Estimation and Improvement of Recovery of Low Grade Copper Oxide Using Sulfide Activation Flotation Method Based on GA–BPNN

: Copper oxide ore is an important copper ore resource. For a certain copper oxide ore in Yunnan, China, experiments have been conducted on the grinding ﬁneness, collector dosage, sodium sulﬁde dosage, inhibitor dosage, and activator dosage. The results showed that, by controlling the above conditions, better sulﬁde ﬂotation indices of copper oxide ore are obtained. Additionally, ammonium bicarbonate and ethylenediamine phosphate enhanced the sulﬁde ﬂotation of copper oxide ore, whereas the combined activator agent exhibited a better performance than either individual activator. In addition, to optimize all of the conditions in a more reasonable way, a combination of the 5-11-1 genetic algorithm and back propagation neural network (GA–BPNN) was used to set up a mathematical optimization model. The results of the back propagation neural network (BPNN) model showed that the R 2 value was 0.998, and the results were in accordance with the requirement model. After 4169 iterations, the error in the objective function was 0.001, which met the convergence requirements for the ﬁnal solution. The genetic algorithm (GA) model was used to optimize the BPNN model. After 100 generations, a copper recovery of 87.62% was achieved under the following conditions: grinding ﬁneness of 0.074 mm, which accounted for 91.7%; collector agent dosage of 487.7 g/t; sodium sulﬁde dosage of 1157.2 g/t; combined activator agent dosage of 537.8 g/t; inhibitor dosage of 298.9 g/t. Using the combined amine and ammonium salt to enhance the sulﬁde activation efﬁciency, a GA–BPNN model was used to achieve the goal of global optimizations of copper oxide ore and good ﬂotation indices were obtained. ammonium salts as the activator to investigate the ﬂotation effect of copper oxide mineral. The dosage rates of the activator agent were 110, 220, 330, 440, 550, and 660 g/t, and the ratio between ammonium bicarbonate and ethylenediamine phosphate was 10:1. Further-more, the collecting agent, vulcanizing agent, and foaming agent dosages were 500 g/t, 1200 g/t, and 100 g/t, respectively. The grinding ﬁneness was − 0.074 mm accounting for 90%. The results are Figure


Introduction
Copper oxide is an important mineral resource, and studying the recovery of low grade copper oxide is of great importance for solving the problems of the shortage of copper resources and promoting its efficient utilization [1][2][3]. The recycling methods of copper oxide mainly include flotation, leaching, and dressing-metallurgy. Flotation is the most widely used copper recycling method [4][5][6]. Because of the hydrophilic nature of copper oxide minerals, vulcanizing agents are generally added to make the surface of sulfide minerals hydrophobic for flotation. However, most copper oxide ores are associated with copper sulfide minerals. The vulcanizing agent reacts on the interface of copper oxide and exhibits different degrees of inhibition on copper sulfide minerals [7,8]. Therefore, the development of effective activators is needed to solve these problems. On one hand, the sulfide concentration in the interface of copper oxide minerals should be increased, but on

Materials
The test core samples were taken from an undisclosed locati China. The particle size distribution of the undressed ore mineral largely showed a block, conglomeratic, and plate-type distribution the undressed ore is shown in Figure 1. It can be seen from Figure eral belonged to high-alkaline minerals. The gangue was mainly and quartz. The copper-containing minerals mainly consisted of m rite. The copper phase analysis results are presented in Table 1. It 1 that the total copper content, oxidation rate, and combination ra and 12.34%, respectively. These values showed that the oxidatio belonged to low-grade copper ore, which is difficult to oxidize. Ba it can be said that the sulfide flotation method can be used to eff mineral resources.  Some commonly used flotation reagents include sodium su ammonium bicarbonate (industrial-grade), ethylenediamine grade), isoamyl xanthate (industrial-grade), sodium hexameta grade), and sodium silicate (industrial-grade). The equipment us included an XMQ67 type ball mill produced by Wuhan prospec HG101-3 type electrothermal blower produced by Nanjing testi and XFD type small flotation machine produced by Jilin prospect  Some commonly used flotation reagents include sodium sulfide (industrial-grade), ammonium bicarbonate (industrial-grade), ethylenediamine phosphate (industrial-grade), isoamyl xanthate (industrial-grade), sodium hexametaphosphate (industrial-grade), and sodium silicate (industrial-grade). The equipment used in the current study included an XMQ67 type ball mill produced by Wuhan prospecting machinery, China, HG101-3 type electrothermal blower produced by Nanjing testing instruments, China, and XFD type small flotation machine produced by Jilin prospecting machinery, China.

