How to desulfurize pyrite has always been the difficulty and focus of pyrite beneficiation. With the development of modern industry, many fields have put forward stricter requirements for the sulfur grade in iron concentrates, generally requiring a sulfur grade of 0.2% to 0.4%. So, what kind of process and method can be adopted to achieve this goal? This article takes a pyrite desulfurization project undertaken by Xinhai as a prototype and briefly explains it.
This pyrite desulfurization project was undertaken by Xinhai in 2020. At that time, the customer's concentrator had been in operation for many years. With the increasing demand for iron concentrate in the market, the iron concentrate produced in the concentrator could no longer meet the market demand. The iron grade in the iron concentrate was about 63.5%, and the sulfur grade was about 0.37%.
In order to reduce the sulfur grade (expected to decrease to below 0.2%), the project leader sought out multiple manufacturers. Due to the need for technical transformation based on the original concentrator, many manufacturers were unable to meet customer requirements. Xinhai stands out among numerous mineral processing service providers.
(1) Beneficiation test
Firstly, the ore samples sent by the customer are divided into three parts, namely, test samples, sieve analysis samples, and laboratory samples, to simulate the original process flow on the project site to prepare iron concentrate.
According to laboratory analysis and sieve analysis tests, sulfur minerals in the raw ore of the project are evenly distributed, and reducing sulfur grade is the main purpose.
After comparative analysis of multiple sets of tests, it was finally determined that the flotation process should adopt a flotation operation of one coarse and two sweeps; The flotation agent uses xanthate and black powder as mixed collectors to flotation sulfur minerals, and copper sulfate and oxalic acid as combined activators. This can effectively reduce the cost of reagents and ensure the sulfur removal effect of the concentrate.
(2) Mine design
After determining the process flow, Xinhai Mine Design Institute conducted a comprehensive planning for the project based on the actual on-site situation provided by the customer, carried out customized construction drawing design, and conducted a reasonable layout of various equipment and pipeline lines.
(3) Pyrite flotation process and equipment
According to the results of beneficiation tests, the pyrite flotation process is determined to be a flotation process flow of one coarse and two sweeps. Pyrite desulfurization equipment mainly includes: BF flotation machine, reagent mixing tank, wear-resistant slurry pump, automatic dosing machine, etc.
Wear-resistant slurry pump: A slurry conveying equipment used in pyrite desulfurization projects to transport the separated concentrate to a thickener or filtration dehydration equipment.
Reagent stirring tank: used to fully stir the pulp, reagent, and air, and feed the evenly stirred pulp into the BF flotation machine.
BF flotation machine: it is the core equipment of the whole pyrite concentrator. It uses reagents to react with sulfur and attach to the flotation foam to separate and remove sulfur and finally obtain higher grade iron concentrate.
After optimization and transformation of the flotation process, the sulfur grade in the final iron concentrate was controlled at 0.15%, or even lower to 0.065%, successfully achieving the customer's desired goal (sulfur grade controlled below 0.2%).
Over the years, Xinhai has continuously optimized and improved its iron ore beneficiation process. With its advanced technical level and rich project experience, it has helped customers solve one difficult problem after another. The pyrite desulfurization project once again confirms the strength of Xinhai.
