CN108588401B

CN108588401B - Oxidation roasting method for hard zinc vacuum smelting furnace slag

Info

Publication number: CN108588401B
Application number: CN201810357797.9A
Authority: CN
Inventors: 刘洪波; 王振杰; 刘安荣; 钟先杰; 钟波; 李世平
Original assignee: GUIZHOU INSTITUTE OF METALLURGY CHEMICAL; LIUPANSHUI ZHONGLIAN INDUSTRY & TRADE INDUSTRIAL Co Ltd
Current assignee: GUIZHOU INSTITUTE OF METALLURGY CHEMICAL; LIUPANSHUI ZHONGLIAN INDUSTRY & TRADE INDUSTRIAL Co Ltd
Priority date: 2018-04-20
Filing date: 2018-04-20
Publication date: 2020-02-07
Anticipated expiration: 2038-04-20
Also published as: CN108588401A

Abstract

The invention discloses an oxidizing roasting method of hard zinc vacuum smelting slag, based on the principle that oxidants such as hydrogen peroxide, manganese dioxide, chlorate and the like have high microwave absorption property and strong low-frequency microwave radiation penetration capacity and iron oxide and lead oxide are high microwave absorption substances, hydrogen peroxide, manganese dioxide or chlorate is added into crushed hard zinc vacuum smelting slag according to 1-1.5 times of the total amount of iron and lead and is uniformly mixed, then the crushed hard zinc vacuum smelting slag is radiated for 20-60min by microwaves with the frequency of 2-10GHz and the power of 500-2000W, the temperature is controlled to be 300-500 ℃, and the oxidation rate of iron alloy and lead alloy in the vacuum smelting slag reaches more than 95%. The invention mixes the vacuum smelting slag in the alloy state with the oxidant, and then can efficiently absorb the microwave, generate instant high temperature, quickly and uniformly oxidize the alloy into the metal oxide, so as to be beneficial to hydrometallurgy leaching.

Description

Oxidation roasting method for hard zinc vacuum smelting furnace slag

Technical Field

The invention belongs to the technical field of microwave metallurgy, and particularly relates to a method for oxidizing and roasting furnace slag left after zinc steaming of hard zinc containing germanium, indium, zinc, iron and lead, which is a byproduct of zinc pyrometallurgy, in a vacuum furnace by microwave radiation.

Background

The materials containing germanium, indium, zinc, iron and lead are smelted by a pyrometallurgical electric furnace or a vertical tank to lead the germanium, indium, zinc and lead to be rich in crude metal zinc, and then are smelted by a silicon carbide tray pyrometallurgy to obtain refined zinc, and meanwhile, the by-products containing germanium, indium, zinc, iron and lead are produced in hard zinc, wherein the hard zinc is in an alloy state. Melting in a vacuum furnace is the best method for processing the alloy. After more than 99% of metal zinc is distilled in vacuum, the obtained furnace slag is mainly iron alloy and lead alloy which are rich in germanium and indium. Germanium and indium are enriched by 10-15 times in the slag. In order to comprehensively recover germanium, indium, iron and lead from vacuum smelting slag, the germanium and the indium are difficult to leach and difficult to extract and recover by directly adopting acid leaching, so that the slag in an alloy state needs to be converted into oxides to be leached and comprehensively recovered.

The currently adopted method is a natural oxidation method, namely vacuum smelting slag is stacked for a long time, air is naturally oxidized, the oxidation rate of the alloy is about 20% when the vacuum smelting slag is stacked for more than half a year, and the oxidation rate is only 10-15% per month even if hydrogen peroxide is periodically mixed or oxygen-enriched air is blown.