Experiments
Ore mineral samples were crushed to −3 mm size using a laboratory crusher, and crushed samples were preserved for further use. A 500 g ore sample was taken for each test. After a certain period of grinding in a wet ball mill, the pulp was moved into an XFD-III flotation tank, which had a volume of 1.5 L. According to the dosing formulation system, the Processes 2021, 9, 583 4 of 14 reagent was selected and added to the mixture. As shown in Figure 2, the flotation process used was the "two roughing-one scavenging". The flotation reagents were matched with a certain solution concentration and were added directly to the pulp. In this work, sodium sulfide was used as the vulcanizing agent; ethylenediamine phosphate and ammonium bicarbonate and the combination of two kinds of activators were used as the activation agent; the collector was isoamyl xanthate; sodium hexametaphosphate and sodium silicate were selected as inhibitor agents; 2# oil was the foaming agent. The temperature was room temperature (298.15 K), and ultrapure water was used as the flotation water. Because of the limitation of process conditions, the influence of pH was not considered. After the flotation, the flotation concentrate was filtered using vacuum filtration, and then the filtrate was placed in a drying oven for drying. After drying, the filtrate was weighed and shrunk. Then, the sample of the copper grade in the concentrate was tested. Based upon the test results, the recovery was calculated. rocesses 2021, 9, x FOR PEER REVIEW process used was the "two roughing-one scavenging". The flotation r matched with a certain solution concentration and were added directly to th work, sodium sulfide was used as the vulcanizing agent; ethylenediamine p ammonium bicarbonate and the combination of two kinds of activators wer activation agent; the collector was isoamyl xanthate; sodium hexametaphos dium silicate were selected as inhibitor agents; 2# oil was the foaming agent ature was room temperature (298.15 K), and ultrapure water was used as water. Because of the limitation of process conditions, the influence of pH w ered. After the flotation, the flotation concentrate was filtered using vacuum then the filtrate was placed in a drying oven for drying. After drying, th weighed and shrunk. Then, the sample of the copper grade in the concentra Based upon the test results, the recovery was calculated.

Results and Discussion
Considering the low grade oxidized copper ore in Yunnan province (C single factor experiment was carried out to examine the changes in variou affect the flotation indices, and the amine activation effect of the ammon demonstrated.

Grinding Fineness
First, under different grinding conditions, the minerals were examine in flotation concentrate and recovery of copper grade. The ground partic 0.074 mm accounted for 70%, 75%, 80%, 85%, 90%, and 95% of the total gr respectively. Under the conditions of a fixed collecting agent dosage of 600 ing agent dosage of 1000 g/t, and foaming agent dosage of 100 g/t, the expe carried out. The obtained results are shown in Figure 3.

Results and Discussion
Considering the low grade oxidized copper ore in Yunnan province (China), first, a single factor experiment was carried out to examine the changes in various factors that affect the flotation indices, and the amine activation effect of the ammonium salt was demonstrated.

