TWI824943B - Method of reducing carbon emissions and improving the environmental performance of concentrate producers and smelters - Google Patents

Abstract

A process which improves the environmental performance of primary non-ferrous metal smelters by reducing carbon emissions, providing enhanced energy utilization, improving consumption efficiencies, and improving worker safety. The smelters include those that smelt nickel, copper and zinc. The process may include a step of providing a concentrate feedstock to a smelter, wherein the concentrate feedstock has been conditioned with an aqueous mixture consisting of a saccharide, a surfactant to enhance entraining of a product into a concentrate, a biocide and/or fungicide to subdue fungal growth, and a tracking element to identify an origin and/or producer of the product.

Description

Ways to reduce carbon emissions and improve environmental performance of concentrate manufacturers and smelters

The technical field of the present invention is to reduce carbon emissions from industrial activities and processes, thereby reducing global warming. The technical field of the present invention is also the improvement of environmental performance of industrial processes. The technical field of the present invention is also the improvement of the financial assessment of companies engaged in industrial processes so that investors can have greater confidence that the company can comply with increased environmental restrictions and remain profitable. The technical field of the present invention is also the tracking, identification and accounting of industrial processes, product integrity and origin. One environmental issue at smelters is carbon emissions that contribute to climate change. Environmental performance is improved by reducing fossil fuel consumption during transportation, smelting and related environmental emission capture equipment. The field of the invention includes in particular non-ferrous metal smelters, such as nickel, cobalt, copper and zinc smelters, and improvements in their environmental performance.

Smelter inputs include intermediates. These intermediates are by-products of metallurgical processes. This may include the same smelter's own slag as returns (i.e. metal in the form of gates, gates, runners, risers and scrap castings, with a known chemical composition, which is returned to the furnace for remelting). It may also include metal-laden slag obtained from other smelters, which may be referred to as external feed or external input. Such external feed may be slag that needs to be reprocessed because it still contains recyclable metal that has not been fully or efficiently smelted.

These intermediates may also include by-products manufactured downstream in the production line, or by metal refineries manufactured downstream. These intermediates may include dust/materials recovered from air emission treatment or waste treatment processes within the metallurgical production supply chain.

These intermediates also include a category of concentrates known as secondary concentrates as they are manufactured according to smelter specifications and are contractual inputs from external recycled feeds manufactured by different industries. These secondary concentrates are finished products produced by industrial metallurgical by-product recyclers and metal bearing metal finishing activities.

Intermediates are important components in short- and long-term smelter operation planning and materials management. There are local and global trading and processing markets for these intermediates, which may originate from mining companies' operations or be obtained from other mining companies and metal processors/manufacturers.

Smelter inputs may also include enhanced feedstock.

Smelters consume large amounts of these intermediates. This consumption can be regular or irregular, depending on market conditions or the needs of the smelter. Therefore, the metallurgical and processing properties of these intermediates can have a significant impact on the transportation and processing of these intermediates, the efficiency of the smelter, and the economic and environmental aspects of the smelter operation.

The present invention includes a process that improves the environmental performance of primary non-ferrous metal smelters by reducing carbon emissions, providing enhanced energy utilization, improving consumption efficiency and improving worker safety. Primary non-ferrous metal smelters include smelters that smelt nickel, copper and zinc.

The present invention includes a process for reducing the moisture level of secondary concentrate raw materials in a smelter, improving the uniformity of the raw materials in the smelter, and enhancing the safety of smelting and related material handling. Material handling includes bedding, blending and compounding of raw materials. Manufacturing process of the present invention (1) Reduce energy consumption; (2) Create additional capacity utilization; (3) Additional recycling of raw materials, industrial materials and fluxes smelted thereby can increase metal production; (4) Enable enhanced raw materials to be introduced at multiple points in the smelting process and enhance operational efficiency and flexibility; (5) Enhanced raw materials can be more effectively introduced into the smelting process through additional mixing and/or blending with the raw materials prior to the final smelting step; (6) Enhance the uniformity of raw materials to create new operational and energy consumption efficiencies; (7) Enhance sampling efficiency, thereby improving the efficiency of the metal recycling accountability process; (8) Significantly reduce dust emissions, enhance worker safety during material handling processes, improve metal recycling accountability, and improve operations and quality control; and (9) Enhance and increase the overall supply chain by increasing the ratio of raw material concentrate to moisture content, thereby increasing the energy required to transport water into the raw material during processing and transportation to the smelter and to remove water during the smelting process Operational efficiencies in energy and metals recycling, including (a) increasing recycling operation capacity and (b) reducing energy consumption in the logistics chain from secondary concentrate recycling manufacturing facilities to primary smelters; and (10) Through elemental analysis of secondary concentrates from primary smelters, process control can be actively identified and verified.