The second method is high temperature oxidizing roasting in a rotary kiln or a reverberatory furnace. The method comprises the steps of adding the vacuum smelting slag and more than 20% of oxidant into a rotary kiln or a reverberatory furnace for high-temperature roasting at 1000 ℃ of 800-fold, or blowing oxygen-enriched air for reinforced roasting, periodically turning over materials, roasting for 4 hours, wherein the oxidation rate of the vacuum smelting slag is 30-40%, and the oxidation rate is about 60% after roasting for 8 hours, because the mixed oxidant is decomposed when the temperature is slowly increased, part of decomposed oxygen generates oxidation, and part of the decomposed oxygen escapes. When the temperature is raised to a high temperature above 800 ℃, little oxidant is mixed. Must be replenished or must be dispensed in considerable excess when dosing. Even if the iron alloy and the lead alloy are crushed to be more than 40 meshes, the iron alloy and the lead alloy need high temperature to be decomposed to react with the oxidant, and the lead alloy in the slag begins to melt at 450 ℃ and is deposited at the bottom of a hearth, so that the lead alloy is not easy to contact with the oxidant and be oxidized. When the material is cooled and discharged, the material is seriously agglomerated, so that the discharging difficulty and the re-crushing difficulty are caused. In addition, the heat transfer of the materials in the rotary kiln or the reverberatory furnace is from the outside to the inside, so that the heat transfer speed is low, the heat loss is large, a cold center phenomenon is inevitably generated, and the oxidizing roasting efficiency is very low in a cold center area. Therefore, the materials must be turned over at regular time. Although rotary kilns are preferred over reverberatory furnaces, turning is not complete, especially when there is a molten state or caking, it is difficult to turn the material.

Therefore, the problems of large oxidant consumption, long roasting time and low efficiency exist when the rotary kiln or the reverberatory furnace is adopted for carrying out the oxidizing roasting of the vacuum smelting slag. The research shows that the material is leached in high acid at temperature over 90 deg.c and over 150g/L for 4 hr, and has germanium and indium leaching rate lower than 20% and germanium and indium leaching rate lower than 40%. And the specific gravity of the alloy is large, so strong stirring is needed for leaching. The lead alloy in the lead alloy is easy to form compact oxide, so that the leaching is prevented.

Disclosure of Invention

The invention aims to provide an oxidizing roasting method of hard zinc vacuum smelting slag, which utilizes the characteristic that oxidants such as hydrogen peroxide, manganese dioxide, chlorate and the like mixed in the vacuum smelting slag can efficiently absorb microwaves, can rapidly oxidize iron alloy and lead alloy rich in germanium and indium in the slag into iron oxide and lead oxide at low temperature in a short time, and is convenient for hydrometallurgical separation and recovery.

The purpose of the invention and the main technical problem of solving the invention are realized by adopting the following technical scheme: an oxidizing roasting method of hard zinc vacuum smelting furnace slag is characterized in that the hard zinc vacuum smelting furnace slag is crushed, mixed with an oxidant, stirred and mixed uniformly, then placed in a microwave field, radiated by low-frequency microwaves, so that the vacuum smelting furnace slag in an alloy state is efficiently and quickly oxidized into metal oxides, and then germanium, indium, lead and iron are respectively recovered by a wet smelting method;

the crushing granularity of the vacuum smelting slag is 0.1-1mm, and the mixing amount of the oxidant is oxidant/iron + lead = 1-1.5;

the low-frequency microwave radiation frequency is 2-10GHz, the microwave field power is 500-.

The oxidant is hydrogen peroxide, manganese dioxide or chlorate.

The oxidant is preferably hydrogen peroxide.

The invention has the beneficial effects that:

(1) the present invention adopts microwave oxidizing roasting to prepare vacuum hard zinc smelting slag, and features that microwave can penetrate through the layers and corners of the material to make the oxidant absorb microwave fast to produce instantaneous high temperature catalysis and to speed the oxidizing roasting of iron alloy and lead alloy material. After iron oxide and lead oxide are generated, high temperature is rapidly generated continuously due to the fact that the iron oxide and the lead oxide are high microwave absorbing substances, and oxidizing roasting is accelerated. The instantaneous high temperature generated by microwave radiation is generated between particles and molecules in the substance. The uniformity is strong, and no heat conduction process exists, so that the phenomena of temperature dead angles and cold centers can not be formed. The oxidation process is carried out instantaneously, the decomposition and escape of the oxidant are less, the utilization rate is high, the lead alloy is oxidized into the high-temperature-resistant lead oxide before being melted under the condition, and even if the temperature is more than 500 ℃, the material can not be agglomerated or a compact oxide layer is not wrapped, so the oxidation efficiency is high.