Grinding Fineness
First, under different grinding conditions, the minerals were examined for changes in flotation concentrate and recovery of copper grade. The ground particles finer than 0.074 mm accounted for 70%, 75%, 80%, 85%, 90%, and 95% of the total ground sample respectively. Under the conditions of a fixed collecting agent dosage of 600 g/t, vulcanizing agent dosage of 1000 g/t, and foaming agent dosage of 100 g/t, the experiments were carried out. The obtained results are shown in Figure 3.
It can be seen from Figure 3 that the content particles that are of −0.074 mm accounted for 90%, and 78.73% of the highest flotation recovery were obtained. When the grinding fineness was lower than 90%, the flotation index was not ideal, which was because of the insufficient dissociation of copper mineral, which could not be sufficiently increased. When the grinding fineness was higher than 90%, the flotation index decreased, which can be attributed to granular slime. Meanwhile, the sulfide ores containing copper was inhibited due to the addition of vulcanizing agent. The flotation concentrate copper grade first increased and then exhibited a decreasing trend, whereas it had the highest value for the grinding fineness of 85%. Therefore, the optimum grinding fineness for −0.074 mm was the one that accounted for 90%. in flotation concentrate and recovery of copper grade. The ground p 0.074 mm accounted for 70%, 75%, 80%, 85%, 90%, and 95% of the to respectively. Under the conditions of a fixed collecting agent dosage o ing agent dosage of 1000 g/t, and foaming agent dosage of 100 g/t, the carried out. The obtained results are shown in Figure 3.

Dosage of the Collecting Agent
The dosages of collecting agent tested were 200 g/t, 300 g/t, 400 g/t, 500 g/t, 600 g/t, and 700 g/t, and the grinding fineness was fixed at −0.074 mm accounting for 90% of the total ground sample. In addition, the vulcanizing agent dosage was set to be 1000 g/t, and the inhibitor agent dosage was 300 g/t. The foaming agent dosage was kept the same and had a value of 100 g/t. The single factor experiment for the collecting agent dosage was carried out, and the results are shown in Figure 4. cesses 2021, 9, x FOR PEER REVIEW It can be seen from Figure 3 that the content particles that are of −0.074 mm for 90%, and 78.73% of the highest flotation recovery were obtained. When fineness was lower than 90%, the flotation index was not ideal, which was be insufficient dissociation of copper mineral, which could not be sufficientl When the grinding fineness was higher than 90%, the flotation index decre can be attributed to granular slime. Meanwhile, the sulfide ores containing inhibited due to the addition of vulcanizing agent. The flotation concentrate c first increased and then exhibited a decreasing trend, whereas it had the high the grinding fineness of 85%. Therefore, the optimum grinding fineness for was the one that accounted for 90%.

Dosage of the Collecting Agent
The dosages of collecting agent tested were 200 g/t, 300 g/t, 400 g/t, 500 and 700 g/t, and the grinding fineness was fixed at −0.074 mm accounting fo total ground sample. In addition, the vulcanizing agent dosage was set to be 1 the inhibitor agent dosage was 300 g/t. The foaming agent dosage was kept t had a value of 100 g/t. The single factor experiment for the collecting agent carried out, and the results are shown in Figure 4. It can be seen from Figure 4 that the recovery rate of the oxide copper creased with an increase in isoamyl xanthate dosage, which was 500 g/t later, unaffected with changes in isoamyl xanthate dosage. The grade of flotation was gradually reduced with the increase in isoamyl xanthate dosage. Ther following single factor experiments, the dosage of isoamyl xanthate was ke g/t.

Dosage of Vulcanizing Agent
The dosage of vulcanizing agent is also an important factor for the flotat It can be seen from Figure 4 that the recovery rate of the oxide copper flotation increased with an increase in isoamyl xanthate dosage, which was 500 g/t later, and became unaffected with changes in isoamyl xanthate dosage. The grade of flotation concentrate was gradually reduced with the increase in isoamyl xanthate dosage. Therefore, in the following single factor experiments, the dosage of isoamyl xanthate was kept to be 500 g/t.

Dosage of Vulcanizing Agent
The dosage of vulcanizing agent is also an important factor for the flotation study of copper oxide ore. The experiments were conducted for sodium sulfide dosages of 400, Processes 2021, 9, 583 6 of 14 600, 800, 1000, 1200, and 1400 g/t. Furthermore, the collecting agent dosage was 500 g/t, and the foaming agent's dosage was 100 g/t. Additionally, the grinding fineness was −0.074 mm accounting for 90%. The experimental results are as shown in Figure 5. It can be seen from Figure 5 that when the sodium sulfide dosag recovery rate was the highest and reached a value of 79.83%%, which grade of 2.88%. Furthermore, the copper grade increased with an inc sodium sulfide. Additionally, when the sodium sulfide dosage was 120 rate was the highest. Therefore, in the following single factor experim sulfide dosage was set to be 1200 g/t.

