Currently, more than 1 million t per year of nickel metal production in the lateritic nickel ore accounted for about 1/3, about 300 000 t, of which nickel-iron technology to produce nickel about 20 million t. However, in the next seven years, that is, before 2007, there will be more than 10 large-scale laterite-type nickel plants planned to be built or expanded in the world. These projects will mainly adopt PAL high-pressure acid leaching technology, not iron-nickel process, and the project scale is generally annual. It is 2 to 50,000 tons of nickel metal, and the total annual output will increase by 200,000 to 300,000 tons of nickel compared with 2000. This is a noteworthy development trend in the world nickel industry.
I. Reasons for the development of the world's lateritic nickel ore
With the economic development of the world in the 1990s, the demand for stainless steel, which accounts for 65% of nickel use, has grown strongly. Nickel demand has increased by more than 4% per year for the first five years. It is predicted that the growth rate will be 3.5% to 4% in the next 5 to 10 years, including Asia. The nickel demand growth rate will be 7%. However, the world's recently available nickel sulphide resources, with the exception of Canada's Voisey bay nickel mine, are almost incomparable. The world has so far discovered about 70 million tons of nickel metal resources. Among them, nickel sulfide is about 30 million tons, accounting for 42%. The rest are laterite nickel. The advantages of developing and utilizing laterite-type nickel are as follows: 1 The laterite-type nickel is rich in resources, and there are 41 million tons of nickel metal in the world, and the exploration cost is low. 2 mining costs are extremely low. 3 The metallurgical process has matured. The red smelting method of the laterite nickel ore has matured and the pressure acid leaching technology has matured. The technology began in the 1950s and was first used in the Moa Bay mine in Cuba, called AMAX® PAL technology. Since then, in the 1970s, Australia's QNI Corporation built the Yabula nickel plant, which was acid-leached to treat laterite nickel mines in New Caledonia, Indonesia and Queensland, Australia. The technology of wet processing of laterite-type nickel ore by Sherritt of Canada has been recognized. 4 Laterite-type nickel ore can produce intermediate products such as nickel oxide, sulfur nickel, iron nickel, etc. Among them, sulfur nickel and nickel oxide can be used by nickel refineries to solve the problem of insufficient nickel sulfide raw materials. As for iron and nickel, it is easier to manufacture stainless steel and reduce production costs. For example, the Indonesian Antam company used the local laterite nickel ore, the cost of producing iron and nickel has dropped to 1.4 US dollars / pound of nickel (1 pound = 0.453 kg) last year, the annual output of nearly 10,000 tons of nickel. 5 The world's lateritic resources are mainly distributed in the near equatorial region, and most of them are close to the coast, which is convenient for outbound transportation. Therefore, although the investment in laterite-type nickel construction plants is relatively large, the annual production capacity per pound of nickel is generally 9 to 11 US dollars. However, due to the above advantages, if the process is reasonable and well-managed, the production cost per pound of nickel can be lower than that of vulcanization. nickel. In the case of Australia's largest nickel company, Western Mining Corporation (WMC), the total cost per pound of nickel (including investment amortization) has fallen from $3.00 in 1996 to $2.00 (2000). Mature clay mines with mature technology and advanced management can also reach this level. In particular, the detailed feasibility study report of the red earth type nickel ore pressure acid leaching technology project in recent years, taking into account the value of cobalt , the production cost per pound of nickel is below 1.4 US dollars. Therefore, the technical center for the development and utilization of laterite-type nickel ore has been converted from a fire method to a wet-process acid-leached metal.
2. Two types of laterite-type nickel ore resources: “wet type†and “dry typeâ€
With the investment in the construction of three laterite nickel plants in western Australia in recent years, people have a new understanding of the utilization properties and types of lateritic nickel resources. They can be divided into two categories: one is called “wet typeâ€. ", mainly distributed in the near equator, such as New Caledonia, Indonesia, the Philippines, Papua New Guinea and the Caribbean; the other type is called "dry", mainly distributed in the southern hemisphere continent far from the equator. It is represented by Western Australia.
3. Recent developments in the development and utilization of laterite-type nickel ore in Western Australia
The development of red earth type nickel ore in Western Australia is a hot spot in the development of nickel industry in the world in recent years. It has also become a hot spot for investors. Since the beginning of 1999, three high-pressure acid leaching nickel plants have been produced in Western Australia. The factory is Cawse, Bulong and Murrin Murrin. The first phase of the project is completed, with an annual production capacity of 0.9 to 10,000 tons and an annual design capacity of 28,000 tons of nickel. It is A$2.16 billion.