The present invention includes the step of drying the feedstock before adding the product conditioning solution. For example, in the case of metal hydroxide materials, the material can be dried to a moisture content of 50 to 90% solids (50% to 10% moisture), preferably 60% to 90% solids (40% to 10% moisture) . The required moisture content depends in part on smelter product specifications.

The product conditioning solution includes saccharide, also commonly referred to as sugar. It is available in the form of a variety of compounds such as fructose, maltose, sucrose, galactose, glucose, etc. Any readily available saccharide may be used in the methods of the present invention. However, sucrose and fructose are generally preferred, and sucrose is generally preferred. Sugars in solutions tend to exhibit viscosity and adhesion, which promotes the aggregation of fine dry particles into larger particles that are less likely to spread through the air. After drying, the sugar will form a crystal structure, thereby maintaining product particle aggregation and dust suppression.

In one embodiment of the invention, a concentrated syrup (75 to 85 Brix) is produced by diluting the concentrated syrup (75 to 85 Brix) or by dissolving dry powdered sugar in water to yield a Brix of 20 to 30 Brix, preferably 25 Prepare a basic sugar solution at the concentration of Brick's Brix. Brix can be measured with any commercially available refractometer capable of measuring the Brix of a sugar solution, such as the Milwaukee MA 871 Digital Brix Refractometer.

In one embodiment of the invention, by diluting a concentrated syrup (75 to 85 Brix) or by dissolving dry powdered sugar in a metal-containing scrap plating solution or other non-ferrous metal-containing solution Alternately prepare the base sugar solution. This increases the total metal content of the metal-bearing non-ferrous metal concentrate and minimizes the amount of water required to adjust the Brix of the sugar component, while also reducing the amount of Brix needed to achieve the desired product conditioning solution. The total amount of sugar required for Brix (a waste plating solution with metal can exhibit a starting Brix concentration of about 10 compared to water with a Brix of 0). Additionally, this helps reduce the amount of entrained moisture while producing a more granular and dust-free product, thereby improving the finished concentrate product.

In a specific example of the present invention, the dispersion of the product conditioning solution in the dry raw material is enhanced by adding a surfactant, preferably an anionic/neutral surfactant. Surfactants have been found to be effective at concentrations ranging from 0.25% to 1% by volume, preferably 0.5% by volume.

In one embodiment of the invention, biocides and/or fungicides are added to the product conditioning solution in order to reduce or eliminate the possibility of bacterial growth and/or mold during long-term storage of the solution or final treated feedstock. Various biocides/fungicides can be used, preferably sorbic acid or potassium sorbate. Potassium sorbate is more preferably used due to its high solubility in aqueous solution and effectiveness at low concentrations. The concentration is preferably between 0.02% and 0.10%, and more preferably 0.025%.

In one embodiment of the invention, product tracking or identification elements are added to the product conditioning solution to provide the ability to verify the administration and concentration of the conditioning solution. Various element identifiers can be added based on known elemental components present in the product. One would choose an element tracer that is known not to be present in the product, preferably a rare earth metal such as lanthanum, scandium or yttrium, most preferably lanthanum. The trace element must be added at a concentration sufficient to be identified in the final product and should preferably be between 500 mg/l and 10,000 mg/l, preferably 1,000 mg/l, in the conditioning solution before application . To know the initial concentration of the trace element in the conditioning solution, a qualified person can: 1) Calculate the initial percentage of conditioning solution added to the product based on the final concentration of the trace element found in the product sample; 2) Confirm that the appropriate amount of conditioning solution has been applied to the product to fully suppress dust; 3) Identify the source and/or manufacturer of the finished product; and 4) Ensure that the product is not counterfeit;

The present invention may be used to audit the use of products as directed by contractual agreements: 1) The added tracer is invisible to the naked eye and can only be detected through chemical analysis; 2) The added tracking agent is invisible to the naked eye and physically undetectable, and cannot be removed once formulated into the product; and 3) The added tracer is not visible to the naked eye, so those administering conditioning solutions may feel the need to dose the entire mass of product to be treated in order to avoid the possibility of detection of inappropriate application.

