Furnace iron alloy product quality is a reflection of ferroalloy products and electric furnace smelting technology indicators. Products that meet national standards, ministerial standards, corporate standards, and user agreement standards are all qualified products.
Qualified products and scraps of standard alloy ferroalloy products are calculated according to standard amounts.
The qualification rate of the electric furnace ferroalloy refers to the percentage of the qualified quantity of the product in the total inspection amount during the reporting period. Its calculation formula is:
Ferroalloy product qualification rate (%) =  Ferroalloy inspection qualified quantity (ton) × 100%
Total amount of iron alloy inspection (tons)
For the production of multi-species enterprises, it is also necessary to assess the overall pass rate of the whole plant. Its calculation formula is:
Comprehensive qualification rate of electric furnace iron alloy (%) = sum of qualified iron alloy inspections (tons) × 100%
The sum of the total iron alloy inspections by category (tons)
Calculation instructions:
(l) The product qualification rate shall be calculated by type and sub-furnace; the neutron and parent unit shall be standard tons.
(2) Under normal circumstances, the product will participate in product quality assessment after it is released.
(3) Stop the furnace:
1) Newly opened electric furnace, after the cycle of large, medium and silicon-calcium furnaces, or the external reason for continuous shutdown for more than 36 hours, the first furnace product produced by the electric furnace will not participate in the quality index assessment (except for the refined electric furnace) ).
Tungsten iron head two furnace products do not participate in quality assessment.
2) The washing furnace before the new furnace is opened or the furnace before the furnace is shut down. The waste products generated after the addition of the washing materials are not counted, and no waste inspection is carried out. However, the electricity and materials consumed during the washing process should not be deducted, and the consumption index should be calculated.
3) Planned maintenance, the external cause of the 5,000 kVA and 5,000 kVA electric furnaces will be continuously de-energized for 48 hours or less, and the waste products generated by the electric furnaces below 5000 kV for 36 hours or less will be subject to quality assessment.
(4) Product refining:
1) The former product charge is useful or at least harmless to the latter product, and the resulting transition product is a good product as long as it meets the quality standard. For waste products that do not meet the requirements of any brand, participate in the calculation of product quality after refining.
2) The conversion of different elements of the former product charge to the latter product (such as silicon chromium- transferred ferrosilicon) can be calculated according to the provisions of the new furnace.
3) The time limit of refining, in principle, should be divided by the time of variable material or the time after the first furnace is blocked. If the first furnace product meets the product quality standard before refining, the operation time of the pre-refining product should be up to the time of the first furnace after the refining; if the first furnace product after the refining If the quality standard is not met or the latter product quality standard is met, the refining time and power consumption are divided by the variable time.
(5) The products produced by running eyes or equipment accidents before the furnace, regardless of the qualified unqualified, regardless of the quantity, will record the furnace number and participate in the calculation of the quality index.
(6) Regardless of the condition of the equipment, the process conditions, and the quality of the raw materials, as long as the production should be calculated, the technical and economic indicators of the products should be calculated. Products produced during the trial production period of new products (up to 3 months) and during the trial production period (up to 6 months) of new electric furnaces may be omitted.
Add quality indicators and other indicators for assessment.
(7) Calculation of unplanned products for product conversion production: electric furnaces (including refining furnaces) produce unplanned products during the smelting process (such as the production of medium chromium in the production of micro-carbon ferrochrome or the production of micro-chromium products in the production of chromium) The actual product grade of the product is put into storage, and the output value and output are calculated. However, it does not participate in the calculation of indicators such as quality, power consumption, and raw material consumption. The electricity and raw materials consumed by this part of the product are deducted from the total consumption.
The method of dividing the calculation:
l) Refined products can be divided and calculated according to the pre-furnace power consumption, smelting time and raw material ratio recorded in the “Smelting Record Cardâ€.
2) Other ferroalloy products, because the production characteristics are continuous operations, can only be calculated by the coefficient method (see table below).
Divide various consumption and working time by coefficient
Project | Unit | 75% ferrosilicon | Special ferrosilicon | Total |
Power consumption | Kilowatt hour | 1560000×0.076999=119964 | 1560000×0.9231=1440036 | 156000 |
2. Silica consumption | Ton | 325×0.0769=25 | 325×0.0769=25 | 325 |
3. Working time | Time | 696×0.0769=53.5 | 696×0.9231=642.5 | 696 |
For example: an electric furnace in a certain month produces 120 tons of special ferrosilicon, brings out 75% of ferrosilicon and 10 tons, consumes 1.56 million kilowatts of total electricity, consumes 325 tons of ore, and has an actual operating time of 696 hours. The calculation steps are as follows:
Find the coefficient:
75% ferrosilicon = 10 = 0.0769
120 tons + 10 tons
The planned grade coincidence rate is the percentage of the product output that meets the planned grade of the planned grade. It reflects the extent to which the target of ferroalloy smelting hits, and also reflects the level of smelting technology operation of ferroalloy workers. Its calculation formula is:
Plan grade compliance rate (%) = actual production volume in accordance with the planned grade (ton) × 100%
Production capacity of the product specified in the plan (tons)
Calculation instructions:
(l) The plan number includes the chemical composition requirements specified in the plan.