(2) The second characteristic of the invention is that the temperature control of the oxidizing roasting can be accurately and freely regulated and controlled by the microwave radiation power. The method is not like a rotary kiln or a reverberatory furnace which can be conducted by external conduction and needs to be heated to a higher temperature. And the gradual high temperature is generated, so that part of the materials are locally sintered into blocks, the particle size of the materials subjected to microwave radiation oxidation roasting is not changed, the materials are more refined, and secondary crushing treatment is not required after the materials are subjected to oxidation roasting.

(3) The third characteristic of the invention is that the heat utilization rate in the microwave field is high, the time is short, the energy consumption is low, and the method is clean and does not pollute materials and environment, thus being a good energy-saving and emission-reducing method.

Detailed Description

The technical solution of the present invention is further defined below with reference to the specific embodiments, but the scope of the claims is not limited to the description.

An oxidizing roasting method of hard zinc vacuum smelting furnace slag is characterized in that the hard zinc vacuum smelting furnace slag is crushed, mixed with an oxidant, stirred and mixed uniformly, then placed in a microwave field, radiated by low-frequency microwaves, so that the vacuum smelting furnace slag in an alloy state is efficiently and quickly oxidized into metal oxides, and then germanium, indium, lead and iron are respectively recovered by a wet smelting method;

The oxidant is hydrogen peroxide, manganese dioxide or chlorate.

The oxidant is preferably hydrogen peroxide.

Example 1:

the hard zinc vacuum smelting slag produced by a certain electric furnace zinc-smelting plant contains 10-30% of iron, 5-8% of lead, 1-2% of zinc, 0.5-2.5% of germanium, 1-5% of indium and 500g/t of silver 200-ion. By phase analysis, 90% of iron is present in the state of iron alloy, and 98% or more of lead is present in the state of lead alloy. 90-95% of germanium, indium, silver, zinc and the like exist in the iron alloy and the lead alloy. Pulverizing to 1mm size, adding 27.5% hydrogen peroxide solution according to hydrogen peroxide/iron + lead =1.2, and mixing. Placing the mixture into a microwave oven, regulating and controlling the microwave frequency to be 2.5-5GHz, the power to be 750-1000W, the radiation time to be 30 minutes, and sampling for phase analysis. The iron alloy phase is reduced to 5.2 percent, the lead alloy phase is reduced to 8.5 percent, hydrogen peroxide is used for leaching for 1 hour at the temperature of 90-95 ℃ with the liquid/solid =5, the leaching rate of germanium and indium is 85.3 percent, the leaching rate of zinc is 95.2 percent, the leached lead slag contains 3.5 percent of iron and 750g/t of silver.

Example 2:

vacuum smelting slag produced by a certain zinc pyrometallurgical enterprise contains 25-35% of iron, 2.5-6.5% of lead, 3% of zinc, 1.5-3% of germanium and 5-6% of indium, through phase analysis, 85% of germanium, indium, iron, lead and zinc exist in an alloy state, manganese dioxide is added according to the ratio of manganese dioxide/iron + lead =1.5 after being crushed to 0.5-1mm and is uniformly mixed, then the mixture is placed in a microwave oven, the microwave frequency is regulated to 5-10GHz, the power is 1000-fold 1500W, the radiation time is 50 minutes, sampling is carried out for phase analysis, the iron alloy phase is reduced to 2.3%, and the lead alloy phase is reduced to 4.8%. The chlorination distillation is carried out by using 8-10N hydrochloric acid, the chlorination distillation rate of germanium is 98.5 percent, and the chlorination leaching rate of indium is 98.2 percent. The chlorination leaching rate of lead and silver is 95.3 percent.