In one embodiment of the present invention, the metal hydroxide feedstock material or material is removed from the dryer by using any of several types of continuous blenders and mechanical bulk batch mixing devices. Other types of materials discharged from (including mechanical dryers or solar drying vessels) accumulate with the product conditioning solution, which is injected into the product by means of an adjustable feed pumping mechanism. The mixing and aggregation of the dry product and product conditioning solution is achieved by mechanical action, resulting in a granular, dust-free, uniform and free-flowing final product.

In one embodiment of the invention, the application of the product conditioning solution is adapted to obtain a dust-free final product during unloading into bulk intermediate containers or active loading of rail cars or shipping containers from bulk handling equipment. Application rates for product conditioning solutions can vary widely based on the physical and chemical properties of individual feedstocks, but application rates will preferably be between 5 and 40 gallons per short ton (2,000 pounds), preferably between 5 and 40 gallons per short ton dry. The product is between 10 gallons and 15 gallons.

It will be apparent to those skilled in the art that various changes and modifications can be made in the invention described herein without departing from the spirit of the invention.

Figure 1 shows a specific example of a method for a nickel smelter according to the invention. External feed 1 (can include intermediates) or raw material manufacturing facilities 1 (a) prepare raw materials or customized raw materials by preparation and mixing), enter the primary smelter blending room, prepare/mix with secondary/flux, refine Mine 3 receives energy from energy source 4 via raw material logistics/transport 2, which receives energy from energy source 9. The output of the primary smelter blending chamber 3 is fed to a fluidized bed dryer 5 which receives energy from an energy source 4 . The output from the pressure filter instrument 3 is fed into the furnace smelting instrument 6 . The output from the furnace smelting instrument 6 is fed to the slag conversion and cleaning instrument 8 which receives energy from the energy source 9 . The output from the smelting instrument 6 may also include slag 7 for disposal. The output from the slag conversion and cleaning instrument 8 may be slag 10 for disposal or delivered to a casting instrument 11 which may receive energy from the energy source 9 . The output from the casting instrument 11 can be fed to a crushing instrument 12 which can receive energy from the energy source 9 . The output from the crushing instrument 12 can be sent to the grinding instrument 13 which can receive energy from the energy source 14 .

The output from the grinding instrument 13 may be fed to the magnetic separation instrument 15 as part of matte processing. The magnetic separation instrument 15 can receive energy from an energy source 16 . The output from the magnetic separation instrument 15 may include metals 17 and non-metals. The non-metals may be delivered to flotation instrument 18 which may receive energy from energy source 14 . The output from the flotation apparatus 18 may be sent to a fluidized bed roasting apparatus 19. The output from the fluidized bed roasting apparatus may be nickel oxide 20.

Nickel refinery 21 may receive nickel oxide 20 and metals 22, such as nickel, copper, precious metals, platinum group metals, and cobalt.

The furnace smelting apparatus 6 and the slag conversion and cleaning apparatus 8 can produce waste gas 23, which can be sent to a sulfuric acid plant 24 which can produce sulfuric acid 25.

Figure 2 shows a specific example of a method for a copper smelter according to the invention. The raw material manufacturing facility 201 prepares raw materials or customized raw materials through formulation and mixing. Energy from the energy source 202 is used to prepare the feedstock and transport 203 the feedstock to the primary smelter blending chamber 204 where there may be additional formulation and blending with secondary, flux and/or concentrate. Transport 203 may also be to flash dryer 205 and/or converter 206. Primary smelter blending chamber 204 may output to flash dryer 205 and/or primary smelter furnace 207.

Primary smelter furnace 207 may output to slag cleaning furnace 208. Both the primary smelter furnace 207 and the slag cleaning furnace 208 can be exported to the discharge 209. Primary smelter furnace 207 may output to matte 210, which is output to converter 206. Converter 206 may output to exhaust 209 and/or anode furnace 211. Anode furnace 211 may output to exhaust 209 and/or anode 212. Anode 212 may be exported to refinery 213. Refinery 213 may output to emissions 209 and/or to anode sludge 214. Anode sludge 214 may be output to sludge treatment equipment 215. Sludge treatment equipment 215 may output to discharge 209. Energy from energy source 216 may be provided to flash dryer 205, primary smelter furnace 207, slag cleaning furnace 208, converter 206, anode furnace 211, refinery 213, and mud handling equipment 215.

