Method for capturing platinum in platinum-containing catalyst for treating VOCs

Abstract

The application discloses a method for capturing platinum in platinum-containing catalysts for VOCs treatment, and belongs to the technical field of precious metal recovery. The method uses iron scale, which is separated from steel billet during rolling and forging, as a capturing agent, and cooperates with industrial waste, i.e. desulfurization gypsum or red gypsum, to capture platinum in the platinum-containing catalysts by the synergistic effect of the two. After pelletizing treatment, the method further carries out microwave rapid drying and surface hardening treatment, so that in the process of sulfidation restructuring roasting, conditions for forming micro zone solid solution and accelerating micro zone solid solution grain growth under the action of a promoter are provided, and the conditions provide conditions for realizing platinum immersion capture, and meanwhile, the influence of external factors such as atmosphere on the sulfidation restructuring roasting can be reduced in the process of sulfidation restructuring roasting. Then, by using the magnetic separation method, non-magnetic substances can all enter the tailings of magnetic separation, and the magnetic separation concentrate with simple composition and easy treatment is obtained, so that the difficulty of platinum extraction and recovery is greatly reduced. The application captures platinum from the platinum-containing catalysts for VOCs treatment, and the recovery rate of platinum is greater than 98%.

Description

Technical Field

[0001] This invention belongs to the field of precious metal recycling technology, specifically relating to a method for capturing platinum from a platinum-supported catalyst used for VOCs treatment. Background Technology

[0002] In recent years, catalytic oxidation combustion has been a common industrial method for the end-of-pipe treatment of VOCs. Platinum is considered the most reactive element in hydrocarbon oxidation, and platinum-based catalysts exhibit a wide catalytic activation temperature range and long-term stability in catalytic combustion performance. They are frequently used in the catalytic oxidation degradation of VOCs containing aromatic hydrocarbons such as benzene, toluene, and ethylbenzene, as well as long-chain alkanes with five or more carbon atoms. However, the catalytic performance of platinum-supported catalysts is affected by the working environment and treatment medium during VOC treatment. After a certain period of use, their catalytic performance begins to decline or even deactivate, necessitating periodic replacement of the platinum-supported catalyst.

[0003] The platinum in the replaced supported platinum catalyst is not lost, forming a platinum-containing secondary resource. Due to the scarcity of primary platinum minerals and the ever-increasing demand for platinum from modern industry, platinum prices remain high. Therefore, recycling and managing spent supported platinum catalysts generated in the VOCs industry has extremely high economic value and social benefits in ensuring the sustainable development of strategic resources.

[0004] Invention patent application CN118880036A discloses a method for recovering platinum group metal catalysts supported on alumina, comprising the following steps: crushing platinum supported on alumina and mixing it with carbonate or bicarbonate at a mass ratio of 1:1-4, then calcining at 400-900℃ for 2-5 hours; converting alumina into sodium aluminate, then leaching with water, filtering, and enriching the platinum in the insoluble residue; dissolving the platinum enrichment residue in aqua regia and treating it to form a liquid, then purifying the precious metals therein; treating the sodium aluminate solution with carbon dioxide, filtering, concentrating, and reusing sodium carbonate in the calcination process; calcining the obtained aluminum hydroxide at 400-700℃ to obtain alumina product, achieving overall comprehensive recovery and recycling of sodium carbonate.

[0005] The above method has obvious advantages, realizing the comprehensive recycling of materials. However, the patent mentions that in the process of recycling the platinum group metal catalyst on the alumina support, it is necessary to calcine the alumina to convert it into soluble sodium aluminate. Sodium aluminate is difficult to filter and is prone to regenerating suspended colloids to encapsulate platinum particles.

[0006] Patent application CN117867286A discloses a method for recovering platinum group metals from leaching residue of a catalyst using high-temperature metallization roasting of magnetite. The method includes the following steps: using wet leaching residue from a spent automotive three-way catalyst as raw material, adding a collector, a co-solvent, and a reducing agent, pulverizing and mixing them in a specific ratio, followed by high-temperature slag formation and smelting, natural cooling, and physical separation of the lower solid layer (due to the density difference between the slag phase and matte) to obtain a solid containing platinum group metals, which is then used for the recovery and extraction of these metals; wherein the collector includes iron concentrate. This method has significant advantages in capturing platinum group metals. However, the patent mentions that high-temperature magnetite roasting and capture requires temperatures above 1400℃. This temperature easily causes iron to react with silicon in the raw material to form a highly inert ferrosilicon alloy that encapsulates the precious metals. This method may have drawbacks such as high requirements for equipment temperature resistance, high energy consumption during processing, and unstable precious metal recovery rates.

