RU2282589C1 - Method of producing sesquialteral antimony oxide - Google Patents

Abstract

FIELD: nonferrous metallurgy.

SUBSTANCE: method comprises oxidative purging of melt with compressed air followed by quenching of gases containing sublimated sesquialteral antimony oxide by means of aspirating atmospheric air. Compressed air needed to purge melt is fed at pressure 1.1-3.0 kg/cm² while simultaneously performing blowing of melt surface with gases preheated to 1000-1400^°C. Gases are supplied to blow melt surface in such a way that volume of gas exceeded by two to seven times volume of compressed air supplied to purge the melt. Purging flare is placed in downstream relation to flare of blowing at an angle 60-90 degrees and at a distance 300-600 mm from the blowing flare.

EFFECT: improved quality of product when process is carried out under high-rate conditions.

2 cl, 1 tbl, 7 ex

Description

The invention relates to ferrous metallurgy, in particular to the production of antimony compounds, and can be used to obtain antimony sesquioxide.

A known method of producing antimony trioxide at a process temperature of 950-1000 ° C by sublimation of antimony with its subsequent oxidation by oxygen from the air supplied to the melt surface blowing (Shiyanov A.G. Antimony production. - M .: Metallurgizdat, 1961, p. .155-156).

The disadvantage of this method is the low intensity, its productivity does not exceed 1.2 t / m ² per day. In addition, along with the production of antimony trioxide, a partial formation of higher oxides occurs, some of which are carried away by the gas stream and trapped together with the trioxide, while the majority is deposited on the walls of the furnace and forms growths. Therefore, after some time, it is necessary to stop the process of obtaining antimony trioxide and carry out an operation to cold clean the furnace of growths from higher non-volatile antimony oxides.

The closest in technical essence and the achieved result to the proposed technical solution is a method of oxidizing metallic antimony, containing impurities of precious metals (RF Patent No. 2083706, IPC C 22 V 11/02, 1997), including blowing the melt with compressed air, evacuating the resulting gases containing one-and-a-half antimony oxide followed by cooling of gases for quenching one-and-a-half antimony oxide, discharge of residues from burning enriched with impurities.

This method of producing sesquioxide of antimony is carried out in an autogenous mode, it includes purging the surface of the antimony melt with oxygen-containing blast at a speed of 150-1850 m / s at an angle of at least 4 ° to the surface of the melt and at a gas removal rate of 0.03-0 from the melt surface, 35 m / s

However, this method provides high quality commercial antimony trioxide only in the initial period of the process.

Further, when conducting the process according to the known method, due to the low velocity of gas removal (0.35 m / s) from the surface of the melt with intensive purging of the surface of the melt, antimony of metal occurs, especially in the zone of contact of the blast with the melt, while the process proceeds in an autogenous mode only by burning metal antimony. Therefore, in the furnace space, the temperature is maintained only by burning the melt, which leads to significant cooling of the roof and the lining of the furnace above the melt. This creates the conditions for the intensive formation on the roof and cold walls of the furnace of higher non-volatile antimony oxides while simultaneously sublimating metallic antimony vapors from the melt, part of which enters the antimony trioxide and gives a grayish tint to marketable products.

Local overheating occurs in the zone of contact of the purge jet with the melt, which leads to an increase in the loss of noble metals of gold and especially silver. Due to the formation of growths of higher antimony oxides in the furnace, the output of antimony in commercial products is reduced. Therefore, after two, three days, the process is stopped for cold cleaning of the furnace from growths of higher oxides. The downtime is from 4 to 5 days (36 hours furnace cooling, 24 hours cleaning of higher oxides, 42 hours furnace heating and melting of the initial metal bath).

Therefore, according to the known method, it is not possible to achieve high extraction of antimony and precious metals in commercial products, as well as to ensure a constantly high productivity of the process. The average productivity of this method (taking into account forced downtime for cleaning the furnace) slightly exceeds the first method for the production of marketable antimony trioxide and averages 1.9 t / day.

The technical result of the claimed invention is aimed at improving the quality of commodity sesquioxide of antimony when conducting the process in an intensive mode and reducing losses of precious metals.

