Pyrometallurgy method of platinum-palladium ore

Abstract

The invention relates to a pyrogenic process smelting method of platinum-palladium ores, which comprises the following steps: firstly, drying platinum-palladium flotation concentrate, then mixing the dried and dehydrated dry concentrate with a flux and a returned material, and feeding the mixture into a smelting furnace to generate low-nickel copper matte rich in platinum group metals and smelting furnace slag; and then the low-nickel copper matte is conveyed to a converting furnace through a chute, high-nickel copper matte rich in platinum group metal is generated after slagging and iron removal, smelting slag is discarded after being depleted through an electric furnace, and the produced low-nickel copper matte returns to the converting furnace. According to the method, the recovery rate and the heat utilization rate of the platinum group metal in the platinum-palladium flotation concentrate pyrometallurgy process can be effectively increased, the smelting time is shortened, in addition, high-nickel-copper matte containing high-grade platinum and palladium serves as a final qualified pyrometallurgy product according to the sulfur affinity and the iron affinity of the platinum group metal element, the platinum group metal element can be early recovered, and the recovery rate of the platinum group metal element is increased. And subsequent wet smelting is facilitated, and the comprehensive recovery rate of the platinum-palladium ore is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal smelting, and specifically relates to a pyrometallurgical method for platinum-palladium ore, and in particular to a pyrometallurgical method for flotation concentrate of platinum-palladium ore. Background Art

[0002] At present, flotation is still the main method for processing platinum-palladium ore, and pyrometallurgy is usually the main method for processing platinum-palladium flotation concentrate. The conventional platinum-palladium metal extraction process firstly enriches the platinum-palladium ore by flotation, then further enriches it by pyrometallurgy, and then uses hydrometallurgical methods to separate the precious and base metals to extract the pure metal of the platinum group metals.

[0003] According to the different properties of flotation concentrate, the smelting processes vary, including the electric furnace-PS converter process, the electric furnace-Kaldo furnace process, the Osmed furnace-PS converter process, etc. These methods have achieved good smelting indicators when processing platinum-palladium flotation concentrate. However, the low reaction efficiency and high energy consumption of platinum-palladium flotation concentrate in the electric furnace smelting process and the existence of low-air pollution problems in the PS converter blowing process will reduce the recovery rate of platinum-palladium concentrate and deteriorate the operating environment, thereby affecting subsequent smelting indicators. Summary of the invention

[0004] The present invention provides a pyrometallurgical method for platinum-palladium ore. By continuously operating the platinum-palladium flotation concentrate in the pyrometallurgical process, that is, continuously carrying out the smelting and blowing processes, the recovery rate and heat utilization rate of platinum group metals in the pyrometallurgical process of the platinum-palladium flotation concentrate are effectively improved, the operating environment is improved, and the energy recovery of the platinum group metal elements is achieved early, which is beneficial to the subsequent hydrometallurgy of the platinum-palladium ore and improves the comprehensive recovery rate of the platinum-palladium ore.

[0005] In order to solve the above technical problems, the present invention provides a pyrometallurgical method for platinum-palladium ore, characterized in that it comprises the following steps:

[0006] Step 1, drying the flotation concentrate to obtain a dry concentrate;

[0007] Step 2, adding a certain amount of flux and return material to the dry concentrate product of step 1, and after batching, sending it to the side-blown smelting furnace via a belt conveyor;

[0008] Step 3, the mixed concentrate after batching in step 2 is transported to the smelting furnace, and reacted to generate low-nickel copper matte rich in platinum group metals with the help of 25% to 100% air / oxygen-enriched air blown into the side lance, and then transported to the converting furnace through the chute, and the slag is sent to the depletion electric furnace;

[0009] Step 4: The low-nickel copper matte rich in platinum group metals produced by the side-blown smelting furnace is transported to a converting furnace for converting, slag making and iron removal to produce high-nickel copper matte rich in platinum group metals, which is the final product of pyrometallurgy.

[0010] In step 1, the particle size of the concentrate product is -74 μm, the content of the particle size is 60%, and the moisture content of the concentrate is 3% to 20%.