Figure 3 is a schematic diagram of savings according to a specific example of the present invention. Energy block 301 results in savings 302 and emissions block 303 .

1: External feeding 1a: Raw material manufacturing facilities 2: Raw material logistics/transportation 3: Primary smelter blending room 4: Source 5: Fluidized bed drying equipment 6: Furnace and smelting equipment 7: Slag 8: Slag transformation and cleaning 9:Energy 10: Slag 11: Casting instruments 12:Broken instrument 13:Grinding instruments 14:Energy 15:Magnetic separation instrument 16:Energy 17:Metal 18: Flotation instrument 19: Fluidized bed roasting equipment 20:Nickel oxide 21:Nickel Refinery 22:Metal 23:Exhaust gas 24:Sulfuric acid equipment 25:Sulfuric acid 201: Raw material manufacturing facilities 202:Energy 203:Transportation 204: Primary smelter blending room 205: Flash dryer 206:Converter 207: Primary smelter furnace 208: Slag cleaning furnace 209: Emissions 210:Matte 211:Anode furnace 212:Anode 213:Refinery 214:Anode mud 215: Mud treatment equipment 216:Energy 301:Energy Block 302: Saving 303: Emission block

[Fig. 1] is a schematic diagram of a specific example of the present invention used in a nickel smelting plant. [Fig. 2] is a schematic diagram of a specific example of the present invention used in a copper smelting plant. [Fig. 3] is a schematic diagram of saving according to a specific example of the present invention.

1: External feeding

1a: Raw material manufacturing facilities

2: Raw material logistics/transportation

3: Primary smelter blending room

4: source

5: Fluidized bed drying equipment

6: Furnace and smelting equipment

7: Slag

8: Slag transformation and cleaning

9:Energy

10: Slag

11: Casting instruments

12:Broken instrument

13:Grinding instruments

14:Energy

15:Magnetic separation instrument

16:Energy

17:Metal

18: Flotation instrument

19: Fluidized bed roasting equipment

20:Nickel oxide

21:Nickel Refinery

22:Metal

23:Exhaust gas

24:Sulfuric acid equipment

25:Sulfuric acid

Claims (10)

A process for reducing carbon emissions and improving the environmental performance of a smelter, the process comprising the step of conditioning concentrate feedstock supplied to the smelter by entraining a conditioning solution into the concentrate feedstock, wherein the conditioning solution is composed of Aqueous mixture consisting of: sugar, surfactant to enhance entrainment of the conditioning solution into the concentrate feedstock, biocides and/or fungicides to inhibit fungal growth, and to identify the conditioned concentrate. Traceability elements of mineral raw material sources and/or manufacturers. The process of claim 1, wherein the aqueous mixture further includes an aqueous solution with metals, and the aqueous solution with metals includes waste plating solution or a selected solution with non-ferrous metals and/or precious metals to enhance the value of the concentrate. The process of claim 1, wherein the sugar may include one or more monosaccharides or disaccharides selected from the following: fructose, maltose, sucrose, galactose and/or glucose. The process of claim 1, wherein the tracking element is composed of a compound including a rare earth metal including lanthanum, scandium or yttrium. A process for preparing concentrate feedstock for use in a smelter, the process comprising the steps of mixing a conditioning solution including sugar with non-ferrous metals and/or precious metal compounds, and adding an additive to enhance the entrainment of the conditioning solution into the concentrate. surfactants, and the further addition of trace elements used to identify the source and/or manufacturer of the conditioned concentrate raw materials. As in the process of claim 5, the sugar may include one or more monosaccharides or disaccharides selected from the following: fructose, maltose, sucrose, galactose and/or glucose. The process of claim 5, wherein the conditioning solution includes water with a concentration between 20 and 30 Brix, a waste plating solution with metal, or another solution with non-ferrous metal. The process of claim 5, wherein the tracking element is a rare earth metal tracer, and the process further includes the step of mixing the rare earth metal tracer with the sugar and the non-ferrous metal and/or precious metal compound. A concentrate feedstock for use in smelters, wherein the feedstock contains sugars, non-ferrous metal compounds and trace elements used to identify the source and/or manufacturer of the adjusted concentrate feedstock. For example, the concentrate raw material of claim 9, wherein the tracking element is a rare earth metal tracking agent.

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