Saw mud is a mixture of stone powder and water produced during the cutting and polishing of marble and granite.Many areas in northern of our country are important stone processing bases, and a large amount of saw mud is produced every year, and its stacking takes up a large area of land resources.The stone powder has a fine texture and is difficult to dispose of. It is easy to fly in the sky in strong wind, and flows into the river with rainwater in rainy days, causing serious environmental pollution.
The main gangue minerals in saw mud include feldspar, quartz, calcite, dolomite, amphibole, etc. The main metal minerals and impurities include iron silicate such as mechanical iron, magnetite, iron oxide, pyrite, and biotite.At present, the comprehensive utilization method of saw mud is mainly to produce concrete aerated bricks and make ceramic raw materials after removing impurities. The former has a large processing capacity and the latter has high economic benefits.
Beneficiation research
In this article, the comprehensive utilization and beneficiation test research is carried out for the representative saw mud in Jining area.The valuable minerals in the saw mud are feldspar, mechanical iron, magnetic iron, etc., and harmful impurities are limonite, biotite, muscovite, calcite, dolomite, hornblende, etc. The material size is uneven, the coarse particles are range from 1-4mm and some -0.037mm fine mud.Among them, the mechanical iron produced during the processing and the magnetic iron in the raw ore can be magnetically separated into iron concentrate products. After strong magnetic separation, iron-containing impurities such as limonite, biotite, and amphibole can be removed. Stone concentrate products, each section of magnetic tailings can be used as aerated bricks or cement materials, so as to achieve the purpose of comprehensive utilization.
1.Process flow determination
Combining the properties of the sawdust sample to determine the beneficiation process: the raw ore is sieved through 30 meshes-+30 mesh coarse-grain grinding to -30 mesh。
——-30 mesh mixed sample iron separation by drum magnetic separator + flat plate + vertical ring + vertical ring strong magnetic iron removal-the concentrate is classified into +300 mesh medium-grain feldspar concentrate products and -300 mesh fine mud ——The fine sludge is then used to remove iron twice through the electromagnetic slurry to obtain a fine powder-grade concentrate product.
2.Raw ore magnetic separation test
The raw ore was sieved with 30 meshes, and the analysis results are shown in Table 1.
Table 1. Result of Beneficiation and Screening Test
Grind the coarse-grained ore with a yield of 17.35% to -30 mesh, mix with the product under the sieve, and go through the conventional magnetic separation process of drum magnetic separator + flat plate + vertical ring + vertical ring. The process flow is shown in Figure 1, and the test results are shown in Table 2.
Figure 1. The process flow of conventional magnetic separation test of raw ore.
Table 2. Results of conventional magnetic separation test
The raw ore is screened + ore grinding + three-time iron removal conventional test process, and the middle and low-end concentrate products can be obtained with a yield of 92.57%, a Fe2O3 content of 0.525% and a whiteness of 36.15%.It should be considered to purify the fine-grained iron oxide and iron silicate in the fine mud with a fine medium, high-field electromagnetic slurry machine after classification.
3.Iron removal from fine mud slurry
The second concentrate of Lihuan is discharged from the fine sludge below -300 mesh through overflow, and the process of removing iron twice by the electromagnetic slurry machine is used to obtain the fine powder concentrate product. The process flow is shown in Figure 2, and the test results are shown in Table 3.
Figure 2. The process flow of the fine mud slurry iron removal test
Table 3. Iron removal index of fine mud slurry
After grading the Lihuan concentrate, the whiteness of the +300 mesh medium-grain feldspar concentrate increased from 36.15% to 56.49%, and the whiteness of the fine mud decreased to 23.07%. -300 mesh fine sludge is removed from the iron twice by the electromagnetic slurry, and a ceramic-grade fine powder product with a yield of 42.31% and a whiteness of 41.80% can be obtained.
3.Whole process test
Comprehensive test conditions and indicators to do the whole process test.
Figure 3. The whole process of sawing mud test process
Table 4. Test indicators for the whole process
Attachment: Biscuits temperature 1200℃
Saw mud ore is sieved + ground + weak magnetic separation + flat plate + vertical ring + vertical ring + grading electromagnetic slurry magnetic separation process to obtain iron ore with a yield of 0.32% and a TFe grade of 62.35%. With a yield of 38.56% and a whiteness of 54.69% of medium-grain ceramic grade feldspar concentrate products and a yield of 42.31% of whiteness of 41.80% fine powder ceramic grade concentrate products; the total yield of magnetic tailings is 18.81% , Can be used as raw material for aerated bricks.
This technological process allows comprehensive utilization of saw mud tailings, and can obtain higher economic benefits and social environmental protection significance.
Post time: Mar-04-2021