JPS58171537A - Method for refining tin and lead in combination with catalytic gasifying method for coal or the like - Google Patents

Abstract

PURPOSE:To refine tin or lead at a relatively low gasifying temp. for coal or the like with high efficiency, by bringing a mixture of coal or the like and ore contg. tin oxide or ore contg. lead into contact with CO2 or/and steam at high temp. to effect the gasification of the coal or the like and the reduction of the tin oxide or lead oxide in the ore simultaneously. CONSTITUTION:Ore contg. tin oxide is screened to 50-60wt% content of tin oxide, and is mixed with coal or coke of 0.01-0.1mm. grain size. The grain size of the ore contg. tin oxide is controlled to 0.01-0.1mm.. The above-described mixture is supplied into a gasifying furnace where the mixture is brought into contact with CO2 or/and steam at>=800 deg.C to gasify the coal or coke and to reduce the tin oxide to metallic tin using part of the formed gas. The metallic tin is removed in a molten state together with the unreacted carbon, the ash in the coal and the impurities in the ore as the residues of gasification from the gasifying furnace, and is separated from these impurities. Metallic lead is separated and recovered from ore contg. lead oxide by the similar method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved process for refining tin and lead, and more particularly to a process for refining tin or lead in combination with a catalytic gasification process for coals.

Tin smelting is carried out by mechanical beneficiation to remove impurities in ore containing tin oxide, and then by roasting and reduction, which involves heating the ore with coal, coke, etc. while excluding air.

Many methods have been known for smelting lead for a long time, one of which is galena (P), which is the main component of lead ore.
A method is known in which b) is converted into lead oxide using air and this lead oxide is reduced using coal, heavy oil, or the like.

On the other hand, many methods for gasifying coal have been known for a long time. In addition, since the oil crisis, many gasification methods have been researched and developed, but many of them require high temperatures and pressures of approximately 1000 degrees Celsius and several tens of atmospheres.
Currently, there are many technical and economic issues that remain to be resolved, such as the coal supply mechanism.

As a result of studying a method of combining tin and lead refining methods and coal gasification to take advantage of the advantages of both, the present inventors found that
The present invention was completed by discovering that tin and lead increase the gasification rate of coal at temperatures above g00°C, and that tin and lead are in a metallic state under such gasification conditions.

The soot and lead refining method combined with the coal catalytic gasification method of the present invention mixes coal or carbide with soot oxide-containing ore or lead oxide-containing ore, and converts the resulting mixture into g0
The coal or carbide is gasified by contacting it with carbon dioxide or/and water vapor at a temperature of 0°C or higher, and the tin oxide or lead oxide in the ore is reduced to metal, and the obtained metal tin or lead metal is Its special mission is to separate it from the gasification residue.

The tin ore used in the present invention is mainly cassiterite, and those containing tin oxide in a wide range of contents are used, but those containing 30 to 70% by weight of tin oxide are particularly preferably used. The lead ore used in the present invention is preferably a lead oxide-containing ore obtained by roasting galena. The lead oxide content in this ore is preferably 7 o-go weight.

The type of coal used in the present invention is not particularly limited, and a wide range of coals can be used, including low-grade coal such as lignite. This is because components such as calcium and silicon:iron in the ash of coal act as catalysts and reducing agents when producing lead oxide and metallic lead from galena. Also, carbide of one coal can be used similarly. Furthermore, carbides of substances other than coal can also be used. The particle size of the coal etc. used can vary widely depending on the reaction method employed;
Preferably particle size θ/- or less, particularly preferably 00/~θ
0! ;m.

The mixing ratio of tin oxide-containing ore or lead oxide-containing ore and coal or carbide is 3% SnO2 or PbO per 100% carbon by weight in the coal or carbide, respectively.
~10 parts by weight or ~10 ~/S parts by weight are preferred.

If the mixing ratio is below the lower limit, it is difficult to efficiently separate metallic tin or lead from the gasification residue, and if it is above the upper limit, the reduction rate of tin oxide or lead oxide is not fast enough. . Another reason for this is that the gasification rate is low below the lower limit.

To mix the above ores with coal, etc., use ore.

Preferably, the particle size is 0/2 or less, and an appropriate method such as mechanically mixing with coal or the like is used.

Carbon dioxide, which is a gasifying agent such as coal, and steam are added alone or in a mixture. The mixing ratio is determined depending on the composition of the generated gas, and for example, a range of θ/−1O is used at a Cot/H20 molar ratio. These gases,
The oxidizing agent can further be used with hydrogen or oxygen-containing gas. The amounts of these gases are those necessary to maintain the desired composition of the product gas and reaction temperature. The amount of carbon dioxide or steam is preferably 1 mole of carbon in the coal or carbide, CO2/~comole or H10/~2 mole.

There is no particular restriction on the reaction pressure, but normal pressure ~ / Q ky /
Preferably it is caG.

The reaction temperature is g00℃, where tin or lead is in a molten metal state.
Although it is above, gSθ°C or above is particularly preferable. goθ
℃ or higher, the catalytic activity of tin or lead for gasification of coal or carbide increases.

This is thought to be because the surface tension of molten tin or lead is small, so that the coals and catalyst can come into good contact under the reaction conditions.

