Flash rotary-flotation blowing slagging method for copper

Abstract

The invention discloses a copper flash rotary-flotation blowing slagging method in the technical field of slagging in the copper flash / rotary-flotation blowing process. The copper flash rotary-flotation blowing slagging method comprises the following steps: a, selecting limestone powder as a slagging flux; b, limestone powder is conveyed through a positive pressure pneumatic conveying pump, and the limestone powder is loaded into a converting furnace through a loading system; the loading system comprises a weightlessness metering scale and a screw feeder; c, preheating the limestone in the converting furnace reaction tower and the settling pond until the limestone is decomposed so as to generate lime; d, the generated lime participates in a slagging reaction in the sedimentation tank to generate slag; the copper flash rotary-flotation blowing slagging method brings remarkable economic benefits, cost can be saved due to the price difference of the limestone powder and the quicklime powder, meanwhile, maintenance and spare part cost is saved, and yield benefits are improved.

Description

Technical Field

[0001] The invention relates to a slag making method for copper flash flotation blowing, and belongs to the technical field of slag making in the process of copper flash / flotation blowing. Background Art

[0002] The copper flash / swirl flotation refining technology is to spray dry copper matte powder into a flash / swirl flotation refining furnace and react with oxygen-rich air under high temperature. The main products are crude copper, sulfur dioxide flue gas, smoke and slag. At present, calcium ferrite system slag (Cu2O·Fe2O3·CaO) is commonly used, and quicklime powder is used as a slag-making flux to make slag using the effective calcium oxide in it. However, there are many problems during high-load production. The reaction heat is difficult to balance, resulting in high return water temperature of the water-cooled components of the furnace body, the inability to slag and serious damage to the furnace lining, and even the possibility of melting through the furnace shell. The traditional way to solve the problem of reaction heat has disadvantages. For example, although reducing the oxygen concentration can alleviate the problem of heat exchange in the furnace body, it will increase the latent heat of smoke, cause coking of waste heat boilers and failure of auxiliary equipment, and affect production and cost; adding quartz sand to adjust the slag type can help slag but make melt discharge difficult and increase costs. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a copper flash flotation blowing slag making method.

[0004] The technical solution of the present invention is as follows:

[0005] A copper flash flotation blowing slag making method comprises the following steps:

[0006] e. Select limestone powder as slag-making flux;

[0007] f. Using a positive pressure pneumatic conveying pump to transport limestone powder and using a loading system to load the limestone powder into the blowing furnace;

[0008] The loading system includes a loss-in-weight scale and a screw feeder;

[0009] g. The limestone is preheated and heated to decompose in the reaction tower of the blowing furnace and the sedimentation tank to generate lime; h. The generated lime participates in the slagging reaction in the sedimentation tank to generate slag.

[0010] As a preferred embodiment, in step a, the grade of limestone powder is PS520; the limestone powder meets the following physical and chemical property requirements: CaO content ≥52%, SiO2 content ≤1.5%, MgO content ≤2.5%, and particle size distribution is -200 mesh ≥90%.

[0011] As a preferred embodiment, in step b, the delivery speed of the positive pressure pneumatic delivery pump is controlled at 4000kg / h-5000kg / h, and the delivery pressure is maintained at 100-200kPa.

[0012] As a preferred solution, in step b, the limestone loading amount is calculated according to the material composition of the limestone powder and the chemical properties of its main component calcium carbonate, and the metering scale and screw feeder are selected based on the calculation result.

[0013] As a preferred embodiment, in step c, the limestone decomposition reaction is:

[0014] CaCO3(s)=(high temperature)CaO(s)+CO2(g)

[0015] △G=169120-144.6T(J / mol), ΔH=169120J / mol, which is an endothermic reaction.

[0016] As a preferred embodiment, in step c, the reaction formula of the generated CaO participating in the flash / spin-flotation blowing slag-making process is:

[0017] Fe2O3+CaO=CaFe2O4

[0018] SiO2+2CaO=Ca2SiO4

[0019] During this process, the pressure inside the blowing furnace is controlled between -60Pa and 80Pa.

[0020] Beneficial Effects

[0021] The copper flash flotation blowing slag making method of the present invention effectively balances the reaction heat, promotes the slagging of the furnace lining, and improves the intrinsic safety level of the metallurgical furnace. The surface temperature of the furnace lining can be reduced by absorbing heat through the decomposition of limestone powder, forming a frozen layer to protect the furnace lining.

