System for bleaching process in titanium dioxide production by sulfuric acid method and automatic control method thereof

Abstract

The invention discloses a system for a bleaching process in sulfate process titanium dioxide production, and relates to the technical field of chemical engineering automation control. The device comprises a bleaching tank, a primary washing and repulping storage tank, a bleaching sulfuric acid storage tank and a solated material storage tank, steam is introduced into the bleaching tank, and the bleaching tank is provided with an aluminum powder adding port; the primary washing and repulping storage tank is connected with the bleaching tank; the bleaching sulfuric acid storage tank is connected with the bleaching tank; and the after-sol material storage tank is connected with the bleaching tank. According to the invention, one-key starting of the bleaching process is realized; the full-automatic control and circulation process of the bleaching procedure is realized; the time of each process can be accurately controlled; and errors during manual operation are reduced. The invention also relates to an automatic control method of the system for the bleaching process in the production of the titanium dioxide by the sulfuric acid method.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical automation control, and more specifically, it is a system for the bleaching process in the production of sulfuric acid process titanium dioxide. The present invention also relates to an automatic control method for the bleaching process in the production of sulfuric acid process titanium dioxide. Background Art

[0002] At present, the automation degree of the production process in the conventional bleaching process in the industry is relatively low, and the control process is on-site manual and partial remote manual. The following main problems exist during the manual control operation of the bleaching process:

[0003] 1) The bleaching process has relatively strict requirements for the addition amounts of crystal seeds and sulfuric acid. According to the specific gravity of ferrotitanic acid, the addition amount of crystal seeds is determined by calculation according to the formula. When operating manually, if the valve is not closed or the pump is not stopped in time, the addition amount will be inaccurate, affecting the product quality. If forgetting to close the valve or stop the pump, it will cause the leakage of dangerous chemicals and material loss, and in severe cases, personnel will be injured.

[0004] 2) Manual feeding is prone to overfilling and underfeeding, affecting production efficiency.

[0005] Therefore, it is necessary to develop a system for the bleaching process in the production of sulfuric acid process titanium dioxide and its automatic control method. Summary of the Invention

[0006] The first object of the present invention is to overcome the deficiencies in the above background art, and provide a system for the bleaching process in the production of sulfuric acid process titanium dioxide.

[0007] The second object of the present invention is to provide an automatic control method for the system for the bleaching process in the production of sulfuric acid process titanium dioxide

[0008] In order to achieve the above first object, the technical solution of the present invention is: A system for the bleaching process in the production of sulfuric acid process titanium dioxide, characterized in that: it includes a bleaching tank, a first washing and repulping storage tank, a bleaching sulfuric acid storage tank, and a post-sol gel material storage tank; steam is connected to the bleaching tank through a bleaching pan steam heating valve, and the bleaching tank is provided with an aluminum powder adding port; the first washing and repulping storage tank is connected to the bleaching tank through a bleaching pan feed valve; the bleaching sulfuric acid storage tank is connected to the bleaching tank through a bleaching pan sulfuric acid adding valve; the post-sol gel material storage tank is connected to the bleaching tank through a bleaching pan crystal seed adding valve.

[0009] In the above technical solution, it further includes a post-bleaching material storage tank, and the bleaching tank is connected to the post-bleaching material storage tank through a bleaching pan bottom valve.

[0010] In the above technical solution, the first washing and repulping storage tank is sequentially connected to the bleaching pan feed valve through a first washing and repulping storage tank pumping pump and a bleaching pan feed flowmeter.

[0011] In the above technical solution, the bleaching sulfuric acid storage tank is connected to the bleaching kettle sulfuric acid adding valve through a bleaching kettle sulfuric acid flowmeter.

[0012] In the above technical solution, the post-sol gel material storage tank is sequentially connected to the bleaching kettle seed adding valve through a seed pumping pump and a bleaching kettle seed adding flowmeter.

[0013] In the above technical solution, the bottom valve of the bleaching kettle is connected to the post-bleaching material storage tank through a bleaching slurry transfer centrifugal pump.

[0014] In the above technical solution, a bleaching kettle stirrer and a bleaching kettle thermometer are arranged inside the bleaching tank.

