RU2353678C1 - Pellet method of sulfide of molybdenite concentrate - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to pelleting of sulfide molybdenite concentrates granulations before oxidising roasting. Pelleting is implemented with addition of binding component - water solution of corn syrup with consumption of corn syrup, which is 3.0-4.0 kg per 100 kg of molybdenite concentrates. Additionally corn syrup contains 36-44% mono - and disaccharides.

EFFECT: receiving of pellets with strength >300 g/pel with using of organic binding, thoroughly decay during the process of oxidising roasting.

4 tbl, 3 ex

Description

The invention relates to the pelletization of ore raw materials, in particular to the granulation of sulfide molybdenum concentrates before metallurgical processing.

Pelletization of ore materials before metallurgical processing is widely used in the production of ferrous and non-ferrous metals [V.I. Korotich. Theoretical Foundations of Pelletizing Iron Ore Materials. M.: Metallurgy, 1966, 312 pp.]. This allows to significantly reduce the dust extraction of the starting products, increase the productivity of the units and ensure the optimal composition of the charge components. Various inorganic and organic reagents are used as binders, such as soda ash, lime, sodium or potassium chlorides, vitriol, alkaline alcohol stillage, waste from the chemical or food industries, etc. [N.I. Meshcharekova. Production of iron ore pellets with organic binders. Express information. Black metals. M .: Chermetinformation, 1985, issue 25, 16 pp.].

The closest technical solution is the pelletizing of molybdenum concentrate before oxidative firing in fluidized bed furnaces using bentonite [A.N. Zelikman. Metallurgy of refractory rare metals. M .: Metallurgy, 1986, 440 p. (pp. 104-105)]. The process is used for oxidative firing of finely dispersed concentrates and unoxidized dusts of dust and gas collection systems (the so-called "cyclone dust"). According to this method, the recommended composition of the charge for pelletizing is as follows: 5-6% bentonite + 11-14% water + the rest is molybdenite concentrate and cyclone dust with an oxidation state of ~ 90%.

Hardware rolling was carried out in a plate granulator with a working angle of 44-48 ° and a stirring speed of 7 to 40 rpm.

The described technique allows to reduce dust removal from 70 to 38% and increase the overall oxidation state of molybdenum cinder to> 99%. Moreover, the oxidation state of cyclone dust increases to ~ 94%, against ~ 70% during oxidative roasting of non-granulated concentrate under comparable conditions. Specifications for dry pellets from molybdenite concentrate are given in table 1.

Table 1. Specifications for molybdenum concentrate pellets. Controlled parameter Dimension Indicator The average size of the pellets mm No more than 4 The number of pellets class - 0.2 mm % No more than 20 Humidity % Less than 13-14 Strength g / approx. Not less than 300

The disadvantage of this method is the dilution of molybdenum cinder due to bentonite containing oxides of silicon and aluminum, which therefore does not decompose during heat treatment of raw materials. This leads to a decrease in the total concentration of molybdenum in the cinder, reduces the productivity of the furnace and affects the efficiency of subsequent leaching of the cinder with solutions of ammonia or soda. It is believed that due to the addition of bentonite to pelletizing, the loss of molybdenum with dump cakes of the hydrometallurgical redistribution increases by 0.05-0.06%.

The technical problem solved by this invention is to replace bentonite with an organic binder, which will completely decompose in the process of oxidative firing. This is achieved by using corn syrup as a binder component, containing 36-44% of mono- and disaccharides and is an alternative reagent to bentonite. At the same time, the quality of the obtained molybdenite pellets corresponds to the quality of the bentonite pellets (basic process) and meets the existing technical conditions (Table 1). It should be emphasized that corn syrup is an affordable and cheap reagent and its production is established in an industrial environment when processing technical varieties of corn in starch plants and other similar enterprises.

The essence of the invention lies in the fact that the rolling process of the molybdenum concentrate is carried out with corn syrup at a flow rate of the binder component of 3.0-4.0 kg of molasses per 100 kg of charge from Mo-concentrate.