[0011] In step 2, the flux content is 5% to 30% of the concentrate mass, including one or two of limestone, lime and quartz.

[0012] In order to ensure a weak reducing atmosphere in the side-blowing smelting furnace, 0% to 8% coal powder is blown into the side-blowing smelting furnace through the spray gun.

[0013] The operating temperature of the side-blown smelting furnace is 1150-1500℃.

[0014] 0.5% to 3% of the mass of the concentrate is pulverized coal into the side-blown smelting furnace through a lance; the particle size of the pulverized coal is 200 meshes.

[0015] The returned material is smoke dust, the content of which is 2% to 15% of the concentrate mass.

[0016] Beneficial effects: The present invention performs drying pretreatment and side-blowing smelting on the platinum-palladium ore flotation concentrate product to improve the smelting reaction rate of the platinum-palladium ore flotation concentrate. In the enhanced smelting (side-blowing smelting) process, the platinum-palladium mineral reacts quickly and thoroughly, and the platinum-palladium metal particles produced by the reaction continuously gather and enrich in the high-nickel copper matte, and are enriched in the alloy phase in the subsequent blowing process, which is beneficial to improving the recovery rate and heat utilization rate of platinum group metals and shortening the smelting time. In addition, according to the sulfur- and iron-affinity of platinum group metal elements, high-nickel-copper matte containing high-grade platinum and palladium is used as the final qualified pyrometallurgical product, which realizes the early recovery of platinum group metal elements, is beneficial to the subsequent wet smelting, and improves the comprehensive recovery rate of platinum-palladium ore. The specific advantages are as follows:

[0017] (1) By pre-drying the flotation concentrate, the moisture content of the platinum-palladium ore flotation concentrate can be reduced, thereby improving the smelting operation intensity;

[0018] (2) The dried flotation concentrate is subjected to side-blowing smelting, i.e., enhanced smelting. The injection of side-blowing furnace air / oxygen-enriched air improves the reaction kinetics, effectively shortens the smelting reaction time, and can achieve early recovery of platinum group metal elements, which is beneficial to improving the smelting recovery rate of platinum group elements;

[0019] (3) The platinum-palladium ore flotation concentrate is subjected to continuous smelting and blowing, that is, the low-nickel-copper matte after smelting enters the blowing furnace through a chute, which saves the equipment investment and heat loss of the bun transportation, is conducive to energy conservation and emission reduction and improves the smelting recovery rate of platinum group elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below.

[0022] The present invention provides a pyrometallurgical method for smelting platinum-palladium ore, comprising the following steps:

[0023] Step 1: Dry the flotation concentrate to obtain a dry concentrate, wherein the concentrate product particle size is -74 μm, the particle size content accounts for 60%, and the moisture content of the dry concentrate is 3% to 20%; further, it may be 8% to 15%;

[0024] Step 2, adding a certain amount of flux and return material to the dry concentrate product of step 1, and after batching, sending it to the side-blown smelting furnace via a belt conveyor;

[0025] The flux content is 5% to 30%, including but not limited to one or two of limestone, lime, and quartz, and the return material is 2% to 15% in the form of smoke;

[0026] Step 3, the mixed concentrate after batching in step 2 is transported to the smelting furnace, and reacted to generate low-nickel copper matte rich in platinum group metals with the help of 25% to 100% air / oxygen-enriched air blown into the side lance, and then transported to the converting furnace through the chute, and the slag is sent to the depletion electric furnace;

[0027] The concentrate generates a sulfide melt of iron, nickel and copper in the smelting furnace, which is called low-nickel copper matte and is rich in platinum group metals; the oxides of magnesium, calcium, aluminum, silicon and iron form an inert slag;

[0028] The melting furnace is a side-blown furnace, and the melting method is an enhanced melting method, which has the advantages of fast reaction speed and high efficiency;

[0029] In order to ensure a weak reducing atmosphere in the side-blown smelting furnace, 0% to 8% of pulverized coal is blown into the side-blown smelting furnace through a spray gun, and further 0.5% to 3% is possible; the particle size of the pulverized coal is 200 meshes.