[0022] The copper flash flotation slag making method of the present invention improves the oxygen concentration and oxygen utilization rate of the flash / flotation converting furnace, the oxygen concentration can be increased by at least 5%, the residual oxygen in the flue gas is reduced by 3%, and the latent heat carried by the smoke is reduced, so that the coking rate of the smoke in the waste heat boiler is reduced, and the operating stability of the waste heat boiler system is improved.

[0023] The copper flash flotation blowing slag making method of the present invention brings remarkable economic benefits. The price difference between limestone powder and quicklime powder can save costs, while also saving maintenance and spare parts costs and improving production efficiency.

[0024] The copper flash flotation blowing slag making method of the present invention reduces carbon emission, saves coal consumption in the limestone sintering process, and reduces carbon emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of the copper flash flotation slag making method. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] See also Figure 1 This embodiment discloses a copper flash flotation slag making method, comprising the following steps:

[0029] Step a: selecting limestone powder as slag-making flux;

[0030] Furthermore, in step a, the grade of the limestone powder is PS520; the limestone powder meets the following physical and chemical property requirements: CaO content ≥52%, SiO2 content ≤1.5%, MgO content ≤2.5%, and particle size distribution of -200 mesh ≥90%.

[0031] Step b: using a positive pressure pneumatic conveying pump to convey the limestone powder and using a loading system to load the limestone powder into the blowing furnace; the loading system includes a loss-in-weight metering scale and a screw feeder;

[0032] Furthermore, in the step b, the limestone loading amount is calculated according to the material composition of the limestone powder and the chemical properties of its main component calcium carbonate, and the metering scale and the screw feeder are selected based on the calculation result.

[0033] Furthermore, in step b, the delivery speed of the positive pressure pneumatic delivery pump is controlled at 4000kg / h-5000kg / h, and the delivery pressure is maintained at 100-200kPa.

[0034] Step c: The limestone is preheated and heated to decomposition in the reaction tower of the blowing furnace and the sedimentation tank to generate lime;

[0035] Further, in step c, the limestone decomposition reaction is:

[0036] CaCO3(s)=(high temperature)CaO(s)+CO2(g)

[0037] △G=169120-144.6T(J / mol), ΔH=169120J / mol, which is an endothermic reaction.

[0038] According to calculations, when the temperature is greater than 896°C, limestone decomposes into CaO and CO2 gas. The flue gas temperature in the flash / swirl flotation refining furnace reaction tower is 1200-1300°C, reaching the limestone decomposition temperature.

[0039] As a preferred embodiment, in the step c, the limestone powder is calcined faster in the reaction tower of the blowing furnace due to the huge temperature difference between the inner and outer surfaces, and the calcination reaction is completed within a few seconds. The generated CaO participates in the flash / spin-flotation blowing slag-making process. The reaction formula of the generated CaO participating in the flash / spin-flotation blowing slag-making process is:

[0040] Fe2O3+CaO=CaFe2O4

[0041] SiO2+2CaO=Ca2SiO4

[0042] During this process, the pressure inside the blowing furnace is controlled between -60Pa and 80Pa.

[0043] Step d: The generated lime participates in the slagging reaction in the sedimentation tank to generate slag.

[0044] Specific application examples are as follows:

[0045] Experimental conditions preparation

[0046] Experiments were conducted in a certain enterprise's flotation furnace. Prepared limestone powder of brand PS520, with CaO content of 53%, SiO2 content of 1.2%, MgO content of 2.2%, and particle size distribution of -200 mesh 92%. Check and debug the conveying and loading system of raw lime to ensure its normal operation, set the conveying speed to 4000kg / h, the conveying pressure to 100-200kPa, the weight loss metering bin is equipped with three weight loss metering scale sensors, and the feeding capacity of the screw feeder is 3-10t / h.

[0047] Experimental process and data monitoring

[0048] Metallurgical calculations were performed, the blowing furnace was charged with dry ice copper powder and limestone powder at 100t / h and 4t / h respectively, and the mixed materials were sprayed into the reaction tower. The temperature in the reaction tower was stabilized at 1260-1270℃, and the furnace pressure was controlled at -70Pa. Samples of materials in the reaction tower were taken from the sampling hole at the bottom of the reaction tower for monitoring, and no limestone powder components were detected, proving that it had been rapidly decomposed in the reaction tower to generate CaO that quickly participated in the slag-making reaction.