[0015] In the above technical solution, a level gauge for the first washing and re-slurrying storage tank is provided on the first washing and re-slurrying storage tank, and a level gauge for the post-bleaching material storage tank is provided on the post-bleaching material storage tank.

[0016] In order to achieve the above second object, the technical solution of the present invention is: an automatic control method for the bleaching process in titanium dioxide production by sulfuric acid method, which is characterized by including the following steps:

[0017] Step 1, manually press the start button;

[0018] Step 2, the level gauge of the first washing and re-slurrying storage tank detects that the first washing and re-slurrying storage tank reaches the set value; the bleaching kettle feed valve opens;

[0019] Step 3, the bleaching kettle feed valve opens for 5 seconds; the first washing and re-slurrying storage tank pumping pump starts;

[0020] Step 4, the bleaching kettle feed flowmeter reaches the set cumulative amount; the first washing and re-slurrying storage tank pumping pump stops;

[0021] Step 5, the first washing and re-slurrying storage tank pumping pump stops for 5 seconds; the bleaching kettle feed valve closes;

[0022] Step 6, the bleaching kettle feed valve closes for 5 seconds; the bleaching kettle sulfuric acid adding valve opens;

[0023] Step 7, the bleaching kettle sulfuric acid flowmeter reaches the set cumulative amount; the bleaching kettle sulfuric acid adding valve closes;

[0024] Step 8, the closing time of the bleaching kettle sulfuric acid adding valve reaches the set time; the bleaching kettle feed valve opens;

[0025] Step 9, the bleaching kettle feed valve opens for 5 seconds; the first washing and re-slurrying storage tank pumping pump starts;

[0026] Step 10, the bleaching kettle feed flowmeter reaches the set cumulative amount; the first washing and re-slurrying storage tank pumping pump stops,

[0027] Step 11, the bleaching kettle stirrer turns on; the first washing and re-slurrying storage tank pumping pump stops for 5 seconds;

[0028] Step 12, the bleaching pot feed valve is closed;

[0029] Step 13, when the opening time of the bleaching pot agitator reaches the set time, add aluminum powder;

[0030] Step 14, confirmation of aluminum powder addition is completed;

[0031] Step 15, the bleaching pot feed valve is opened;

[0032] Step 16, the bleaching pot feed valve is opened for 5 seconds, and the pumping feed pump of the first wash and repulping storage tank is started;

[0033] Step 17, the bleaching pot feed flowmeter reaches the set cumulative amount; the bleaching pot steam heating valve is opened to the set opening degree;

[0034] Step 18, the bleaching pot feed flowmeter reaches the set cumulative amount; the pumping feed pump of the first wash and repulping storage tank is stopped;

[0035] Step 22, the pumping feed pump of the first wash and repulping storage tank is stopped for 5 seconds; the bleaching pot feed valve is closed;

[0036] Step 20, the bleaching pot thermometer detects that the temperature of the bleaching pot reaches the set temperature, and the bleaching pot steam heating valve is closed;

[0037] Step 21, when the closing time of the bleaching pot steam heating valve reaches the set time, click to confirm the addition of seeds;

[0038] Step 22, the bleaching pot seed addition valve is opened;

[0039] Step 23, the bleaching pot seed addition valve is opened for 5 seconds; the seed pumping feed pump is started;

[0040] Step 24, the bleaching pot seed addition flowmeter reaches the set cumulative amount calculated by the model; the seed pumping feed pump is stopped;

[0041] Step 25, the seed pumping feed pump is stopped for 5 seconds; the bleaching pot seed addition valve is closed;

[0042] Step 26, when the closing time of the bleaching pot seed addition valve reaches the set time; the liquid level gauge of the post-bleaching material storage tank detects the liquid level of the post-bleaching material storage tank;

[0043] Step 27, the post-bleaching material storage tank reaches the low set liquid level; the bottom valve of the bleaching pot is opened;

[0044] Step 28, the bottom valve of the bleaching pot is opened for 5 seconds; the centrifugal pump for transferring bleached slurry is started;

[0045] Step 29, when the starting time of the centrifugal pump for transferring bleached slurry reaches the set value; confirm that the discharging is completed;

[0046] Step 30, the centrifugal pump for transferring bleached slurry is stopped; the bleaching pot agitator is closed;

[0047] Step 31: Stop the centrifugal pump for transferring bleaching pulp; close the bottom valve of the bleaching pan.

