Direct flotation inhibits gangue minerals by effective inhibitors, and the phosphorus mineral is enriched in foam by collecting agent. This process is suitable for low grade phosphate ores including magmatite type apatite and sedimentary metamorphic type phosphorite ore
Mainly used for the separation of phosphate and dolomite; dolomite is collected with fatty acid collector in weak alkaline medium, and the phosphorus mineral is enriched in the groove. The biggest advantage of reverse flotation process is the realization of the normal temperature flotation.
In alkaline conditions, double-reverse flotation makes the silicate surface positively charged, and the anionic collector separates minerals meaning floating dolomite firstly, and then reverse floating silicate; the product is heavy concentrate in groove; the production line can be carried out at normal temperature and coarse grain condition.
A phosphorite in Yunnan belonged to low grade siliceous and calcareous collophanite with fine particles and close distribution of useful minerals and gangue minerals. The plant adopted flotation and reverse flotation process, but there were some defects in the flotation reagent dosage and high temperature. In order to reduce the cost, the plant authorized Xinhai to take technical reformation. Xinhai used the double reverse flotation for phosphorite after the test. Xinhai achieved 40% concentrate grade when the crude ore grade was 18.55%. Indexes comparison as follow:
|Comparison of Reformation||Process||Grade of Phosphate Concentrate /%||Recovery Rate of Phosphate Concentrate /%|
|Before Reformation||Flotation and Reverse Flotation Process||29.74||70.27|
|After Reformation||Double-Reverse Flotation Process||32.58||72.18|
By this technical reformation, the technology principle was more reasonable; the non-alkali process, no pollution to the environment; the normal temperature condition could effectively reduce the cost.