Method for smelting base metal of low phosphorous stainless steel by using low-grade limonite of containing nickel-chromium

Abstract

This invention relates to a method for smelting low-phosphorus stainless steel base material from nickel and chrome-containing low-grade limonite. The method comprises: (1) pre-treating nickel and chrome-containing low-grade limonite via sieving, pulverizing and drying to obtain ore powder and ore blocks with different particle sizes, and mixing with fuel and flux to obtain sinter ore; (2) mixing various dedusted ashes, sintered return fines, and ore powder with an adhesive and a reductant, and passing into cold-pressed balls or carbon-containing balls under high pressure; (3) drying the carbon-containing balls, adding into a converter, and reducing to obtain pre-reduced balls; (4) mixing the sinter ore with partial ore blocks, the cold-pressed balls, the carbon-containing balls, the pre-reduced balls, the fuel, the flux and auxiliary materials, and smelting in a blast furnace to obtain molten nickel and chrome-containing alloy or molten iron; (5) mixing with the cold-pressed balls, the carbon-containing balls and the pre-reduced balls, and smelting in an electric furnace or a converter to reduce, decarbonizes, dephosphorize and obtain clean molten stainless steel base material that can be directly used in steel making; (6) casting with a continuous caster to obtain solid stainless steel base material that can be directly used in steel making. The method has such advantages as low cost, little pollution, abundant raw materials, high recovery rate of alloy elements, and few harmful elements.

Description

technical field [0001] The invention relates to a method for smelting a low-phosphorus stainless steel base material by using low-grade limonite containing nickel and chromium, which belongs to blast furnace, electric furnace and converter smelting processes. Background technique: [0002] At present, in the stainless steel smelting process, its raw materials are mainly composed of: blast furnace molten iron + clean stainless steel return steel + high-carbon ferrochrome + high-purity ferronickel, or clean stainless steel return steel + common scrap steel + high-carbon ferrochrome + high-purity nickel Iron is mainly smelted in electric furnaces or converters. With the widespread application of stainless steel, the output has increased significantly year by year, resulting in a shortage of nickel metal, so the price of nickel has skyrocketed. However, the production of high-carbon ferrochromium and high-purity ferronickel by conventional methods has high process costs, complic...

AI Technical Summary

Problems solved by technology

With the widespread application of stainless steel, the output has increased significantly year by year, resulting in a shortage of nickel metal, so the price of nickel has skyrocketed. However, the production of high-carbon ferrochromium and high-purity ferronickel by conventional methods has high process costs, complicated production processes, and low output. Low pollution, serious pollution, consume a lot of energy, and the price is high, and in the subsequent smelting process, it needs to be diluted into stainless steel, resulting in greater waste of energy and manpower

Now some enterprises have switched to non-pure nickel raw materials (mainly nickel, chromium pig iron or ferronickel) to smelt stainless steel, but these nickel and chromium pig iron mainly use 300m 3 The production of the following small blast furnaces has serious environmental pollution, and the nickel and chromium pig iron contains high impurities such as phosphorus and sulfur. Usually, the dilution method is used to add clean stainless steel back to the steel to reduce the phosphorus and sulfur content in the finished product, but at the same time reduce The content of alloying elements such as nickel and chromium is reduced, which brings difficulties to subsequent stainless steel production operations

The low-grade limonite containing nickel and chromium is rich in resources and low in price, but the iron content in this ore is low, the nickel content is low, the chromium content is high, the composition is complex, and there are many gangues, resulting in a large amount of slag in blast furnace smelting, and the viscosity of slag iron Large, it is difficult to smelt with the existing conventional technology