Zhongwei Co., Ltd.: decomposition of technical difficulties in signing side blowing process for high matte project

Zhongwei signed with RIGQUEZA the project of smelting high matte nickel metal with an annual output of 30,000 tons in laterite nickel mine. The total investment of the project is about 243 million US dollars, of which the first phase of the project plans to produce 10,000 tons of high nickel-containing metal per year, with a total investment of about 81 million US dollars. The unit investment intensity is 8100 US dollars / metal ton, which is better than the general high matte nickel fire project with a unit investment intensity of 12000 US dollars / metal ton.

The suitability of side-blowing process in laterite nickel ore: the oxygen-rich side-blowing process is not a new process, and the application of oxygen-rich side-blowing process in laterite nickel ore is called side-blowing reduction technology of oxygen-enriched pulverized coal, which belongs to the popularization of side-blowing immersion combustion pool smelting technology in the smelting field of laterite nickel ore.

This technology is suitable for the treatment of nickel laterite. The violent bubbling of the molten pool and the tumbling of the liquid slag produce a huge reaction interface. Iron and nickel oxides are heated, melted and reduced to form molten nickel, which is precipitated and separated into the static slag layer below the muzzle of the gun. Under the action of gravity, the slag iron begins to separate. As a result, a slag layer without iron is formed in the upper part of the hearth, and molten nickel is deposited at the bottom of the furnace and released from the iron mouth room when it reaches a certain amount. After the gangue (SiO2, MgO, Al2O3, CaO, etc.) in the ore is melted, a liquid slag with good performance is formed and discharged from the slag discharge outlet.

Key benefits include:

The raw materials come from a wide range of sources and are easy to prepare. It can deal with different types of laterite nickel ore, the raw material preparation is simple, and both lump ore and powder ore can be used. Due to the difficulty of flotation of nickel laterite, primary ores generally contain 20% of free water and 35% of bound water. The smelting reduction of laterite nickel ore with oxygen-enriched side-blown pulverized coal can be directly added to the furnace for smelting reduction smelting after preliminary drying to 10% of physical water (or steam deep drying to 0.3% of physical water), eliminating the traditional process of sintering, pre-reduction and other processes.

The content of harmful elements is low. In view of the high temperature (1450-1550) and high reduction environment in the furnace in this process, harmful impurities such as Si/P/S are slagged with other metals or reduced into flue gas to improve the quality of the finished products.

High oxygen concentration and high heat utilization rate. In the smelting process, flue gas is the main culprit of heat loss, and under normal circumstances, flue gas can take away 50-60% of the waste heat. In the side blowing process, oxygen-rich air and pulverized coal can be injected, the oxygen-rich concentration is up to 70-90%, the amount of smelting waste gas is small, and the heat loss of flue gas is small.

The reductant has strong adaptability. Does not need to use coke or coking coal; can use a wide range of coal; helps to reduce costs.

Process route: laterite nickel ore-drying kiln (dehydration)-rotary kiln (deep drying roasting)-side blowing furnace (material melting, reduction)-slag discharge-waste heat recovery, dust recovery.

The difference between RKEF- high nickel matte process and RKEF- high nickel matte process: there is no essential difference between the whole process logic of side blowing reduction technology of oxygen-rich pulverized coal and RKEF- high nickel matte process. The main differences are as follows: the process of one-step roasting-pre-reduction can be omitted; the adaptability of oxygen-rich raw materials is stronger; and the equipment is changed from electric furnace to side-blown furnace.

Technical application difficulties: the process can be replicated in doubt, mainly lies in: at present, there is no successful application case in the field of laterite nickel ore, and the technical stability still needs to be tested in large-scale industrial production; it is difficult to obtain experienced talents because of less talent reserve; after putting into production, there are higher requirements for the matching degree of each process route and for the technical and operation team.

Investment, operating costs:

Investment cost: according to the disclosure of Zhongwei shares, its unit investment intensity is 8100 US dollars / metal ton, which is significantly better than the general high matte nickel fire project unit investment intensity of 12000 US dollars / metal ton. Due to the less disclosure of the process part, we speculate that the specific reasons may be: 1) because the electric furnace is static smelting, the efficiency is slightly lower than that of the side-blown furnace, and the electric furnace needs more equipment per unit capacity. As a result, the investment of the electric furnace process is higher than that of the side-blowing process; 2) the domestic replacement of the key equipment results in a lower investment.

Operating costs: since the side-blowing process requires lower quality of raw materials and reducing agents and is slightly higher than the RFEF- high nickel matte process in terms of efficiency, the unit operating cost (based on nickel laterite-nickel sulfate) should be slightly lower than the RFEF- high nickel matte process ($9000-$11000 / tonne). The main equipment consumables of side blowing process are spray gun and refractory brick. Due to the protection of the copper water jacket, the spray gun is generally replaced for half a year, and the price is between 3000 and 5000; refractory bricks mainly play the role of thermal insulation to reduce the heat loss of the furnace.

Construction cycle: theoretically, it will take 1-2 years, but due to the lack of application maturity of the project, the commissioning phase may be overdue. At present, according to the third quarterly report, the joint venture Indonesia Hang Seng New Energy Materials Co., Ltd. (Zhongwei equity 15%) has completed the industrial and commercial registration procedures.

It is suggested to pay attention to the disclosure of the Zhongwei project that if the project is successfully put into production, it may impact the existing laterite nickel ore pyrometallurgical technology route and further reduce the pyrometallurgical process investment and operating costs.