The specified technical result is achieved by the fact that the method of producing one and a half antimony oxide, including oxidative blowing of the melt with compressed air followed by quenching of gases containing sublimates of one and a half antimony oxide, by suction of atmospheric air, while compressed air for blowing the melt is supplied at a pressure of 1.1-3, 0 kgf / cm ² , with simultaneous oxidative blowing of the melt surface by gases heated to a temperature of 1000-1400 ° C, while the supply of gases to the melt surface blowing is carried out so that the gases are two to seven times in volume h exceeded the amount of compressed air supplied to the purge, and the purge of the purge is placed in the direction of movement of the gases at an angle of 60-90 degrees at a distance of 300-600 mm above the blower torch.

The heating of gases to 1000-1400 ° C is carried out due to the operation of the gas burner in the oxidizing mode, and the air supply to the combustion is carried out in excess when the coefficient of excess air is α = 1.1-2.4, and the burner is equipped with a pre-chamber to stabilize the combustion of the flame.

Due to the selected mutual arrangement of the blowing and blowing torches and supplying them in a certain volume ratio (2-7 times more than for blowing) and supplying a high-temperature torch to the oxidative blowing at a temperature of 1000-1400 ° C, a quick mixing of the cold blowing torch with the heated blowing stream of an oxidizing gas torch. As a result, a mixture of hot gas flows, which more evenly and gently come into contact with the surface of the melt, comes to the surface of the melt. Therefore, practically no formation of metal splashes occurs, and only slight ripples of the melt are observed, which contributes to the intensification of sublimation of sesquioxide of antimony with a significant decrease in the transition of lead and noble metal impurities into the gas phase.

The high temperature of the mixture of gas streams interacting with the melt contributes to the formation of sesquioxide of antimony with its transition to the gaseous state. When the gas burner operates in the specified oxidation mode, the entire furnace space and the inner walls of the furnace lining are uniformly heated from the high-temperature torch, which sharply reduces the condensation of antimony sesquioxide vapors on the furnace walls and their further oxidation to a higher valence form.

The use of a burner as an additional tuyere when supplying excess air to the combustion with an excess air coefficient α = 1.1-2.4 provides selectively intense oxidation of antimony metal, and the claimed volumetric ratio of blowing blast to purge (2-7 times more than purge) provides quick evacuation of one and a half oxide from the furnace space.

The relative position of the blow-off torch at an angle of 60-90 degrees at a distance of 300-600 mm above the blow-off torch ensures efficient formation of the gas mixture and heating of the blow-off blast by the blow-off torch, while the heated gas mixture interacts with the melt surface.

Accordingly, this increases the rate of entrainment of antimony oxide gases from the furnace space, which almost completely prevents its transition to a higher valence form. In addition, the high-temperature gas mixture has a lower oxygen content than the air stream, which ensures the selective oxidation of antimony to one and a half oxide and reduces the likelihood of oxidation of impurities such as lead, silver and gold.

The results of the industrial operation of the proposed method for producing one-and-a-half antimony oxide are shown in the table (the table also contains data on the prototype for comparison).

The percentage of the main impurities in the refined antimony, which is processed for the production of antimony sesquioxide, in all examples was: lead from 0.3 to 0.8; arsenic from 0.05 to 0.07; iron from 0.06 to 0.07.

In addition, the initial refined antimony, which was sent for processing to obtain one and a half antimony oxide, could be both without impurities of precious metals and contain them. The gold content in refined antimony obtained in swimming trunks with impurities of precious metals was 20–40 g / t, and silver was 8–20 g / t.

Due to the fact that the process for producing one and a half antimony oxide is limited by the maximum allowable saturation of the melt residues with impurities, the duration of one melt depends on their initial content in refined antimony. Therefore, for clarity, examples are given that were obtained during several melts without stopping the process for cold cleaning of the furnace from growths of higher antimony oxides. In addition, the main process parameters indicated in the examples were periodically reproduced in the process of enrichment of the residual melt with impurities present in the initial refined antimony.

At the same time, the duration at which the given process modes were maintained corresponded to the onset of an equilibrium state between the given variable factors and the results dependent on them:

- the quality of one and a half antimony oxide with intensive process management by the proposed method;

- reduction of losses of precious metals;

- increasing the duration of the continuous process without stopping the furnace for cold cleaning of the furnace from higher oxides.

Melting 1.