Dosage of the Activation Agent
On one hand, the addition of sodium sulfide enhanced the interf of the oxidized ore, the hydrophobicity of the interface of the oxidizing tion effect of the oxidized ore. However, on the other hand, it inhibit which was detrimental to the flotation of sulfide ore. Therefore, the u was needed; an activator plays an important role in achieving an enh the ore and the reduction of sulfide for reducing the inhibitory effect. ylenediamine phosphate and ammonium bicarbonate were used indivi bination of these were used as combined amine and ammonium salt to of flotation on copper oxide minerals. Ethylenediamine phosphate is flotation activator, has a wide range of applications in industrial produ good results. First, the activation effects of ammonium bicarbonate an phosphate were explored. Six different dosage rates of ethylenediamin selected for the experiments. These dosage rates were 50, 100, 150, 20 The dosage rates for ammonium bicarbonate were 200, 300, 400, 500 Furthermore, the collecting agent dosage and foaming agent dosage w g/t, respectively. In addition, the grinding fineness was −0.074 mm ac It can be seen from Figure 5 that when the sodium sulfide dosage was 1200 g/t, the recovery rate was the highest and reached a value of 79.83%%, which corresponded to a grade of 2.88%. Furthermore, the copper grade increased with an increase in dosage of sodium sulfide. Additionally, when the sodium sulfide dosage was 1200 g/t, the recovery rate was the highest. Therefore, in the following single factor experiments, the sodium sulfide dosage was set to be 1200 g/t.

