is common. Double contact converter second layer outlet SO ₃ gas passes through high-temperature heat exchanger 4HE (A) and low-temperature heat exchanger 4HE (B) to absorb SO ₃ in sulfuric acid in the intermediate absorption tower (Abt) . Furthermore, an acid cooler (not shown) for continuously removing heat generated in a steady state such as oxidation heat and dilution heat in the absorption tower is also installed.
Some smelters incorporate SO ₂ coolers, SO ₃ coolers, waste heat boilers, and economizers in the flow instead of general heat exchangers and acid coolers to recover heat and eliminate excess heat due to increased production. I am planning.

As described above, when the SO ₂ concentration is 10% or more, the conversion rate decreases, and it has been known that the SO ₃ cooler is effective in dealing with this.
For SO ₃ coolers, when used in a low temperature state, SO ₃ condenses and the inside of the pipe is blocked, or if moisture is mixed in the gas, it becomes sulfuric acid and causes corrosion of the pipe wall. In many cases, it is operated at 160 ° C or higher.
For this reason, when installing SO ₃ coolers etc. in the converter group shown in Fig. 1 for the purpose of energy saving, etc., the existing heat exchanger (HE in Fig. 2) will be abolished due to this temperature restriction. It is not common because new equipment must be installed.

The invention of the prior application was able to perform efficient heat recovery by installing an SO ₃ cooler without significantly changing the existing converter system by performing appropriate gas distribution while monitoring the temperature of the converted gas. has the gist that promote increased production, the SO ₃ which is converted from the SO ₂ to SO ₃ by the converter of contact sulfuric acid production unit, the manufacturing method of the contact type sulfuric acid method which leads to the absorption tower through a heat exchanger, A flow control valve and an SO ₃ cooler are arranged in parallel from the gas passage from the heat exchanger to the absorption tower in the bypass gas passage, and the gas temperature in the SO ₃ cooler arranged in parallel is 160 ° C. or higher. In this method, excess hot air is used for drying the silicate ore as a solvent.

Next, an embodiment of the invention of the prior application will be described with reference to FIG. FIG. 3 is a diagram showing a flow relating to the converter and subsequent ones shown in the flow sheet of FIG.
The feature of this flow is that the SO ₃ cooler (SC) is installed so as to bypass the high temperature heat exchange 4HE (A) and the low temperature heat exchange 4HE (B). A gas flow rate control valve (VG) is arranged at the inlet or outlet side of the SO ₃ cooler (SC) so that the amount of gas passing through the SO ₃ cooler can be arbitrarily changed.
F is a fan that pumps outside air into the cooler (SC). With such an equipment configuration, when the temperature of the converted gas becomes high, the gas flow rate adjustment valve (VG) is opened and the SO ₃ gas is bypassed to maintain a high conversion rate and cooler (SC ) Recovered heat is used to dry the silicate ore.
This recovered heat has a temperature of 280-300 ° C. Moreover, the temperature drop during conveyance from the gas cooler to the ball mill is about 70 ° C. Since the recovered heat is a clean gas of air itself, even if it leaks to the outside of the ball mill, there is no concern about air pollution, and an excessive dust removal load is not applied to the bag filter attached to the rotary kiln. When the gas flow rate adjustment valve (VG) is closed, it is preferable to use the heat recovered by the four low-temperature heat exchanger HE (B) for drying the silicate ore.

  Furthermore, according to the present invention, the temperature of exhaust gas from the ball mill increases due to hot air blowing, and the dust collector provided on the exhaust side, such as a bag filter, may be thermally damaged. As a countermeasure, if air is blown into the pipe between the ball mill discharge side and the dust collector, the temperature of the exhaust gas is lowered and thermal damage can be prevented. In this case, the temperature of the exhaust gas is measured, and air, that is, cold air may be sent from the outside air only when necessary.

  In the present invention, thermometers can be installed at various locations to monitor the grinding process. For example, a thermometer installed on a feed chute can detect hot air blown up. Moreover, since the temperature rises when the silicate ore closes the hot air blowing port, the thermometer installed at the hot air blowing port can detect clogging of the feeding port.

The silicate ore drying method using the recovered heat in the bypass gas cooler has been described above. Needless to say, in the present invention, other surplus heat recovered in the smelter can be used for drying. Furthermore, although only silicate ore was mentioned as a solvent, lime can be pulverized together with silicate ore depending on the smelting method and the copper ore raw material circumstances. In addition, recycled materials such as honey snake can be pulverized and dried as other materials.