(2) The matching rate of the planned grades shall be calculated according to the grades, and the calculation shall be completed according to the varieties; the neutron and parent units shall be standard tons.
(3) The actual output (sub-item) that meets the planned grade is not offset between the grade and the variety, that is, when the actual output that meets the planned grade is less than the planned output of the grade, it is calculated according to the actual amount; when the actual output that meets the planned grade is greater than the When the grade is planned to produce,
The excess is not counted. The indicator value is not more than 100%.
(4) The sub-items and parent items calculated by the compliance ratio of the whole plant comprehensive plan are the sum of the sub-items and the parent items of the matching rate of each model. [next]
The unit product power consumption (referred to as “unit power consumptionâ€) is the amount of electricity consumed in the production of 1 ton of qualified ferroalloy during the reporting period. Its calculation formula is:
Unit product power consumption (kWh·hour/ton)= Product total power consumption (kWh·hour)
Qualified product production (tons)
Unit product smelting power consumption (kWh·hour/ton)= Total electricity consumption of product smelting (kWh·hour)
Qualified product production (tons)
Calculation Description: The parent unit in the formula is standard tons.
The total power consumption of the product includes the power consumption of the product smelting process and the oven electricity, washing furnace electricity, power electricity, lighting electricity, etc. when the product is produced. The total power consumption of product smelting includes power consumption and furnace power consumption during product smelting.
The active watt-hour meter of the electric furnace shall be verified by the instrument department of the power laboratory with a standard electric meter within the specified date of each month. The positive and negative error coefficients after verification shall be verified and adjusted in the month. Its calculation formula is:
Total electricity consumption after verification (kWh·hour) = electric furnace power consumption × (1 - (early error at the end of the month) error / 2)
Calculation instructions:
(l) The newly-opened oven electricity refers to the amount of electricity consumed from the time when the oven is powered up until the first furnace is blocked. It should be deducted from the total power consumption.
(2) Due to external reasons (limited electricity, waiting for materials, natural disasters, etc.), the electric furnaces of 5000 kVA and 5000 dry volt-ampere are continuously powered off for more than 48 hours, and the electric furnaces below 5000 kVA (excluding refining furnaces) are continuously powered off. When the above oven is used,
When calculating the electricity consumption of product smelting, it should be deducted. The electric furnace of 5000 kVA and 5000 kVA is continuously de-energized for 48 hours or less, and the electric furnace of 5000 kV or less is continuously powered off for 36 hours or less. Product smelting power consumption should not be deducted.
(3) The furnace after the refining of the refining furnace and the external reasons cause the electric power consumed by the continuous power failure for more than 24 hours, which is deducted when calculating the electricity consumption of the product smelting. Its calculation formula is:
Oven electricity (kW·hour)=planned average power×(average smelting time of two furnaces-month average furnace smelting time)
(4) The energy consumption per unit process of the electric furnace ferroalloy is calculated according to the calculation formula of the unit energy consumption of the steelmaking process.
The raw material consumption per unit product (referred to as raw material consumption) is the average amount of raw materials consumed per unit of product expressed in terms of the physical quantity (dry weight) of the raw materials and the amount of the raw materials. It is the basis for formulating raw material plans and checking the implementation of consumption quotas. Its calculation formula
for:
Raw material consumption per unit of product (kg / ton) = actual consumption of raw materials (dry weight) kg
Qualified product production (tons)
The amount of raw material consumption per unit of product (dry grams / ton) = actual consumption of raw materials (equivalent amount) kg
Qualified product production (tons)
Calculation instructions:
(l) The actual consumption of raw materials refers to the quantity of furnaces. Does not include library consumption, road consumption, field consumption and processing loss.
(2) Products that calculate unit consumption are limited to products that are officially put into production. New products, scientific research products, and products produced before the trial production in the trial production stage do not calculate the unit consumption index.
(3) While calculating the consumption of raw materials, it is necessary to list the main raw materials (including the semi-finished products used) into the furnace grade, moisture and origin.
(4) The charge is calculated as the dry weight after removing the water.
(5) The raw materials consumed in the process of washing the furnace shall not be deducted.
(6) The raw material consumption per unit of product calculated according to the amount of conversion, the equivalent standard is:
1) chrome ore is divided by 45% containing Cr 2 O 3 ;
2) Manganese ore (manganese-rich slag-containing): smelting manganese silicon alloy, high carbon ferromanganese 32% manganese by folding; smelting manganese by 38% in low carbon equivalent.