Dosage of the Activation Agent
On one hand, the addition of sodium sulfide enhanced the interfacial vulcanization of the oxidized ore, the hydrophobicity of the interface of the oxidizing ore, and the flotation effect of the oxidized ore. However, on the other hand, it inhibited the sulfide ore, which was detrimental to the flotation of sulfide ore. Therefore, the use of an activator was needed; an activator plays an important role in achieving an enhanced oxidation of the ore and the reduction of sulfide for reducing the inhibitory effect. In this study, ethylenediamine phosphate and ammonium bicarbonate were used individually, and a combination of these were used as combined amine and ammonium salt to examine the effect of flotation on copper oxide minerals. Ethylenediamine phosphate is as a copper oxide flotation activator, has a wide range of applications in industrial production, and achieves good results. First, the activation effects of ammonium bicarbonate and ethylenediamine phosphate were explored. Six different dosage rates of ethylenediamine phosphate were selected for the experiments. These dosage rates were 50, 100, 150, 200, 250, and 300 g/t. The dosage rates for ammonium bicarbonate were 200, 300, 400, 500, 600, and 700 g/t. Furthermore, the collecting agent dosage and foaming agent dosage were 500 g/t and 100 g/t, respectively. In addition, the grinding fineness was −0.074 mm accounting for 90%e, and the vulcanizing agent dosage was set to be 1200 g/t. The test results are as shown in Figures 6 and 7.
It can be seen from Figures 6 and 7 that both ammonium bicarbonate and ethylenediamine phosphate had a positive effect on sulfide flotation of copper oxide ore. Additionally, the dosage of ethylenediamine phosphate was obviously lower than that of ammonium bicarbonate. As low-dosage activators, the optimal dosages of ethylenediamine phosphate and ammonium bicarbonate were 150 g/t and 600 g/t, respectively. On the basis of a single-factor activator test, a dosage test was conducted on the combined activator (combination of amine and ammonium salts). The test selected a combination of amine and ammonium salts as the activator to investigate the flotation effect of copper oxide mineral. The dosage rates of the activator agent were 110, 220, 330, 440, 550, and 660 g/t, and the ratio between ammonium bicarbonate and ethylenediamine phosphate was 10:1. Furthermore, the collecting agent, vulcanizing agent, and foaming agent dosages were 500 g/t, 1200 g/t, and 100 g/t, respectively. The grinding fineness was −0.074 mm accounting for 90%. The results are shown in Figure 8. flotation activator, has a wide range of applications in industrial produ good results. First, the activation effects of ammonium bicarbonate an phosphate were explored. Six different dosage rates of ethylenediam selected for the experiments. These dosage rates were 50, 100, 150, 20 The dosage rates for ammonium bicarbonate were 200, 300, 400, 50 Furthermore, the collecting agent dosage and foaming agent dosage w g/t, respectively. In addition, the grinding fineness was −0.074 mm ac and the vulcanizing agent dosage was set to be 1200 g/t. The test resu Figures 6 and 7.   It can be seen from Figures 6 and 7 that both ammonium bicarbon diamine phosphate had a positive effect on sulfide flotation of coppe tionally, the dosage of ethylenediamine phosphate was obviously lowe monium bicarbonate. As low-dosage activators, the optimal dosages o phosphate and ammonium bicarbonate were 150 g/t and 600 g/t, respect of a single-factor activator test, a dosage test was conducted on the c (combination of amine and ammonium salts). The test selected a com and ammonium salts as the activator to investigate the flotation effec mineral. The dosage rates of the activator agent were 110, 220, 330, 440 The results presented in Figures 6-8 show that the dosage for the combination of amine and ammonium salts was significantly less than that for the individual salts (when used as activators). Additionally, the combined activation agent had an obvious effect on the flotation recovery of copper and exhibited more stringent requirements for the dosage. When the dosage was low, the activation effect was not obvious. At a high dosage rate, an obvious inhibitory effect was observed on the mineral. Jiang and Mao [12,13] studied the enhancement of copper recovery from pure mineral malachite through experiments using the combined ammonia-ammonium activator. The results showed that the combined ammoniaammonium activator (based on ethylenediamine phosphate and ammonium bicarbonate) exhibited better activation effects along with good synergistic effects. The results were in accordance with those obtained in the present study. Therefore, the dosage of 440 g/t was preliminarily selected for the combined activator agent to carry out further investigations.
(combination of amine and ammonium salts). The test selected a com and ammonium salts as the activator to investigate the flotation effe mineral. The dosage rates of the activator agent were 110, 220, 330, 44 and the ratio between ammonium bicarbonate and ethylenediamine p Furthermore, the collecting agent, vulcanizing agent, and foaming ag 500 g/t, 1200 g/t, and 100 g/t, respectively. The grinding fineness was − ing for 90%. The results are shown in Figure 8. The results presented in Figures 6-8 show that the dosage for t amine and ammonium salts was significantly less than that for the indi used as activators). Additionally, the combined activation agent had an the flotation recovery of copper and exhibited more stringent requireme When the dosage was low, the activation effect was not obvious. At a h obvious inhibitory effect was observed on the mineral. Jiang and Mao enhancement of copper recovery from pure mineral malachite through the combined ammonia-ammonium activator. The results showed that monia-ammonium activator (based on ethylenediamine phosphate and bonate) exhibited better activation effects along with good synergistic were in accordance with those obtained in the present study. Therefore

Dosage of the Inhibitor Agent
On the basis of the above test results, the ratio of sodium hexametaphosphate and sodium silicate was selected to be 1:1. The dosages were 100 g/t, 200 g/t, 300 g/t, 400 g/t, 500 g/t, and 600 g/t. Furthermore, the grinding fineness was kept the same as −0.074 mm accounting for 90%. The dosages of vulcanizing agent, combined activator agent, and collecting agent were 1200 g/t, 440 g/t, and 500 g/t, respectively. The results are shown in Figure 9.
ocesses 2021, 9, x FOR PEER REVIEW g/t was preliminarily selected for the combined activator agent to carry out furth tigations.