[0048] Step 32: Without pressing the program start button again, the DC second system automatically detects the start conditions and automatically proceeds to Step 2 - 32.

[0049] In the above technical solution, the seed addition calculation model is: Seed addition volume = Cumulative feed volume of metatitanic acid material × (Specific gravity of metatitanic acid - 1) × Concentration coefficient × Proportion of added seeds ÷ Seed concentration ÷ Seed conversion rate.

[0050] Compared with the prior art, the present invention has the following advantages:

[0051] 1) The present invention realizes one - key start of the bleaching process; realizes full - automatic control and circulation process of the bleaching process; can accurately control the time of each process; reduces errors during manual operation.

[0052] 2) The present invention enables full - automatic control and data monitoring of the bleaching process from feeding, detection, calculation, quantitative addition of auxiliary materials, to discharging, avoiding the imbalance of production stability caused by parameter disorders.

[0053] 3) The present invention is easy to operate, has a high degree of automation, a high safety factor, and good stability, truly realizing the automatic control of the process, not only reducing the labor intensity but also reducing the production cost.

[0054] 4) The present invention establishes an independent calculation model for adding seeds in bleaching. Through the material density and feed rate, according to the parameters of the added auxiliary material medium (density, proportion, content), the addition amount is calculated in real - time and the addition amount is automatically adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic structural diagram of the present invention.

[0056] Among them, 100 - bleaching tank, 110 - bleaching pan steam heating valve, 120 - aluminum powder addition port, 130 - bottom valve of the bleaching pan, 140 - centrifugal pump for transferring bleaching pulp, 150 - bleaching pan stirrer, 160 - bleaching pan thermometer, 200 - first - wash and re - pulp storage tank, 210 - bleaching pan feed valve, 220 - first - wash and re - pulp storage tank pumping pump, 230 - bleaching pan feed flowmeter, 240 - first - wash and re - pulp storage tank liquid level gauge, 300 - bleaching sulfuric acid storage tank, 310 - bleaching pan sulfuric acid addition valve, 320 - bleaching pan sulfuric acid flowmeter, 400 - storage tank for materials after sol - gel, 410 - bleaching pan seed addition valve, 420 - seed pumping pump, 430 - bleaching pan seed addition flowmeter, 500 - storage tank for materials after bleaching, 510 - bleaching - after - material storage tank liquid level gauge. DETAILED DESCRIPTION OF THE INVENTION

[0057] The implementation of the present invention will be described in detail below in conjunction with the accompanying drawings. However, they do not constitute a limitation to the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0058] Referring to the accompanying drawings, it can be seen that a system for the bleaching process in titanium dioxide production by sulfuric acid method comprises a bleaching tank 100, a first-wash and re-slurry storage tank 200, a bleaching sulfuric acid storage tank 300, and a post-sol slurry storage tank 400. Steam is connected to the top of the bleaching tank 100 through the bleaching pan steam heating valve 110, and an aluminum powder addition port 120 is provided at the top of the bleaching tank 100. The first-wash and re-slurry storage tank 200 is connected to the top of the bleaching tank 100 through the bleaching pan feed valve 210. The bleaching sulfuric acid storage tank 300 is connected to the top of the bleaching tank 100 through the bleaching pan sulfuric acid addition valve 310. The post-sol slurry storage tank 400 is connected to the top of the bleaching tank 100 through the bleaching pan seed addition valve 410.

[0059] It further comprises a post-bleaching material storage tank 500, and the side of the bottom of the bleaching tank 100 is connected to the top of the post-bleaching material storage tank 500 through the bleaching pan bottom valve 130.

[0060] The first-wash and re-slurry storage tank 200 is connected to the bleaching pan feed valve 210 through a first-wash and re-slurry storage tank pumping pump 220 and a bleaching pan feed flowmeter 230 in sequence.

[0061] The bleaching sulfuric acid storage tank 300 is connected to the bleaching pan sulfuric acid addition valve 310 through a bleaching pan sulfuric acid flowmeter 320.

