CN1434140A

CN1434140A - Method for preparing coal base reductant for pyrometallurgical refining copper

Info

Publication number: CN1434140A
Application number: CN 02113269
Authority: CN
Inventors: 刘中华; 陈雯
Original assignee: LIGONG JINGCHENG SCIENCE AND TECHNOLOGY Co Ltd KUNMING
Current assignee: LIGONG JINGCHENG SCIENCE AND TECHNOLOGY Co Ltd KUNMING
Priority date: 2002-01-21
Filing date: 2002-01-21
Publication date: 2003-08-06
Anticipated expiration: 2022-01-21
Also published as: CN1208485C

Abstract

The present invention provides a coal base reductant for pyro-refining copper and its preparation method. It is made up by using coal or coke as raw material and pulverizing it into powder whose grain size is below 5 mm. Said reductant contains (wt%) 15-90% of fixing carbon, 2-60% of volatile matter using hydrocarbon as main component, sulfur whose content is less than 2% and other mineral component, and its final composition is 100%. When it is blown into molten copper by using high pressure air to make reduction process, and when the coal whose iron content is higher is used as main body of reductant, the iron-removing agent quartz sand can be added into the coal, its added amount is less than 10%, and when the coal with higher sulfur content is used as main body of reductant, the desulfurizer can be added in the coal, its added amount is less than 10%.

Description

Preparation method of coal-based reducing agent for copper fire refining

The invention belongs to the technical field and relates to the field of nonferrous metallurgy, in particular to a preparation method of a coal-based reducing agent for copper pyrometallurgy refining.

Background art the principle of the existing copper fire refining production process is that compressed air is blown into copper liquid at the furnace temperature of 1200-:

cu dissolved in copper bath₂And (3) contacting O with impurities (Me') in the copper liquid to oxidize the O:

then, carrying out a reduction process by using a reducing agent (R), and removing excessive oxygen in the copper liquid under the condition of a reducing atmosphere:

at present, the reducing agents used in the copper refining reverberatory furnace in the world are mainly: heavy oil, liquefied petroleum gas, diesel oil, natural gas, ammonia, propane, raw wood and charcoal powder.

When petroleum products such as heavy oil, liquefied petroleum gas, diesel oil and the like are used as reducing agents, the production cost is increased due to the higher price, the supply is influenced due to geographical position limitation, and a large amount of black smoke is emitted due to incomplete combustion in the reduction process to cause environmental pollution.

When a reducing agent such as natural gas, ammonia, propane, or the like is used, there is a large limitation in resource conditions and industrial conditions. When the reducing agent is used, the requirement on storage conditions is very high, and the safety problem is particularly noticed when the reducing agent is used under the high-temperature condition of copper smelting; on the other hand, a large amount of black smoke is emitted due to incomplete combustion in the reduction process, so that the environment is polluted.

When raw wood, charcoal powder and the like are used as reducing agents, the reducing agents are prepared from natural ecological resources, so that the natural environment is greatly influenced, such as forest cutting, vegetation destruction, water and soil loss and the like are caused.

The invention aims to overcome the defects of the prior art and provide a novel coal-based reducing agent used for copper pyrometallurgy as a substitute of the traditional reducing agent and an application method suitable for the reducing agent.

The invention is realized by the following technical scheme:

the method comprises the following steps: under the condition of not adding any mineral substance, coal (including peat, brown coal, bituminous coal and anthracite) or coke is crushed and processed into a powdery state with the granularity of less than 5mm to prepare a reducing agent which contains 15-90% of fixed carbon, 2-60% of volatile matter mainly containing hydrocarbon, less than 2% of total sulfur and other mineral components, and the final component is 100%, and the reducing agent replaces the conventional reducing agents, and is blown into liquid copper by high-pressure air to carry out the reduction process of copper fire refining.

