I. Introduction

Type manganese ores of manganese carbonate in the main, 73% of the total reserves. The grade of this type of ore is very low. Generally, the grade of Mn is below 20%. Most of them are marine sedimentary and sedimentary metamorphic manganese deposits, with reserves of 39.336 million tons, mainly distributed in Yunnan, Sichuan, Hunan, Hubei, Guangxi and other provinces ( Area). Among them, the reserves of high- phosphorus manganese ore are 238.851 million tons, accounting for 60.61%. The research on enrichment and phosphorus reduction of manganese carbonate ore has been paid attention to.

2. Beneficiation of high phosphorus and low manganese manganese carbonate ore

China's manganese ore has formed a relatively complete industrial system in the selection and smelting. At present, the main methods for enriching manganese ore are re-election, magnetic separation, flotation, and enrichment by fire, or a combination of several methods. Manganese carbonate ore is mainly flotation, sometimes accompanied by re-election and strong magnetic separation. The manganese ore in a certain area of ​​Shaanxi is a high-phosphorus and low-manganese manganese ore. The ore contains low manganese (11%), high impurity phosphorus (1.10%), manganese minerals mainly manganese carbonate, and manganese oxides are rare. Manganese carbonate minerals include manganese dolomite, rhodochrosite, and manganese calcite , which account for 67.20%. Among them, mainly manganese dolomite, rhodochrosite accounts for about 8%, and manganese calcite is rare. Manganese dolomite is mainly composed of granular and vein aggregates, with a vein diameter of 0.085 to 0.1455 mm and a granular particle size of 0.0291 to 0.0485 mm. The rhombohedral ore is spherical or ring-shaped, and contains quartz fine particles or carbonaceous and shale, and the particle size is mostly in the range of 0.0485 to 0.194 mm. The gangue minerals are quartz, dolomite, calcite and the like. The harmful impurities are colloidal phosphate, which has the biological structure of mollusks, such as bryozoans and ostracods, and is connected with quartz and manganese dolomite as vein aggregates, resembling opal, crack cleavage, and cleavage along cracks. It is replaced by calcite, with a particle size of 0.1455-0.0813 mm and a small amount of fine-grained apatite. The results of multi-element analysis of raw ore are shown in Table 1, and the results of phase analysis of manganese are shown in Table 2.

Table 1 % of multi-element analysis of mines

Table 2 Results of phase analysis of ore manganese

Cuien Jing, any gold ju ^[1] according to the characteristics of the ore, the comparison test Desliming desliming and not, classification and dry classification is not strong magnetic separation schemes, identified by desliming - grade - magnetic separation process. The wet magnetic separation scheme was used to recover the manganese in the 22.59% of the slime, and the manganese concentrate with a yield of 44.01%, manganese content of 18.41% and phosphorus of 0.31% was obtained. The manganese recovery rate reached 71.16%.

The grading dry strong magnetic separation can remove about 67% of the phosphorus in the ore, that is, the content of manganese in the magnetic separation concentrate can be increased to 18.41%, and the phosphorus can be reduced to 0.31%, which has reached the grade requirement of the fifth-grade manganese concentrate. If we want to increase the grade of manganese and reduce the phosphorus to below 0.2%, it is still a problem that is difficult to solve by this method.

The raw ore milled to -74 wilt 5 accounted for 65%. After deliming, the coarse sand and the slime were separately subjected to wet strong magnetic separation to obtain a product containing 17.14% manganese, a recovery rate of 63.03%, and a phosphorus content of 0.41%.

The experiment also carried out neutral calcination, chemical phosphorus removal research. The conditions of the baking time and temperature were tested in a box muffle furnace. The grade is increased to 26% to 28%, and the phosphorus content is also increased to 0.43% to 0.53%. According to the chemical properties that manganese oxide is not easy to react with dilute sulfuric acid, and phosphorus is easily dissolved by dilute acid, a dilute sulfuric acid leaching phosphorus removal test is carried out. Acid leaching is carried out under mechanical agitation. When the sulfuric acid concentration is 6%, the leaching time is 60-90 min, and the solid-liquid ratio is 1:7 to 1:15, the manganese concentrate grade is increased to 30% to 33%, and the phosphorus is lowered. Below 0.2%, the purpose of removing phosphorus and improving the grade of manganese concentrate is achieved.