[0062] The post-sol slurry storage tank 400 is connected to the bleaching pan seed addition valve 410 through a seed pumping pump 420 and a bleaching pan seed addition flowmeter 430 in sequence.

[0063] The bleaching pan bottom valve 130 is connected to the post-bleaching material storage tank 500 through a bleaching slurry transfer centrifugal pump 140.

[0064] A bleaching pan stirrer 150 and a bleaching pan thermometer 160 are provided inside the bleaching tank 100.

[0065] A first-wash and re-slurry storage tank level gauge 240 is provided on the first-wash and re-slurry storage tank 200, and a post-bleaching material storage tank level gauge 510 is provided on the post-bleaching material storage tank 500.

[0066] An automatic control method for the bleaching process in titanium dioxide production by sulfuric acid method is characterized by comprising the following steps:

[0067] Step 1, manually press the button;

[0068] Step 2, the first-wash and re-slurry storage tank level gauge 240 detects that the first-wash and re-slurry storage tank 200 reaches the set value; the bleaching pan feed valve 210 is opened;

[0069] Step 3, the bleaching pan feed valve 210 is opened for 5 seconds; the pumping - out pump 220 of the first - wash and repulping storage tank is started;

[0070] Step 4, the bleaching pan feed flowmeter 230 reaches the set cumulative volume; the pumping - out pump 220 of the first - wash and repulping storage tank stops;

[0071] Step 5, the pumping - out pump 220 of the first - wash and repulping storage tank stops for 5 seconds; the bleaching pan feed valve 210 is closed;

[0072] Step 6, the bleaching pan feed valve 210 is closed for 5 seconds; the sulfuric - acid adding valve 310 of the bleaching pan is opened;

[0073] Step 7, the sulfuric - acid flowmeter 320 of the bleaching pan reaches the set cumulative volume; the sulfuric - acid adding valve 310 of the bleaching pan is closed;

[0074] Step 8, the closing time of the sulfuric - acid adding valve 310 of the bleaching pan reaches the set time; the bleaching pan feed valve 210 is opened;

[0075] Step 9, the bleaching pan feed valve 210 is opened for 5 seconds; the pumping - out pump 220 of the first - wash and repulping storage tank is started;

[0076] Step 10, the bleaching pan feed flowmeter 230 reaches the set cumulative volume; the pumping - out pump 220 of the first - wash and repulping storage tank stops,

[0077] Step 11, the bleaching pan agitator 150 is turned on; the pumping - out pump 220 of the first - wash and repulping storage tank stops for 5 seconds;

[0078] Step 12, the bleaching pan feed valve 210 is closed;

[0079] Step 13, the opening time of the bleaching pan agitator 150 reaches the set time, and aluminum powder is added;

[0080] Step 14, the confirmation of adding aluminum powder is completed;

[0081] Step 15, the bleaching pan feed valve 210 is opened;

[0082] Step 16, the bleaching pan feed valve 210 is opened for 5 seconds, and the pumping - out pump 220 of the first - wash and repulping storage tank is started;

[0083] Step 17, the bleaching pan feed flowmeter 230 reaches the set cumulative volume; the bleaching pan steam heating - up valve 110 is opened to the set opening degree;

[0084] Step 18, the bleaching pan feed flowmeter 230 reaches the set cumulative volume; the pumping - out pump 220 of the first - wash and repulping storage tank stops;

[0085] Step 19, the pumping - out pump 220 of the first - wash and repulping storage tank stops for 5 seconds; the bleaching pan feed valve 210 is closed;

[0086] Step 20: When the thermometer 160 of the bleaching pot detects that the temperature of the bleaching pot 100 reaches the set temperature, the steam heating valve 110 of the bleaching pot is closed.

[0087] Step 21: When the closing time of the steam heating valve 110 of the bleaching pot reaches the set time, click to confirm adding seeds.

[0088] Step 22: Open the seed adding valve 410 of the bleaching pot.

[0089] Step 23: Open the seed adding valve 410 of the bleaching pot for 5 seconds; start the seed pumping pump 420.

[0090] Step 24: When the seed adding flowmeter 430 of the bleaching pot reaches the set cumulative amount of the calculation model; stop the seed pumping pump 420.