Example 3:

the vacuum smelting slag of the example 1 is used for natural stacking without mixed oxidant for 30 days, phase analysis is carried out, the natural oxidation rate of iron and lead alloy is less than 5 percent, the iron and lead alloy is naturally stacked for 30 days at normal temperature after being mixed according to hydrogen peroxide/iron + lead =1.5, the phase analysis is carried out, the oxidation rate of the iron and lead alloy is 10-15 percent, the iron and lead alloy is mixed with the hydrogen peroxide according to the proportion and then is roasted for 2 hours in an electric furnace at the temperature of 500-600 ℃, the oxidation rate of the iron and lead alloy is 15-18 percent, and the oxidation rate is improved to 25-26.3 percent after being roasted for 5. The oxidation rate is improved to 30 percent after 8 hours of roasting. The roasting is continued for 12 hours, and the oxidation rate is increased to 31.5 percent. After 16 hours, the oxidation rate is 32%, and the oxidation rate is 25.3% after 16 hours by using manganese dioxide as an oxidant. The roasting temperature is increased to 800-1000 ℃, hydrogen peroxide is used as an oxidant, the roasting time is 16 hours, and the oxidation rate of the lead and iron alloy is about 25 percent. Manganese dioxide or sodium hypochlorite is used as an oxidant, and the oxidation rate of the lead alloy and the iron alloy is about 30 percent after the manganese dioxide or the sodium hypochlorite is roasted for 16 hours. This is related to the fact that hydrogen peroxide is more easily decomposed than solid oxidants such as manganese dioxide at high temperature, and oxygen is easily escaped and lost. 20-30% of the material is melted and agglomerated after being roasted and cooled at the temperature of 800-1000 ℃, and particularly the agglomeration is more serious for the material with high lead alloy content.

Example 4:

the vacuum smelting slag of example 2 is crushed to 40-60 meshes (less than 0.5 mm), then 150g/L sulfuric acid mixed liquor containing 20% hydrogen peroxide is leached for 3 hours at the stirring speed of 900 rpm at 90-95 ℃ with the liquid/solid =5, the leaching rate of germanium is 15.8% and the leaching rate of indium is 28.3% calculated by the leached slag, then the leached slag at one time is mixed with 200g/L sulfuric acid mixed liquor containing 10% hydrogen peroxide and stacked for 7 days, and then secondary leaching is carried out according to the leaching condition at one time, the leaching rate of germanium is 35.2%, the leaching rate of indium is 43.1%, the total leaching rate of germanium at two times is 48.5% and the leaching rate of indium is 67.2%. The secondary leaching slag is treated for the third time and the fourth time according to the conditions, and the leaching rate of germanium and indium can reach more than 90 percent.

Based on the characteristic that hydrogen peroxide, manganese dioxide and chlorate have high microwave absorption capacity and the principle that iron oxide and lead oxide are high microwave absorption substances, hydrogen peroxide, manganese dioxide or chlorate which is 1-1.5 times of the total amount of iron and lead is added into crushed hard zinc vacuum smelting slag and is uniformly mixed, then the crushed hard zinc vacuum smelting slag is radiated by microwaves with the frequency of 2-10GHz and the power of 500-2000W for 20-60min, the temperature is controlled to be 300-500 ℃, and the oxidation rate of iron alloy and lead alloy in the vacuum smelting slag reaches more than 95%.

It should be noted that the above embodiments are only for further illustration and description of the technical solution of the present invention, and are not for further limitation of the technical solution of the present invention.

Claims

1. An oxidizing roasting method of hard zinc vacuum smelting furnace slag is characterized in that the hard zinc vacuum smelting furnace slag is crushed, mixed with an oxidant, stirred and mixed uniformly, then placed in a microwave field, radiated by low-frequency microwaves, so that the vacuum smelting furnace slag in an alloy state is efficiently and quickly oxidized into metal oxides, and then germanium, indium, lead and iron are respectively recovered by a wet smelting method;

the crushing granularity of the vacuum smelting slag is 0.1-1mm, and the mixing amount of the oxidant is 1-1.5 percent of the oxidant/iron + lead;

the low-frequency microwave radiation frequency is 2-10GHz, the microwave field power is 500-2000W, the microwave radiation time is 20-60min, and the microwave field temperature is 300-500 ℃;

the oxidant is hydrogen peroxide, manganese dioxide or chlorate.

2. The oxidizing roasting method of hard zinc vacuum smelting slag according to claim 1, characterized in that: the oxidant is preferably hydrogen peroxide.