Antimony sulfide ore separation commonly employs a flotation process, known for its advantages of simplicity, high antimony recovery rate, and low ore dressing costs. In order to optimize the plant's ore dressing process, improve ore dressing indicators, and reduce production costs, ore dressing experiments were conducted on this antimony sulfide ore, focusing on the flotation process and reagent dosages.
In this ore, representative ore samples were crushed, mixed, and screened to obtain test materials. Analysis revealed that the main valuable element antimony had a grade of 2.16%, primarily in the form of sulfides with an oxidation rate of only 4.15%. The main antimony minerals were stibnite, with small amounts of antimony iron ore and antimony calcium stone, and trace amounts of yellow antimony ore and sulfide lead antimony ore. The sulfides were mainly pyrite, and gangue minerals consisted mainly of quartz, sericite, and calcite.
(1) Stibnite (Antimony Sulfide)
Stibnite is the primary antimony-containing mineral in the sample. It averages 71.54% Sb (antimony) content and has a coarse particle size. Stibnite is commonly associated with gangue minerals such as quartz, while a few stibnite grains are finely embedded in gangue minerals like quartz, calcite, and sericite.
(2) Pyrite (Iron Sulfide)
Pyrite in the sample has relatively high sulfur content. It appears uneven in size, often in the form of coarse-grained self-shaped crystals embedded in gangue minerals like quartz. Its association with stibnite is less intimate.
(3) Quartz
Quartz is one of the main minerals in the sample. Most of the quartz is α-quartz, with a considerable portion having self-shaped granular morphology. Some quartz is intergrown with sericite, while others are associated with pyrite or other minerals as cement.
(4) Sericite
Sericite in the sample forms fine-grained, flaky aggregates. It is a major component in the cementing material of quartz particles, and a few sericite grains are closely associated with iron dolomite.
Based on ore dressing reagent experiments, the activating agent used is lead nitrate with a dosage of 400 g/t; the collecting agent used is M7 reagent, with a roughing dosage of 200 g/t; the dispersant is hexametaphosphate, with a dosage of 200 g/t.
Determination of Grinding Fineness:
Using a "1 Roughing, 1 Scavenging" process with lead nitrate (400 g/t), M7 (200 g/t), and pine oil (40 g/t) under roughing conditions, the impact of grinding fineness on the indicators of coarse and scavenger antimony concentrates was investigated. As grinding fineness increased, the antimony recovery rate in the coarse and scavenger concentrates gradually increased. However, when the content of particles finer than -0.074 mm exceeded 74.56%, the grade of the antimony concentrate decreased significantly, with minimal improvement in antimony recovery rate. Therefore, the appropriate grinding fineness is when particles finer than -0.074 mm account for 74.56%.
Determination of Flotation Process:
(1) Open Circuit Test
Using a "1 Roughing, 2 Scavenging" process, the cumulative antimony recovery rate reached 94.41%. After three stages of scavenging, the antimony concentrate grade reached 43.99%, with an antimony recovery rate of 78.26%.
(2) Closed Circuit Test
Under the condition of a grinding fineness of -0.074 mm accounting for 74.56%, using sodium hexametaphosphate as the dispersant, lead nitrate as the activating agent, M7 as the collecting agent, and pine oil as the foaming agent, a "1 Roughing, 3 Cleaning, 2 Scavenging" closed-circuit flotation process was employed. This yielded an antimony concentrate with a grade of 35.30% and an antimony recovery rate of 93.52%.