[0091] Step 25: Stop the seed pumping pump 420 for 5 seconds; close the seed adding valve 410 of the bleaching pot.

[0092] Step 26: When the closing time of the seed adding valve 410 of the bleaching pot reaches the set time; the liquid level gauge 510 of the post-bleaching material storage tank detects the liquid level of the post-bleaching material storage tank 500.

[0093] Step 27: When the post-bleaching material storage tank 500 reaches the low set liquid level; open the bottom valve 130 of the bleaching pot.

[0094] Step 28: Open the bottom valve 130 of the bleaching pot for 5 seconds; start the centrifugal pump 140 for transferring bleached slurry.

[0095] Step 29: When the starting time of the centrifugal pump 140 for transferring bleached slurry reaches the set value; confirm the end of discharging.

[0096] Step 30: Stop the centrifugal pump 140 for transferring bleached slurry; turn off the agitator 150 of the bleaching pot.

[0097] Step 31: Stop the centrifugal pump 140 for transferring bleached slurry; close the bottom valve 130 of the bleaching pot.

[0098] Step 32: Without pressing the program start button again, the DC second system automatically detects the start conditions and automatically proceeds to Steps 2 - 32.

[0099] Seed addition calculation model: Seed addition volume = Cumulative feed volume of metatitanic acid material × (Specific gravity of metatitanic acid - 1) × Concentration coefficient × Proportion of added seeds ÷ Seed concentration ÷ Seed conversion rate.

[0100] In actual use, agitators are provided in the first washing and repulping storage tank 200, the post-sol material storage tank 400, and the post-bleaching material storage tank 500.

[0101] Other parts not described belong to the prior art.

Claims

1. A system for the bleaching process in titanium dioxide production by the sulfuric acid method, characterized in that: It includes a bleaching tank (100), a first-wash and repulping storage tank (200), a bleaching sulfuric acid storage tank (300), and a post-sol slurry storage tank (400); steam is connected to the bleaching tank (100) through a bleaching pan steam heating valve (110), and the bleaching tank (100) is provided with an aluminum powder adding port (120); the first-wash and repulping storage tank (200) is connected to the bleaching tank (100) through a bleaching pan feed valve (210); the bleaching sulfuric acid storage tank (300) is connected to the bleaching tank (100) through a bleaching pan sulfuric acid adding valve (310); the post-sol slurry storage tank (400) is connected to the bleaching tank (100) through a bleaching pan seed adding valve (410).

2. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 1, characterized in that: It further includes a post-bleaching material storage tank (500), and the bleaching tank (100) is connected to the post-bleaching material storage tank (500) through a bleaching pan bottom valve (130).

3. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 2, characterized in that: The first-wash and repulping storage tank (200) is connected to the bleaching pan feed valve (210) through a first-wash and repulping storage tank pumping pump (220) and a bleaching pan feed flowmeter (230) in sequence.

4. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 2, characterized in that: The bleaching sulfuric acid storage tank (300) is connected to the bleaching pan sulfuric acid adding valve (310) through a bleaching pan sulfuric acid flowmeter (320).

5. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 2, wherein: The post-sol slurry storage tank (400) is connected to the bleaching pan seed adding valve (410) through a seed pumping pump (420) and a bleaching pan seed adding flowmeter (430) in sequence.

6. A system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 2, characterized in that: The bleaching pan bottom valve (130) is connected to the post-bleaching material storage tank (500) through a bleaching slurry transfer centrifugal pump (140).

7. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 1, characterized in that: A bleaching pan stirrer (150) and a bleaching pan thermometer (160) are arranged in the bleaching tank (100).

8. The system for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 2, wherein: The first-wash and repulping storage tank (200) is provided with a first-wash and repulping storage tank liquid level gauge (240), and the post-bleaching material storage tank (500) is provided with a post-bleaching material storage tank liquid level gauge (510).