4.5 tons of refined antimony were poured into a preheated furnace (due to the operation of a gas burner with forced supply of air blast from a fan), while the melt level in the furnace was 220 mm.

Example 1

After pouring refined antimony, the gas burner was transferred to the mode of oxidative melt blowing. For this, the gas flow rate for combustion was set at 35 m ³ / h, and the blast air flow rate for combustion was 420 m ³ / h. Accordingly, the melt was blown with a high-temperature oxidation torch obtained by supplying excess air to the burner (air excess coefficient α = 1.2). At the same time, a stream of compressed air was supplied at a temperature of 25 ° C in an amount of 150 m ³ / h under a pressure of 2.0 atmospheres (kgf / cm ² ). In this case, the jet was directed by installing a lance in the roof of the furnace at a distance of 600 mm perpendicular to the blow torch (at an angle of 90 degrees). The temperature of the mixture of blowing and blowing torches was 1400 ° C (according to the pyrometer). The vacuum at the outlet of the furnace was measured in the neck at the inlet of the exhaust gases into the quenching chamber. A vacuum in the furnace at the entrance to the quenching chamber was set at 7 mm water column, which contributed to the fast quenching of gases in the quenching chamber with sublimation of antimony sesquioxide due to suction of atmospheric air to a temperature of 300-350 ° С.

Measurements of the temperature of the oxidizing torch coming from the prechamber, which provides stabilization of combustion and the formation of a blowing torch, were carried out with an optical PROMIN pyrometer.

Through the igniter window, the melt surface was clearly visible, on which light ripples from the action of a mixture of gas jets were observed.

In this mode (see experiment 1 in the table), the process of producing sesquioxide of antimony was carried out under strict control for 24 hours, which corresponded to the onset of an equilibrium state between the systems for the production of Sb ₂ O ₃ , capture and packaging of marketable sesquioxide of antimony.

As metal antimony was sublimated, solid metal ingots of refined antimony of the initial composition were loaded. The melt level in the furnace ranged in height from 160 to 210 mm. 4.5 tons were loaded per day (400-500 kg per load).

The exhaust gases containing one and a half antimony oxide were quenched at the outlet of the furnace by suction of atmospheric air and sent to the dust collection system. The captured dust was analyzed for the content of the main normalized impurities with the determination of the color characteristics of the marketed antimony sesquioxide (see experiment 1 in the table). The total operating time in the indicated modes of conducting the process was three days.

The extraction of antimony in a one-and-a-half antimony oxide was determined by calculating the amount of loaded antimony with refined metal and the amount of obtained commodity Sb ₂ O ₃ taking into account the metal residue in the furnace and the weight of slips taken during the experiment. The extraction of antimony in the first 24 hours was 92%, in the next two days 94%.

Example 2

In experiment 2, see the table, changed the parameters during the production of one and a half antimony oxide. The antimony metal melt was blown with oxidized gases obtained during operation of the gas burner in the blowing tuyere mode at α = 1.8 (gas flow rate 31 m ³ / h, air 560 m ³ / h). At the same time, through a lance installed at a distance of 400 mm at an angle of 80 degrees, compressed air was supplied to the blower for blowing under a pressure of 1.3 kgf / cm ² , in an amount of 120 m ³ / h. The temperature of the blast of compressed air was 20 ° C. The volumetric ratio of the purge blast to the blower was 1 to 5, and the temperature of the mixture of gas purge and blower 1350 ° C. Gas cooling and hardening of sublimates was ensured by suction of atmospheric air at a vacuum of 6 mm water column. The process modes selected in Example 2 were constantly kept for two days, which ensured the high quality of marketed antimony trioxide.

Example 3

After changing the operating modes of the process (see experiment table 3), a high-temperature torch was applied to the blower from the burner operating in the oxidizing mode (α = 1.1), and at the same time, compressed air was supplied to the blower under a pressure of 2.2 kgf / cm ² . In this case, the purge torch was directed along the direction of flow of the blowing gases due to the installation of the purge lance at an angle of 70 degrees at a distance of 450 mm from the blow torch. The ratio of the purge blast to the blower was 1 to 3.5.

As the melt burned out, refined metal antimony was loaded, in which the percentage of normalized impurities was: for arsenic, 0.06-0.08; iron 0.05-0.07; lead 0.3-0.6. One-and-a-half antimony oxide obtained in example 3 in the specified modes of conducting the process corresponded to the high quality of marketable products.