[0007] Chinese patent application CN110846505A discloses a method for recovering platinum group metals (PGMs) from VOCs waste catalysts. The method involves crushing the PGM-containing VOCs waste catalyst to 100-200 mesh, mixing it with a slagging agent and 5-50% (by weight of the raw material) of a scavenging agent, pelletizing, and air-drying until the moisture content is less than 5%, then smelting at 1000-1700℃ for 1-3 hours, followed by natural cooling. The enrichment basicity of the pyrometallurgical process is controlled at 0.7-1.5, yielding slag and matte or alloy phases. The alloy is then mixed with 1-5 times its volume of reactive metals for a secondary smelting process. After water quenching and powdering, a wet sol-solution treatment with hydrochloric acid and an oxidant is performed to obtain a PGM-containing solution. Finally, the high-concentration PGM-containing solution is refined to pure platinum or pure palladium.

[0008] The above-mentioned patent has obvious advantages, but the patent mentions that after pelleting, it is naturally air-dried to a moisture content of less than 5%. The efficiency of natural drying is limited. The patent uses iron and other substances as a trapping agent to carry out two melting processes at 1000-1700℃, which is an ultra-high temperature melting process. This process easily generates a highly inert ferrosilicon alloy phase to encapsulate precious metals.

[0009] Therefore, given the shortcomings of existing platinum-supported catalyst recovery processes, such as the energy consumption required for ultra-high temperature smelting; the ease with which platinum group metals are encapsulated by newly generated inert substances during high-temperature smelting; the high reagent cost caused by the generation of multi-metal synergistic matte; and the long separation process and high reagent consumption of multi-metal matte, it is of great significance to develop a process for recovering platinum from platinum-supported catalysts that has a short process flow, low auxiliary material consumption, low energy consumption, and high platinum recovery rate. Summary of the Invention

[0010] To address or partially address the problems existing in related technologies, this invention provides a method for capturing platinum from a platinum-supported catalyst used for VOCs treatment.

[0011] This invention provides a method for capturing platinum from a platinum-supported catalyst used for VOCs treatment, comprising the following steps: (1) The platinum-loaded catalyst, sulfiding agent, scavenging agent, reducing agent and accelerator are crushed separately, then mixed evenly and pelletized to obtain pellets; (2) The pellets were placed in microwaves for treatment, and then calcined in a protective gas to obtain the calcined product; (3) Mix the calcined product with water, then add a dispersant and wet grind, then sieve to obtain a slurry; (4) Add water to the slurry to prepare a new slurry, and then perform magnetic separation to obtain platinum and non-magnetic tailings for the preparation of high-strength cement raw materials.

[0012] This invention utilizes iron scale detached from steel billets during rolling and forging as a trapping agent, combined with industrial waste—desulfurized gypsum. After microwave drying to form pellets and surface hardening, the pellets undergo sulfidation reconstruction and calcination. The reduced carbon inside the pellets reduces the iron scale to ferrous oxide and elemental iron, while the carbon also partially reduces the gypsum to calcium sulfide. Calcium sulfide and calcium sulfate readily form a low-melting-point solid solution, improving the heat transfer efficiency in the micro-area. Simultaneously, under the catalysis of iron and the action of a grain growth promoter, sulfur in the desulfurized gypsum migrates at low temperatures to form an iron matte solid solution zone. This zone grows under the action of the grain growth promoter, causing platinum in the raw material to be impregnated by the iron matte solid solution and migrate into the iron matte, thus achieving platinum trapping and yielding a sulfidated reconstituted body. Because the iron matte in the sulfidated reconstituted body is magnetic, magnetic separation is used to separate platinum-rich concentrate for platinum recovery. The magnetic separation tailings can be used as raw material for the production of high-strength cement.