The parent unit in formula (7) is standard tons. [next]
The main element smelting recovery rate refers to the degree of utilization of a major element of the product during the smelting process. It is an indicator of the extent of metal recovery during smelting. Its calculation formula is:
Main element smelting recovery rate (%) = qualified product containing main element weight (ton) × 100%
The raw materials in the furnace contain the main element weight (tons)
Calculation instructions:
(1) For products that are produced in several steps in the process, the total recovery should be equal to the product of the step recovery.
(2) The waste alloy or alloy powder (including the cross-furnace) purchased by the enterprise shall list the calculation unit consumption and participate in the calculation of the recovery rate of the alloy elements.
(3) For composite iron alloys, such as manganese silicon, silicon chromium, etc., only one of the main elements is selected. The principle of primary and secondary differentiation is:
1) Proportion of product ingredients:
2) The degree of luxury of the element.
(4) The formula for calculating the recovery rate of carbon-manganese and medium-manganese in the flux-free method, the parent term is unchanged, and the sub-item should be added with the main element amount in the slag×the main element utilization rate of the slag.
Worker physical labor productivity refers to the average number of ferroalloys produced by each worker and apprentice during the reporting period. It shows the production capacity of production workers in a certain period of time. Its calculation formula is:
Worker physical labor productivity (ton/person) = Â Qualified product production (tons)
Average number of workers and apprentices (person)
Calculation Description: This formula is applicable to independent ferroalloy plants. For non-independent ferroalloy workshops (or electric furnaces), it should be noted that the product output is consistent with the range of workers producing the product; the neutron unit is standard ton.
The electric furnace calendar utilization factor refers to the average daily qualified ferroalloy production of the rated capacity (megavolt-amperes) of the unit transformer in the calendar time. It reflects the degree of utilization of electric furnace capacity and the level of operation and the level of corporate management. Its calculation formula is:
Electric furnace calendar utilization factor (ton / megavolt-ampere-day) = Â Â Â Â Â Â Â Â Product qualified amount (tons)
Transformer rated capacity (megavolt-amperes) × calendar days (days)
Calculation instructions:
(1) The utilization coefficient of the electric furnace calendar shall be calculated according to the type and the electric furnace. The unit of the sub-item is the standard tons.
(2) The capacity of the transformer shall be calculated according to the rating of the nameplate; the capacity of the transformer shall be calculated according to the actual capacity after the measurement.
The average daily output is the average daily production capacity of the electric furnace during the reporting period. Its calculation formula is:
Average daily production (ton/day) = Qualified product production (tons)
Actual working days (days)
Calculation explanation: The actual number of working days should be consistent with the operating rate index; the unit in the formula is standard tons.
The electric furnace calendar operation rate refers to the percentage of the actual working time of the electric furnace to the calendar time. It is an indicator of the extent of time utilization of the electric furnace. Its calculation formula is:
Electric furnace calendar operation rate (%) = Actual working time (hours) × 100%
Calendar time (hours)
Calculation instructions:
(l) The actual working time refers to the calculation from the time of power transmission to the electric furnace, and should include the necessary auxiliary time (such as voltage change, discharge electrode, power failure time of the refining furnace).
(2) The sub-items and parent items of the calculation of the electric furnace calendar operating rate of the whole plant are the sum of the sub-items and the parent items of the operating rate of each electric furnace. [next]
The life of the refining furnace lining refers to the number of furnaces of iron alloy smelted every time the furnace is replaced. It is the basis for reflecting the utilization degree of the lining refractory material, the refractory material and the quality of the furnace, operation and maintenance of the lining. Its calculation formula is:
Refining furnace lining life (furnace) = total number of furnaces (furnace)
Change the number of linings (times)
Calculation instructions:
1) Since the furnace lining is put into use and the replacement of the new furnace lining is stopped, the number of furnaces for smelting the iron alloy during this period is called "heart age".
(2) Refining the furnace lining, regardless of the degree of repair, as long as the replacement is repaired, it is calculated once.
The average electric power of the electric furnace (ie, the average working capacity) refers to the effective output of the average output of the electric furnace during the actual working time. Compared with the rated capacity of the transformer, it can accurately reflect the utilization of the capacity of the electric furnace during the working time. Its calculation formula is:
Average power (kW) = total smelting power consumption (kWh·hour)
Actual working time (hours)
Calculation instructions:
(1) The total power consumption of smelting shall include electricity for the furnace and electricity for the furnace.
(2) The actual working time should be consistent with the sub-item for calculating the calendar operating rate of the electric furnace.
The slag-iron ratio is an indicator of the amount of slag observed. Choosing a reasonable slag type is a key to the iron alloy smelting operation technology.
The slag-iron ratio refers to the ratio of the actual slag amount to the actual iron output. That is, the amount of slag produced per ton of iron produced. Its calculation formula is:
Slag-to-iron ratio (ton/ton) = total slag (tonnes)
Total iron output (tons)
Calculation Description: The total amount of iron produced, including waste products, is calculated in physical quantities.
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