(1) Resources
Western Australia's laterite-type nickel ore resources are very rich, but it was not until 1996 that it was explicitly developed. The total amount of resources explored is 12 million tons of nickel metal, with an average nickel content of 0.8% to 1% and Co 0.06% to 0.08%. These resources are the weathering products of several giant ultra-basic rock belts in the eastern part of Western Australia. They are distributed in the same area as the nickel sulfide ore and gold ore belts in the famous Archean greenstone belt. The infrastructure is good and the natural gas pipeline energy exists. The terrain is flat, mining conditions are superior, and mining costs are extremely low.
In addition to Western Australia, laterite-type nickel ore resources are also distributed in East Australia. They are produced in the northern part of Queensland and the Midwest of New South Wales. They have discovered 3 million tons of nickel metal and a total of 15 million tons in Australia. The amount of nickel metal. In addition, there are 4,000,000 WA nickel sulfide t amount of metal nickel laterite nickel sulfide produced in the same ultrabasic a belt, but not in the same vertical symbiosis on deposit, i.e. not as copper deposits that, once There are usually primary copper sulfide ores below the copper deposits in the bio-enrichment zone. (Western Australia's nickel sulphide is said to be large and poor. For example, the reserves of Mt keith are nearly 500 million tons of ore, 0.54% Ni, large exposed, and the annual mining volume is 10 million tons. 360,000 tons of concentrate, containing 47,000 tons of nickel.)
(2) HPAL high pressure acid leaching technology
The basic process used in these three plants is High Pressure Acid Leach (HPAL), but the process in the second half is different. The Cowes Nickel plant produces nickel hydroxide intermediates and then electrolyzes metal cathode nickel and cobalt sulfide. The process of the Bron plant does not pass through the process of nickel hydroxide intermediate products, directly producing nickel and cobalt metal. Molin Moline is similar to the on-site process at the Moy Bay Nickel Plant in Cuba, and uses the Canadian Sherritt technology to produce mixed nickel/cobalt intermediates and then electrolytically refine to produce metallic nickel and diamonds.
Take the Cowes Nickel Factory as an example to introduce its process. Feed preparation and rough selection to improve grade (feeding + water + flocculant floccant) → PAL pressure acid leaching (adding acid and steam, in high pressure vessel) → concentration and neutralization reaction (add lime, flocculant, the process Neutralize some of the material after the reaction to the tailings reservoir) → Mix the hydroxide precipitate (add magnesium , lime, flocculant) → Nickel electrolysis, refining (add ammonia, CO 2 , steam, reactant, ammonia sulfide and energy) → Product metal nickel (cathode nickel) and product cobalt sulfide precipitate.
The Coase Nickel Plant is the best one after the three plants are put into operation. The production process runs smoothly and reaches the expected amount of nickel leaching. The main reactants are also below the design level, and qualified nickel metal products have been produced. By the end of October 2000, 7000 tons of metallic nickel had been produced, reaching 82% of the design capacity. The cost of producing nickel has dropped from $4.10/lb. nickel to $1.54/ 碲 nickel. There have been many problems during the trial production, but it is not fatal.
(3) Problems in trial production and their causes
In the first two years of the trial production process of the three plants, there were some problems in the operation of the equipment and the process. The main reason was that the materials of the equipment were improperly selected, resulting in failure. In the technical design, the supply capacity of clean water, circulating ammonia and steam was insufficient. For the problem of disjointed, etc., but take the Cowes factory as an example. Describe the problems and remedies in the operation of equipment and processes. 1 Cracks appear on the joint line of the original titanium electrode used in the high-pressure vessel (corrected); 2 equipment failure and local equipment materials are dissolved due to poor conditions during the reaction, failure of the pipe joint and some pressure-bearing materials Improper choices, such as pumps, valves, and piping materials. (Corrective method: replace the material); 3 The closing valve of the high pressure container is not working properly. (Replace the valve); 4 There is mud on the feed agitator in the high pressure vessel. (Solution: Control the composition of the feed slurry and adjust its composition to make the feed slurry pass through the high pressure container. 5 The scale of the water desalination equipment is insufficient, which restricts the effective supply of water in the steam generating power generation equipment (Remedy: reduce chemical substances) The dosage, improvement process and maintenance process. Long-term solution: Rebuild a spare water desalination device to increase the reserve of treated water.) 6 sulfur pump has insufficient practical function (install a larger sulfur pump). Insufficient design scale for leaching limits the scale and yield of metal production processes (recovery: reduce the reuse line of ammonia, and implement the process of tightening ammonia.) 8 The content of zinc in nickel metal products exceeds the original design standards, ( adjustment indicators, and continue to implement the adjusted index) .⑨ high-grade cobalt ore containing high amounts of manganese, resulting in lime consumption and increased recycling process load increases (solution: ore, reducing the high grade cobalt ore The content ratio keeps the Mn content in the ore feedstock less than 3%).