[0013] This invention fully utilizes two types of industrial waste, offering advantages such as effective waste utilization and cost-effective platinum capture. Microwave irradiation surface hardening treatment reduces atmospheric influence during the sulfidation reconstruction calcination process, facilitating the formation of solid solution micro-regions within the material. This achieves efficient platinum capture from platinum catalysts at temperatures lower than traditional smelting temperatures, reducing energy consumption. Furthermore, this method can migrate and enrich platinum from complex, degraded platinum-supported catalysts into simpler, more easily processed iron matte through sulfidation reconstruction. This transfer process is completed at lower temperatures and avoids the formation of difficult-to-process phases such as ferrosilicon alloys. This invention offers advantages such as short processing time, streamlined process, environmental friendliness, high platinum yield, and low cost in the method of capturing platinum from platinum-supported catalysts for VOCs treatment, showing promising application prospects.

[0014] Preferably, the mass ratio of the platinum-loaded catalyst, sulfiding agent, scavenging agent, reducing agent, and accelerator is 1:0.3~1:0.1~0.5:0.1~0.3:0.05~0.15.

[0015] Preferably, the sulfiding agent is desulfurized gypsum or red gypsum; the collecting agent is iron oxide that falls off during the rolling and forging process of steel billets; the reducing agent is one or more of carbon, petroleum coke, coking coal, and graphite mixed in any proportion; and the accelerator is one or more of sodium borate, sodium chloride, calcium chloride, and sodium carbonate mixed in any proportion.

[0016] Preferably, in step (1), the particles are crushed to a particle size of 58~106um.

[0017] Preferably, the diameter of the pellet is 10-30 mm.

[0018] Preferably, the microwave output frequency is 2450MHz, the microwave output power is 100-1100W, and the microwave duration is 10-30min.

[0019] Preferably, the calcination temperature is 850-1250℃, the time is 3-6 hours, and the protective gas is nitrogen, hydrogen, or argon.

[0020] Preferably, in step (3), the mass ratio of calcined product to water is 1:1-2; the amount of dispersant added is 100~500 g / ton of calcined product; the dispersant is one or more of sodium silicate, sodium pyrophosphate, and sodium polyacrylate mixed in any proportion; and the wet grinding time is 3-15 min.

[0021] Preferably, the mass concentration of the new slurry is 5-30%.

[0022] Preferably, the magnetic field strength of the magnetic separation is 300-900 Gs.

[0023] The technical solution provided by this invention has the following beneficial effects: (1) The present invention uses the iron scale that falls off during the rolling and forging process of steel billet as a trapping agent, and combines it with industrial waste - desulfurized gypsum or red gypsum, and uses the synergistic effect of the two to trap platinum in the platinum-supported catalyst.

[0024] (2) The raw materials of this invention are subjected to pelletizing treatment, followed by microwave rapid drying and surface hardening treatment. This provides conditions for the formation of micro-region solid solutions and the accelerated growth of micro-region solid solution grains under the action of promoters during the sulfidation reconstruction roasting process, thereby achieving platinum leaching and capture. At the same time, the influence of external factors such as the atmosphere on sulfidation reconstruction roasting can be reduced during the sulfidation reconstruction roasting process. Then, by using magnetic separation, all non-magnetic materials can be sent to the magnetic separation tailings to obtain a magnetically separated concentrate with simple composition and easy processing, which greatly reduces the difficulty of extracting and recovering platinum.

[0025] (3) The present invention captures platinum from a platinum-supported catalyst for VOCs treatment, with a platinum recovery rate of more than 98%. Therefore, the present method for capturing platinum from a platinum-supported catalyst for VOCs treatment has the advantages of short time, short process, environmental friendliness, high platinum recovery rate and low cost, and has good application prospects. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the platinum-supported catalyst for VOCs capture and treatment according to the present invention. Detailed Implementation

[0027] The platinum-supported catalyst used in the embodiments and comparative examples of this invention is a catalytic combustion platinum-supported catalyst for VOCs treatment, purchased from Suzhou Binsheng Environmental Technology Co., Ltd.

[0028] Example 1 like Figure 1 As shown, a method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 150g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, desulfurized gypsum, steel scale, coking coal and sodium borate to 75 μm respectively, and then mix them evenly according to the mass ratio of 1:0.5:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 20mm pellets.

[0029] (2) The pellets were placed in a 2450 MHz microwave field and dried for 20 minutes. The microwave output power was 800W. Then, under nitrogen protection, the temperature was raised to 1000℃ and kept at that temperature for 4 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0030] (3) The calcined product and water were mixed at a mass ratio of 1:1 and added to a conical ball mill. 1.5 ml of sodium silicate was added at the same time. The mixture was ball-milled for 10 min and passed through a 150-mesh sieve to obtain a slurry.