Example 4

After 12 days of the process, the concentration of lead in the melt increased to 10%, and the gold content was 500 g / t, silver 230 g / t. Then they began to burn the melt in the purge and blow mode, see experiment 4. In this case, the gas burner worked in the oxidative blow mode α = 1.3. At the same time, the compressed air blow-off torch was directed along the gas movement at an angle of 60 degrees at a distance of 600 mm above the blow-off torch. The melt was burned for 20 hours, and after the melt level was reduced to 50 mm, the residues from burning (900 kg) were released from the furnace, the gold content in them was 2070 g / t, silver 1050 g / t.

After the release of the residues from burning from the furnace, the first melting was completed. Inspection of the furnace showed that the furnace practically does not contain growths of higher antimony oxides.

The total duration of the first heat was 12 days. During this time, 4.5 tons were poured into the furnace and 60 tons of refined antimony, obtained for 7 heats in a refining furnace, were loaded. The weighted average content in these swimming trunks was close to the original antimony and amounted to

- normalized impurities, in%: arsenic - 0.08; iron - 0.06; lead - 0.5;

- noble metals: gold - 29.8 g / t, silver - 15.6 g / t.

According to the results of the first heat, the recovery of gold was 96.9%, silver 93.9%.

During the first heat (12 days), the process modes were periodically changed within the limits specified in examples 1, 2, 3 and 4 (see table, experiments 1,2,3 and 4). The indicated modes of conducting the process were changed so that they were tested repeatedly (at least three times) during the enrichment of the residual antimony melt with impurities contained in the initial refined antimony. The duration of the process in each experiment shown in the table was kept under strict control for at least 12 hours. The quality and composition of antimony sesquioxide obtained during this time corresponded to the requirements for high-purity commercial antimony sesquioxide. The high quality of marketable antimony sesquioxide was obtained as a result of conducting the process within the declared limits, which were worked out during the industrial production of antimony sesquioxide.

Melting 2.

A new portion of fresh, refined antimony metal 5 tons was poured immediately after the release of the residues from burning. The gold content in this metal was 30 g / t, silver 12 g / t.

Example 5

The gas burner was transferred to the following mode of melt blowing: gas consumption 40 nm ³ / h, combustion air 560 nm ³ / h with an excess air coefficient α = 1.4, and air was supplied to the purge under a pressure of 2.1 kgf / cm ² in the amount 155 nm ³ / h. The temperature of the mixture of blowing and blowing blast was 1380 ° C. A vacuum at the inlet to the quenching chamber was installed with an 8 mm water column. This mode of conducting the process was maintained for five days (see experiment 5 in the table). At the same time, over five days 28 tons of refined antimony were burned and 31 tons of marketed antimony sesquioxide were obtained. The average productivity of marketable products - one and a half antimony oxide was 6.2 tons / day.

Example 6

On the following days (13 days), the process was conducted in the mode specified in experiment 6, while maintaining a constant melt level of 250-300 mm due to the loading of new portions of fresh metal. When conducting the process in test mode 6 for 60 days, 60 tons of refined antimony were processed, and a high-quality marketed antimony one and a half oxide was obtained, see experiment 6.

Example 7

Over the next 30 hours, the melt was burned under the regime specified in experiment 7, and the residues from burning were released. In total, 91 tons of refined antimony were burned during the second heat and 1360 kg of residues from burning were obtained, with a gold content of 1805 g / t and silver - 750 g / t.

The total load of refined antimony in the second heat was 93 tons of refined antimony, while the weighted average content was: gold - 27.3 g / t; silver - 11.5 g / t.

Based on the data in the table, it is seen that the proposed method can significantly increase the performance of the process when conducting the process in the declared modes due to longer continuous operation of the furnace without stopping for cold cleaning.

This is confirmed by the results of experiment 8, obtained after 50 days of continuous operation of the furnace without stopping for cold cleaning of the furnace.

While according to the method specified in the prototype, the quality of one and a half oxide deteriorates over time due to the intensive formation of non-volatile higher antimony oxides and after three, after a maximum of ten days, continuous operation of the furnace, the process has to be stopped for cold cleaning from higher antimony oxides (see .example 11, 12).