[0049] After 2 hours of feeding, slag samples were taken every hour for inspection, and 48 samples were sent continuously. The inspection results showed that CaO / Fe was stable at 0.3-0.35, which met the process control requirements. During the test, the separation of slag and crude copper was good, and the slag discharge was normal.

[0050] The return water temperature of the water cooling element of the lining was monitored. Before using limestone powder to make slag, the return water temperature of the water cooling element of the lining in the local area of ​​the reaction tower reached 60°C, and it dropped to 52°C after use. After 48 hours of the test, the furnace was shut down for inspection. The slag hanging condition of the lining of the working surface of the reaction tower was observed from the outside of the furnace body. The overall slag thickness increased by 50mm and was uniform.

[0051] Increase the oxygen concentration. Before use, the oxygen concentration is 80%, corresponding to a smoke dust charge of 10 t / h, to ensure that the return water temperature of the reaction tower lining water-cooling element does not exceed 60°C; after use, increase the oxygen concentration to 93%, corresponding to a smoke dust charge of 6 t / h, at which time the return water temperature of the reaction tower lining water-cooling element does not exceed 52°C.

[0052] Improve oxygen utilization and reduce flue gas residual oxygen. Before the test, the flue gas residual oxygen content fluctuated between 4% and 5%, and after the test, the flue gas residual oxygen content was less than 2%. After the test, the acidity of the flue gas acid-making system decreased by 20%. The above test data indirectly reflects the improvement of oxygen utilization.

[0053] The smoke coking condition was monitored. After the 48-hour industrial test was completed, the above steps were followed to carry out a one-month industrial test. It was found that the smoke coking condition had improved. During the second industrial test, no abnormal smoke adhesion or coking problems occurred. The frequency of daily coking detection and cleaning was reduced from 5 times / week to 2 times / week.

[0054] According to the statistical cost and output data, the price difference between quicklime powder and limestone powder brings direct economic benefits of 4.5188 million yuan / a, the stable operation of the waste heat boiler system saves 2.3194 million yuan / a in maintenance and spare parts costs, the high and stable production load creates output benefits of 2.7083 million yuan / a, and the limestone sintering process eliminates coal consumption of 4,200t / a and reduces carbon emissions by 2,856t / a.

[0055] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A copper flash flotation blowing slag making method, characterized in that: The following steps are involved: a. Select limestone powder as slag-making flux; b. Using a positive pressure pneumatic conveying pump to transport limestone powder and using a loading system to load the limestone powder into the blowing furnace; The loading system includes a loss-in-weight scale and a screw feeder; c. The limestone is preheated and heated to decomposition in the reaction tower of the blowing furnace and the sedimentation tank to produce lime; d. The generated lime participates in the slagging reaction in the sedimentation tank to generate slag.

2. A copper flash flotation slag making method as claimed in claim 1, characterized in that: In the step a, the grade of the limestone powder is PS520; the limestone powder meets the following physical and chemical property requirements: CaO content ≥52%, SiO2 content ≤1.5%, MgO content ≤2.5%, and particle size distribution of -200 mesh ≥90%.

3. A copper flash flotation slag making method as claimed in claim 1, characterized in that: In the step b, the delivery speed of the positive pressure pneumatic delivery pump is controlled at 4000kg / h-5000kg / h, and the delivery pressure is maintained at 100-200kPa.

4. A copper flash flotation slag making method as claimed in claim 1, characterized in that: In the step b, the limestone loading amount is calculated according to the material composition of the limestone powder and the chemical properties of its main component calcium carbonate, and the metering scale and the screw feeder are selected based on the calculation result.

5. A copper flash flotation slag making method as claimed in claim 1, characterized in that: In the step c, the limestone decomposition reaction is: CaCO3(s)=(high temperature)CaO(s)+CO2(g) △G=169120-144.6T(J / mol), ΔH=169120J / mol, which is an endothermic reaction.

6. A copper flash flotation slag making method as claimed in claim 5, characterized in that: In the step c, the reaction formula of the generated CaO participating in the flash / spin-flotation blowing slag-making process is: Fe2O3+CaO=CaFe2O4 SiO2+2CaO=Ca2SiO4 During this process, the pressure inside the blowing furnace is controlled between -60Pa and 80Pa.

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