Table 2 gives comparative data on the strength of molybdenum pellets obtained using various binders (water, sulphite-alcohol stillage, corn syrup, bentonite), and table 3 shows the technical conditions for corn syrup and its typical composition.

table 2 Strength of pellets of molybdenite concentrate using various binders (pellet size 2-3 mm). Binder component Bond consumption in kg per 100 kg of Mo-concentrate The strength of the pellets of natural drying at 22 ° C for 24 hours, g / approx. The strength of the pellets dried at 100 ° C for 3 hours, g / ok water fifteen 30-40 50-60 Water + bentonite (10% solution) 6 300-350 350-400 Water + barda (10% solution) 1,5 40-50 70-80 Corn syrup (25% aqueous solution) 3 250-300 300-370

Table 3. Specifications and composition of corn syrup (per 100 g of product) Indicator Dimension Characteristic Appearance - Thick viscous liquid without extraneous taste and odor Color - Colorless to pale yellow Hydrogen indicator pH 4.0-6.0 The content of mono - and disaccharides g 36-44 Starch content g 35 Mass fraction of total ash % No more than 0.4 Water content g No more than 22 Sulfur dioxide content mg No more than 40 Microimpurities:
Calcium
Magnesium
Phosphorus
Iron mg 36
17
eighteen
0.1 Proteins, Fats g 0.3 Transparency - Opalescence allowed

From the data of table 2 it can be seen that the use of corn syrup provides sufficiently strong pellets comparable to the characteristics of the basic granulation process with bentonite. At the same time, it should be noted that with good recyclability of molybdenite concentrate, the use of just water or sulphite-alcohol stillage as binder does not allow to obtain pellets of the required strength.

Technical characteristics of dry molybdenite pellets obtained by pelletizing with a solution of corn syrup according to the above technology are given in table 4.

Table 4 Technical characteristics of dry molybdenite pellets obtained by pelletizing with a solution of corn syrup (10% sugar). Monitored parameters Dimension Indicator Pellet Size mm 2-3 Strength g / ok 300-370 Humidity % 11.5-12.4

Example 1

Molybdenite concentrate from the Erdenet deposit (Mongolia) enters pelletization, containing (in%): Mo 50.7 (~ 84% MoS ₂ ); SiO ₂ 6.6; Cu 0.70; P 0.02; As 0.01; Re 0.04, humidity + oil up to 8.0%. The particle size of the concentrate ranged from 0.5 to 5-6 microns. The mass of the 5-6 micron fraction was 75-80%. The average specific surface area of the concentrate particles, determined by the method of low temperature adsorption (BET), was 13.75 m ² / g.

Pelletization was carried out in a dish-shaped semi-industrial granulator, which is an inclined plate with a threshold. The diameter of the plate is 0.45 m, the working angle of inclination is ~ 45 °, the rotation speed is 40 rpm. The water consumption during rolling averaged 10-15%, which corresponded to the accepted industrial regimes.

The composition of the mixture: 6% bentonite + 11% water, the rest is molybdenum concentrate. The obtained pellets were dried at a temperature of 100 ° C for 3 hours.

The characteristics of bentonite pellets are as follows: 2-3 mm in size, strength 400 g / approx., Humidity 13%.

Example 2

Similar to example 1, but as a binding component used corn syrup containing 43% of mono - and disaccharides (corn starch).

The composition of the mixture: 4% corn syrup + 8% water, the rest is molybdenum concentrate. The pellets were dried at a temperature of 100 ° C for 3 hours.

The obtained pellets were characterized by the following indicators: size 2-3 mm, strength 370 g / ok., Humidity 12.4%.

Example 3

Similar to example 1, but as a binder component used corn syrup in example 2 containing 43% mono - and disaccharides.

The composition of the mixture: 3% molasses + 9% water, the rest is molybdenum concentrate. Pellets were dried in vivo for 24 hours.

The obtained pellets met the following indicators: size 2-3 mm, strength 300 g / approx., Humidity 11.5%.

The above examples prove the achievement of a positive result in the implementation of the proposed technical solution.

Claims (1)

The method of pelletizing sulfide molybdenum concentrates before oxidative firing granulation using a binder component, characterized in that as a binder component use an aqueous solution of corn syrup with a flow of corn syrup 3.0-4.0 kg per 100 kg of molybdenum concentrate, while corn molasses contains 36-44% of mono - and disaccharides.