9. An automatic control method for the bleaching process in titanium dioxide production by sulfuric acid process, characterized in that, It includes the following steps: Step 1, manually start the button; Step 2, the first-wash and repulping storage tank liquid level gauge (240) detects that the first-wash and repulping storage tank (200) reaches the set value; the bleaching pan feed valve (210) is opened; Step 3, the bleaching pan feed valve (210) is opened for 5 seconds; the first-wash and repulping storage tank pumping pump (220) is started; Step 4, the bleaching pan feed flowmeter (230) reaches the set cumulative amount; the first-wash and repulping storage tank pumping pump (220) is stopped; Step 5, the first-wash and repulping storage tank pumping pump (220) is stopped for 5 seconds; the bleaching pan feed valve (210) is closed; Step 6, the bleaching pan feed valve (210) is closed for 5 seconds; the bleaching pan sulfuric acid adding valve (310) is opened; Step 7, the bleaching pan sulfuric acid flowmeter (320) reaches the set cumulative amount; the bleaching pan sulfuric acid adding valve (310) is closed; Step 8, the closing time of the bleaching pan sulfuric acid adding valve (310) reaches the set time; the bleaching pan feed valve (210) is opened; Step 9, the bleaching pan feed valve (210) is opened for 5 seconds; the first-wash and repulping storage tank pumping pump (220) is started; Step 10, the bleaching pan feed flowmeter (230) reaches the set cumulative amount; the first-wash and repulping storage tank pumping pump (220) is stopped, Step 11, the bleaching pan stirrer (150) is opened; the first-wash and repulping storage tank pumping pump (220) is stopped for 5 seconds; Step 12, the bleaching pot feed valve (210) is closed; Step 13, the bleaching pot agitator (150) is turned on for the set time, and aluminum powder is added; Step 14, confirmation of aluminum powder addition is completed; Step 15, the bleaching pot feed valve (210) is opened; Step 16, the bleaching pot feed valve (210) is opened for 5 seconds, and the first wash and repulping storage tank pumping pump (220) is started; Step 17, the bleaching pot feed flowmeter (230) reaches the set cumulative amount; the bleaching pot steam heating valve (110) is opened to the set opening; Step 18, the bleaching pot feed flowmeter (230) reaches the set cumulative amount; the first wash and repulping storage tank pumping pump (220) is stopped; Step 19, the first wash and repulping storage tank pumping pump (220) is stopped for 5 seconds; the bleaching pot feed valve (210) is closed; Step 20, the bleaching pot thermometer (160) detects that the temperature of the bleaching pot (100) reaches the set temperature, and the bleaching pot steam heating valve (110) is closed; Step 21, the bleaching pot steam heating valve (110) is closed for the set time, and click to confirm the addition of seeds; Step 22, the bleaching pot seed addition valve (410) is opened; Step 23, the bleaching pot seed addition valve (410) is opened for 5 seconds; the seed pumping pump (420) is started; Step 24, the bleaching pot seed addition flowmeter (430) reaches the cumulative amount set by the calculation model; the seed pumping pump (420) is stopped; Step 25, the seed pumping pump (420) is stopped for 5 seconds; the bleaching pot seed addition valve (410) is closed; Step 26, the bleaching pot seed addition valve (410) is closed for the set time; the post-bleaching material storage tank level gauge (510) detects the level of the post-bleaching material storage tank (500); Step 27, the post-bleaching material storage tank (500) reaches the low set level; the bleaching pot bottom valve (130) is opened; Step 28, the bleaching pot bottom valve (130) is opened for 5 seconds; the bleaching slurry transfer centrifugal pump (140) is started; Step 29, the running time of the bleaching slurry transfer centrifugal pump (140) reaches the set value; confirm that the discharging is completed; Step 30, the bleaching slurry transfer centrifugal pump (140) is stopped; the bleaching pot agitator (150) is closed; Step 31, the bleaching slurry transfer centrifugal pump (140) is stopped; the bleaching pot bottom valve (130) is closed; Step 32, without pressing the program start button again, the DC second system automatically detects the start conditions and automatically proceeds to steps 2 - 32.

10. The automatic control method for the bleaching process in titanium dioxide production by sulfuric acid method according to claim 9, characterized in that, Seed addition calculation model: Seed addition volume = Cumulative feed amount of metatitanic acid material × (Specific gravity of metatitanic acid - 1) × Concentration coefficient × Proportion of added seeds ÷ Seed concentration ÷ Seed conversion rate.

Images