The second method comprises the following steps: when coal with high iron content is used as the main body of the reducing agent, less than 10 percent of iron removal agent quartz sand can be added into the coal and is crushed and mixed with the coal uniformly for use, the particle size range can be between 100 meshes and 200 meshes, and the particle size range is determined according to the copper liquid impurities, the oxidation depth and the blown air amount of the refining furnace. The presence of quartz in the slag greatly reduces the activity of FeO, allowing iron to enter the slag without being substantially retained in the liquid copper. After the coal-based reducing agent with uniformly mixed powder is blown into the copper liquid, the dissolved oxygen in the copper liquid is removed, and meanwhile, the iron in the coal can be prevented from polluting the copper liquid, so that the refining purpose is achieved.

The third method comprises the following steps: when coal with high sulfur content is used as main reducing agent, desulfurizer less than 10% such as sodium carbonate, sodium fluoride, calcium carbonate, CaC can be added into coal₂CaO, and the like. One or more desulfurizing agents may be added as occasion demands. Mixing with coal, making into powder with particle size below 5mm, and mixingThe copper liquid is uniformly used for replacing various traditional reducing agents, and is blown into the liquid copper, so that the dissolved oxygen in the copper liquid is removed, and meanwhile, the sulfur in the coal can be prevented from polluting the copper liquid, and the purpose of refining is achieved.

The method four comprises the following steps: when coal with high sulfur content and high iron content is used as a main body of the reducing agent, the first method and the second method can be used simultaneously or sequentially, so that sulfur and iron in the coal can be reduced or prevented from entering the copper liquid when oxygen in the copper liquid is removed, and the purpose of refining is achieved.

In the reduction stage of the copper reverberatory furnace fire refining, in order to improve the refining effect, a new process of deep oxidation-deep reduction and repeated oxidation-reduction can be adopted to achieve the purpose of impurity removal and reduction. Air can be supplemented in the flue of the reverberatory furnace, so that a small amount of unreacted reducing agent and decomposed substances thereof are combusted, the blackness of the flue gas is reduced, the content of suspended substances in the flue gas is greatly reduced, and the flue gas emission meets the national standard.

Compared with the prior art, the invention has the following advantages:

1. the raw materials are wide in source, cheap and easy to obtain. In order to improve the percent of pass of the anode copper product in the reduction process, coal with low sulfur, low iron and low ash content is generally used as a matrix of a reducing agent. All coals with low sulfur, low iron and low ash content, such as lignite, bituminous coal and anthracite, can be used as the matrix of the reducing agent.

2. The treatment process and the use process of the coal are combined into one, and the process is simple. If the impurity content of coal is high, the additive sodium carbonate, calcium carbonate and CaC are mechanically added before being used as reducer₂And CaO or quartz sand can prevent impurity components from entering the copper liquid while deoxidizing, and impurities are not introduced to enter the production flow.

3. Is beneficial to environmental protection. The coal is taken as the matrix of the reducing agent, and when the coal is taken as the reducing agent instead of the raw wood and the charcoal, the felling of the forest can be directly reduced; under the condition of replacing all the traditional reducing agents, the air is added into the flue, so that the organic matters are completely combusted, and the discharged flue gas has no adverse effect on the environment.

4. The cost is low. Coal as mineral resources is abundant in geology, cheap and easily available, and easy to transport, store and process. The cost of using coal and additives is much lower than using heavy oil, liquefied petroleum gas, diesel oil, natural gas, ammonia, propane, raw wood, charcoal powder, etc. on the basis of removing oxygen per unit mass. In addition, the labor procedure of workers is simplified during reduction, the labor intensity is reduced, and the reducing agent is convenient to store and transport.

The following are typical examples of the present invention.

Example 1

Crude copper composition (%): cu 98.8, Fe 0.01, S0.3, others (not shown).

The process conditions are as follows: conveying wind pressure is 0.2-0.7Mpa, a flue damper is arranged between a horizontal flue and a vertical flue of the refining furnace, the oxidation end temperature is 1150-1180 ℃, the atmosphere in the furnace is controlled to be reducing atmosphere, positive pressure in the furnace is 5-20Pa, and slag in the furnace is removed completely.