[0030] The side-blown smelting furnace is blown with 25% to 100% oxygen enrichment, and further may be 25% to 70%;

[0031] The operating temperature of the side-blown smelting furnace is 1150-1500°C, and further may be 1200-1400°C.

[0032] The low-nickel copper matte produced by the side-blown smelting furnace is transported to the converting furnace via a chute, eliminating the equipment investment and heat loss of transporting the matte.

[0033] Step 4: The low-nickel copper matte rich in platinum group metals produced by the side-blown smelting furnace is transported to the converting furnace for converting, slagging and iron removal to produce high-nickel copper matte rich in platinum group metals, which is the final product of pyrometallurgy:

[0034] The blown slag can be returned to the smelting furnace.

[0035] Step 5, the slag from step 3 is depleted in a depletion electric furnace to produce low-nickel-copper matte rich in platinum group metals, and the slag is discarded;

[0036] Step six, returning the low nickel-copper matte in step five to the blowing furnace in step four.

[0037] Since the material is fed by a belt, the present invention can also process high-grade lump ores with larger particle sizes (less than 50 mm), and has stronger adaptability;

[0038] The present invention adopts a side-blowing furnace as the smelting furnace, and the smelting method is an enhanced smelting. Under the condition of oxygen-enriched blowing by the side-blowing lance, the kinetic conditions of the solid-liquid reaction are positively affected. Compared with traditional electric furnace smelting, side-blowing smelting has the advantages of fast reaction speed and high efficiency.

[0039] The core technology of this process is continuous smelting. The smelting furnace directly discharges low-nickel copper matte to the converting furnace through the chute without pouring the buns. Therefore, the converting furnace is not limited to top-blown furnaces, and other similar heatable furnaces and kiln equipment can be used, such as side-blown furnaces, bottom-blown furnaces, etc.

[0040] Example 1

[0041] The platinum grade of a platinum-palladium flotation concentrate is 40.5g / t, the palladium grade is 38.1g / t, the nickel content is 4.3wt%, the copper content is 3.7wt%, the sulfur content is 18.3wt%, and the magnesium oxide content is 22.5wt%. The concentrate (100 parts by mass), flux (10 parts by mass of lime), and return material (5 parts by mass of smelting + blowing dust) are mixed and sent to the side-blown furnace for smelting via a belt conveyor, and the molten pool temperature is controlled at 1420℃. Compressed air is used as a carrier gas, and coal powder (1 part by mass, with a particle size of 200 mesh) is sprayed into the side-blown furnace as a reducing agent through a side-blowing spray gun to ensure a weak reducing atmosphere in the furnace. At the same time, compressed air with a pressure of 0.6MPa is introduced through the side-blowing spray gun. The low-nickel copper matte rich in platinum group metals generated in the side-blown furnace is discharged through a chute, and the excess slag is discharged to the depletion electric furnace for depletion. Low-nickel copper matte rich in platinum group metals is blown in a top-blown blowing furnace to make slag and remove iron, and a flux (quartz mass 10 parts) is added to produce high-nickel copper matte rich in platinum group metals. After smelting and blowing, the yield of platinum group metals is 97.63%, and the smelting reaction takes 0.4-0.8h. The smelting time is significantly shortened compared to the electric furnace smelting time, and the recovery rate of platinum group metals is increased by 0.5-1.2 percentage points.