(1) According to the present invention, since the silicate ore is forcibly dried by hot air in addition to natural drying by frictional heat, the ore does not stick in the mill pot and the pulverization rate is increased (claim 1).
(2) Drying heat efficiency is improved by preventing hot air from leaking outside the ball mill.
(3) By preventing the hot air from leaking out of the ball mill as in claim 2, the pressure in the mill pot can be controlled. As this method, it is possible to prevent ore blowing on the feed belt by generating a differential pressure using an exhaust fan (claim 3). Further, the drying capacity can be increased by the hot air pushing fan, and thereby the pulverization capacity can be increased (Claim 4).
(4) Further, by using surplus heat recovered by the bypass gas cooler proposed in the prior application as hot air, the heat energy used in the entire smelter is reduced (claim 5).
(6) It is possible to prevent damage to the dust collector and protect the dust collection cloth of the bag filter (claim 6).
Hereinafter, examples of operations in the smelter of the present applicant will be described as examples and comparative examples.

The ball mill used for pulverization of silicate ore in the applicant's smelter has a diameter of 3.6 m, a length of 10.5 m, and a ball amount of 65 t (21,700 pieces). The rotation speed is constant at 16 rpm.
FIG. 4 shows a longitudinal sectional view of the used ball mill on the supply side.
The ball 2 and the silicate ore 3 are mixed in the mill pot of the ball mill 1, and the silicate ore 3 is pulverized when the mill pot rotates about the rotation axis XX. A circular opening 1 b is formed in a surface 1 a intersecting the rotation axis XX of the mill pot 1, and silicate ore 3 is introduced from the opening 1 b by an ore chute 4. On the other hand, the ball mill 1 is inclined downward to the right in the drawing, or the guide mountain is formed in a spiral shape on the inner wall, so that the contents are moved in the right direction as it rotates.

The cylindrical body 5 is attached to the opening 1b so as to allow the ball mill 1 to rotate, and an intake fan is provided on the discharge side so that gas does not leak from these gaps. Sealing means such as keeping pressure is adopted. Hot air, which is a feature of the present invention, is sent from the cylinder 5 into the mill pot as indicated by an arrow.
FIG. 6 shows an ore chute 4 composed of a semicircular guide 4a and a lid 4b. As shown in the left front view of the cylinder 5 shown in FIG. 7, push fans 6a and 6b are arranged on the cylinder, and hot air is pushed in to blow air.
Table 1 shows the operation results.

The comparative example in Table 1 is the operation result of one day by the conventional operation method which does not use hot air.
Examples 1 and 2 are operation results when the operation in which hot air was blown in under the conditions shown in the table was performed for one day. In these operational results, the pulverized ore moisture is almost the same, but regarding the amount of feed, it can be seen that the example is higher than the comparative example of 1.4 to 10 t / h, and the pulverization rate is higher.

  As described above, according to the present invention, in ball milling of silicate ore used as a solvent for copper smelting, even when the water content of silicate ore is high, the pulverization efficiency can be increased.

It is a schematic diagram explaining the method which concerns on Claim 3 of this invention. It is a sulfuric acid conversion system diagram in the refinery of the present applicant. It is the systematic diagram which improved FIG. It is a fragmentary sectional view of the ball mill which enforces the method concerning Claim 4 of the present invention. It is sectional drawing of an ore throwing chute. It is a left front view of the cylinder shown by FIG.

Explanation of symbols

1 Ball mill 4 Ore charging chute 5 Cylinder

Claims (6)

A copper smelting solvent that feeds silicate ore into the ball mill pot from an opening formed on one of the wall surfaces of the pot that intersects the rotation axis of the horizontal ball mill, and discharges the crushed silicate ore from the opening on the opposite side. In the ball mill pulverizing method, a copper smelting solvent ball mill characterized in that drying of the silicate ore is promoted by blowing hot air into the ball mill pot through any of the openings during rotation of the mill pot. Crushing method. In order to allow rotation of the ball mill pot, a chute for feeding the silicate ore is inserted into the cylinder mounted in the opening so that the tip faces the inside of the mill pot, and the cylinder 2. The method for ball milling a copper smelting solvent according to claim 1, wherein the hot air is blown through a body. 3. A ball mill pulverizing method for a copper smelting solvent according to claim 2, wherein hot air in the mill pot is sucked by a suction fan provided on the pulverized ore discharge side of the ball mill. 3. The ball milling method of a copper smelting solvent according to claim 2, wherein hot air is pumped into the ball mill by a pushing fan provided in the cylindrical body. The SO ₃ that has been converted from SO ₂ to SO ₃ by the converter of contact sulfuric acid production unit, the manufacturing method of the contact type sulfuric acid method which leads to the absorption tower through a heat exchanger, to the absorption tower from the heat exchanger The flow rate control valve and the SO ₃ cooler are arranged in parallel from the gas passage to the bypass gas passage, and the gas flow rate is adjusted so that the gas temperature in the parallel arranged SO ₃ cooler is 160 ° C. or higher. _The method of ball milling a copper smelting solvent according to any one of claims 1 to 4, wherein the gas recovered by a _three cooler is used as the hot air. 6. The copper product according to claim 1, wherein the temperature of the exhaust gas is lowered by feeding air into a gas flow path between the ball mill and a dust collector provided on the discharge side thereof. Ball milling method for smelting solvent.