Third, the low-grade refractory manganese ore dressing test in a certain place

Yu Xinwen, Yang Xiaojun ^[2] conducted a beneficiation test on a low grade refractory manganese ore. Rhodochrosite primary metal minerals pyrolusite, water (brown) manganese, magnetic iron pyrite and other gangue minerals quartz, dolomite, clay minerals, followed by chlorite, sericite, epidote Stone, biotite, etc.

The ore manganese grade is 17.61%, manganese is mainly contained in manganese carbonate, the occupancy rate is 74.96%, followed by pyrolusite and water (brown) manganese ore. The rhombohedral ore is formed into a granular shape with a fine particle size, generally -0.03mm, which is a micro-mudling rhombohedral ore, which is composed of a strip of rhodochrosite. The strips have different shades of brown and red, and have a certain direction. Sexual, nearly parallel. It is closely symbiotic with minerals such as quartz, dolomite, chlorite and sericite. The ore is mainly composed of a strip-like structure, followed by a star-sparse-sparse disseminated structure. The structure is dominated by micro-mud structure, followed by his granular structure and self-shaped semi-automorphic granular structure.

The results of manganese phase analysis of the ore: 74.96% manganese in manganese carbonate; 8.80% manganese in pyrolusite; 8.35% manganese in water (brown) manganese ore; 3.63% manganese in manganese silicate; 4.26% manganese.

The particle size composition of the ore is shown in Table 3.

Table 3 ore size composition %

When the ore fineness -74μm accounts for 91%, the YL-1 collector is used . After one rough selection, one sweep, and three selected closed-circuit processes (see Figure 1), the yield is 57.89%. 23.35% manganese recovery with a recovery rate of 76.58%.

Figure 1 closed circuit test process

Through flotation, the manganese concentrate grade was increased from 17.61% to 23.35%, and manganese minerals were effectively enriched. There is no mention of the sorting effect of phosphorus, but the manganese concentrate is further subjected to neutral calcination to obtain a concentrate product containing Mn 30.55%; Fe 6.81%; P 0.14% of metallurgical manganese ore A5 grade standard.

Due to the influence of impurity phosphorus, the low-phosphorus manganese carbonate ore beneficiation enrichment, neutral roasting, manganese oxide concentrate, impurities meet the smelting requirements, suitable for use in the steel industry; high-phosphorus manganese carbonate ore by ore enrichment, the obtained manganese concentrate It is more suitable as a raw material for manganese sulfate or electrolytic manganese, and sometimes it is not used directly by enrichment.

Fourth, the practice of mineral processing of Guangxi Daxin mine

(1) History of research on manganese ore dressing in Daxin, Guangxi, China. The structure of the ore is fine particles (particle size is generally -5 μm), composed of particles and veins, the particles are in the form of a ruthenium, and the rubber structure is fine-grained carbonate. Minerals, black hard chlorite, chlorite, quartz, hematite, mica, etc. The structure is mainly layered, stratified, cowpea or block. The ore is high-silicon, low-phosphorus, low-iron manganese ore mainly composed of rhodochrosite and calcium rhodochrosite. The main minerals are rhodochrosite, calcium rhodochrosite, manganese calcite, lithium- containing calcite, limonite, magnetite, and the main gangues are quartz, chlorite, mica, etc. ^[3] . The main chemical components of the ore are shown in Table 4. The preliminary study on the ore dressing test of the Lower Manganese Mine by various research institutes before 2000 is shown in Table 5.

