Combined separation process of demagnesiumization, classification and desiliconization of low-grade collophosphate

Abstract

The present invention relates to a combined demagnesing, grading, and desiliconization process for low-grade collophosphate ore. The ground phosphate ore pulp is introduced into a pre-flotation process for demagnesing to obtain demagnesed concentrate and demagnesed tailings. The demagnesed concentrate is subjected to gravity separation and classification using a non-standard spiral chute separator dedicated to phosphate ore. The physical difference in the specific gravity of apatite and ferroaluminosilicate in the ore is utilized to separate the demagnesed concentrate into high-grade coarse-gravity roughing concentrate and gravity roughing tailings. The gravity roughing tailings are directly introduced into a gravity sweeping operation to separate low-grade fine-gravity tailings and gravity mide. The gravity mide and gravity roughing concentrate are combined into gravity concentrate. The gravity concentrate enters a separate flotation process I for desiliconization to obtain concentrate I and tailings I. The gravity tailings enter a separate flotation process II for desiliconization to obtain concentrate II and tailings II. The technical solution of the present invention can obtain high-quality concentrate I with a P2O5 grade of ≥32.5%, a total concentrate P2O5 grade of ≥31%, and a recovery rate of ≥80%.

Claims

1. A combined separation process for demagnesiuming, grading and desiliconization of low-grade collophosphate, characterized in that: The following steps are involved: (1) The ground phosphate slurry is introduced into the pre-flotation process for demagnesiumization to obtain demagnesiumized concentrate and demagnesiumized tailings; (2) introducing the demagnesized concentrate obtained in step (1) into a gravity roughing operation for classification, separating to obtain a high-grade coarse-grained gravity roughing concentrate and a gravity roughing tailings, introducing the slurry of the gravity roughing tailings into a gravity sweeping operation for classification, separating to obtain a gravity tailings and a gravity middling, and combining the gravity middling and the gravity roughing concentrate into a gravity concentrate; (3) The gravity concentrate obtained in step (2) is diluted with water and then introduced into a separate flotation process I for desiliconization to obtain concentrate I and tailings I. The gravity concentrate needs to be diluted with water before entering the flotation process I to adjust its concentration to 25-35wt%; the desiliconization collector added in the flotation process I is a cationic collector N-(2-hydroxy-1,1-dimethylethyl) dodecylamine; (4) The gravity separation tailings obtained in step (2) are thickened and introduced into a separate flotation process II for desiliconization to obtain concentrate II and tailings II. The gravity separation tailings need to be thickened before entering the flotation process II, and their concentration is adjusted to 20-30wt%. The desiliconization collector added in the flotation process II is a cationic collector N-(2-hydroxy-1,1-dimethylethyl) dodecylamine and a non-ionic surfactant dehydrated sorbitan oleate and any one of C7-C9 high carbon fatty alcohols in a mass ratio of 50-60:10-25:8-15.

2. The combined separation process of demagnesiuming, grading and desiliconization of low-grade collophosphate according to claim 1, characterized in that: The collophanite is a low-grade calci-silico collophanite, in which the P2O5 grade is lower than 27 wt %. The collophanite is mainly composed of three types of minerals: phosphate, dolomite and silicate minerals.

3. The combined separation process of demagnesiuming, grading and desiliconization of low-grade collophosphate according to claim 1, characterized in that: The pre-flotation operation in step (1) is a closed-circuit process of single reverse flotation, one roughing and one scavenging, one roughing stage with drug addition, and scavenging without drug addition, so as to realize the slurry of demagnesized concentrate and control the slurry concentration at 15-25wt% by adding the amount of flushing water.

4. The combined separation process for demagnesing, grading and desiliconization of low-grade collophosphate according to claim 1, characterized in that: The equipment used in the gravity separation operation in step (2) is a spiral chute with a diameter of 0.9-1.2 meters, a moment-to-diameter ratio of 0.32-0.34, and a screw pitch of 0.38-0.42 meters. The concentration of the ore pulp entering the chute needs to be controlled between 20-60%.

5. The combined separation process of demagnesiuming, grading and desiliconization of low-grade collophosphate according to claim 1, characterized in that: In step (2), the demagnesium concentrate framework is introduced into the gravity roughing operation for classification, and is separated into high-grade coarse-grained gravity roughing concentrate with a P2O5 grade of ≥28% and +0.074mm 50-60wt% and gravity roughing tailings; The slurry of the gravity separation roughing tailings is introduced into the gravity separation sweeping operation for classification, and the low-grade fine-grained gravity separation tailings with P2O5 grade ≤23%, -0.074mm80-90wt% and gravity separation middlings are separated.

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