Reverse flotation to remove hematite from quartz sand ore

I. Introduction

Industrial minerals such as quartz sand, porcelain clay and feldspar are often associated with iron oxides that weaken the transmission in the fiber, affecting the transparency of your glasses, discoloring ceramics and lowering the melting point of refractories. Iron content can be reduced to a level using physical or physicochemical, chemical methods, the most appropriate severe damage method, based on the mineral form and the distribution of iron concentrate in the ore. Batch flotation is an effective separation method commonly used to separate hematite from quartz sand ore. Batch batch flotation machines have been widely used to investigate the impact of various operating parameters on flotation performance. Most of the flotation studies so far, especially regarding reagent selection, have been implemented so intensively. This is mainly because batch flotation experiments are a way to evaluate mineral flotation responses in a variety of operating conditions in a fast and inexpensive manner. In addition, evaluating the effects of changing flotation variables is easy to implement for batch data fitting dynamics ratio equations. The design and operating angles are important for this flotation dynamics model, providing the basis for simulating industrial flotation loops and obtaining different rate equations. However, which function differs in the work is more suitable for representing actual data, especially for a wide range of flotation conditions. Many parameters are used to model and simulate the flotation loop for batch flotation testing. The aim of the study was to explore the use of a batch of small sand experiments in a hematite process in the reverse flotation separation of silica and a laboratory mechanical flotation device for research and development commonly used in industry. Kowli-Kosh Silica (located in Fars Province, southwestern Iran) was selected as a feasibility study for possible use in the glass industry. The effects of different operating parameters, such as the type and concentration of the collector, the type of acid, the pH, the adjustment time, the concentration of the sand, the particle size and the temperature, were studied as the efficiency of the reverse flotation separation. Data analysis will be used to determine the change in the efficiency of hematite reverse flotation separation for different experimental parameters and can be used to determine the kinetics of the separation.

Second, the experiment

A large amount of quartz sand (silica sand) was taken from the Kowli-Kosh quartz sand mine and then reduced in hematite by a reverse flotation process. The composition of the original sample was 97.38% SiO2 and 0.213% Fe2O3, as well as trace amounts of Al2O3, CaO, MgO, Na2O, K2O, TiO2. In order to remove the hematite from the quartz sand ore, the sample is first finely pulverized and cleaned using a milling machine, and then the particle size is graded and used in the flotation cell. Four different particle sizes were separated from 150 to 840 um and were selected for reverse flotation experiments. The schematics and diagrams of this Denver flotation cell used in this study are shown in Figures 2(a) and (b), respectively, in each test, a given number of a certain range of particle size distributions of quartz sand and The amount of tap water required is mixed in the flotation cell and given the number of revolutions of the agitation. Set the pH and add the required amount of collector to facilitate the separation. The foaming agent (65) was added while the system was allowed to mix and mix for 6 min as the conditioning time (optimal pulping time was 5-6 min) after which air entered the bubble through the rotor at the bottom of the tank. The air flow is regulated by a needle valve that is used to control the speed of the suspended agitator of the particle system. The flotation will last for 8 minutes, during which time the foam is manually removed from the level of the flotation cell. Make up the water added to the tank to compensate for the system's displacement and maintain the solids ratio. The purified quartz sand was collected at the bottom of the tank and analyzed for hematite content by washing, drying, weighing and atomic absorption spectrometry (A-10, Varian Australia). Block diagram for hematite removal proccss Special care is taken to select the appropriate ore hematite collector, which does not interfere with the hydrophobicity of the quartz particles. In the current work, a mixture ratio of AERO-801 and AERO-825 was found to be a suitable condition for flotation of hematite gangue at pH = 2.5. The performance of the enhanced flotation in front should have an appropriate particle size, proper bubble distribution, which will bring hematite particles to the interface at the upper part of the tank. In the current study frother-65 was used to promote separation. Experimental data indicates that the optimum concentration of this blowing agent is 15 ppm.