As the reaction method, various methods such as fixed bed, fluidized bed, transport bed, and molten bed are used. Further, any of a continuous type, a discontinuous type, an internal heating type, and an external heating type can be used. Continuous internal heating is preferred.

The gasification rate of coal is preferably in a range such that carbon remains in the gasification residue (consisting of lime ash, ungasified carbon, tin or lead, or impurities in ore) from S to 10. By maintaining the residual amount of carbon within the above range, tin or lead is maintained in a metallic state.

The following method is preferably used to separate tin and lead as metals from the gasification residue.

Since both tin and lead melt even at a low temperature of about 1 Ioo°C, it is preferable to separate them by utilizing this property. In other words, tin is extracted from the gasification residue kept at 300 to 1ioo°C to the carbon-rich upper layer and the Fe, Cu, lower layer.
Separately collect the middle part of the main components. On the other hand, as with tin, lead was separated from the lower layer by specific gravity sorting at about 900°C.

The gasification residue from which the tin or lead has been separated is either recycled to the gasifier or the carbon contained therein is combusted to provide heat for the process. A portion of the formed gas is oxidized in the reactor. It is consumed for reducing tin or lead oxide, but most of it is used as fuel or raw material for chemical synthesis.

The method of the present invention will be specifically explained with reference to FIGS. 1 and 2. In FIG. 7, the tin oxide-containing ore is beneficent to a tin oxide content of 50 to 60% by weight.

Particle size 0θ/~0. /rm of coal or coke. The particle size of the tin oxide-containing ore is θO/~0/■. The mixture is fed to a gasifier of a suitable type, g00
Coal or coke is gasified by contacting it with carbon dioxide or/and water vapor at temperatures above 0.degree. A portion of the gas produced reduces the tin oxide to metallic tin.

The produced metal tin is taken out of the gasifier in a molten state as a gasification residue along with unreacted carbon, coal ash, and impurities in the ore. separated from impurities.

The separated crude tin is purified by a known dry method or electrolytic method to remove impurities such as arsenic, copper, bismuth, and antimony, and is made into a product. On the other hand, the residue separated from the crude tin may be supplied with air to burn unreacted carbon, and the heat at this time may be supplied to the gasification step.

FIG. 2 shows the process of the present invention using a lead oxide-containing ore, which is similar to the process shown in FIG. just,
The only difference is that galena is beneficent and air oxidized to convert lead sulfide to lead oxide, which is then mixed with coal or coke. Since the obtained crude lead contains impurities such as gold, sulfur, copper, bismuth, arsenic, antimony, and tin, these impurities are removed by a known dry method or electrolytic method to obtain a product.

According to the present invention, by combining the catalytic gasification of coal and the refining of tin or lead, the catalytic gasification of coal can be performed at a lower temperature and with higher efficiency than the conventional gasification temperature due to the catalytic action of tin or lead. At the same time, the tin oxide-containing or lead oxide-containing ore fed to the catalytic gasification step can be refined.

The present invention will be further explained by showing examples below.

Example / A test gasifier with an inner diameter of 5 ctn and a height of gOcm was charged with 50% by weight of coal 0/2 and Sn 02 having a composition of button/.
A mixture containing 0.02 kg of tin oxide ore was charged.

Table: Air was supplied to this gasifier from the bottom of the furnace, and the temperature inside the furnace was raised to gSO°C by the heat of combustion of coal. Next, instead of air, CO! is added from the bottom of the furnace! θ/rl/hr steam 0.
/rr? / hr and 02θ/rr? /hr
Gasification and reduction of tin oxide were carried out while keeping the temperature inside the furnace at 50° C. by supplying . Note that the amount of gasifier supplied was decreased in accordance with the amount of coal that decreased over time. Seven hours after the start of the reaction, the supply of the gasification agent was stopped, and the gasification residue containing 10% by weight of metal tin (by weight), ash (10% by weight), and 30% by weight of unreacted carbon was extracted from the gasifier, and the temperature was brought to about 300°C. The molten metal tin is collected separately from the ash and unreacted carbon. The amount of coarse tin obtained was 0.0/kr.

On the other hand, the dry gas composition of the produced gas 70 minutes after the start of gasifying agent supply is H2/g%, CO57%, C02j5%, and C02j5%.
H40,/%.

Example: Instead of the tin oxide-containing ore, a lead oxide-containing ore containing 0.0% by weight of pbo go obtained by roasting galena was used.
The operation was carried out in the same manner as in Example except that 2ky was used.

Metallic lead was extracted from the obtained gasification residue at a temperature of about 330° C. as a melt in the lower layer, and was separated from ash, slag, and the like. Separated crude lead is 0.0/,! ; It was kg.

The composition of the dry gas produced 70 minutes after the start of gasification was as follows.

H215%, CO55CH, CO230% and CH40
/blood.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of a tin refining process according to the present invention, and FIG. 2 is a flow sheet of a lead refining process according to the present invention.

Claims (1)

[Claims] / Coal or carbide is mixed with tin oxide-containing ore or lead oxide-containing ore, and the resulting mixture is brought into contact with carbon dioxide or/and steam at a temperature of 300°C or higher to gasify the coal or carbide and to A tin and lead refining method combined with a catalytic gasification method for coals, characterized by reducing tin oxide or lead oxide in ore to metal and separating the obtained metallic tin or metallic lead from gasification residue.