As can be seen from the data in the table, the proposed method in comparison with the prototype provides:

1. Obtaining a pure one and a half antimony oxide.

2. Increasing the productivity of the process due to the longer continuous operation of the furnace, even after 50 days the quality of marketable antimony sesquioxide has not changed during the process within the declared modes.

3. Higher extraction of antimony and precious metals by reducing the yield of circulating products (higher antimony oxides) and removals (slips).

In slips, the content of gold and silver, depending on the concentration of noble metals in the melt, reached 20-100 g / t and 15-80 g / t, respectively. The slip was sent to the head of the process for the refinement and return of precious metals.

Table
The results of the production of sesquioxide of antimony according to the proposed method (for comparative evaluation, data on the prototype) No. Key process parameters Recovery% The quality and composition of antimony sesquioxide Blow ratio, purge / blow The pressure of the compressed air on the lance, kgf / cm ² Temperature, degrees centigrade Coeff. excess air to the burner Commodity Sb ₂ O ₃ Turnovers: Slip, Sb ₂ O ₄ and Sb ₂ O ₅ Sb ₂ O ₃ ,% Sb ₂ O ₄ and Sb ₂ O ₅ ,% Pb,% Au g / t Ag, g / t Insoluble residue in acids,% Color Sb ₂ O ₃ , Purge Blowing one 2 3 four 5 6 7 8 9 10 eleven 12 13 fourteen fifteen The proposed method Melting 1 (experiments 1, 2, 3 and 4) one 1/3 2 25 1400 1,2 92-94 1-4 99.6 traces 0.10 traces 0.15 0,03 white 2 1/5 1.3 twenty 1350 1.8 92-94 2-4 99.1 0.08 0,07 0.10 0.2 0.06 white 3 1 / 3,5 2.2 twenty 1400 1,1 93-95 2-3 99.5 0.09 0.20 0.10 0.5 0.10 - "- four 1/4 2,8 thirty 1320 1.3 93-95 1-3 99.55 0,07 0.18 0.20 0.4 0.11 - "- Melting 2 (experiments 5, 6 and 7) 5 1/5 2.1 twenty 1380 1.4 92-93 1-5 99.45 0.11 0.30 0.30 0.5 0.09 - "- 6 1/6 3.0 28 1250 2.0 91-93 2-6 99.0 0.13 0.35 0.35 0.6 0.10 - "- 7 1/7 1,1 thirty 1000 2,4 91-94 2-5 99.1 0.14 0.26 0.30 0.6 0.18 - "- The results of the experiment after 50 days of continuous operation 8 1/4 2,5 thirty 1300 1,5 90-94 2-4 99.5 0.10 0.34 0.25 0.4 0.15 - "- Outside the claimed modes of the proposed method 9 1/2 3,5 thirty 1500 1.05 87-89 6-9 98.9 0.3 0.5 0.8 1.3 0.5 White with a gray tint 10 1 / 7,5 1,0 thirty 1000 2.6 85-90 6-8 98.8 0.6 0.6 0.6 1,1 0.7 White yellow tint According to the prototype method eleven Purge four thirty Absent Burner off 70-85 10-16 98.9 0.9 0.6 0.8 2.0 0.9 White with a yellow-gray tint 12 3,5 25 70-80 12-20 99.1 0.8 0.5 0.6 3,7 1,0

Claims (2)

1. A method of producing a sesquioxide of antimony, including oxidative purge of the melt with compressed air followed by quenching of gases containing sublimates of sesquioxide of antimony, by suction of atmospheric air, characterized in that the compressed air to purge the melt is supplied at a pressure of 1.1-3.0 kgf / cm ² with simultaneous oxidative blowing of the melt surface with gases heated to a temperature of 1000-1400 ° C, while the supply of gases to the melt surface blowing is carried out so that the gases are two to seven times the volume of compressed air, fed to the purge, and the purge of the purge is placed in the direction of movement of the gases at an angle of 60-90 degrees at a distance of 300-600 mm above the torch of the blower. 2. The method of producing one and a half antimony oxide according to claim 1, characterized in that the melt of metal antimony is blown in an oxidizing mode of operation of a gas burner, which is equipped with a prechamber, while the combustion air is supplied in excess with an excess air coefficient α = 1,1- 2.4.