[0031] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 650 Gauss at a flow rate of 3 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 98.2%, and the platinum enrichment ratio of the concentrate was 6.3 times.

[0032] Example 2 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 200g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, desulfurized gypsum, steel scale, coking coal and sodium borate to 75 μm respectively, and then mix them evenly according to the mass ratio of 1:0.5:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 20mm pellets.

[0033] (2) The pellets were placed in a 2450 MHz microwave field and dried for 20 minutes. The microwave output power was 800W. Then, under nitrogen protection, the temperature was raised to 878℃ ​​and kept warm for 4 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0034] (3) Mix the calcined product with water at a mass ratio of 1:1 and add it to a conical ball mill. Add 3 ml of sodium silicate at the same time, ball mill for 10 min, and pass through a 150 mesh sieve to obtain slurry.

[0035] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 600 Gauss at a flow rate of 3 L / min to obtain a platinum-rich concentrate. The platinum recovery rate was 97.5%, and the platinum enrichment ratio of the concentrate was 4.4 times.

[0036] Example 3 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 200g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, red gypsum, steel scale, coking coal + graphite (mass ratio 1:1), and sodium borate to 75 μm respectively, then mix them evenly according to the mass ratio 1:0.4:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 30mm pellets.

[0037] (2) The pellets were placed in a 2450 MHz microwave field and dried for 20 minutes. The microwave output power was 1100W. Then, under nitrogen protection, the temperature was raised to 1200℃ and kept at that temperature for 4 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0038] (3) Mix the calcined product with water at a mass ratio of 1:1 and add it to a conical ball mill. Add 2 ml of sodium silicate at the same time, ball mill for 10 min, and pass through a 150 mesh sieve to obtain slurry.

[0039] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 600 Gauss at a flow rate of 3 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 98.7%, and the platinum enrichment ratio of the concentrate was 6.1 times.

[0040] Example 4 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 300g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, red gypsum, rolled steel scale, carbon powder and sodium borate to 75 μm respectively, and then mix them evenly in a mass ratio of 1:1:0.5:0.1:0.05 and then use a pelletizing machine to pelletize them to obtain 15mm pellets.

[0041] (2) The pellets were placed in a 2450 MHz microwave field and dried for 30 minutes. The microwave output power was 800W. Then, under nitrogen protection, the temperature was raised to 1250℃ and kept for 3 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0042] (3) Mix the calcined product with water at a mass ratio of 1:1 and add it to a conical ball mill. Add 2 ml of sodium silicate at the same time, ball mill for 3 min, and pass through a 150 mesh sieve to obtain slurry.

[0043] (4) The ball-milled slurry was prepared to a slurry concentration of 5% and passed through a magnetic separator with a magnetic field of 300 Gauss at a flow rate of 1 L / min to obtain a platinum-rich concentrate. The platinum recovery rate was 98.6%, and the platinum enrichment ratio of the concentrate was 6.4 times.

[0044] Example 5 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 500g of platinum-loaded catalyst, crush and grind the platinum-loaded catalyst, desulfurized gypsum, rolled steel scale, carbon powder and sodium borate to 75 μm respectively, and then mix them evenly in a mass ratio of 1:0.3:0.1:0.3:0.15 and then use a pelletizing machine to pelletize them to obtain 10mm pellets.

[0045] (2) The pellets were placed in a 2450 MHz microwave field and dried for 10 minutes. The microwave output power was 100W. Then, under nitrogen protection, the temperature was raised to 850℃ and kept at that temperature for 6 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0046] (3) Mix the calcined product with water at a mass ratio of 1:2 and add it to a conical ball mill. Add 2 ml of sodium silicate at the same time, ball mill for 15 min, and pass through a 150 mesh sieve to obtain slurry.

[0047] (4) The ball-milled slurry was prepared to a slurry concentration of 30% and passed through a magnetic separator with a magnetic field of 900 Gauss at a flow rate of 6.5 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 98.6%, and the platinum enrichment ratio of the concentrate was 5.8 times.

[0048] Comparative Example 1 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 150g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, steel scale, coking coal and sodium borate to 75μm respectively, and then mix them evenly according to the mass ratio of 1:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 20mm pellets.

[0049] (2) The pellets were dried in a 2450 MHz microwave field for 20 minutes, then heated to 1000℃ under nitrogen protection and kept warm for 4 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0050] (3) The calcined product and water were mixed at a mass ratio of 1:1 and added to a conical ball mill. 1.5 ml of sodium silicate was added at the same time. The mixture was ball-milled for 10 min and passed through a 150-mesh sieve to obtain a slurry.