Dosage of the Inhibitor Agent
On the basis of the above test results, the ratio of sodium hexametaphosp sodium silicate was selected to be 1:1. The dosages were 100 g/t, 200 g/t, 300 g/t 500 g/t, and 600 g/t. Furthermore, the grinding fineness was kept the same as −0 accounting for 90%. The dosages of vulcanizing agent, combined activator agent lecting agent were 1200 g/t, 440 g/t, and 500 g/t, respectively. The results are s Figure 9. It can be seen from Figure 9 that the flotation recovery of the copper oxide reached a maximum value of about 300 g/t for the inhibitor. The addition of inhi improve the flotation recovery of the copper oxide ore; however, the effect w small. Furthermore, low and high dosages of the inhibitor showed an adverse the flotation recovery.
The results of single-factor tests showed that by controlling the grinding collecting dosage, sodium sulfide dosage, combined activator agent dosage, and It can be seen from Figure 9 that the flotation recovery of the copper oxide mineral reached a maximum value of about 300 g/t for the inhibitor. The addition of inhibitor can improve the flotation recovery of the copper oxide ore; however, the effect was quite small. Furthermore, low and high dosages of the inhibitor showed an adverse effect on the flotation recovery. The results of single-factor tests showed that by controlling the grinding fineness, collecting dosage, sodium sulfide dosage, combined activator agent dosage, and inhibitor dosage, better sulfide flotation indices of copper oxide ore can be achieved. Compared with the individual ammonium bicarbonate and ethylenediamine phosphate salts, the combined activator agent showed a better activating effect, and the dosage required was also lower than that of the individual ammonium bicarbonate. To optimize all of the conditions in a more reasonable way, the BP neural network and genetic algorithm were combined, and the results are discussed in the following section.

Prediction from the BP Neural Network
Five variables, namely, the (a) grinding fineness, (b) combined activator agent dosage, (c) sodium sulfide dosage, (d) collecting agent dosage, and (e) inhibitor dosage were selected as the input layer neurons for the BP neural network. Based upon this, the recovery rate of the oxide copper flotation concentrate was estimated as the output factor. In this way, based on the flotation concentrate recovery rate and operating conditions, the BP neural network prediction model was established. The input node number of the model was 5, and the output node number was 1. It is worth mentioning that when the input layer node was N, the hidden layer nodes were chosen to be 2 N + 1 [26][27][28]. Under these conditions, the identified single hidden layer BP network could accurately reflect the actual situation and could guarantee the accuracy of the network. Therefore, the hidden layer neurons were set to be 11 [29,30], and the BP neural network structure was set to be 5-11-1, as shown in Figure 10. MATLAB (MathWorks, Massachusetts, United States) was used to carry out the numerical calculations and simulations of the BP neural network algorithm. Furthermore, C language was used for programming and to call the corresponding toolkit function. In the BP neural network algorithm, Equation (1) in the input layer was used to input the original data to carry out the process of normalization [31,32].
where max X , min X , and ' i X respectively represent the maximum, minimum, and experimental values of the original sample data.
The sigmoid function was used as the transfer function in the network hidden layer. The gradient descent method was used to train, and the "traingd" function was selected as the objective function.
As shown in Figures 3-5, 8, 9, 30 groups of experimental data were used as the sam- MATLAB (MathWorks, Massachusetts, United States) was used to carry out the numerical calculations and simulations of the BP neural network algorithm. Furthermore, C language was used for programming and to call the corresponding toolkit function. In the BP neural network algorithm, Equation (1) in the input layer was used to input the original data to carry out the process of normalization [31,32].
where X max , X min and X i respectively represent the maximum, minimum, and experimental values of the original sample data.
The sigmoid function was used as the transfer function in the network hidden layer. The gradient descent method was used to train, and the "traingd" function was selected as the objective function.
As shown in Figures 3-5, 8 and 9, 30 groups of experimental data were used as the samples for the BP neural network model. These data samples were randomly sorted. Additionally, 20 groups of data were randomly selected as the optimization samples for the BP neural network, and the remaining 10 groups of data were selected as the test samples used to test the network model. The results of the BP neural network calculations were stored for the next step of the genetic algorithm. The minimum error for the objective function was set to be 0.001 (for convergence), the iteration process was repeated 10,000 times, and the vector value was 0.05.
The BP neural network algorithm was run. It was found that the fitting line of the copper recovery, as predicted by the BP neural network model, was consistent with the target line. The coefficients of deter-mination (R 2 ) value was 0.998, as shown in Figure 11, showing good agreement between the experimental and predicted results. Figure 12 shows the values of error for the BP neural network predictions. After 4169 iterations, the optimization target had an error of only 0.001 and met the maximum error requirement. Figure 13 shows the predicted output values of the training performance (in graphical form).
To intuitively test the accuracy of predictions made by the BP neural network, the relationship between the copper recovery prediction rate and the actual value is shown in Figure 14. It can be seen from Figure 14 that the predicted copper recovery rate from the BP neural network model was consistent with the experimental value, showing accurate results obtained using the BP neural network model.