Under the working conditions, the bituminous coal is crushed into powder to be used as a reducing agent, no mineral substance is added, and the powder is blown into liquid copper by high-pressure air through a conveying device for reduction refining.

The anode copper composition (%) after reduction was: 99.3 of Cu, 0.005 of Fe and 0.015 of S, and the balance being qualified.

Example 2

Crude copper composition (%): cu 98.5, Fe 0.03, S0.02, others (not shown).

The process conditions are as follows: the same as in example 1.

The reducing agent is anthracite, the reducing time is 1 hour, the air is stirred, and the air is supplemented in the flue.

When the working conditions are met, anthracite is crushed into powder to be used as a reducing agent, mineral substances of additives such as quartz sand and the like which are less than 10 percent are added, and the powder is blown into liquid copper by high-pressure air through a special conveying device for reduction refining.

Reduced anode copper composition (%): cu 99.0, Fe 0.003, S0.010, and the others are qualified.

Example 3

Crude copper component (%): cu 98.5, Fe 0.03, S0.02, others (not shown).

The process conditions are as follows: the same as in example 1.

The reducing agent is lignite, mineral substances such as sodium carbonate and limestone which are less than 10 percent are added, the reduction time is 1.5 hours, air stirring is carried out, deep reduction is carried out, adjustment is carried out after moderate oxidation, and air is supplemented to a flue.

When the working conditions are met, the lignite is crushed into powder to be used as a reducing agent, mineral substances of additives such as quartz sand and the like which are less than 10 percent are added, and the mixture is blown into liquid copper by high-pressure air through a special conveying device for reduction refining.

Reduced anode copper composition: 99.5 of Cu, 0.001 of Fe, 0.010 of S and the balance of qualified products.

Example 4

Crude copper composition (%): cu 99.0, Fe 0.01, S0.4, others (not shown).

The process conditions are as follows: the same as in example 1.

The reducing agent is lignite, quartz sand is firstly added, slag is removed for multiple times for 2.2 hours, air is stirred, and air is supplemented to a flue.

When the working conditions are met, the lignite is crushed into powder to be used as a reducing agent, no mineral substance is added to be used as an additive, and the powder is blown into liquid copper through high-pressure air by using a special conveying device to be reduced and refined.

Reduced anode copper composition: 99.7 of Cu, 0.002 of Fe and 0.005 of S, and the balance being qualified.

Claims

1. The preparation method of the coal-based reducing agent for copper fire refining is characterized by comprising the following steps: coal or coke is used as raw material, and is crushed into 5mm below grain size to prepare reducing agent containing fixed carbon 15-90%, hydrocarbon as main volatile matter 2-60%, total sulfur less than 2 and other mineral components in 100%, and the reducing agent is blown into copper liquid with high pressure wind for reduction.

2. The method of claim 1, wherein: the coal includes peat, lignite, bituminous coal, anthracite.

3. The method of claim 1, wherein: when coal with high iron content is used as a main body of the reducing agent, the quartz sand which is used as the iron removal agent and is less than 10 percent is added into the coal, and the coal and the quartz sand are crushed to a crushed state with the granularity of 100 meshes and 200 meshes before use and are uniformly mixed for use.

4. The method of claim 1, wherein: when coal with high sulfur content is used as main body of reducing agent, less than 10% of desulfurizing agent such as sodium carbonate, sodium fluoride, calcium carbonate and CaC is added into the coal₂And CaO, and the like, and one or more desulfurizing agents can be added into the mixture, and the mixture and the coal are prepared into a powdery state with the granularity of less than 5mm before use and are mixed uniformly for use.

5. The method of claim 1, wherein: when coal with high sulfur content and coal with high iron content are used as main reducing agent, less than 10% of desulfurizing agent and iron-removing agent are added into the coal simultaneously or successively.