Third, the results and discussion

(I) Removal efficiency In this study, the flotation method was used to evaluate the removal efficiency of hematite, expressed as η, as defined below: Ci and Cf are the concentrations of the starting and final hematite in the quartz sand ore, respectively. The effect of pulping time on hematite removal efficiency is shown. The pulping time of 5-6 minutes as shown results in the highest removal efficiency of hematite. Prolonged time may cause the collector to separate from the surface of the hematite or the adsorption of some of the collector due to the presence of Ca2+ and Fe2+ quartz particles in the water, which may result in a decrease in hematite removal efficiency. . The water content of the floating mixture is an important factor in the removal efficiency. The effect of concentration of solids in the slurry on the removal efficiency of hematite is shown. It can be seen that the removal efficiency of hematite decreases linearly with the increase in the weight percentage of the solid slurry. This may be due to the fact that the bubbles that are stripped from the particle surface simultaneously increase the slurry concentration and reduce the number of bubbles for a given air flow rate. It is worth noting that although the decrease in η with the slurry concentration is small, this is the result observed in repeated experiments.

The experimental results show that the type of acid and the cooperation of the working temperature of the tank have an important influence on the removal efficiency of hematite. Figure 5 indicates that a substantial increase in the performance of the tank is related to the temperature at which the acid is present. However, H2SO4 achieves higher removal efficiency earlier than HCl at low temperatures to 55 degrees Celsius. On the other hand, the use of HCl at high temperatures allows the tank to achieve better performance. The amount of collector in the separation of quartz weight ratio and removal efficiency. This chart shows that as the amount of collector increases, more hematite is separated from the quartz sand. However, when the amount of the collector exceeds 1.5 g/kg of quartz sand in the tank, the removal efficiency becomes inefficient.

It can be clearly seen that PH=2.5 is most suitable for the flotation process. Under the optimal process conditions, H2SO4 and HCl are 0.022% and 0.0185%. The iron content of the quartz sand product obtained under the respective environmental conditions is suitable for any glass except optical glass.
(II) Dynamics Modeling Dynamics modeling is very important for the flotation process. From the design and operation point of view, it provides the basis for the simulation of industrial flotation lines. The stepwise separation of hematite from the slurry is the result of hematite being transferred from the selected particles of the slurry to the foam and transferred to the foam. The effect of the foam on the overall reaction of flotation kinetics can be determined by a simple method that does not distinguish between the mixing and foaming stages. This is a traditional approach that is suitable for most batch flotation studies. The change in removal efficiency due to the distribution of different particle sizes in the flotation cell according to the change in time is shown. As the particle size decreases, the removal efficiency increases. This is reasonable because small-sized particles are more likely to float due to the lighter weight and the hematite contained that are more susceptible to exposure and separation.

In batch flotation systems it is generally assumed that the overall flotation reaction of different ores can be described as a concentration (aggregate) of floating minerals on a first-order process. However, here the flotation kinetics are planned based on the nth process and have the following equations: where dCHm/dt represents the rate of change of hematite concentration over time, k is the flotation rate constant and n It is the assumed order. How to determine the values ​​of k and n are based on experimental data and competing lines plotted on different particle size distributions as shown in FIG. A nonlinear least squares regression is used to determine the n and k values. The experimental data obtained from the current flotation experiments can best match the curve of the first-stage flotation rate versus time determined by each particle size range of flotation.

Fourth, the conclusion

The hematite is reversely floated from a batch of quartz sand ore that has been used locally using laboratory mechanical flotation cells. Quartz sand samples of known size are known to be mixed with tap water and the required amount of Aero-8 collector and acid are added to the mixture. Control flotation at the specified airflow rate and agitation level. The effects of various operational parameters including the type and concentration of the collector, the type of acid, pH, pulping time, solids concentration, particle size distribution and temperature were all studied in the reverse flotation. The following conclusions can be drawn from the experimental results.

a. The best collector concentration was found to be 1.5 g/kg quartz sand.

b. The performance of the tank is improved in the presence of sulfuric acid and hydrochloric acid, whereas the effect of sulfuric acid at a low temperature of 55 degrees Celsius is more pronounced, and hydrochloric acid exhibits a better effect when it is greater than 55 degrees Celsius.

c. The optimum pH of the process is 2.5 when using H2SO4.

d. The first-order kinetics of hematite removal from quartz sand is obtained over a wide range of particle size distributions.

e. The best slurry reaction time is 4-6min f. The solid slurry ratio is preferably not more than 30%.

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