Genetic Algorithm Optimization
The genetic algorithm model was used to optimize the data obtained from the BP neural network model. The input and output values were consistent with those of the BP neural network, and the parameter design values are presented in Table 2. After 100 generations, the fitted results are shown in Figure 15.     To intuitively test the accuracy of predictions made by the BP n relationship between the copper recovery prediction rate and the actu Figure 14. It can be seen from Figure 14 that the predicted copper rec BP neural network model was consistent with the experimental value results obtained using the BP neural network model.    To intuitively test the accuracy of predictions made by the BP n relationship between the copper recovery prediction rate and the actua Figure 14. It can be seen from Figure 14 that the predicted copper reco BP neural network model was consistent with the experimental value results obtained using the BP neural network model. After genetic algorithm optimization, the results obtained were as follows: the maximum predicted output value was 87.62, and the independent variables a, b, c, d, and e had the values of 91.7, 537.8, 1157.2, 487.7, and 298.9, respectively. To verify the reliability of the optimization results, the optimization parameters of the selected model were tested. The grinding fineness, combined activator agent dosage, sodium sulfide dosage, isoamyl xanthate dosage, and inhibitor dosage were 92%, 550 g/t, 1150 g/t, 500 g/t, and 300 g/t, respectively. A recovery of 87.35% was achieved, which corresponds to the grade of 2.68%. Moreover, the flotation recovery was nearly 2% higher than that before the optimization. The results showed that the model based on the genetic algorithm and BP neural network, and when it was used for the cupric oxide flotation, it showed reliable accuracy and optimization ability. As a result, the optimized flotation conditions were accepted.

Genetic Algorithm Optimization
The genetic algorithm model was used to optimize the data ob neural network model. The input and output values were consistent neural network, and the parameter design values are presented in Ta erations, the fitted results are shown in Figure 15.

Genetic Algorithm Optimization
The genetic algorithm model was used to optimize the data obtained fro neural network model. The input and output values were consistent with those neural network, and the parameter design values are presented in Table 2. Afte erations, the fitted results are shown in Figure 15.  After genetic algorithm optimization, the results obtained were as follows imum predicted output value was 87.62, and the independent variables a, b, c had the values of 91.7, 537.8, 1157.2, 487.7, and 298.9, respectively. To verify the of the optimization results, the optimization parameters of the selected model w The grinding fineness, combined activator agent dosage, sodium sulfide dosage xanthate dosage, and inhibitor dosage were 92%, 550 g/t, 1150 g/t, 500 g/t, an respectively. A recovery of 87.35% was achieved, which corresponds to the grade Moreover, the flotation recovery was nearly 2% higher than that before the opti The results showed that the model based on the genetic algorithm and BP neural

Conclusions
The results of single-factor experiments showed that the activator agent had a good activating effect on the sulfide flotation of copper oxide ore. Compared with the individual use of either ammonium bicarbonate or ethylenediamine phosphate, the combined activator agent had a better activating effect, and the required dosage was also lower than that for the individual activator. The combined activator agent had obvious effects on the copper flotation recovery in that it showed stringent dosage requirements.
The prediction results of the BP neural network model showed that the R 2 value was 0.998, and the predicted results were in accordance with the experimental values.