Table 4 Main chemical composition of ore%

Table 5 Results of ore dressing test of Xiaoxi manganese mine by various scientific research institutes

From the above test results, before the 1992 Maanshan Mine Research Institute and other research institutes conducted magnetic, heavy, floating single or joint sorting process tests, but no matter which method of mineral processing is adopted, the concentrate grade is not high, and only The geological grade of the original ore is slightly higher, and the recovery rate is not satisfactory. It can be seen that the ore is a type of refractory ore ^[4] .

(II) New progress in the beneficiation of Guangxi Daxin Xialing Manganese Carbon Mine In 2001, the comprehensive index of the single strong magnetic separation test jointly conducted by the Daxin Branch Research Institute and the Changsha Research Institute of Mining and Metallurgy was good. The concentrate was restored to the original geological grade and the metal recovery rate. Also better ^[4] . The plant was technically modified, and the permanent magnet separator developed by Changsha Research Institute of Mining and Metallurgy replaced the original CS-1 magnetic separator to select manganese carbonate.

The process flow of this design is determined as follows: the broken part is a three-stage one closed process, and the double-layer sieve is used for wet screening, and the mesh holes are 20 mm and 7 mm. The ore size is -450mm, the product size is 20~7mm for coarse concentrate and 7~0mm for fine concentrate. Strong magnetic separation process: 20~7mm grain size is pre-roughed by dry permanent magnet selection, qualified coarse grain concentrate is selected, and the tailings return to the fine crushing and -7mm grain size of the crushing system to enter the main plant for fine graining. The grade wet-type permanent magnets were selected by a coarse sweep and selected to obtain a -7mm fine-grained concentrate and a sweeping tailings.

The 600,000 t/a manganese carbonate plant was completed and put into production at the end of August 2006, reaching a raw ore processing capacity of 50.26 t/h. Raw ore grade Mn 18.17%, Mn ^{2 +} 14.62%, total concentrate grade Mn 21.52%, Mn ^{2 +} 17.82%, tailings grade Mn 5.13%, Mn ^{2 +} 2.89%; the total concentrate yield is 79.56%, and the ore dressing metal recovery rate is 94.23%.

V. Conclusion

The beneficiation of manganese carbonate ore was put into production with Guangxi Daxin 600,000 t/a manganese carbonate selection plant, and the good ore dressing index of manganese concentrate grade Mn 21.52%, total concentrate yield 79.56%, and ore dressing metal recovery rate of 94.23% was obtained. The mineral processing technology has been improved unprecedentedly, and it has leapt to a new level and entered the world.

The separation of phosphorus in manganese carbonate ore has been concerned by people. Although it can be dephosphorized by physical beneficiation or chemical method, the cost, process and manganese loss are its limitations, and no substantial breakthrough has been made. . In recent years, the bioleaching method has made great progress in the field of heavy metal sulfide ore. The research on phosphorus reduction in manganese carbonate ore has just started, and it is expected to further strengthen the experimental research.

references

[1] Cui Enjing, Ren Jinju, et al. Experimental study on phosphorus removal by high phosphorus and low manganese refractory ore removal[J]. Nonferrous Metals (Selection Part), 2004(3): 36~39.

[2] Yu Xinwen, Yang Xiaojun, et al. Experimental study on ore dressing of low grade refractory manganese ore in a certain area[J]. Nonferrous Metals (Selection Part), 2007(3): 15~17.

[3] Li Guiliang, Liu Chunjie. Development and Utilization of Manganese Carbonate Mineral Resources in Guangxi Daxin Manganese Mine[J]. China Manganese Industry, 1999(1): 16~19.

[4] Huang Guanhan, Nong Delian, et al. Design and production practice of 600,000 t/a manganese carbonate plant in CITIC Dameng Mining Co., Ltd. [J]. China Manganese Industry, 2007 (4): 48-50.

Compared with the castings, metal after forging processing can improve its organizational structure and mechanical properties. Casting organization after forging method of thermal deformation due to metal deformation and recrystallization, make original bulky dendrite and columnar grain to grain is fine and uniform axial recrystallization organization, make the ingot in the original segregation, porosity, porosity, slag compaction and welded, such as its organization become more closely, plasticity and mechanical properties of the metal.