[0051] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 650 Gauss at a flow rate of 3 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 34.76%, and the platinum enrichment ratio of the concentrate was 6.8 times.

[0052] Comparative Example 2 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 150g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, Fe2S, steel scale, coking coal and sodium borate to 75 μm respectively, and then mix them evenly according to the mass ratio of 1:0.5:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 20mm pellets.

[0053] (2) The pellets were dried in a 2450 MHz microwave field for 20 minutes, then heated to 1000℃ under nitrogen protection and kept warm for 4 hours. After being taken out and cooled naturally, the calcined product was obtained.

[0054] (3) The calcined product and water were mixed at a mass ratio of 1:1 and added to a conical ball mill. 1.5 ml of sodium silicate was added at the same time. The mixture was ball-milled for 10 min and passed through a 150-mesh sieve to obtain a slurry.

[0055] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 650 Gauss at a flow rate of 3 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 92.92%, and the platinum enrichment ratio of the concentrate was 5.8 times.

[0056] Comparative Example 3 A method for capturing platinum in a platinum-supported catalyst for VOCs treatment includes the following steps: (1) Take 150g of platinum-supported catalyst, crush and grind the platinum-supported catalyst, desulfurized gypsum, steel scale, coking coal and sodium borate to 75 μm respectively, and then mix them evenly according to the mass ratio of 1:0.5:0.3:0.2:0.1 and then use a briquetting machine to briquette the mixture to obtain 20mm pellets.

[0057] (2) The pellets were heated to 1000℃ under nitrogen protection and kept at that temperature for 4 h. After being taken out and cooled naturally, the calcined product was obtained.

[0058] (3) The calcined product and water were mixed at a mass ratio of 1:1 and added to a conical ball mill. 1.5 ml of sodium silicate was added at the same time. The mixture was ball-milled for 10 min and passed through a 150-mesh sieve to obtain a slurry.

[0059] (4) The ball-milled slurry was prepared to a slurry concentration of 20% and passed through a magnetic separator with a magnetic field of 650 Gauss at a flow rate of 3 L / min to obtain platinum-rich concentrate. The platinum recovery rate was 56.27%, and the platinum enrichment ratio of the concentrate was 7.2 times.

[0060] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for capturing platinum in a platinum-supported catalyst for VOCs treatment, characterized in that: Includes the following steps: (1) The platinum-loaded catalyst, sulfiding agent, scavenging agent, reducing agent, and accelerator are crushed separately, then mixed evenly and pelletized to obtain pellets; the sulfiding agent is desulfurized gypsum or red gypsum; the scavenging agent is iron oxide that falls off during the rolling and forging process of steel billets; the reducing agent is one or more of carbon, petroleum coke, coking coal, and graphite mixed in any proportion; the accelerator is one or more of sodium borate and sodium carbonate mixed in any proportion. (2) The pellets were placed in microwaves for treatment, and then calcined in a protective gas to obtain the calcined product; (3) Mix the calcined product with water, then add a dispersant and wet grind, then sieve to obtain a slurry; (4) Add water to the slurry to prepare a new slurry, and then perform magnetic separation to obtain platinum and non-magnetic tailings for the preparation of high-strength cement raw materials.

2. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: The mass ratio of the platinum-loaded catalyst, sulfiding agent, scavenging agent, reducing agent, and accelerator is 1:0.3~1:0.1~0.5:0.1~0.3:0.05~0.

15.

3. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: The microwave output frequency is 2450MHz, the microwave output power is 100-1100W, and the microwave time is 10-30min.

4. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: The calcination temperature is 850-1250℃, the time is 3-6 hours, and the protective gas is nitrogen, hydrogen or argon.

5. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: In step (3), the mass ratio of calcined product to water is 1:1-2; the amount of dispersant added is 100~500 g / ton of calcined product; the dispersant is one or more of sodium silicate, sodium pyrophosphate, and sodium polyacrylate mixed in any proportion; the wet grinding time is 3-15 min.

6. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: The new slurry has a slurry mass concentration of 5-30%.

7. The method for capturing platinum in a platinum-supported catalyst for VOCs treatment according to claim 1, characterized in that: The magnetic field strength of the magnetic separation is 300-900 Gs.

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