[0042] Example 2

[0043] The total grade of platinum and palladium in a platinum-palladium flotation concentrate is 153g / t, the nickel content is 2.2wt%, the copper content is 1.1wt%, the sulfur content is 7.0wt%, and the magnesium oxide content is 17.5wt%. The concentrate (100 parts by mass), flux (6 parts by mass of lime), and return material (3 parts by mass of smelting + blowing dust) are mixed and sent to the side-blown furnace for smelting via a belt conveyor, and the molten pool temperature is controlled at 1380℃. Compressed air is used as a carrier gas, and coal powder (1 part by mass, particle size of 200 mesh) is sprayed into the side-blown furnace through a side-blowing spray gun as a reducing agent to ensure a weak reducing atmosphere in the furnace. At the same time, compressed air with a pressure of 0.6MPa is introduced through the side-blowing spray gun. The low-nickel copper matte rich in platinum group metals generated in the side-blown furnace is discharged through a chute, and the excess slag is discharged to the depletion electric furnace for depletion. Low-nickel copper matte rich in platinum group metals is blown in a top-blown blowing furnace to make slag and remove iron, and flux (10 parts by mass) is added to produce high-nickel copper matte rich in platinum group metals. After smelting and blowing, the yield of platinum group metals is 98.78%, and the smelting reaction takes 0.4-0.7h. The smelting time is greatly shortened compared to the electric furnace smelting time, and the recovery rate of platinum group metals is increased by 1.0-1.5 percentage points.

[0044] The smelting method of the present invention used in the above embodiment can significantly reduce the smelting reaction time and improve the yield of platinum group metals. In addition, according to the characteristics of pyrometallurgy, high-nickel copper matte rich in platinum group metals is used as the final qualified product of pyrometallurgy, thereby achieving early recovery of platinum group elements and helping to improve the comprehensive recovery rate of platinum-palladium ore.

Claims

1. A pyrometallurgical method for platinum-palladium ore, characterized in that: The following steps are involved: Step 1, drying the flotation concentrate to obtain a dry concentrate; Step 2, adding a certain amount of flux and return material to the dry concentrate product of step 1, and after batching, sending it to the side-blown smelting furnace via a belt conveyor; Step 3, the mixed concentrate after batching in step 2 is transported to the smelting furnace, and reacted to generate low-nickel copper matte rich in platinum group metals with the help of 25% to 100% air / oxygen-enriched air blown by the side lance, and then transported to the converting furnace through the chute, and the slag is sent to the depletion electric furnace; Step 4: The low-nickel copper matte rich in platinum group metals produced by the side-blown smelting furnace is transported to a converting furnace for converting, slag making and iron removal to produce high-nickel copper matte rich in platinum group metals, which is the final product of pyrometallurgy.

2. The pyrometallurgical method of a platinum-palladium ore according to claim 1, characterized in that: The blowing slag produced in step 4 is returned to the smelting furnace.

3. The pyrometallurgical method of a platinum-palladium ore according to claim 1, characterized in that: The method further comprises the step five of depleting the slag from the step three through a depletion electric furnace to produce low-nickel-copper matte rich in platinum group metals, and discarding the slag.

4. The pyrometallurgical method of a platinum-palladium ore according to claim 3, characterized in that: The low-nickel copper matte produced in step five is returned to the blowing furnace in step four.

5. The pyrometallurgical method of a platinum-palladium ore according to claim 1, characterized in that: In step 1, the particle size of the concentrate product is -74 μm, the content of the particle size is 60%, and the moisture content of the concentrate is 3% to 20%.

6. The pyrometallurgical method of a platinum-palladium ore according to claim 1, characterized in that: In step 2, the flux content is 5% to 30% of the concentrate mass, including one or two of limestone, lime and quartz.

7. The pyrometallurgical method of a platinum-palladium ore according to claim 1, characterized in that: In order to ensure a weak reducing atmosphere in the side-blowing smelting furnace, 0% to 8% coal powder is blown into the side-blowing smelting furnace through the spray gun.

8. The pyrometallurgical method for smelting platinum-palladium ore according to claim 1, characterized in that: The operating temperature of the side-blown smelting furnace is 1150-1500℃.

9. The pyrometallurgical method for smelting platinum-palladium ore according to claim 1, characterized in that: 0.5% to 3% of the mass of the concentrate is pulverized coal into the side-blown smelting furnace through a lance; the particle size of the pulverized coal is 200 meshes.

10. The pyrometallurgical method for smelting platinum-palladium ore according to claim 1, characterized in that: The returned material is smoke dust, the content of which is 2% to 15% of the concentrate mass.

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