Due to the above-mentioned equipment failures and problems in the process, the production cost of the trial production process is overrun. The feasibility study of these projects should be less than 1.4 US dollars per pound of nickel. The production cost of the Bronze Nickel plant before October last year is from 7.20 US dollars / lb of nickel fell to 3.10 US dollars, still high, not yet stable; 2 extended production time; 3 due to improved materials and equipment components, adding new equipment, additional infrastructure costs.
The reasons for the problems in the above equipment and process are as follows: (1) The composition complexity and clay content of the “dry†laterite nickel ore in Western Australia are underestimated; 2 the choice of equipment materials is insufficient for its pressure resistance and corrosion resistance; 3 The corrosion degree of salinity in the water source of Western Australia is not enough; 4 The capacity of the feeding part in the design structure of the refining system is insufficient, and there is no room for strain. In addition, the industrial scale of these three plants has not undergone a small industrial trial production stage before the launch of the small industrial trial production stage is also a significant defect or mistake.
Fourth, the development trend of laterite-type nickel ore
Although these problems occur in the materials and processes of the three PAL nickel plants in Western Australia, they are not fatal and can be corrected and remedied. All three projects have produced products with qualified indicators, and the cost is decreasing, which tends to reach production. Therefore, there are a number of new red clay-type nickel mine PAL nickel plant construction and expansion projects in the world, the development trend is very obvious, can be summarized as:
(1) Due to the significant reduction of available resources for nickel sulphide, the increase in nickel production in the world over the next decade will be mainly due to the development of lateritic nickel resources. In the development of lateritic nickel resources, the development trend of PAL technology is greater than that of iron and nickel. technology;
(2) The investment cost of the PAL wet process technology and the red earth type nickel ore fire smelter is roughly the same, that is, the annual production capacity is 8 to 12 US dollars per pound of nickel. However, the PAL technology nickel plant will significantly reduce its infrastructure investment in the next round of construction or expansion projects;
(3) The production cost of the PAL process is generally lower than the iron-nickel process, and the PAL method consumes significantly less energy than the iron-nickel process. Therefore, economically, the PAL technology method will show its superiority;
(4) Because the "wet type" laterite mineral resources have the advantages of high grade, less clay and easy treatment, compared with the "dry" laterite resources, the development of "wet" resources has the advantage of development and utilization.
(5) The PAL technology of laterite-type nickel ore can produce intermediate products on site: nickel hydroxide or sulfur nickel, which can provide the expansion of existing nickel refineries or solve the problem of insufficient supply, which is currently many in the West. The business direction taken by the nickel company. This business idea is worth learning from.
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The design theme of the accessories for the injection charger base is the product design and mold design of the universal charger base, which is designed for the production of injection mold. Plastic parts
The preliminary analysis of the structure shows that the sprue and the sequence type, the structure and the adoption of a two-cavity mold are due to the large area of plastic parts. Due to the structural characteristics of plastic parts, it needs to use inclined sliding traction mechanism. The specific design process is as follows: first, the performance analysis of the plastic injection molding process. This includes analysis of the structural dimensions of the material properties of the plastic parts and molded plastic parts. Second, it is the choice of how to inject a reasonable machine. Choosing the right injection molding machine is the foundation of this design. Again, this is in the form of the mold structure preparation. The form structure of the mold must be calculated and a reasonable choice is based on the dimensions of the structure. The fourth step is to design the pouring system.
The fifth step is such a design in the design and mold parts of the calculation focus. The sixth step is to draw the sliding cover design of the oblique profile and the calculation of the core mechanism.
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